Good cam for "i" engine Track/ Autocross car

[klrskies]

What works well?

[Dave]

The stock one . . .

[EtaSport]

The stock one . . .

I second. Depending on what type of track you are on, its unlikely you'll find something with a better low end torque curve and high end power.

[klrskies]

Any modifications to the rest of the valve train?

[formula driver]

Any modifications to the rest of the valve train?

A good rebuild with proper valve clearence will go a long way.

[klrskies]

Etasport,

tell me about your "frankenstein"

[rwh11385]

What works well?

Since a cam would put you in SM in SCCA (and Hoosier BMW only rarely if ever has an Auto-X), I would say stock.

And if you're bored with your car, a 284/274 cam would be more fun at the track. But everyone here knows my stance on these kinds of things. i.e. if you are in A group or instructing, fine. But people still learning or hell, just starting to, need not be upgrading their cars.

[klrskies]

Due to suspension mods it's already disqualified from stock. I'm just racing for my own best time.

[nando]

if you were talking purely street, I'd reccomend the 284/272. it will idle fine, I didn't really notice much of a torque loss below 3500rpm, and oh boy it's fun above 4k! but since you are racing you have to consider classes as heeter stated.. and you don't want to be putting cams into an M20 that will gain you 10-15hp (if you do a lot of other work to the motor) when it bumps you into another class where people will have WAY more power than you'll ever hope to gain.

[rwh11385]

Due to suspension mods it's already disqualified from stock. I'm just racing for my own best time.

you do know there are other categories than just stock and street modified.... right?



he's still not in SM and can't imagine you have more suspension mods than him...

[klrskies]

Ground control coil overs and Koni's so far. It's a play car as well, not exclusively intended for autocross... engine will be modded as well.

[rwh11385]

join the club. GC's are legal for STS/STX/DSP, etc etc

Cams, stroking, engine swaps, and turbos are what will net you a jump in class. Headers, honed manifold, big bore TB, MAF conversion, exhaust, chip, injectors are legal in DSP. basically it is external to the head = fair game

cams won't even do that much for an e30. it's not worth it really. maybe 5hp and mostly just moving the powerband. fyi, final gear changes are legal in DSP which will more worthwhile than opening up the head, IMO

[klrskies]

As this is an all-round play car, I'd like to build a 2.8~2.9 displacement out of a stock e36's cast 2.8 crank, 130 mm rods, M20 "i" pistons or larger 85~86 mm pistons, and cammed & ported "i" head. M30 air valve, 2.5-3.0 exhaust w/o cat. Looking for an honest 210-220 Crankshaft HP. Don't want to turn more than 6,800 RPM either.

I think I need a cam change to get a modded motor to breathe well on the top end with the larger displacement. I don't want to kill the bottom end with a radical cam so probably something 280 degrees or less without extreme overlap is what I'm thinking. Emissions aren't an issue either.

[EtaSport]

My engine is an eta with a built top end. I ran a 274 cam which had a very linear power delivery. Now I've got a stock I cam and it works well for my city driving, and has a larger pull above 3k than my crappy 274. Of course I went with a regrind, and I know you'll have better results with a schrick or something like that.

[bimmer8604]

i ran a schrick 272(untill it broke) now I have an IE Reground 272. eh, i dont really care, and with the schrick the dyno results didnt really prove anything. The cam did come free with the car as it was allready installed, so it was just an added bonus. my SCCA didnt even care i had the cam and let me run in STX.

If your going full out and building a motor with new shit and stuff like that, go ahead and put in a cam. ive heard a lot of good things going with a 282 as its still pretty smooth. I think others have said that 292 is too much.

Kyle