Your Engine Specifications?

[Nima]

Compare these info here...

your engine? why do you prefer to use this in comparison with other options?
its price?
its weight?
what is its torque and power curve?
your past engines? and the advantages and limitations of them...

in the page 3 I started the other subjects from engine specification...

[pengulns2001]

i dont think your going to get many answers if you want something structured use all the engine teams info you have read and make a spreadsheet in excell or something... besides these answers do you no good at all.

we have an F4i
its price you can find on ebay
its weight you can find anywhere
its max tq is 52ft/lbs to the tires
its max power is 92hp to the wheels
my past engines have been many

this info does you no good, you dont know how i got that power, you dont know what the design process was you cant re-produce those numbers... it will change way before comp

[Nima]

Originally posted by pengulns2001:
i dont think your going to get many answers if you want something structured use all the engine teams info you have read and make a spreadsheet in excell or something... besides these answers do you no good at all.

we have an F4i
its price you can find on ebay
its weight you can find anywhere
its max tq is 52ft/lbs to the tires
its max power is 92hp to the wheels
my past engines have been many

this info does you no good, you dont know how i got that power, you dont know what the design process was you cant re-produce those numbers... it will change way before comp
penguins,
You can't underestand me and my friends when you are living somewhere that everything is free to do...
You can't underestand when a person didn't see even a 600 motorcycle in his country... You can't underestand that we want to design a formula student car with nomoney!
Yes you and RiNaZ are right about the Q & A politenees but think a moment to your position and me. I am in Iran...there isn't anything in its place.
to notify you I have downloaded the almost teams websites compeletly and there is more than 4 gig of fsae data... I've don every thing that I could do... You cant underestand someone in an other world with no similarity to the US and europe!
I dont know what you are thinking about us but it is better to change your meditation about some one like me...
I'm so sorry for me...
please underestand us... please http://fsae.com/groupee_common/emoticons/icon_frown.gif

[pengulns2001]

you have the internet right? i mean your on this forum? if you dont have the internet than maybe i see where your coming from, but if you have excell and the internet i cant see where your coming from

[pengulns2001]

if you had questions about something extremly specific about the engine that you could only know by having one and measuring it i would be happy to help you out, if you wanted a compressor flow map for the turbo i would send it to you. if you want dyno charts to compare where you at i can post them but you have to be more specific,

[pengulns2001]

your questions are just to generic to even be able to asnwer, you have to be asking this for a reason, and it has to be more specific... to be honest im using an F4i because they used one last year and our team was to stuborn to change probably not the reason you want to chose one

and yeah i just tripple posted and should be shot

[Nima]

Originally posted by pengulns2001:
you have the internet right? i mean your on this forum? if you dont have the internet than maybe i see where your coming from, but if you have excell and the internet i cant see where your coming from
yes I have excel
I did this but these information isn't sufficiant for me to select an engine..
the F4i is the best engine probably...but why it is the best...

[pengulns2001]

if you have done this than what is your question, you already have the answers to your questions in your first post if you did this in excel so what do you want to know, i will answer it but i need to know what your real question is.

[pengulns2001]

figure out your engines flow rate demand for 100% VE then figure out how much of that you can pull through the restrictor, if you can go with a smaller engine do it. i will hopefully be switching to a 450 in the future without sacrificing much of anything.

[Nima]

I want to know these informations more and more... it is so clearly that avery team don't put their informations with its reasons in the web... so I want to collect these info...
just select the engine at first

[pengulns2001]

if a team hasnt put their information then they probably wont, people dont like answering extremely general questions, a lot of reasons arent engineering based. some teams are stuck in a rut... well weve used this for 3 years might as well keep using it. or whats the cheapest on ebay, or hey this is free lets use it etc

[Nima]

so you mean I remove this discussion?

[Igor]

No, don't remove the discussion. Just be more specific as to what information you are looking for. The questions you asked would usually not help someone in deciding what engine to use.

Why don't you tell us what kind of engines are easy to get hold of in Iran that are within your budget and ask for opinions on them. Or which suitable engines could be shipped from Europe if your budget was xxxx.

If you can afford/aqcuire one, the F4i is probably most suitable for a starting team. Lots of teams have spare parts at the competition you could borrow if you break something.
But actually any 4-stroke engine of 250-600cc will do just fine. The hardest part is selling the idea to the rest of the team that you can do well without a sexy 600 sport engine.
Many teams have done well with smaller engines with the Briggs and Stratton car and the Yamaha 450s as the best examples.

We understand things are harder in Iran than over here but that shouldn't be an insurmountable problem. Talk to the guys from Delhi, they have (had) similar issues.

Good luck,
Igor

[Mike Cook]

Nima,

http://www.break.com/index/americafy.html

Good Luck.

[illiterate]

well i don't know what nima is talking about.
qoute:
"You can't underestand when a person didn't see even a 600 motorcycle in his country... "
This guy is certainly not doing his homework. The engines are certainly available. If you still cant find a sporty 600 here's a hint. They are smuggled over from europe via afghanistan. Do your homework man

[pengulns2001]

that team america post might have been a little un-called for but pretty funny to watch

[Nima]

Originally posted by illiterate:
well i don't know what nima is talking about.
qoute:
"You can't underestand when a person didn't see even a 600 motorcycle in his country... "
This guy is certainly not doing his homework. The engines are certainly available. If you still cant find a sporty 600 here's a hint. They are smuggled over from europe via afghanistan. Do your homework man
I have just found smuggled 1000cc and no 600.

[Nima]

I must notify that I know the difference between 450 and 600 engine, their prices, weights and their power-tourq-rpm info...
but I think these are not sufficient for selecting an engine...
If I get a mistake please say me why...

[magicweed]

When selecting the engine for our car, we used three very basic criteria:

Availability
Ease of maintenance
Team familiarity

Looking at these three things, we made our engine descision, which came down to the F4i and the R6 engine. Both engines under the most basic FSAE conditions will produce 60+ hp and 40+ ftlbs of torque, and these are acceptable levels to be competetive. Horsepower and torque don't become deciding factors in an FSAE car until everything else has been determined to be at it's limit, which for any team with under 5-10 years experience hasn't happened yet. Basically, what I feel you should base an engine selection on, after satisfying those three rules, is development potential over the course of the teams life, and how it fits your design philosophy. If you want to make a light weight car at reasonable expense, go with the single. Or if you're simply looking to have a consistent powerplant in your car, while you refine everything else, go with the 4 cylinder 600cc, or any other engine based on what you're looking for in a car. For a team just starting, and in the situation you're in, my recomendation would be to simply get and engine, and go from there. And expercise great caution when running and tunning it, since there is a very real possibility of it getting "hurt" in the beginning (we melted a set of valves on our R6 the first year). When you get everything functional, come back and we can talk about the benefits of acoustic tunning and intake charge velocity, as well as optimum diffuser angle in a 20mm restrictor. http://fsae.com/groupee_common/emoticons/icon_wink.gif

[pengulns2001]

how exactly do you go about melting valves http://fsae.com/groupee_common/emoticons/icon_confused.gif... nima the only reason to select an engine is tq curve... reliablity doesnt even matter they only have to last like 1000 miles so i dont really know what else your looking for... maybe ease of getting parts but obviously in your area its pretty much impossible to get ANY parts... oh and weight... so yeah you pretty much got the info you need now you just need to buy on and start working with it

[js10coastr]

Nima,

I think that what you're doing is very ambitious, and that you have much larger obstacles than teams in the US, Austrailia and Europe... and I applaud your effort.

