Thread: C3 cams on a 10:1 motor

yeah, Thor thats what you wanted to hear. huh?

Guys me and Thor have a long standing fued. DE vs VE. we are very good frends but quite competitive non the less.

Just curious was that a 14.0 with street tires?

yo, romes... i think you should consider using the gti-r de head if your going n/a high comp build... turbofreak did a 13:1 build back in the day with some custom cams and easily made 200whp with little tuning.

I think it would be best you grab one of those heads, port&polish it (sherwood), 87mm 11:1 pistons with valve reliefs, custom intake and exhaust (i can help you build both of those) and get cam regrinds of the stock gtir cam to some custom spec (youd need a guru like bigtoe/chuck to recommend stn), some standalone management (horatio brown tune) and I think you should get what your looking for, and i dont think itll be too expensive (and daily capbable)... what u think?

I opted for a set of c2 cams in my daily driven car. I find the lumpy idle addictive, power below 3700rpm near to stock, power with AC on almost non existant (it causes my car to stall and extremely laggy off the line). This is in a AUDM 9.5:1 sr20de with x-force extractors (now has SSACs), pod filter, tunable ecu, Supertech double valve springs and Supertech Ti retainers.

Driving around town my car is quite usable, and once it hits 3700-3800 rpm, it really opens up. Hit me up via pm for some links to videos of driving etc...

I'd also encourage you to take what alot of people have said up here with a grain of salt and probably give a little more weight to the comments of people whom have actually had a set of c3s in their car (or in my case, cams with a close profile... well almost! ). Failing that, you could always put in the c3s, see how they go for daily driving. If they're no good, buy some c2s and sell off the c3s for a neglible "R&D" loss.


Well if your using a stock tune, of course you're going to see a power loss with C3s. The cam profile is far too different/radical from stock cams, and you're quite possibly going to cause some damage to your engine running without (if I recall, the stock tune runs the cams quite lean). Try getting a tune, and see the world of wonder that is opened up.

bgh

I had these same sort of questions when I bought my car from Dave Coleman. He drove it with the C2's and so did his GF around slow-mo Irvine CA traffic, the A/C is fully functional, etc. But he did have two "preset" tunes for the C2's, the best I can describe them as tune 1 is better for midrange and not as aggressive, tune 2 is max top end power. So obviously it worked for him on the USDM 9.8:1 motor.

DC said the idle was lumpy, but not at all in a bad way with the C2's. I still have the same "switchable" ECU in the car, running a JWT enhanced "stock motor" tune probably a lot like the POP (a guess, since it was custom, IDK). I guess I will find out, probably this Winter after I get the car through damn CT emissions testing "as is" - because NFW I expect it to pass with the bigger cams, it's borderline stock (fails on NOx and at the margin for HC). It seems I keep destroying cats with extended track use, probably because it runs a little rich up top and tends to light off some unburned HC's in the cat. AFR is around 12.0-12.2 6000-7500+ rpm.

My opinion aside, why would you go against the collective advice of Jim Wolf and Clark Steppler and do something they really don't recommend for the street? They're obviously not conservative, or they would not even call the C2's "streetable", but they do - with the right tune. It's obvious you can tune for a wider range sacrificing some upper end, OR tune to their strength, which is top end power. Not both. And most likely, the lower tune sucks for making more power, but may be marginally more drivable about town. Otherwise I doubt I would have this elaborate JWT 3-setting daughter board ECU in my car.

Check out the Green curve for typical I/H/E and stock ECU - sorry the quality isn't better. One chart they do not show here is stock cams and JWT tune with I/H/E etc. on a 10:1 which is what I run now. The second pic links to that. Note performance above 5500 is better than stock ECU considerably just in the flat curve from 6200 to redline at peak stock cam whp. Note that the C3 cams tested here are not on my car. But IIRC, this resting was done at JWT using their equipment and dyno.





The C2's are proven with a streetable tune, but look at their low end torque hit - not pretty. Personally I don't care because I would only want the power above 4k, I never spend any time below that when I am concerned about going faster. Also note that blue line is with tune, not without, but surprisingly the green C3 line w/o JWT tune, i.e. stock ECU is not as bad as you'd expect, something I can't explain.

Either one bears out that from 3800-4000 rpm with stock tune or not, that's where you'd expect to see some benefit, and below that, not so good.

But both sort of defy "conventional wisdom" and I tend to agree if you haven't tried it with your motor, YMMV...

My dyno graph. Please note that dynos over here read a little lower and direct comparisons of numbers is pretty useless. It's more to show you the curve etc.

Has any smoothing been applied to the curve?

I realize direct comparisons of numbers are meaningless to a point - but am I not converting correctly 110 kW = 148 whp? I have not seen 196 ft-lb of torque out of a DE in any NA configuration, is this being measured comparable to how we rarely see more than 140-160 ft-lbs at most. Sorry if I missed it, was the engine stroked or overbore, or just tuned for maximizing midrange torque? If seems hard to reconcile any dyno having a spread of +60 ft-lbs of torque as attributable to different dyno, different conditions. That would be ~40-50% which would have to be attributable to dyno to dyno variation unless it's measured somehow differently.


Thanks in advance. Curve looks great.