GT12 Turbo Single

[threehondas]

I'm having a hell of a time making any power above 6000 rpm with my GT12 on a Suzuki LTZ-470 Single. I make 40 ft-lbs up to 6000rpm then it falls to 15 ft-lbs above 6500 @8psi boost. Pressure taps on the turbine inlet&outlet as well as compressor inlet coming soon.

I'm running about 12.6 air fuel, egts around 1600F@full load, and 34deg advance at 6500.

I've got a bunch of things to try but if any of you turbo teams have had any of these symptoms let me know.

Details: http://engsoc.queensu.ca/formulacar/engine/

Thanks,
Bruce

[Jay Fleming]

I don't know for sure, but from what I hear the GT12 likes around 1100F exh Temp. i dont know if that would cause your problems, but i'd hate to see a turbo burn up because of it.

[threehondas]

Thanks for the idea, but Garrett told be its good to 950C/1740F. You'd be hard pressed to stay under 1100F without the turbo!

Bruce

[Robert]

Have you tried retarding the timing a little more? Turbos sometimes need the timing retarded a little at higher RMP. One of our past cars using a GT Turbo ran about 32 deg of total timing and slowly droped to 28 above 8000 RPM. (the trigger wheel may have been slightly off for total timing numbers) I dont know if this will work for you but it is worth a try.

[threehondas]

You started backing off the advance as rpm came up? Interesting. You didn't happen to take compressor inlet pressures did you? How long ago did you run the turbo?

Bruce
http://engsoc.queensu.ca/formulacar/engine/

[Kirk Feldkamp]

If you can't get it to make the power up top with tuning... then it's probably manifold stuff at this point. I'm actually surprised that you could get it to spool that hard down low... but apparently it's enough to make 40 ftlbs, which isn't bad for that small motor. I'm assuming you're not using a boost controller yet...? Like Robert said, try backing the timing out a bit up top too. It'll help pass some unburnt fuel into the exhaust and help spool some more (if that is indeed the problem). Thank you 80's F1. http://fsae.com/groupee_common/emoticons/icon_eek.gif

Ooooooo yeaaaah, something I ran into on a buddy's turbo Hayabusa was plug gap. The thing would make power up to say 8000, then die. We dropped the gap to .020 and the thing wen't through the roof. I'd almost recommend trying that before doing anything else. If you're using stock N/A coils and stock plugs gapped to stock gap, it's a good possibility you're might be having problems with the spark even with 8psi. Maybe even a different coil or different plug type (surface gap plugs, maybe) would help that too.

If simple stuff like that doesn't help, you should be asking yourself questions like... What is the exhaust length like? What diameter pipe are you using for the primary (only http://fsae.com/groupee_common/emoticons/icon_wink.gif )? What is the taper like from exhaust port to turbine inlet? ***<--Super Important!*** It sure sounds like you're getting the thing to spool like a deamon down low, but you're either overspeeding the turbine up top, or you're choking the restrictor. I'm almost dead certain you're not choking the restrictor with a 470cc motor at 6500 rpm, unless there is something funky I don't know about regarding turbo singles and a restrictor. Pulsing may well still be an issue. I'd be interested in seeing your compressor inlet pressures in relation to RPM.

The motor has a 9000 RPM redline with stock springs? Is there any indication that you might be floating the valves after 6500? Once you start boosting on the motor you're going to need to add spring if they were already on the soft side before boost. All the Japanese bike manufacturers tend to make the springs float a tick after the quoted redline, so I wouldn't be surprised if that were the case. I've heard of pushrod V8's losing 3000 redline RPM, and subsequently hammering pistons, because the tuner failed to realize that the boost effectively drops the spring rate. CamProPlus and SpringMaster should answer those questions for you.

What was the stock powerband like? Where is peak torque for it? What's the stock cam setup like (lift, duration, centers, and overlap)? This might solve a batch of questions as well... If it's a high RPM motor stock, then you may need to rock the centers apart to reduce the overlap. You'll really screw the turbo's top end with a high RPM N/A cam!

Also, is that the compressor tube you're planning on running in the car? IMHO you're probably going to see a bunch-o-lag with that much plenum and up-pipe volume. Each time you close the throttle, the turbo has to refill and re-pressurize the plenum before it starts to jump up onto the tuning again. You've obviously seen what closing the throttle does to manfold pressures! http://fsae.com/groupee_common/emoticons/icon_wink.gif We ended up putting very thin, short, aluminum tubes in the up-pipe so we didn't crush it like the picture on your website shows. It works quite well.

Did you ever figure out the oil blowby issue? It looks like your turbo is mighty low, but there isn't a really good picture of the frontside of the motor on your website...

-Kirk

[threehondas]

Well Kirk, thats a whole bunch of questions.

I can try less advance as soon as I'm back on the dyno (maybe tuesday).

The spark plug gap is at .025 with the electromotive tec3 coils (25,000 V) that should be able to arc that gap no problem. I already called them. I've tried three different temp ranges as well - no difference.

Primary OD is 1 5/8" I think... I cant remember. There is a 7 deg taper per wall into the turbine. I agree lenth maybe an issue, as well as volume, but honestly I cant make it any shorter or the turbo gets too close to the gas tank, and any longer I have no idea where to put everything. Yes, I'm getting a nasty harmonic at a calculated 6900 rpm (using the speed of sound ect...) but I thought it would be negligable.

