Since I am our engine development leader, and there has been very little said about engines so far on this board, I thought I'd start up a topic. I'm interested in what type of modifications other schools are doing to their engines, specifically those using 600cc sportbike engines. I'll happily share our list as it is right now:

-Custom 304SS exhaust manifold
-Aluminum/fiberglass intake manifold, restrictor
-EM TEC-II engine manangement system
-RC Injectors
-Adjustable cam sprockets
-Manual cam chain tensioner (we're using a GSX-R engine, and this is a weak point)
-Custom aluminum radiator

Its by no means a revolutionary engine design, but what we're going for is reliability, then performance. I'm not interested in big HP numbers at all, I just want a very driveable engine that won't let us down in detroit. (or after that)

What are you other guys up to as far as engines go?

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UVIC Formula SAE Team

http://www.engr.uvic.ca/~fsae

Lots of drawings but very little built here, as we'll start out by keeping the engine mostly stock, except for the exhaust, for our first tests. We're using a CBR600F2 engine and the carbs will stay on until we have time to switch to an EFI system, probably after suspension testing is completed (being a three-and-a-half person team, we just don't have the resources for serious parallel development )

Our restrictor will be CNC-machined aluminium with a sheet metal manifold, while the exhaust is made with 304 stainless- nothing too fancy. I mostly used some of my own codes as well as a general-purpose 2D flow solver for design purposes.

I briefly considered some head work but it's probably not worth the trouble; I know light port & polishing can have a significant effect on these engines but the restricted airflow would likely offset these gains.

dont port the heads. the gains to be had are more than likely going to be detrimental, usually the only gains on cbr 600 motors are from doing a clover leaf in the combustion chamber by welding in between the valves, and that is often attributed simply to higher compression ratios. If someone made power by basic porting (particularly one of the FSAE teams) id love to see their flowbench #s. They would have to use some bizarre cam to make power, especially considering the restrictor. Is anyone custom grinding cams?

we are the music makers and we are the dreamers of the dreams
--willy wonka

I'd agree that the ports are probably plenty big for the reduced velocity, and polishing would probably hurt atomization.

I built our past two headers from mild steel and had them coated. Any particular reason you went with Stainless vs. mild steel? I imagine it's be lighter but harder to properly weld and much more expensive.

-Charlie Ping
Auburn University FSAE 1999-present

As stated by many of the judges your engine will not win the competition. Reliability should be of more consideration than power.

A couple things to keep in mind is to reduce weight (reciprocating is huge) and keep power available. A lot of this deals with power transfer from the engine to the ground.

Something learned is that Titanium headers, while expensive, are light. We saved 8lbs when switching from mild steel. As the part is not structural a perfectly inert atmosphere is not required to weld them.


Ian Dawkins

Ian Dawkins
Michigan Tech
Engine Group

I looked into it with a mild interest last year. I could not find 1-3/8" titanium mandrel bends. I didn't spend days looking, but do you have a source? We've determined that 1-1/2" is not optimal.

-Charlie Ping
Auburn University FSAE 1999-present

Try burns stainless, at www.burnsstainless.com

-------------------------
UVIC Formula SAE Team

http://fsae.uvic.ca

Has anyone ever made significant gains by porting and polishing their head with the restrictor? We here at the U of S are seriously considering, but want to know if it's worth the time (2 or 3 weeks without a head), the money, or the effort. If anyone knows whether or not this is a feasible step to take, please give your $0.02, as it would be greatly appreciated. Thanks

Kevin Hall

quote:

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Originally posted by Richard Lewis:
Try burns stainless, at http://www.burnsstainless.com

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They do not list 1 3/8, do you know that they carry it?

-Charlie Ping
Auburn University FSAE 1999-present

Ooops no, I just thought you were looking for titanium mandrel bends in general.

-------------------------
UVIC Formula SAE Team

http://fsae.uvic.ca

I don't have any flow bench data yet but think of it this way. Additional air flow losses ANYWHERE on a restricted engine are massive because air is the limiting factor in performance. Otherwise we'd all be pumping out over 100 hp.

So you port your valves, get slightly better flow, that flow will translate DIRECTLY into engine power as opposed to an unrestricted bike engine that doesn't really care because it's got plenty of air to begin with so losses are less significant.

I figure it would be worth it if you've got a local shop to do it.

That's my $.02

Anybody calculated the engleman port inductance for the CBR F4i?.... wanna help a brother out.....

man just gonna get a "local shop" to port a head? You are in for a big surprise, if youre logic is that "well porting must be good becuase we already have a restrictor!" you are in for a big surprise

For what its worth, on a 1.8L honda gsr engine, we made 943 HP at the wheels with a STOCK STOCK STOCK port size and valve size. yeah there was no restrictor, yeah there was a turbo, but that head is intended to flow 140 hp at the wheels.

we are the music makers and we are the dreamers of the dreams
--willy wonka

Yeah, the last thing these bike heads need is port work. IMO, the only possible gain to be had in the head is cleaning up any flashing and possibly a little work around the valves.

The biggest gains in FSAE come from fine tuning your engine management system to make the car easier to drive.

We have decided against porting. We may investigate a three angle valve grind, as we have a spare head, and could get a set ground, and flow bench to see the difference. Dyno testing has been under way for a while now, and is proving to be the most useful tool anyone can use. Our idle has drastically improved, and the engine comes closer to being "drivable" every week. Thanks for all your help. Good luck.

http://www.engr.usask.ca/~sae/

quoting Ian Dawkins:
"your engine will not win the competition. Reliability should be of more consideration than power."

I'm sure you'll be saying that when Cornell laps you at the endurance with their 85+ horsepower engine.

FFGeoff...
Imagine how much power you would've got if you ported properly instead of wasting your time increasing turbo boost trying to force air through ports that were CLEARLY too small

Let her breathe baby............
let her breathe....

Look at skidpad G's that's where the speed is on a track. I do have to say Cornell has a good engine package but not because the peak power. Peak power that was generated on the chassis dyno was boosted hard and running rich, both bad for reliability and fuel economy (therefor not used in the endurance run).

The thing that is good about Cornell's engine package is a very wide drivable power curve. We are not professional drivers and we do make mistakes. Good bottom end torque allows for a lot less gear shifts (count up the number of shifts then multiply it by "shift times" and then factor in percentage of missed shifts and it will equal a ton of time over an endurance race) and will result into a more forgiving engine package.

Jeff

quote:

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Originally posted by FFgeoff:

For what its worth, on a 1.8L honda gsr engine, we made 943 HP at the wheels with a STOCK STOCK STOCK port size and valve size. yeah there was no restrictor, yeah there was a turbo, but that head is intended to flow 140 hp at the wheels.

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I wanna see some dyno run results. And that doesn't mean engine dyno, i want to see h.p. "at the wheels". What kind of chain could take that power, and how did you not shred your tires, let alone dyno a 900+hp bike in the first place? Again, none of these poser calculations to prove the power, I want dyno graphs!

quote:

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Originally posted by Displayname:
I wanna see some dyno run results. And that doesn't mean engine dyno, i want to see h.p. "at the wheels". What kind of chain could take that power, and how did you not shred your tires, let alone dyno a 900+hp bike in the first place? Again, none of these poser calculations to prove the power, I want dyno graphs!

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He's not talking about a bike engine, he's talking about the 1.8L Honda engine in the Integra GSR, the B18c. This is the popular engine of choice for many front engine/fwd dragsters, and the HP #s are semi-believable. So no chain involved, and they make plenty of tires that can handle those HP levels.

www.formularpi.com