The first step in choosing an engine and it's parameters is to decide what your overall design goal is. Usually the overall goal is to design a car that will win the competition, and from there you have to choose a design philosphy that you think is the best way to acheive that goal. Some teams choose a philosophy that includes larger horsepower numbers, others tune for driveability... some teams use a turbo to get a flat torque curve and others choose to look elsewhere (variable runner lengths...) to achieve their goals. Some teams have decided to go with less horsepower, but in turn less weight by going with a 450cc engine.

You and your team have to decide which is the best and most feasible way to go to achieve your goals. Best of luck to you.

[Nima]

thanks coaster
I have visited your site
you said your engine is single cylinder Yamaha WR450 engine and Chosen over the previous, YZF R6, in order to reduce weight. your car weight is 136 kg... it is very light... if you have choosed the cbr 600 f4i in your same car, what ma be happend ...
I mean in your acceleration, vlocity, fuel consumption, cost and... I mean is it optimum at this case you have choosen?
If yes please say your reasons...

your past car has the YZF R6... why you prefer to lay aside it in addition to less weight?

[Nima]

Originally posted by pengulns2001:
how exactly do you go about melting valves http://fsae.com/groupee_common/emoticons/icon_confused.gif... nima the only reason to select an engine is tq curve... reliablity doesnt even matter they only have to last like 1000 miles so i dont really know what else your looking for... maybe ease of getting parts but obviously in your area its pretty much impossible to get ANY parts... oh and weight... so yeah you pretty much got the info you need now you just need to buy on and start working with it
thanks penguins
you mean we must design for only 1000 miles?
is it a accepted reason for the judges?

[pengulns2001]

you dont design for 1000 miles... unless you are REALLY bold, the judges would probably accept the reasoning if you told them you built your engine to last only 1000 miles but a lot of factors go into how long and engine will last

the point i was really trying to make though is that if your worried about reliability you really dont need to be. if you look at the original applications of any engines we can get their break in period is longer than 10 of our competitions put together so there is no reason for an engine to fail, other than poor tuning or improper building... in which case it doesnt matter what engine your running... so what you should be looking at is packaging, weight, power... how big do you want your car to be? how light can you make it? if you are short on funds or a first year team plan on having a HEAVY car, in the event you do have a heavy car you want a lot of power to push that car... if you go the other way with you design and you want a car that weighs lets say 400lbs or less maybe you go with a smaller motor... 450 or maybe even smaller like the briggs motor... there is not perfect motor and there is no exact reason to pick a motor

[Nima]

my weight may be 250 kg
so I must use a 600!

is this reasoning sufficient?

[pengulns2001]

600 pounds isnt THAT heavt but i would go with a 600... and a turbo if you can afford/tune it

[VFR750R]

I realize that you're in a terrible position to be able to compete at any level in FSAE. I also realize that you have no access to the information that we do in the US and access to any and all engines.
I also realize your english is not perfect and the translation isn't perfect, but you ask us questions that judges at competition would ask. There is no universal answer and people don't want to tell you exactly how they come up with their design decisions.

That's YOUR job as a mechanical engineering student. That's what you get out of this project. YOU decide an engine based on all the information you have. We can tell you how much different engines weigh. You can find torque curves online @ www.motorcycle.com (http://www.motorcycle.com). You can go to manufacterers websites to look at any things that YOU feel are important to an FSAE entry.

I'll tell you Cornell runs a YZF600 engine. I'll tell you one of the reasons is the torque peak is at a lower RPM then any 600 engine except the FZR600...which we have also ran. Is it the best for FSAE, i don't know. Do we feel it gives us the best chance to win...yes. Other teams think a WR450 gives their team the best chance to win. That's what makes FSAE so great. We choose on a team by team basis what gives us the best chance to win.

[Nima]

penguins
this discussion is between me and you. and its so well for me... I want to search and study about the all fluids mechanical designs of the engine system after select the engine... according to you and the other guys says, I may select the honda cbr 600 F4i... so in the future I will be back to the forum to discuse about them! http://fsae.com/groupee_common/emoticons/icon_wink.gif

[pengulns2001]

np, the f4i is by far the most common and information is readily available so for a first year team i think its a pretty good choice.

good power can be made with minimal mods and i know first hand the stock bottom end and head can take a turbo no problem... VFR750 do you know off hand your bore and stroke? im curious as to why you make power where you do i would assume its more a camshaft, head port thing... which are both easily modified

[VFR750R]

The YZF has a bore of 62mm and stroke of 49.6mm and an FZR is 59x54mm. I don't think bore and stroke is a large factor in peak torque or peak torque rpm, but the older design has less aggresive camshafts from the factory. Despite rumors, our internal mods have never been more then rebuilding engines with stock parts, so it's important to have an engine with the parts you want in the first place.

[Nima]

thank you all: <span class="ev_code_GREEN">penguins, VFR750R, js10coastr, Igor, illiterate and magicweed </span> to help me and share your experiments.
I am perfectly enjoying have discussions...

[VFR750R]

http://motorcycle.com/mo/mccompare/600ss/600sstqc.gif

This is what I'm talking about...this is from 97

[Nima]

Originally posted by VFR750R:
http://motorcycle.com/mo/mccompare/600ss/600sstqc.gif

This is what I'm talking about...this is from 97
VFR750R
I can't see the photo
there is a FORBIDDEN error on page...

[VFR750R]

just go to www.motorcycle.com (http://www.motorcycle.com) go to "bikes we've tested" scroll to the bottom and find the 600cc bike shootout from 97 and in the article there is power and torque graphs

[VFR750R]

also
http://sportrider.com/bikes/dynos/

[Nima]

thanks VFR750R
there is somethings I exactly would like to know
ok I think to review my decision about engine selection... if the availability of the engine is not a restriction I will choose everithing I want... But the 600 F4i looks commonly used with almost fsae teams... I must be carefull to select engine... OK?

[drivetrainUW-Platt]

read the Printed Program from the event if you want teams specs....

[Nima]

oh... it's a good offer
but where can I get this printed programs

[magicweed]

Its a descriptive program distributed to every team that gives the specifications to each car at competition. It goes in numerical order and has most of the vital statistics for each car, within a certain amount of number fudging. They are only available at competition as far as I know, so someone would have to scan in the pages and host them for you.