I'm running springs from the higher perf DRZ dirt bike motor capable of 11500 RPM (dont ask how I know http://fsae.com/groupee_common/emoticons/icon_wink.gif, so I dont think they're floating but boost induced valve sealing is a really cool idea I've never thought of!!! Not sure how I'd check that though.

Cams are the next problem... I'm running a pretty wild cam as far as street cars are concerned, or mild as far as motorcycles are concerned. I have the numbers from the DRZ (sister motor) but the LTZ cam I'm using are milder still:

DRZ:
In open: 20deg BTDC
In close: 55deg ABDC
Ex open: 56deg BBDC
Ex closes: 19ATDC

Cams are gonna be the first thing I'm gonna try. I've got a set of HOTCAMS I used to use with the NA motor, with adjustable sprokets (however they're higher lift) that I'm gonna give a shot as soon as I'm back on the dyno, but cam stuff is time intesive, because as I retard the intake my clearance at the top of the exhaust stoke goes super close... under a dozen thou. I've already clipped the intake valves before with great results http://fsae.com/groupee_common/emoticons/icon_eek.gif. Email me for pics of a shattered top end!

The stock power band had pk torque at around 6000rpm but I dont have my dyno sheet with me. If you want it, email me.

I hear you on my intake volume. So far I've ditched that volume section and I'm just running a 2' section of 1 3/4" tubing from the compressor to the inlet port. However these singles just love intake volume. For example, 0.75L to 3.5L NA adds 24 horsepower with the same runner!

Oil - well I ended up plumbing vaccuum to the crankcase and that has helped, however I'm running an electric oil pump that doesn't regulate pressure for oil temp or turbo speed. I have to do this 'cause the LTZ is roller bearing crank and only puts out 8 psi oil press. stock. So when the oil is cold I have 70 psi oil pressure, but once the engine is warm, it falls to a reasonable 30 psi. I'm also gonna try a thinner cold weight oil like a 5w30 mobil.

Hope that answers it all. Any more ideas? Looks like the dyno will reveal all.

Bruce

[BryanH]

You have a serious dyno in your shop!
You guys are doing what I've always wanted to try. The problem is possibly excessive exhaust manifold pressure, indicated by the high EGT & torque curve coming to a early stop.
You need to datalog the EMAP (at least 25 times/sec)
Your turbo outlet pipe looks way too small, needs to be at least 2". I have a feeling that the solution will be using a GT25 turbine hsg & wheel to keep EMAP on the exhaust stroke below 20psi at the redline, and then it will make power but be laggy as hell. Maybe this is why you never see turbo singles?
What's the compression ratio?

[threehondas]

Our CR is 11.3.

I know its high but I'm hoping with 100, and under 10 psi it should be a wild ride. I wish I checked your post earlier I just built a whole new intake and exhaust (1.75 OD after turbine instead of 1.5) check it out:

http://engsoc.queensu.ca/formulacar/engine/

Bruce

[Kirk Feldkamp]

Lookin' good. When will we get to hear some results from the new system?

Where did you get your nozzle for the turbo inlet? I hate paying $$$ for the ones from Burns Stainless. Anyone with experience making these?

-Kirk

[threehondas]

Yeah Burns is good - I dont think anyone will deny that, but some of the bends are a little oval, and did I mention $$$$?

Vertex is cheaper:

http://stores.channeladvisor.com/vertexnow

They're silicon hose is also thicker and stiffer than pegasus or chassishop.

Bruce



Originally posted by turbotwig:
Lookin' good. When will we get to hear some results from the new system?

Where did you get your nozzle for the turbo inlet? I hate paying $$$ for the ones from Burns Stainless. Anyone with experience making these?

-Kirk

[markocosic]

What's the situation now?

If you think ist a nasty harmonic doing the torque curve in, perhaps a single-three-single manifold could help?

Single pipe out the head, then '1' '4/3' and '5/3' pipes joining back into a single pipe at the turbo.

Idea being that as the '1' pipe 'blocks' with the harmonic you still get decent performance from the '4/3' and '5/3' pipes. 'Fools' the turbo into thinking its bolted onto a 3-cyl engine too as far as timing of the exhaust pulses is concerned?

[seerhou]

Hi Everyone,

Can anyone tell me the specification of the Garret GT12? I need to know the turbines and compressor details.

For Compressor

How much "Pressure Ratio", "RPM", and "Power Used".

For Turbine

How much "Exhaust pressure and Temperature", "RPM", and "Power Produced".

Actually I've send a lot of message about the specification and cataloque to some distributor who sell Garret Turbocharger but they have no response to me.

Does anybody can help me about the specification and the information that i need for Garret GT12.

Thank you so much.

Regards,
Seer Hou.

[seerhou]

Dear everyone,

Does anyone can help me how to calculate turbocharger by matching the engine? Help me... http://fsae.com/groupee_common/emoticons/icon_frown.gif

[markocosic]

Here's a couple of compressor and turbine maps:

GT12 Compressor (http://not2fast.wryday.com/turbo/maps/GT12compress.jpg)

GT12 Turbine (http://not2fast.wryday.com/turbo/maps/GT12turbine.jpg)

Are these the trims you were thinking of running?

