Thread: C3 cams on a 10:1 motor

SSAC header with 2.5" collector and a 2.5" exhaust absolutely do not match well with C3 cams. Same thing goes for the over size valves. Over size valves and C3 cams really need a better header and 3" exhaust.

I'll call them for you then.

-The header will hold you back in the top end. If you are doing that much work, I would go 12.5. Maybe look into a custom DE intake manifold that works will with a N/A setup as well.

The JWT techs were all busy so I left my name and number and they are going to call me back.

but Reece remember I only want about 200whp. Dont you think the list is enuf to give me that with out a 12.5:1 CR or a custom intake manny

plus I cant run that high a CR as the gas we get here is real crap its E10 -10% Ethanol and the octane level is about 89

Ben, the reason for the 2.5'' exhaust is because the exhaust will be ran fairly straight, right to the back of the car with just 2 45 degree mandrel bends angling it from the middle of the car to the muffler. this is also in an attempt to keep the torque up.

the ASP header is kinda expensive and is hard to ship here because of how combersome it is. I have the SSAC already so I was just gonna work with it.

should I run the SSAC with a 3 inch exhaust instead
or
should I definitely get a ASP header even though it is gona prove really expensive as our duties here are like 50% of the cost of the item.

oh also, and I already have the 2 X 2.5'' 45 degree pieces of mandrel bent piping.

That's a myth. You won't lose anything going bigger.

If you are married to the SACC header because of cost reasons (which I completely understand) then yes, at least do a 3" exhaust.


As for your power goals... Let me take a real good look at your proposed mods.

You plan on a 92mm bore and 11.0:1 compression pistons? But you're only concerned about the C3 cams working with the stock 10:1 pistons right? Because the 92mm pistons you can have valve reliefs cut into them, correct?


I don't see why you couldn't break 200 WHP with your proposed modifications. Obviously people might question your sanity (not going with a VE) but that's for them to do.

yes the 92mm pistons will have valve reliefs as high CR, large bore pistons dont go well if they are flat, with big cams and oversized valves. they dont go well at all without valve reliefs. I plan to get the pistons custom made from CP, but right now, I have got 10:1 and they have no valve reliefs. so Iam wondering.

naw I wana do it with a VE. i need to prove a point to some VE guys here, that the DE is still in the game. also we have never seen a build like this or a DE with 200whp here. I like travelling the path less travelled. the next project will be a VE in a Primera/G20 P11 and when I am building that. i will be looking to net about 230whp with just bolt ons.

Why not just VE with boltons? Easier, faster, cheaper.

exactly. You are wasting a TON of money. It looks like a cut and paste wishlist.

Dave C pulled a very conservative 161 whp (+37 whp peak at 7300 rpm) on my car with 91 octane, 20 degs timing, C2's, JWT ECU custom tune and Ti retainers with just bolt-ons and smaller hotshot header (than the SSAC), USDM 9:8 CR (?) OEM motor, pulleys, small intake (well under 3"). C3's are 0.526 vs. 0.500 and 285 deg vs. 275, they're not going to be radically different than the C2's, just incrementally (possibly with many IF's) a little more. When he did those tests the car wasn't even running particularly well, had some ignition gremlins. The motor had over 105k on it when he ran those tests, too.

I hit low 140's whp with pretty much the same bolt-on's, larger intake and a stock internals 10:1 with stock cams, and the JWT tune for the I/H/E mild mod USDM motor that came new with the car. That was hampered by apparently running a little rich up top, possibly due to about half a tank of race gas left in the car.. I haven't tested out the C2 profiles and still am sitting on a pair of cams w/o springs.

Sure I can see adding the C2's to the 10:1 if only because I'm confident with the larger header and intake, 10:1 vs. USDM motor, etc. I should see more power to the wheels but honestly anything above ~170 whp would be really a surprise. 180 whp would be a gift or more likely serious dyno error. I'd never use this approach as a basis for a 200 whp NA motor, mostly because even with that fine list of mods I'd expect to fail.

That said, my car with the 10:1 compared to the VE before the cam kicks in with my current mods won't be any slower out on the track, and with some good tuning and the C2's I'd be giving up 10-20 whp on average compared to a lot of VE's I have seen. And that's probably mostly from 5500-6500 rpm. At 7000+ rpm I'd make 90% of the whp of a VE, and on the track I spend an awful lot of time up there, for very long periods of time w/o reliability issues.

Super responsive setup already with lower hp, I can't see putting a ton of mods into the internals other than dropping in my C2 cams. Beyond that, I would want to do up a very special nice VE, which would cost a hell of a lot less or at least deliver a lot more for my $$$. Beyond that, FI. Building a screaming NA motor starting with a stock lower end, no question I'd go with a VE. Things like 11:1+ CR bring their own special challenges, above all, whatever I use has to be dead reliable.

But dropping all that on a basic 10:1, you are out almost $900 easily on C3 cams and springs alone, less if you have a line on C2's which are more plentiful. I'll probably end up doing the cams first since I have been batting this back and forth for almost 2 years, or just get a VE for my SCC car and put its motor into my 2nd B13 which sorely needs replacement.

Ultimate NA builds are ultimately expensive, I would want to end up with a 10-12k redline motor and 240+ chp like my Dad's old Cosworth BDA/Ford Formula Atlantic motors, which managed that in the 1970's w/o fuel injection or real EM. Otherwise it would be a disappointment to me.