[Nima]

thanks Magicweed
Actualy I didn't know it befor so it must be helpful for someone want to know the excactly and compeletly engine specifications...

So if anybody have the scaned version of the printed programs please send me at nima_r@me.iut.ac.ir or link me to it on the web if it is.

[KU_Racing]

apparently penguins2001 doesnt watch much FSAE competition. judging by the number of blown motors there were last year, id say reliability matters just a little bit.

[pengulns2001]

and apparently you didnt read my post... if a motor blows up its because it was built improperly, didnt have good enough cooling, was tuned poorly or some other factor OTHER THAN WEAR... if you really want to argue that motors meant to be on vehicles that last 10000+ miles and 10+ years should be a reliability concern be my guest

[KU_Racing]

I would argue that a large majority of FSAE motors have reliability issues, strictly because a lot of them come off of bikes that are wrecked. On top of that, i guarantee that very few FSAE teams, if any, follow factory break-in specifications- for example, the break in procedure for a brand new kawasaki ninja 600 is 500 miles at less than 3000 rpm, then 250 more at less than 7000. i serioiusly doubt that any fsae teams break their motors in on a dyno for the equivalent amount of time, which is probably in the 15 hour range (by my guestimation) one last thing- no sportbike motor is designed to last 100,000 miles, ( i assume the 10,000 in your post is a typo.. if im wrong then correct me) i seriously doubt you could find a sportbike with 100,000 or anywhere even close to that many miles on the original motor and internals.

[pengulns2001]

i didnt say 10,000 miles over 10 years i meant 10000 miles or 10 years. you dont want to follow stock break in procedure, do some research on break in procedures you will find that the over whelming majority of engine builders and machine shops including the one i work in reccomend quite the opposite for break in... especially on a new motor or a coated one

[VFR750R]

Penguins is right about breakin and engine life. Factory breakin procedures are based mostly on the saftey of the customer and not on the ultimate peformance of the engine. That being said, most street engines have different ring configurations then race engines and do take longer to break in, although that doesn't mean they'll break if you run them hard. The biggest thing is getting several heat cycles in new pistons and being moderate load on rings for first couple hours of run time.

A prime example of street engines taking time to break in, I once read about a CBR900RR that already had 25,000miles on it. It was entered into a 6 hour endurance race and made more hp after the event then before.

We are much harder on the engines however then any factory designed for. High revs and lots of WOT mean high piston temps and fatigue. Especailly for turbo teams. So even a NA FSAE engine will not last as long as it will in the bike on average.

[KU_Racing]

correct me if I am wrong...
That being said, most street engines have different ring configurations then race engines and do take longer to break in, although that doesn't mean they'll break if you run them hard.

the f4i is a street engine.

[cieutag]

IF properly broken in I don't think wear on the motor is a problem these things are meant to spin at 14-17K we barely get ours up to 10-11K because of the restrictor. That being said one would think that most engine problems come from other systems' shortcoming cooling, oiling etc. These motors don't see high revs (at least our GSXR doesn't) compared to what they run from the factory.

[pengulns2001]

... your better off breaking in your f4i hard... if you dont want to do it its not going to hurt anyone else so go ahead and spend 17 hours on the dyno at 3000 rpms but you wont get anything out of it

[VFR750R]

CBR600 is a race engine for the street if that makes since, and the average street rider will put 5% maybe of his time at WOT and 90% of the time will be at cruise in 6th at 4-5000rpm. Tell me how much time you spend below 5000rpm, it better not be much. The point is the average stress on the engine is higher in our application then an average street engine sees over its lifetime.

[VFR750R]

Oh, do you think American Honda rebuilds engines on their supersport race bikes once a year? I bet they get fresh engines every race.

[JuicedH22]

well, I guess I will chime in and say that as far as break in is concerned, that breaking the engine in under light load higher rpm is important, especially if it is a fresh motor (i.e. new rings, honed, etc) You need to do so or the "pattern" on the cyl. walls will be "poor" and ring eff. will be "poor" (sorry for the qoutes I tried to dumb it down for the potential people who will read this and not understand)

My break-in recommendation is around 15 hrs or so under 9 grand, light loading (if you have a dyno this would be running solely off the roll inertia) then increment up to 11-12 grand and mid level loading.

As far as reliability and engine life. For example, we still operate and maintain our 2002 thru present cars.(The 2003 car has countless hours now of driving time, as it has proven the most reliable car thus far) NONE have "blown" an engine. The worst is overheating to the point of losing combustion, a day later it was running laps again... There has been an engine blown during testing, and that was due to the idiots running it with no motor oil.

[Garlic]

Don't 'dumb it down' Show what you know.

I've never seen a race engine broken in with light loading. And I've seen NASCAR, endurance racing, open wheel, you name it. It's all at least 75% load right from the start (as soon as temps are up).

[pengulns2001]

i usually let temps get up once and change the oil just to get whatever out of it assembly lube and whatever else might be in there, then i basically just dyno tune it

[Nima]

I haven't had an experiment in racing motorcycle and its engine, but being in the mini baja team of the IUT for tow past years, caused to understand me that the reassemble of the engine may couse to disturb all tolerances and the original assemblies... so you cannot disscuse its reliability and time...

[Nima]

I've recently found that the printed program is helpful for someone want to know the excactly and compeletly engine specifications...

if anybody have the scaned version of the printed programs please send me at nima_r@me.iut.ac.ir or link me to it on the web if it is.

[Dan G]

Nima, I have the 2005 program here at my desk. I'll scan those pages in and post them up for all to see.

[Dan G]

Ok, here's the link:

http://s51.yousendit.com/d.aspx?id=3T3J5YVALEES11OWQC13WYHTGU

Nima, I sent a unique link to your email.

[pengulns2001]

yeah when you re-build an engine you need to plastigage everything to make sure you have factory specs when you put it back together, if you build it right then you can still discus reliability

[Nima]

Originally posted by Dan G:
Ok, here's the link:

http://s51.yousendit.com/d.aspx?id=3T3J5YVALEES11OWQC13WYHTGU

Nima, I sent a unique link to your email.
Thanks Dan
It may help me in my designs...

[Kunal]

can anyone tell me wat the BBCC of the Honda f4i is?

[CornellGixxer]

Reliability and longevity are two different things. An engine can be designed or tuned to run reliably for 150 miles (F1 anyone??) but shortly after that they are garbage. The amount of time and effort you are willing to put into replacing used components will have a major impact on how you choose to design/tune your motor.

One of our professors used to tell us a story of two amateur racers, both with the same model car. Week in and week out the same guy comes away with the win, and the other guy cant figure it out... he knows roughly what mods the other guy is running but theres gotta something he's missing. He tries a new, more aggressive cam, and it works great... for about a weekend, before the lobes and buckets got chewed up and needed to be replaced. So, in disgust he goes back to running his tried and true cam profile... and goes right back to losing. Finally he sells the car and decides to leave racing. After his last race he walks over to his ever-winning competitior and asks him what sort of cam he runs. He names the agressive cam that only lasted the losing driver a single weekend. Confused, the loser says "I ran those, they were great but they only lasted me a single weekend, how did you get them to last?" The winner replies, "I replace them."