Max flowrates through the restrictors are about 7.6 and 8.4lb/min for the 19/20mm diameters and you'll be at 80-85kPa pressure downstream of the restrictor at that flowrate - should be enough info to see where your operating point is on those maps?

[rjwoods77]

Hey Marko,

Is that rating right? 8.4lbs(air)/min will equal .134 ft^3/min.

(8.4 lbs(air)/min) * (ft^3/62.4 lbs(air)) = cfm

Am I missing something or are you wrong?

[KevinD]

(8.4 lbs(air)/min) * (ft^3/62.4 lbs(air)) = cfm


your used the density of water not air. try using .075 lb./cu.ft at 70degF @sea level

[rjwoods77]

too much fluids. ahhhhghggggggg. thanks kevin.

[seerhou]

Thanks marko,

From your information, you say that the pressure downstream of the restrictor is 80-85kPa, is that means the Pout which we need to assume to calculate the corrected flow? The formula of corrected flow is:-

corrected flow = [actual flow *
( Tin/545)^0.5]/[Pin/Pout]

Is that the Pout are from 80-85kPa. Is this value I should put to Pout in this formula?

Thank you so much

Regards,
SeerHou
desmundhor@yahoo.com

[markocosic]

You can plug numbers in all day, but the numbers you see on the real thing will be VERY sensitive to how you design your erstrictor/intake/turbo/throttle system.

Perhaps a team running turbos already can give you an idea of what pressures you see at the turbo inlet at peak power?

As a sanity check, using a 14.7:1 air-fuel ratio, 8.5lbs/min airflow and 18,500BTU/lb from the fuel gives ~250bhp heat release, so for 30% efficient engine you get 70bhp out.

sanity check (http://www.google.com/search?hl=en&lr=&safe=off&rls=GGLD%2CGGLD%3A2004-45%2CGGLD%3Aen&q=10697+BTU+per+minute+in+horsepower)

Another sanity check - WRC cars make ~300bhp through a 34mm restrictor. (20^2 / 34^2) * 300 = 104bhp if you can get your engien up to WRC car specs.

Final sanity check - lok at the turbos Garrett list for FSAE. Peak efficiency and nice wide spread of pressure ratios at ~8lbs/min airflow.

8lbs/min will do you for estimating airflow needs. You'll not see any more than 85kPa on the downstream side of the restrictor, probably a lot less. How much less depends on lots of stuff which I can't begin to guess at - you'll have to ask others or try it for yourselves?

[seerhou]

Thanks Marko

For the pressure of my engine,I think i need to do an experiment on the engine to get the pressure.After getting the pressure, I can get the mass flow rate of the engine. So using corrected flow formula,i can get the actual flow rate.After getting the actual flow rate, I need to get the pressure ratio(Pout/Pin).Then finally i can plot the compressor maps on Garret GT12 to see whether my calculation is over the surging limit line or not,am i right?

Thank you.

Regards
Seerhou

[CAV]

Problems aside, it is great to see someone doing a turbo single. I haven't seen that at competition in recent years. One question, doesn't your manifold pressure pulsate pretty bad at low load or idle? Assuming you're using speed-density EFI, is that much of a problem? how much does your map bounce around?

Also, I would doubt a "hot" cam that's designed for NA applications helps your turbo application, but post the results if it does help!

thanks

[seerhou]

Hi Everyone,

Does anyone can tell me about the GT12 Compressor map? I saw the map,it's only tell me the surging limit. How about the turbocharger efficiency and the RPM of the Turbocharger. Some compressor maps are given the efficiency and RPM but how come GT12 Compressor maps is not give? Can anyone tell me about that?

Thank you so much

Regards,
SeerHou
desmundhor@yahoo.com

[threehondas]

Okay this pressure after the restrictor or turbo inlet pressure business:

First off, as far as I know pressure in the throat of the diffuser varies significantly with area so blanket statements talking about pressure post restrictor mean absolutely nothing without a reference to area!!! I've bench tested my diffuser and back pressure varies from 33 kpa to 98 kpa with position from restrictor.

My spreadsheet for flow rates indicates that in a diffuser you can achieve M=1 at the throat with a back pressure of only 95 kpa at an area of 0.000666m^2. You can drop the back pressure all you want but you wont get anymore flow. Therefore my pressure ratio uses 95.7kpa as inlet pressure to the turbo. Currently my boost doesn't go over 170 kpa measured at the intake runner which puts the PR @ 1.75 adjusted. Look that up on the GT12 map if you want - It should be right in the meaty zone. Plus the GT12 is the turbo for these guys that race quads... I've seen few sites/vids with guys running these on sport quads and haling *ss. So hopefully the sizing cant be too far off if anything they're a tad big for my 470 - unless the restrictor plays a signifcant role in dropping the pressure prior to the compressor. Which leads to the next problem...

Anybody know what would be the best compressor to use since the inlet velocity is so high? usually these things draw from almost still air right? We making them deal with 90m/s due to the restrictor...???

Now M=1 is supposed to occur at 9.6 lbs/min (85.06CFM) or in my case 10250 rpm which is still safe piston speed on my engine. I tested my nozzle, and it "seemed" to choke at 110 CFM - or thats all the air a V6 could pull through it at WOT. I took pressure readings as a function of distance from the restrictor and indeed this was choked behavior or very close to it.

Now cams. NO THE HOT CAMS DO NOT HAVE DESIRABLE PROFILE FOR TURBO. However, they do have adjustable timing sprockets that are!

Fuel injection and idle you say? Yeah its a complete b*tch. Last year at competition I ran NA and had a good 1800 rpm idle running solely on MAP with a 3.5L intake without searching up and down like all FSAE motors. Yes it does fluctuate a lot, but I didn't have any problems. Infact I was quite proud. THIS year is a whole different story. 3.5L intake volume including the I.C. but I cant get it to idle at all below 2700 RPM without stalling. Increased back pressure due to turbo surging??? Hilarious since idle is 1000 rpm away from pk torque. Now I'm running off TPS below 3000RPM and then blend over to MAP pressure only above 3000rpm. It helps starting but idle is still crap. I did starting and idling for 6 hours last weekend and got nowhere. Oh well, its a race car not a grocery getter.

No, I have not been spinning on the dyno lately - I've been outside trying to pass noise. Finally got it down! went from 115 to 105 with a different exhaust and header/tailpipe. At this point last year I was making 120dB! PS: That turbo took 10dB out of the exhaust note. Sorry guys no big power yet. lots of torque though.

Oh and this line about the restrictor taking 25% of the horsepower away is NOT true. I make 38Hp with a carb and stock ignition running 13.0:1 AFR, and 38Hp restricted @ the same AFR with similar torque curves. Go make a compressible flow sheet and you'll see why torque falls off on those big engines.

Oh yeah those things called Final Exams? I'm doing those now... not to mention I haven't been to a single class since reading week...so dyno time will have to wait.

Keep those questions coming - and thanks for the help guys!

Bruce

[John Bucknell]

I tried answering Bruce's question last night, but the internet cafe in Greymouth bounced me about 99% of the way through - anyhow, here's what I said.

The idle speed issue makes me think you have a vacuum leak of some nature, hot cam or no. Either that, or you need to pull some spark out at low MAP/throttle angle to get the speed down. Turbines don't have enough backpressure at those flow rates to make any difference on idle.

As for vacuum you are pulling at WOT in front of the turbo, seems kind of low. I seem to remember most NA FSAE engines getting about 75 kPA MAP around peak power. Any more detail there?

Finally, 170 kPA MAP should feel real good off the corner.

[threehondas]

John,

Yep one vacuum leak on the crankcase. Now I'm into the minimum turn on time - I'm using a one huge 550cc injector this year and I guess I went overboard.

I'm strapped to the dyno again to finish things off. Should have some more infor on Monday (I'm only allowed to run during school hours).

I've also been too afraid to pressure tap the inlet to the turbo. If the system is well behaved I'm not going to. But if I have some high rpm issues again I'm going to have to tap it.

[John Bucknell]

How low is that idle speed with minimum on time? The high-impedance injectors I work with are a bit smaller (487cc), and we can idle down at around 2ms on time at 600 rpm with a 590cc cylinder. That's with 75psi fuel pressure as well.

Hope you make some good noise Monday.

[threehondas]

So I'm using one RC550cc low impedance, and the software shows minimum turn on time at around 1.20ms. I'm trying to run below that. I'm bumping into it at 2300rpm.

Man... 75psi? I'm only using 37. I guess I can't fire mine as accurately as you can? also the whole high vs low impedance thing/peak and hold vs non-peak and hold. How are yours fired? I'm peak and hold (supposedly).

What are you using 590s on?

[John Bucknell]

Bruce,

Keeping in mind I work on production car engines - a 590cc cylinder is actually just one of four. Anyhow, my controller uses a square wave pulse to drive the injector (we don't talk peak and hold or saturated drivers, but I suspect it is the former) - and my 2ms at idle includes an offset of 0.6ms battery offset (a variable that changes with battery voltage, but essentially the extra pulsewidth it takes to get the pintle off the seat - so no fuel is being delivered in that on time).

Low impedance typically means a rather large diameter coil winding - and thus why most race injectors are of low impedance because you can get more total flow because the coil diameter is larger. However, they are harder to package and require more coolling on the controller because of the increased amperage and thus why they aren't used in production controllers.

I would recommend yanking a lot of spark advance out at closed throttle/low map to reduce your idle speed (assuming you haven't already). We typically only need 1 or 2 degrees total advance with 30 kPa of MAP to generate zero torque at 600 rpm.

[Kirk Feldkamp]

John,

For a MAP based system, how do you guys populate the fuel and ignition maps on the dyno? Of course with the TP based system you hold a TP and slowly release the load... but I can't see how you could make "sweeps" with the MAP setup. It seems like you'ld be forced to do some sort of wastegate trickery to hit most of the sites. Then again, we don't hit all the spots on the TP map either...

http://fsae.com/groupee_common/emoticons/icon_confused.gif

-Kirk

[John Bucknell]

Kirk,

I am fortunate enough to have a motoring AC dyno. That is to say it can both add and subtract power from the crankshaft - and coupled with a sophisticated feedback mechanism can hold rpm dead steady no matter what the load (can go from absorbing 300 to adding 300 bhp in about 100ms). So I tell it to hold rpm and roll throttle up and down to get to the MAP I want. With a brake dyno, it's a bit harder - but doable. The key is doing throttle (or wastegate control - should you have the latter) and load changes simultaneously, albiet very slowly - which effectively zig-zags up an rpm/map surface. If you have feedback mechanisms on your load control, it is much easier. Best to populate the areas you haven't been yet with pig rich fuel and safe spark. Of course, you'll want to control your charge temps during this slow process so you'll need a pretty effective liquid-air charge cooler.