[threehondas]

I believe FSAE motors raced at detroit have a higher failure rate than those in the bike due to the following reasons:

While in the bike in stock trim, yes, the engine will see highter piston speeds (14-???k vs ~12k). However, piston speed is not everything. I think some teams meet or exceed stock torque at lower engine speeds. Doesn't higher torque mean higher BMEP and hight temps/rod/crank/bearing loads?

Oil Starvation. Ever seen a bike pull a 1.5g turn standing straight up? I rest my case. For those of you with dry sumps/modded pans, how many are 100% certain you'll have infinite oil flow regardless of how long you've had that rookie going around that skid pad? I guess proper warm up and get lumped into this category... kinda speaks for itself.

Too much case sealant on rebuild or mainenance. People smear that orange permatex junk all over the case halves, clutch covers, insert leaky part name here, hoping to fix that pesky leak... in this case more doesn't equal better. One little flake of that stuff in the wrong spot and you're toast. I know "but theres a filter..." but sometimes, I dont know how, one little piece of that gets by...

Noise Tests/Rev Limiter with no load. For guys that dont practice a noise test: No load at 12000 RPM Kills motors. Go only as high as you have to, only twice. Once to test your muffler (with a certified meter), once at competition. Also if I had a dollar for everytime I heard a rev limiter at competition I'd be a very rich man. Nuff said.

Dyno motors on track. Say your new to tunning... I feel like I still am, one slip on the keyboard and before you know it you're lean, super advanced, egts super high or low. Then after a small? 'one time' (read many) mistake, the same motor has to endure driver training, racing, and then well, the thing is gonna wear out a little sooner that you thought.

Also, transmission failure often gets lumped into "engine failure". Yes, there are teams that have an excellent transmission/shifter setup/driver, AND there are those that DO NOT. I can hear the clunks and bangs from across the lot at competition. I dont hear the same clunks and bangs at motorcycle track days I've attended.

All this talk about rebuilding engines... I believe a motor with a nikasil or other ceramic cylinder should not be honed/resurfaced (I'd love to hear some imput on this! just hit me with a PM). Therefore is a ring replacement advisable? I vote no. So whats the point with say, rebuilding a CBR if you cant hone? but if your rings are good odds are your oil supply has been good and you bearings are all probably ship shape.

Japanese engines wont last forever, but they're damn good for motorcycles, and they're nearly just as good in FSAE cars. I've had two honda motorcycle engines fail in my possession and care and I still got 90,000km out of each of 'em with track days. So what if they burned a liter of oil with every tank of gas for the last 10,000km, but they didn't explode.

[Nima]

hey guys
I have found a team in australia that design and manufacture their own engine...
What your idea for maufacture an engine?
I think it is crazy!

[pengulns2001]

i think that was actually WWU those are the only guys to do it as far as i know (wwu is in the US)

[Nima]

It is exactly the Melbourne University Racing in 2004 I think...

[Nima]

penguins,
I really want to know why the max torque is important for the performance of the car, such as acceleration... the most important is the upper torque in the shorter rpm... I think the engine will not go its tourqe up to the max... won't it?

[pengulns2001]

... can you re phase the question sorry im not really sure what your asking

no offense of course i know english isnt your first language

[magicweed]

Actually, I think he was refering to the Wattard 2Inline Twin that has been used by Melbourne in the past. As far as the creation of peak torque, it all depends on what kind of car you're building. I believe that we can generate near unrestrcited power levels from these sport bike motors if the restrictor, intake and exhaust are designed correctly. And even if the choke flow of the restrictor at high rpms occurs, the amount of torque generated will be equal or greater than the stock bike itself. As for where the torque application is most important, thats up to each individual team. However, there is one thing you need to ask yourself. How can I change the natural characterisitics of an engine designed by teams of experienced engineers? The simplest way to make lots of power is to emulate the stock bike in terms of exhaust primary length and intake runner length. A good tune and some time on the dyno should yield the same, or larger torque figures than the stock bike, in a similar range. If you wanted to more down in the range, head design, camshaft profile, duration and LSA come into play more heavily. Queensland already seems to be experimenting with resleeving the intake ports to change the natural characteristic of the engine. These are just basic things, but they all come back to the question of "What is the overall goal of my car?" Driveability, power, innovation, specialization in one event. Determine how you want to drive, and what your motor needs to do in order to drive that way, and then design for that. If you want to make torque all over, run a turbo with an ethanol fuel. An average system should produce over 45 ftlbs from 5000rpm to 10000rpm, just due to the higher boost levels possible.

[PatClarke]

Nima, I understand what your dilemma is. There are no 600 engines available easily in Iran, and you are canvassing your options.
I understand your intention is to enter Class 3 in FStudent, in which case you dont need any engine! Just a design.
Your Class 3 design doesnt have to be what eventually becomes your Class 1 entry, whenever that might be.
Entry to FStudent means you will meet lots of teams who will tell you lots of ways to get an engine. BTW, there is no reason why you couldn't use two 250cc singles!
Meanwhile, stop worrying about engines and get on with your design. Go to the Australian or German sites and read my guide for new teams!!

Pat

[ad]

pat, can you please check your private messages

[PatClarke]

Andrew, I havent got a PM from you. Perhaps email me at suddenlee at hotmail
Pat

[Nima]

ok pat,
I have really done whatever I could do. It is not possible to use 250 cc engine... beacuse of restrictions on the space of the car and the torque we needed...
it is not suitable for us I think... decide to select an engine want a compelete comparement of the all cocdidates engines in the same conditions... but it may be very cautiously and I belive that the most of the US, Europe and Australian teams select their engines in a simpler way...!

[Nima]

Originally posted by pengulns2001:
... can you re phase the question sorry im not really sure what your asking

no offense of course i know english isnt your first language
Well I'm sorry for my poor english!
I mean that for comparing engines, I must comare their torques at the each same RPMs... in acceleration development, some of parameters come in my equations...
I know that the max torque informations from the engines are not useful for my acceleration calculations... so I must consider a spicial zone of the torque curve that may affect the acceleration... If I made maistake please say me...
http://photos1.blogger.com/hello/134/9876/640/146-0408-comp-t-01.jpg

[BeaverGuy]

I would suggest comparing the torque curves at an output shaft speed instead of engine speed. The reason for this is each engine has different primary reduction and gear ratios that make engine RPM comparisons close to useless. You should be able to find these ratios for several engines either on the manufacturer's website or at APE Racing (http://www.aperaceparts.com/tech.html) the list of engine specs are at the bottom of the page.