Did this answer your question?

[threehondas]

It works eh guys?

After blowing the seam on the carbon intake and fixing it,

I got 55 hp at 7200RPM today... then melted our carbon muffler. Torque has stayed pretty flat at around 39ftlbs from about 3800 rpm upwards. MAP was bumping up to 180kpa. I've got a new stainless case for the muffler on the go and an exam to write tomorrow. But I plan to run to around 9500 to 10000rpm on Thursday. hopefully 60hp is around the corner. Acording to the spreadsheets, I'll choke the restrictor at 9400. We'll see what happens.

[Kirk Feldkamp]

Yeah, really really fortunate. I don't think you could ever really do that with a manually controlled water brake. The time response on that sounds next to impossible on a race motor that wants to take off on you. The method sounds simple enough, provided the controls are good enough to hold the RPM.

Thanks,
Kirk

[threehondas]

So I melted the clutch today. 62hp and 47ftlbs of torque at the crank. I expect to get 68 tomorrow.

The clutch came out in peices. See website tomorrow for pics. Should have a video mid dyno pull of it losing the clutch and me scrambling to slow the motor down.

It WAS a KG "race clutch" with stiffer springs and slightly different plates.

For tommorow's testing I'm gonna replace the springs with solid rods that I can clamp the clutch together using the bolts that would normally tension the springs.

For use in the car however I've ordered a Barnett Clutch but I'm worried that it wont hold the torque even with the springs shimmed.

Any Ideas? Please Help!!!

[John Bucknell]

You've hit upon the downside of bike motors with integral trans. We had so many problems with our turbo land speed record car (FZR750 making like 300 bhp) we ended up pinning the clutch together and bump starting it - course then we ended up popping gears (and cases, and layshafts, etc).

Beware making a lot more torque than the driveline is designed for. You may ultimately have to limit boost in the mid-range to avoid this issue.

[threehondas]

You had a hand in building a 300hp FZR750??? I'd love to hear all about it. Drop me an email.

[James Waltman]

http://hardmanracing.com

John,
What's the goal for this year? Something like 330+mph right? I'm sure some people here would be interested in hearing a little about the project...

[Kirk Feldkamp]

What the powerband shape coming out like on the single? Are you using a boost controller yet? Care to post any dyno graphs so we can see where it's at? Peak numbers are fun and all, but i'm interested in the whole curve! http://fsae.com/groupee_common/emoticons/icon_smile.gif

-Kirk

[John Bucknell]

James,

It seems unlikely we'll break 300 mph without an intake manifold (ahem http://fsae.com/groupee_common/emoticons/icon_smile.gif). Actually, the rest of the car is so far behind we'll be likely to be running 2.0L naturally aspirated which will put us in the mid 200s. Last fall a streamliner in our class set the fuel record at 250 mph - which we hope to beat.

Bruce,

Making power with turbos is no secret http://fsae.com/groupee_common/emoticons/icon_smile.gif. Actually, FZRs are pretty easy because the separate jugs and crankcase - just EDM a thicker base gasket, retime the cams back to stock and blow 30 psi on it with a Mitsubishi TD05-16G (we ran a pretty stout ERC leaded race gas as well A-8C (http://www.ercracingfuels.com/ercA8c.htm)). There's detail shots of the engine here Speed Car Engine (http://hardmanracing.com/blank.html). Course we couldn't make more than two passes on the same engine (total of 10 miles) without popping the trans. You'll notice on the website the inconsistency of the records - because several times on the return pass the trans broke, and we had to settle for the speed we went in the fourth mile (or even third). Also wheels outside the body for lakester class sucked 30 mph out of the car.

[threehondas]

Well I've done it now...

Sheared teeth in fith (top) gear on the dyno in steady state. Its gonna be a long weekend building spare bottom ends. I guess I have to turn the boost down below the 10psi I run now. I can build three spares and I think well end up using them all.

So we can make almost 70hp but the transmission and clutch cant take it. If you have any experience beefing up a stock transmission, I'd love to hear it. I'm really upset we've made this power but cant use it. http://fsae.com/groupee_common/emoticons/icon_frown.gif.

Any suggestions welcome.

[Z]

[QUOTE]Originally posted by threehondas:
Well I've done it now...
So we can make almost 70hp but the transmission and clutch cant take it...
I'm really upset we've made this power but cant use it. http://fsae.com/groupee_common/emoticons/icon_frown.gif.
[QUOTE]

Bruce,

I've followed this thread for a while and I'm impressed with what you've done.

But (at the risk of sounding like a cynical old fart, and no offense intended - honestly!) I think this is another example of a team NOT doing the right thinking early. The problems you are having seem quite predictable. Given that FSAE is a sort of "one-shot" event I think the turbo-supercharging of a small engine/gearbox package should perhaps have been done as a parallel project - ie. to be used next year, if it proves successful this year.

Anyway, what can you do now? New beefed up clutch and gears (only need, say, low and high gear)? Or, if the clutch is on the gearbox input shaft (?), then maybe a new primary drive that spins the clutch and gears faster will do. This puts less torque on the gears. You may have to use a higher (numerical) ratio final drive. Or just settle for 50-60hp? (Contingency for all this should have been arranged 9 months ago!)

Sorry for the bad vibes... I know what it feels like to spend a year paddling up "Shit Creek", then suddenly you realise you're sitting in a barbed-wire canoe and you've lost the paddle!

Z

[threehondas]

Z,

I agree with you. I was not pro-turbo from day one. I dont believe playing with a stock engine's safety factors. If two sae vehicles where sitting on a showroom floor, one with a turbo that is taxing the stock internals, or a naturally aspirated four cylinder that runs near its stock torque I'd like to have the naturally aspirated motor.

We had a lot of pressure from the faculty to turbo the single cylinder. In fact I wasn't really given a choice. Am I surprised its breaking parts? Nope. I think the whole team loves to gamble...every year its the same thing - they try to change everything and expect it to work with untrained drivers and un-tested parts. Our car will make a great show piece for the faculty and a bit of ticking timebomb. Ever noticed the engine is still on the "engine" dyno? I the team still has not completed the rolling chassis. Our school has a pour attitude towards racing, and it shows in our results.

BB

[John Bucknell]

Bruce,

Just out of curiousity - how much boost are you making up top? It is possible that you might be able to run lower boost to limit torque and still make decent power. If you aren't running on the wastegate any longer, then it is the restrictor holding you back and you can lower the MAP in the mid-range. Just a thought (it's what we do on production motors).

[threehondas]

John,

10-11psi across the rev range. Restrictor effects seem to be present at 9100+ RPM, or at least some losses in the system start to play a role. I'll try to post data logs and torque/HP curves tomorrow night.

Yes I was running waste gate control via solenoid valve in the manifold pressure/waste gate line and controlling it with duty cycle and a fequency, but it was taking too long to get a steady state boost level.

Obviously I can turn down the boost. However the transmission I have has done 3 years of dyno duty. Its rather funny to look at, considering it never runs in any other gear than fith.

Its been a long weekend... Three motors to build - 1 dyno, 1 race and 1 spare. The engine lab is hilarious with parts from wall to wall.

Can anybody recomend a cheap an easy way to measure turbine inlet pressure? I tried but it didn't work. I'd really like to know for design judging purposes.

BB

[Dan B]

Originally posted by threehondas:

Can anybody recomend a cheap an easy way to measure turbine inlet pressure? I tried but it didn't work. I'd really like to know for design judging purposes.


GM 1 or 2 bar map sensor.
See last 3 pages of this pdf for calibration data.
http://www.ttspowersystems.com/software/dm3.4.1/docs/dm32man.pdf

Pin A -- Ground
Pin B -- Sensor output
Pin C -- +5 volts

1 Bar GM part # 2503679
standard part # AS-5
Pretty much any normally aspirated TBI GM car, plus plenty of others
2 Bar GM part # 16009886
Wells part # SU-129
standard part # AS-4
91-93 GMC Syclone & Typhoon 4.3 turbo
87-90 Pontiac Sunbird Turbo 2.0
84-86 Sunbird (actually any J-car) turbo 1.8
3 Bar GM part # 16040749

[threehondas]

Yeah but how do you get exhaust gas @ 1700F to the sensor? I was using coiled up copper pigtails with compression fittings to dissapate the heat but they crack off with hard running.

You can see them somewhere in the pics on the website.

[Dan B]

Originally posted by threehondas:
Yeah but how do you get exhaust gas @ 1700F to the sensor?

For some reason I was thinking compressor inlet???

[John Bucknell]

Use stainless bungs welded to the manifold and stainless lines to the MAP sensor. It's how all the cool kids are doing it.

[BryanH]

Bruce, congrats for getting the beast to 70 hp. At this point you probably dont want to know how much can be gotten from a FSAE'd WR450......
I find it hard to believe that the 400 tranny has been designed so close to its original power output, more likely the steady state dyno work raised the trans temps enough to weaken the gears. The oil film on the teeth breaks down locally and gears get Very hot, then teeth break off. I see it on big HP circuit racing & offroad cars. Synthetic gear oil like castrol SAF-XA stops carnage, but obviously cant use on a cycle gearbox,
I am fairly sure the gearbox will be OK on the track if you are using a top line synthetic race oil like Motul,Yamalube Mobil 1 etc and an oilcooler to keep oil temp <200f
JB, I'd love to hear your impressions of V8supercar.
Bryan H

[threehondas]

Brian,

My oil temps on the dyno haven't been higher than 170f since I changed the fan arrangement in the dyno cell. I had one day of sustained running where they crept up to 230F at which point we stopped testing.

I've been using an automotive 5w30 Mobil 1. I KNOW ITS NOT IDEAL FOR MY APPLICATION. But its cheap, and keeps the turbo oil pressure low at startup so my intake doesn't fill with oil.

I was thinking that the automotive based oil could have had something to do with my recent failures. But I really dont think it did.