[pengulns2001]

you actually looking for area under the curve... if you have 120ft/lbs of tq but your curve looks like /\ then your realy not going anywhere fast. the "zone" that effects your acceleration is area under the tq curve in between your shift points..

lets say you shift at 12000rpms and that drops you back down to 7500 in the next gear, the zone that matters is 7500 to 1200... if your engine makes poor tq below that it doesnt really effect anything

[PatClarke]

Nima,
Go back and read my suggestion again. I suggested TWO 250 engines! I have always considered that to be a viable solution for teams like yours!
PDR

[kwancho]

Originally posted by Suddenlee:
Nima,
Go back and read my suggestion again. I suggested TWO 250 engines! I have always considered that to be a viable solution for teams like yours!
PDR
One driving the lef t wheel, and one driving the right? Who needs a diff, when you can have a throttle that varies with steering position?

[Chris Davin]

Originally posted by Nima:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by pengulns2001:
... can you re phase the question sorry im not really sure what your asking

no offense of course i know english isnt your first language
Well I'm sorry for my poor english!
I mean that for comparing engines, I must comare their torques at the each same RPMs... in acceleration development, some of parameters come in my equations...
I know that the max torque informations from the engines are not useful for my acceleration calculations... so I must consider a spicial zone of the torque curve that may affect the acceleration... If I made maistake please say me...
http://photos1.blogger.com/hello/134/9876/640/146-0408-comp-t-01.jpg </div></BLOCKQUOTE>

Nima,

I think the Kawasaki ZX-6R is a 636cc engine, which is obviously above the 610cc limit for Formula SAE.

[Nima]

yes chris,
I just wanted to show a compared torque graph...

[Nima]

penguins,
I did what ever you and the other guys say to me about the engine selection... I cant select without a strong reason...
I listed the almost engines that can be used to fsae and compare their specifications... I found the acceleration parameters and connected them to the acceleration:

a=f(M,G,rpm,v,tyre,c,A)
that:
a: vehicle acceleration
G: vehicle gravity
M: vehicle mass
rpm: engine rpm
v: vehicle velocity
tyre: friction and the traction forces
c: aerodynamic drag coefficient
A: body surface that faceed front

but in the same conditions for all engines, we have:

a=f(rpm,v)

I have the 20,13,7in avon tyre, the transmition and the gear ratio of the engine gear box, for example honda cbr600f4:
Transmission Overall Ratios

6th 5.792:1

5th 6.407:1

4th 7.283:1

3rd 8.441:1

2nd 10.568:1

1st 14.520:1

I know that the optimum engine is one that make my acceleratin better...
If I reduce any parameter, say what it is...

[khnbm]

Nima!
you're becoming useless your time to get nothing! the engine parameters is clear in all engine handbooks... http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Nima]

Originally posted by khnbm:
Nima!
you're becoming useless your time to get nothing! the engine parameters is clear in all engine handbooks... http://fsae.com/groupee_common/emoticons/icon_wink.gif
I think you didn't read this discussion... for inform you, I didnt find any engine handbook to underestand the design parameters of the engine systems... there is only basic fundamentals...
it doesnt say me how to select my engine...

[RiNaZ]

http://fsae.com/groupee_common/emoticons/icon_smile.gif i cant help but smile ... that's how low it's been now

[KU_Racing]

Seriously, I am getting tired of reading this post. Alright. Here is how to select an engine. Decide what the maximum amount that you want your car to weigh. This will determine if you want a single, a twin, etc. Then go buy an engine. The restrictor means that all engines of the same displacement will make the same power numbers. SO JUST PICK ONE AND GO WITH IT!!!!!!!

[Nima]

You say some evident way to design! You get your design simple and think I dont know...
It is clear to me that the almost fsae teams ignore many parameters to slur over their knowledge limitations... But I dont want to go through this way, I think this is a one-week work! and seems not to be a perfect experiments...

[Nima]

I have a question that seems very laughable!
I dont know that the torque curve and the hp is measured at the and of the gearbox or at the crankshaft rpm...
http://photos1.blogger.com/hello/134/9876/640/hp%20%26%20power%20curve%20comparison%203.jpg

[KU_Racing]

Somebody correct me if I am not right.
Nima, the torque is measured at the trannsmission output shaft, but the RPM is measured at the crank.

[Chris Davin]

Actually, I would expect most motorcycle engine performance curves to be measured at the wheel, because this is what motorcycle enthusiasts care about. Those horsepower numbers look like they're at wheel, too.

RPM is always measured at the crankshaft. Torque is measured at the wheel (or output shaft) but back-calculated as though it were at the crankshaft.

[jonnycowboy]

Originally posted by VFR750R:
Oh, do you think American Honda rebuilds engines on their supersport race bikes once a year? I bet they get fresh engines every race.

ok I think I can answer this question... I worked for Diablo Honda here in Canada this summer (race team, we won the pro supersport (600cc) and pro superbike classes (1000cc+)) and whenever we could, we rebuilt the engines. If we had a race the weekend after (or practice) we didnt rebuild, but 2 weeks was enough time to tear down the 4 engines we used (good and backup ones, with 2 spares).

As to breaking in the engines, the technique for race engines is rev high (in neutral, light load) a few times, run it on the dyno to tune it (~50-100 runs, 4th gear under inertia load only). But ya, nowhere near 200-250kms recommended for under-3000rpm running in the service manuals. This is to better seal the rings. Of course it leads to lower reliability but also produces more power (any reputable engine builder will say the same thing). On race days, a few dyno pulls to tune with respect to ATM conditions and then just a predefined 'warmup' sequence with holding at ~9000-10000 rpm, and then 'blipping' from 4000-12000, with intermittent periods held at 4-6000 rpms.

[jonnycowboy]

Originally posted by KU_Racing:
Somebody correct me if I am not right.
Nima, the torque is measured at the trannsmission output shaft, but the RPM is measured at the crank.

yup thats right, the graphs that were posted were probably intertia dynos (which vary with tyre wear!)... and end up ~10hp less than crank hp..

[jonnycowboy]

Originally posted by Nima:
You say some evident way to design! You get your design simple and think I dont know...
It is clear to me that the almost fsae teams ignore many parameters to slur over their knowledge limitations... But I dont want to go through this way, I think this is a one-week work! and seems not to be a perfect experiments...

I beleive that most people posting in this forum do know what they're talking about. if you want to know more, start reading the books!! two books especially come to mind: "Internal Combustion Engine Fundamentals", "4-stroke engine performance".
both will help you in your quest for selecting the best engine.
More practicaly thought,
you have 2-3 engine choices, since producing your own is too expensive:
1 - 600cc 4-cylinder motorcycle engines
2 - small v-twins from either motorcycles (sleeved sv650?) or lawn tractors (with combined CVT)
3 - Lightweight 426-450cc single-cylinder (big weight savings, integrated transmission and really easy to incorporate restrictor

I think that if it was possible, the best engine choice would be a single-cylinder 610cc engine. (if possible, a bored and stroked dirtbike engine).. it would combine light weight with low to high end power. We are running F4i right now but its possible that we might change next year. I would like to see a single cylinder 426 and see how much it can be bored/stroked, anybody have any info on that?

Increasing power with same displacement means one of three things: increasing compression ratio, super/turbocharging, and finally increasing flowrate (higher volumetric efficiency and lower residual gas fraction)

[Nima]

In this post, many ways have been suggested to select the engine for FSAE... Your comments make me happy and give me to think more...
In any case, I prefer to wright a programme that its input is rpm and the engine torque@rpm and its output is the time of vehicle passing the 75 meter... So I input the engine and my output means the acceleration... The best acceleration in this case help me to select my engine... It is clear that the losses will be considered...
This is my reflection...
If I'm wrong, correct me...

[KU_Racing]

Nima, it is my opinion that you have overemphasised the selection of your engine. THe engines are all extrememly similar, and you are unlikely to gain a perceptable amount of performance from an angine change. In your situation, I would be more worried about the availability of spares and parts, and how the physical motor will integrate into your chassis.

[cieutag]

I agree that you are overemphasizing the performance of the engine, remember the restrictor is going to throw in new complications that can't be figured out by stock torque & hp curves. Also consider cost, availibilty of spare engines, parts, weight, complexity of wiring (the GSXR is complicated as hell). I think the initial desicion isn't as important its how you test & tune. This will determine how well your engine performs. One last comment don't pick your engine based on accelerations times its not the biggest event and the results will be very close, and they cannot be accurately computed with stock hp numbers.
Hope this helps

Chip

[LCheung]

Whoa, hold on a minute. What makes you think the engine torque and power numbers determines your 75 meter times?

Traction and gearing is a large factor for the 75m run. Not to mention something as simple as losing time to shift.

[CornellGixxer]

Engines are a touchy subject on these boards because everyone and every team has their own priorities and ideas on what is better. While some teams emphasize lightness and simplicity, others try to wring out every performance advantage possible despite "small" weight penalties. You should first figure out what your overall design philosophy is... and this will depend heavily on your manpower, money, experience and resources.

Personally, I love a good 4 cylinder turbo powerplant http://fsae.com/groupee_common/emoticons/icon_wink.gif... but do I think thats the only route to FSAE gold... definetly not. BTW, your engine choice should be based on much more than base engine torque and calculated acceleration runs. Bore to stroke and compression ratios, stock redline, weight, packaging, availability of spare parts, etc should be your bread and butter when it comes to making this important decision. Good luck.

[Nima]

Originally posted by KU_Racing:
Nima, it is my opinion that you have overemphasised the selection of your engine. THe engines are all extrememly similar, and you are unlikely to gain a perceptable amount of performance from an angine change.
KU_Racing,
There is many differences between 400cc and 600cc in their torques... so thay cant be similar... but in almost 600cc engines you're right...

[Nima]

Originally posted by cieutag:
I agree that you are overemphasizing the performance of the engine, remember the restrictor is going to throw in new complications that can't be figured out by stock torque & hp curves. Also consider cost, availibilty of spare engines, parts, weight, complexity of wiring (the GSXR is complicated as hell). I think the initial desicion isn't as important its how you test & tune. This will determine how well your engine performs. One last comment don't pick your engine based on accelerations times its not the biggest event and the results will be very close, and they cannot be accurately computed with stock hp numbers.
Hope this helps

Chip
cieutag,
I am actually working on the engine, sitting for class3 formula student... so considering the availibilty of spare engines, parts, complexity of wiring is meaningless...
But the weight and cost will be considered...
If I'm making a mistake in Class3 designing, correct me...

[Nima]

Originally posted by LCheung:
Whoa, hold on a minute. What makes you think the engine torque and power numbers determines your 75 meter times?

Traction and gearing is a large factor for the 75m run. Not to mention something as simple as losing time to shift.
The traction force that act on the tyres is:
F=M*a
F: Traction force
M: vehicle mass
a: longitudinal acceleration

so traction force means the vehicle longitudinal acceleration and it is not an independent parameter from vehicle longitudinal acceleration...
Gearing will be considered with the gear ratio and its losses...
The losing time to shift is the same for almost engines...

[illiterate]

Originally posted by jonnycowboy:
I think that if it was possible, the best engine choice would be a single-cylinder 610cc engine. (if possible, a bored and stroked dirtbike engine).. it would combine light weight with low to high end power.
well it might have a high torque output but i tend to think it will lack power in the high RPM range. Anyway, I saw a 600 single a few weeks back. It was some suzuki dirtbike but not rebored. It was missing a carburettor otherwise it appeared to be ok. Cost around 400$.

[VFR750R]

I think I've mentioned this before, all things being equal torque is directly proportional to displacement. A 610cc single has no more potential for peak torque then a 610cc 4, and as far as low-end torque goes, it may have more potential but as a percentage of peak rpm, a 4 cylinder will almost always have a wider powerband. In addition, many racing series using mulitple cylinder engines have different cylinders tuned for different rpms. For example the outer 2 cylinders could have longer intake runners then the inside 2 cylinders so they have different tuning peaks, broadening the powerband, although with a lower peak torque value. Similar to the concept of the variable runner length design but with much less complexity. This obviously cannot be done with a single without a varible runner length

[Jersey Tom]

Not even looking at racing series, even the stock F4i intake has two shorter intake runners and two longer.

[cieutag]

You'll have to excuse me I'm not to familiar with student, but availabilty and complexity should still be of concern in a class3. You want to be able to make this vehicle one day don't you? I would not design around anything that cannot be built, bought or otherwise acquired. you might not actually have to get these engines, parts etc. but if its a pain I think it should be considered. Also you can't make engine choices off of stock numbers because these aren't stock motors.

just my two cents
Chip

[Nima]

Originally posted by cieutag:
You'll have to excuse me I'm not to familiar with student, but availabilty and complexity should still be of concern in a class3. You want to be able to make this vehicle one day don't you? I would not design around anything that cannot be built, bought or otherwise acquired. you might not actually have to get these engines, parts etc. but if its a pain I think it should be considered. Also you can't make engine choices off of stock numbers because these aren't stock motors.

just my two cents
Chip

I think engine design in sitting for class1 is much classic than the class3! If you are in class1, you may see a cheap engine and try to buy it without any reasons, because of your budget limitations... and then put in working order your vehicle with this engine... and there may not happen any problem in your presentations... This is good... Useing these chances push the teams to arrive their aims...
BUT if any teams work on class3 FS, they must answer the smallest chooses, designs and suppositions in their class3 FS to the judges...
this is the only reason that I overemphasizing my designs... http://fsae.com/groupee_common/emoticons/icon_wink.gif
Thanks

[cieutag]

Well as I said I'm not familiar with FS, but in our situation the above stated issues matter much more, sorry I can't help I'm just in a different situation.