The rebuild weekend didn't go so well... some stripped phillips screws, helicoils, and a ceased bearing on the new tranny I put in really slowed things down. Testing this afternoon maybe...

[threehondas]

Brian,

(OFF TOPIC)

V8 Supercar!?

It used to be on speedchannel sunday nights. I thought it was the best racing on TV. Real cars, going Real Fast. I hear it brings some huge crowds to small towns? True???

I hear you're big race enthusiasts down under. Motorsports aren't that popular in canada compared to the rest of the world.

[BryanH]

Try http://www.motul.com/uk/produits/
Their 4stroke race oil is worth the money.

(J.B. toured a V8Supercar raceshop in OZ and was going to watch a round in new Zealand, which turned into a wet & wild crashfest)

[Hoosier Daddy]

Originally posted by threehondas:
Brian,

(OFF TOPIC)
Motorsports aren't that popular in canada compared to the rest of the world.

This wasn't always the case... And it still isn't in Quebec.

[John Bucknell]

I didn't actually get to see V8 supercars on other than tv (due to a key failure on the bike I was riding on the way to Pukakua - broke off in the ignition), but I did put up some pics ->my off-topic discussion (http://fsae.com/eve/forums/a/tpc/f/648600998/m/43210088421)

[threehondas]

Yay!

1 brand new head + redone valve seats + new rings + cylinder hone + new trans ==

Another blown trans.

I think the locked clutch may be introducing a shock load into the transmission. Also there is some low RPM vibration in the driveshaft that connects the output spline to the dyno.

Sheared teeth while tuning at much lower torque than the original failure (28%TPS, 3500RPM, 110Kpa MAP) about 35ftlbs torque. still more than stock but not much more.

Therefore the failure is due to the locked clutch or vibration in the dyno shaft in conjunction with higher torque than stock.

A spare trans is being sent out for heat treatment (if possible), and I'll have a new trans in the "new" motor in by tomorrow morning.

I promise no more working on the maps, just a pull then I'm done and in the car.

[GTmule]

Crazy thought:

I'm not sure how your gearbox is layed out but:

as a sort of sacrifice of a couple gears, can you put the same gear in the 3rd spot that's in the first spot, and the same gears again in 4 that's in 2. You'd then have to rig up a way to get the box in 1st and 3rd at the same time ("1st gear") and then 2nd and 4th ("2nd gear"), or some similar arrangement. It may take maching a new shifter bearell, I dunno, I haven't messed w/ the bike boxes much.....

[Z]

Another thought:

Many bikes have a "cush-drive", ie. rubber "cushions", typically where the rear sprocket mounts to the rear wheel. Also the standard chain drive of bikes provides some cushioning to protect against torque impulses.

Maybe you have a heavy, stiff driveshaft to the dyno that is acting like an inertial "anvil" that the torque pulses can hammer the gear teeth against?

So maybe if you put some rubber "doughnuts" in the dyno driveshaft, and/or drive it via a chain...???

Z

[threehondas]

Z,

Thats exactly what we think too. Both failures occured below 4500 rpm. With the six springs in the back of the clutch fully compressed due to exessive torque (ie more than stock) there is nothing left to dampen the torque on the power stroke.

We will do the power curves on a chassis dyno (with our fingers crossed).

[BryanH]

Might be combustion problem. Without giving too much away,(your setup is unique anyway) what is your ign timing 2k to 8k @ 1bar absolute and 2bar absolute?
Fuel should be around .93 @ 1bar and .78 @ 2bar,(it will run leaner on track,as much as .08 if you are mapping steady state)
Bryan H.

[BryanH]

forgot to add that the lack of give in clutch pack has certainly amplified the problem, and the problem is between the piston and the gearset, not after the gearset

[Andycostin]

We had all kinds of similar probs last year. Rolling Chassis Dyno was converted to operate as an Engine Dyno too, but kept burning out clutches.

As far as we can see, due to the pulsation of the engine (each combustion torque peak) trying to accelerate the massive rotational inertia of the rolling dyno, the clutch being the weak point gave way after a while.

Have spent the last 3 months designing a housing/transmission system that will allow us to use a 'Torsional Coupler' from Gates (transmission company). The idea is that the Torsional Coupler (big inline rubber toothed belt) will absorb any pulsation from the engine.

Gotta thank the Technicians at uni who've spent weeks doing all my machining and putting it all together (would've cost a fortune otherwise) http://fsae.com/groupee_common/emoticons/icon_biggrin.gif.

Guess that the real test will be when we get the engine running in the next fortnight. Hope all the hard work and money hasn't just been a waste!!!

[Mountainman]

You keep mangling 5th gear, right?
As the reduction on the gears goes down, so does the gear tooth strength rating. The lower reduction on 5th is probably going to make it of limited use with that much power.

Two things you can do.

1. Check out the DRZ400S and see if Suzuki made 5th gear wider (stronger) to deal with extended street use. Chances are they may have, KTM and Yamaha do similar tricks.. they figure you won't cruise on the highway with a woodsbike/quad, so they narrow up 5th to make a lighter tranny.

2. Change your final drive ratio to avoid running in 5th gear..

-JW

[threehondas]

Well,

The last time I tried to do a dyno pull I had a fantastic transmission failure.