Chip

[Big Bird]

Hi there Nima,

First of all, congratulations to you and your team on taking the step to enter this competition. I would say it is hard enough for the rest of us to figure out where to start our designs, and most of us live in countries with strong automotive histories. I can only imagine what it is like to design an FSAE car from scratch when you haven't got previous designs to gauge from.

Just a few comments regarding your statement that issues like manufacturability, parts availability etc are not relevant in Class Three. I would argue that they are, as the art of design is not just about finding maximum performance, it is about matching your vehicle design to your available time and resources to achieve the best overall result.

We attended Formula Student in the UK a couple of years ago, and i have to say that the design judges were remarkably open-minded when it came to a team's design strategy, (probably even more so than our own Oz comp). We showed up with a single cylinder 450cc car, with our justification being that engine performance is not critical in this competition, and we were happy to trade some straight line acceleration for weight, packaging and manufacturability considerations. We also had some basic figures comparing the time worth of a few extra horspower, to the risk of trying to do too much and failing to get the project done on time. (And if you look through the results of any FSAE/FStudent event you will notice that completing and testing your vehicle on time is a much more significant problem than not having enough vehicle performance).

The response from the judges was that they were impressed that we were able to look beyond the "we must have the best engine performance" premise, and that we came up with an alternative strategy that maximized our chances of completing the task at hand.

Design judges recognize that for any single problem there will be multiple solutions, and they are looking for the line of reasoning that led you to the final design that you chose. Primarily they will be judging you on the strength of your argument, not whether or not you got the "correct answer" for your engine / chassis / tyre combination. If you decided to choose a CBR/ZXR/FZR600 (etc) they would ask you why (and I assume much of the argument would lean towards engine performance being of primary importance). If you chose a single cylinder engine, you could argue that you traded some engine performance for reduced manufacturing time, for instance. If you chose a snowmobile engine with a CVT, you could argue that elimination of gearchanges eases the mental load on the driver on corner entry, at the cost of some power transfer efficiency. Etc etc etc.

The one thing that judges will frown upon is that you have magically designed a car that has the most power, AND the least weight, AND uses the least fuel, AND is the quickest to manufacture, AND is the easiest to drive, etc. They have heard it all before, and have seen far too many teams that have come up with the "perfect" design - and then failed in the process of building it.

It is the quality of your argument and your research that will win respect from the design judges. If you can propose a design that is simple enough to be built and tested within the manufacturing resources available to you, and you have done the research to justify your arguments, then that will impress design judges more than yet another team spruiking that they are gunna build the fastest FSAE car ever.

I hope this is helpful, apologies for the wordiness.

[PatClarke]

Nima,
What Geoff DIDN'T tell you in his 'wordy' response is that the RMIT single cylinder car won that event outright!
I can promise you that a relatively unmodified Yamaha 450cc trailbike engine didn't hamper them at all.
There is a lesson for all in there!
(Sorry if I've embarassed you Geoff .... nyuk nyuk)
P
Regards
Pat

[jonnycowboy]

Originally posted by Jersey Tom:
Not even looking at racing series, even the stock F4i intake has two shorter intake runners and two longer.
its true but if i'm not mistaken its due to the shape of the intake manifold, to distribute air better to all cylinders.

[jonnycowboy]

Originally posted by VFR750R:
I think I've mentioned this before, all things being equal torque is directly proportional to displacement. A 610cc single has no more potential for peak torque then a 610cc 4, and as far as low-end torque goes, it may have more potential but as a percentage of peak rpm, a 4 cylinder will almost always have a wider powerband. In addition, many racing series using mulitple cylinder engines have different cylinders tuned for different rpms. For example the outer 2 cylinders could have longer intake runners then the inside 2 cylinders so they have different tuning peaks, broadening the powerband, although with a lower peak torque value. Similar to the concept of the variable runner length design but with much less complexity. This obviously cannot be done with a single without a varible runner length

I agree with everything you say, however I beleive the benefits of low weight and low rotational intertia from a single will outweight the possible benefits from variable intake lengths or a 4-cyl engine.

[KU_Racing]

I would have to disagree. If anything, a single has more rotational intertia- it has a much bigger piston moving through a longer stroke, plus the crank has to have significantly more counterweight material. I think the much higher rev range of a 4-cylinder is the main advantage.

[Bill Kunst]

Originally posted by KU_Racing:
I would have to disagree. If anything, a single has more rotational intertia- it has a much bigger piston moving through a longer stroke, plus the crank has to have significantly more counterweight material. I think the much higher rev range of a 4-cylinder is the main advantage.

Please don't let me be critical. A single for most people is the best choice. It is for more feasible. If you think of the first year teams, and the questions they ask, one cylinder is challenge enough. I remember when I was in their place and struggling to make it. I think that we can agree on that?!

As for the four cylinder, can you say "boat anchor". Really, there are no light fours.
They are awesome, sound awesome, and if you can build everything elese light and reliable enough, will whoop the shizzat out of everything on the track.

And for almost everything else available in this displacement. Basically anything commercial or made by WWU. Triumph triple- not much lighter. Most twins- made to suck A$$ in some four wheeler. Really, who has had a good application of a twin? Let me know, I would love to see it.

And the final engine...drum roll please...can you say APRILIA. Ooo Baby, Ooo Baby!! New release, the 450cc and 550cc twins. Factory 13K redline. Mid 70's Hp, ultralite (used on a supermotard). Drysump. Looks cool. Looks cool. Did I mention...oh yeah. Please, someone, some team, sell a frosh to slavery and bring this to comp.

http://www.maxmoto.co.uk/aprilia_45_v2.shtml

http://www.aprilia.com/models03/offroad/eng/modello_techinfo.phtml?id=98

Just had to have an opinion on best engine.
Bill

[absolutepressure]

Hmm, interesting, so did they kick Bombardier to the curb? "The fact that this was an in-house project is significant, and shows that Aprilia have moved on from their Rotax days, and now have the capability to develop a complete range of engines of different configurations." The ones who got left out (http://www.rotax.com/en/Engine/2004/Motorcycle/Description.htm)

[Nima]

http://photos1.blogger.com/blogger/5538/2294/1600/1.jpg
Can anyone tell me how did this Torque curve been measured... I think this curve measured at the output of the gearbox @ cranckshaft rpm, but don't know that this curve measured at what gear... is the curve at the one gear or it may be changed at the measurement...

There is another problem... the torque is not been produced by engine, It's the output need... it means if our rear tyres be in the air and dont touch the road, so the engine torque is zero @ any rpm...
So I think this curve may not help us...
If I'm wrong, correct me...

I have another problem... in this curve, I dont know what the <span class="ev_code_BLUE">corrected Torque</span> or <span class="ev_code_BLUE">SAE Torque</span> Mean...?
thanks...

[Geoffct]

The torque is measured by a dynamometer or dyno for short. A dyno provides a load for the engine and then measures the output torque and rpm.

For measuring motorcycles an inertial dyno is typical used. In interial dyno uses a roller of given inertia, which is spun by a stationary bike's rear wheel. The roller's change in rotation rate is sampled often, by simple physics, torque is recorded. The engine rpm is proportional to rear wheel speed and is calculated by the dyno operator. In order to give the most accurate results, these measurement are typically done in a higher gear, say 4th or 5th. 6th gear could work, but is avoided for safety (its very fast)

You are somewhat correct, if the rear wheels are in the air, torque is zero. But if you are designing your car to have the rear wheels (ever) in the air, you are doing something wrong.

Corrected torque or SAE torque is corrected for variations in temperature, pressure, and humidity.

[Nima]

Originally posted by Geoffct:
The engine rpm is proportional to rear wheel speed and is calculated by the dyno operator. In order to give the most accurate results, these measurement are typically done in a higher gear, say 4th or 5th. 6th gear could work, but is avoided for safety (its very fast)

So the torque is measured at the higher gear...
I want to calculate something need the torque curve @ engine rpm at one specified gear ( it ia not important what gear ), so it is important what gear excactly... the higher gear can be the 4th or 5th...
if the torque measured at 5th gear and the rpm be the 5th gear rpm, there is not a problem...
the problem is:
the rpm is at cranckshaft and the torque measurment is on higher gear like 5th or 4th...
so I must know the excactly gear that the engine is tested in that gear ratio... how can I find this gear?
If any body know, please reply...
thanks

[BeaverGuy]

That curve is for the torque and engine RPM before any of the gearing.

It was probably measured at the wheel but they divided the gear ratio out.

[Geoffct]

Originally posted by BeaverGuy:
That curve is for the torque and engine RPM before any of the gearing.

It was probably measured at the wheel but they divided the gear ratio out.

Like Josh mentioned, the transmission, chain, and tire ratios are devided out of the measured torque to get the engine torque.

Ie: lets say gear ratio in fourth is 1.3:1 The chain is 4:1 and the tire is 11" radius, and the measured force is 120lbs, then the torque is 120lbs*11"/(1.3*4) which equals 21 ft lbs (http://www.google.com/search?num=100&hl=en&lr=&safe=off&q=120lbs*11inches%2F%281.3*4%29+to+ft+lbs&btnG=Search)

The operator of the dyno must measure all of these ratios, and enter them into the dyno software.

So for all practical purposes, the engine torque measured before the transmission is the same for every gear. This is what is given in the graph you have. The transmission is designed to get keep the vehicle near the peak horsepower at all times.

[VFR750R]

So to clarify; what you have is engine torque and engine RPM measured at the rear wheel. There is no calculations to be done. To get foward thrust you need to multiply these numbers by the gear ratios YOU choose. Remember to use a primary reduction ratio, transmission ratio and final drive ratio in calculating force at the contact patch of the tire. Primary and transmission ratios are internal and cannot be changed. These can be found easily online for any engine currently made. The maximum tractive force is calculated using static rear weight, total weight, weight transfer and a friction coefficient for the tire. Use this maximum tractive force as a cap as any torque applied more then this will just spin the tire with respect to the ground.

[Nima]

I fined out that the manifold pressure may be near to the atmospher... 100kpa... and the manifold valume must be near to 50 or 60 persent of the total displacement... am I right?

thanks

[fart can]

Originally posted by Bill Kunst:
[QUOTE]Originally posted by KU_Racing:
And the final engine...drum roll please...can you say APRILIA. Ooo Baby, Ooo Baby!! New release, the 450cc and 550cc twins. Factory 13K redline. Mid 70's Hp, ultralite (used on a supermotard). Drysump. Looks cool. Looks cool. Did I mention...oh yeah. Please, someone, some team, sell a frosh to slavery and bring this to comp.

http://www.maxmoto.co.uk/aprilia_45_v2.shtml

http://www.aprilia.com/models03/offroad/eng/modello_techinfo.phtml?id=98

Just had to have an opinion on best engine.
Bill

I'm with Bill- italian v twins are the shit. But they are expensive too, and I think that is the biggest drawback. Anyone else think so? Furthermore, they aren't as easy to get as the mass produced japanese fours. Anyone tried to buy a good v twin from an aprilia or ducati? Or a triumph triple? And Bill- for a good application of a parallel twin, check out Laverda-- they used to make pretty cool twins and triples, but now they just make ATV's, but their old twins are legendary.
Will

[raska]

Anybody going to play with any parallel power strokes aka "big bang" engines ala evolving MotoGP?

Or have any thoughts about them? It hasn't been talking about here from what I can see other than somebody mentioning a Cycle World article in the November 2004 issue, which I haven't read, but would like to.

[Micko..]

I would have thought that doing this would have issues with restrictor flows. I am not an engine guy at all but i would think that halving the frequency and doubling the volume of air pulsing through the restrictor would not be kind for power production. Maybe this can be overcome with appropriate plenum size/design? maybe it is not an issue at all?

cheers

Miko

[VFR750R]

This is one of the main reasons why a single doesn't make good restricted power, and a positive side effect for running a turbo. You're right that a bigger plenum dampens the pulses seen by the restrictor, but at the expense of throttle response. The more cylinders you have the more peak hp and better throttle response you will get (within reason of course, it is a diminishing return system in both cases).

[Bill Kunst]

Isn't this where the ITB's would level the field a little (at least NA field)?

[VFR750R]

Well, it would allow you relatively instant throttle response regardless of number of cylinders or plenum size...but what fun would that be, the bigger the better.

[buggaero]

All said and done..... what is cbr 600's engine motor weight... with all the components or without... any which way you wanna tell...

I have found it to be 70kgs approx engine motor weight. (without components) on a forum, and the guy claimed it as per his Catia part model.

Just want to double check it wiith your confirmation or correction.

And yeah.. Never seen oe in life. It may happen soon but before design spec submission.
So kindly correct/confirm.

[Rex Chan]

I just realised that this thread is from 2006 (5 year old thread)! However, since I actually have some useful info, I'll answer buggaero's question:

We (MUR Motorsports/Melbourne Uni) run a 03-06 CBR600RR. I weighed it in 2010, and got a number of 55kg. The scales were ok, so probably within 0.5kg of that.

This was the complete engine block, but no intake/exhaust/cooling/oil/fuel/ignition systems. So, just the block & head, with internals. No oil pan (orignal wet sump, or the dry sump pan we ran in 2010). Can't remember if it had the starter motor or not. Probably had the oil filter and oil cooler.

So, 70kgs sounds a bit high, but may have included all other systems. We don't actually know how much all that other stuff weighs. I wouldn't trust a CAD model to get overall weights, but is ok for individual parts, if you spec the density right. Stuff always weighs more in real life, because there are always brackets that weigh lots more than the parts you actually designed.