It sheared 5 teeth off fifth and bent the output shaft on the trans, and distorted the engine case. So my good motor is no longer. We built up our old 2004 motor with new bearings and rings and bolted that up in the car.

We've run the car for the past week. The headgaskets blow with the top engine mount bolt in, and leaving it out cures the problem. Unfortunate.

The biggest problem is oil in the intake. Lots of it. After 20 min you have to drain the lowest point in the system you get 500ml of oil coming out. If the intake 'burps' you get a fantastic cloud of blue smoke. If the intake 'burps' hard enough you could hydrolock the motor at high rpm. I'm really scared of it. Actually Terrified.

So if you're trying to find our car look for the biggest cloud of blue smoke in the paddock.

However the car is really fast @ 385lbs wet and tuned to 62hp and 47ft-lbs. I'm running out of gears in a bad way though. I've got a sprocket coming in but it may not get here in time and I'm worried that in the endurance were gonna ride the rev limiter all the way down the straight in 5th. I didn't really account for so much thrust and was just concered with top speed.

Throttle response coming on throttle is good, and with the sidepod off you can hear the turbo from a half mile away! But throttle response coming off throttle is terrible, which makes shifting difficult, and I think acceleration will be a disaster for this reason alone.

The DRZ trans had the same facewidths in each gear however the shift pattern is significantly different than LTZ. To use DRZ gears a new shift drum would have to be machined.

There have been no transmission issues in the car as of yet and the barnett clutch is holding up nicely. But that torque managed to break a driveshaft on the first day out (while trying to break in the engine!) Some thicker wall stuff has sorted that out.

[Kirk Feldkamp]

You and Arizona might be able to have a "biggest plume of blue smoke" competition. http://fsae.com/groupee_common/emoticons/icon_wink.gif

In the car your transmission problems may well disappear. On the dyno you're going to be loading the motor a LOT harder than you will in a 385lb car. You probably wont ever truly make full power in the car on the courses we run (at the FSAE comp) anyway!

[Denny Trimble]

If you need a rear sprocket, let me know what chain type and size, we have a bunch of old spares and blanks (46 to 60ish teeth) for 520, 525, 530 chains. Our truck is already gone, but I could bring them on the plane... http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Kirk Feldkamp]

Security Person: "Sir, what the heck is this?"

Denny: "Um, tools of the trade?"

Security Person into radio, "I'm gonna need backup."

[Travis Garrison]

Have you considered a drain for your intake? Poke a hole in it and run a healthy length of hose off of that...if you can keep your oil in a relatively long column (inside a tube) you should be fairly safe.

You might consider something with check valves if you're really scared. Assuming you balanced your "reservoir" (maybe a really healthy coil of hose with one end going into the low point and the other into a high spot instead of just being pluged) a ball check valve would keep your oil from jumping out of the tube.

Just tossing it out there...

-Travis Garrison
U of Washington

[threehondas]

Turbotwig,

If arizona wants a duel, its on! I guarantee they'd go down. (And I got more sheared gearbox teeth than them too)

Denny,

I'd kill for a rear sproket right now. We need something smaller than a 41T (520 Chain) that we could punch a 6x~100mm pattern in. Thanks for the offer!

Travis,

I already have a drain. I have an o-ringed an plug on the lowest point of the intake system. I'm not sure I totally understand the check valve coil of tube thing.

Oh and this just in: Our tire mounter just bent three of our wheels. We're now done testing, since we only have one set. New rims are being delivered at the hotel. Yah!

[Kirk Feldkamp]

That may be a good duel! The lady announcing at the Fontana event was calling it a bug fumagator. http://fsae.com/groupee_common/emoticons/icon_eek.gif The track workers kept trying to meatball flag the car, and she kept having to tell them "No guys, that car just smokes." Then again, the were using a Borg Warner unit (I think) with E85 and a dry sump. You'ld think that the dry sump would help, but i think they were still running full oil pressure to the CHRA. Anyone from Arizona care to comment?

-Kirk

[Travis Garrison]

Sorry, I guess I didn't describe that very well..

Maybe a bad sketch will help...

http://img127.echo.cx/img127/7553/oildrain5qb.th.jpg (http://img127.echo.cx/my.php?image=oildrain5qb.jpg)
http://img127.echo.cx/my.php?image=oildrain5do.jpg

...maybe not...

Its just an idea we were kicking around at WWU when we had the same problem....just a way to give the oil somewhere safe to go while you're driving...I think if you used a check valve you would want to vent the end of the hose to the plenum so you didn't end up with a gas pocket underneath the oil in the tube.

-Travis Garrison

[Denny Trimble]

Threehondas,
I don't think I have what you need, I have a 42t but it's already got an intricate pattern milled out of it to a large diameter.

I'll let you know if I come across something that will work.

[Matt Gignac]

Originally posted by threehondas:
Turbotwig,

If arizona wants a duel, its on! I guarantee they'd go down. (And I got more sheared gearbox teeth than them too)



But McGill's car from last year still probably would smoke you all out. I remember the announcers saying it looked like we blew the engine there was so much smoke. This year better oil flow control and some seal work should help the situation, so hopefully we won't give you a run for your money.

Matt Gignac
McGill Racing Team