1stz06

iTrader: (18)

I am posting this for a good friend of mine
J.R.
I had a 408 built several months ago that I was running some stg III LS6 heads (flowed 302 at 600), lunati cam 236/238 595/595 112 LSA, and TPIS 1 3/4 LT's with random tech highflow cats. The car only put down 462RWHP and 471RWTQ which kinda pissed me off.

So I saved a few dollars and purchased some AFR 205 with a stage 1 port job (flowed 329 at .600), kook 1 7/8 headers with off road x-pipe (no cats), and a cam that the engine builder suggested (comp cam 242/250 645/646 112LSA). The end results were still very disatisfying..........504RWHP and 478RWTQ.

There has to be a better cam to run with these heads that will give me similar results without the car being so lazy for street use. I don't drive this car everyday but I want to be able to enjoy it on the street AND be able to run in the 10's on the track.

I would really like to hear some other combos that you are running because this cam is WAY too big and I think I could pick up some more HP and a lot more tq with a different cam.

I really need some help here.

beardWS6

iTrader: (1)

Is it a A4 or 6sp? Also, what do you mean lazy for the street? That is a pretty big cam for street use. What intake,TB and size,MAF, etc do you have? Do you have all the bolt-ons, pulley etc? Alot of little things add to big power.

SSilverSSurfer

iTrader: (8)

if its an auto then thats some good numbers, also might be the tuner

1stz06

iTrader: (18)

Sorry about that. Here is the set-up:
97 C5 with 6sp
Fast 90/90
ASP underdrive pulley
stock MAF but I did a home port job a couple years ago on it
It has all the stuff that is needed to make big power. I have to get it above 2500rpm to get it movin. I understand that but I want comparable power and still have good street manners. It doesn't seem like this head and cam combo are working well together.

Any suggestions??

slow trap

iTrader: (22)

those numbers seem alittle low but not very out of range.do you know what is your cr ?with the right cr i would expect 525-530 rw with that setup.

SSilverSSurfer

iTrader: (8)

who built the motor

11SECDWS6

iTrader: (3)

Those are not bad numbers, really. I would have chosen the 225s over the 205s w/ a 408, but those still should make good power. What exactly where you expecting? Also, what compression are you running?

I would think you could get a '10' with over 500 rwhp. The only way to find out is take it to the track...

1stz06

iTrader: (18)

We were expecting 525RWHP and 485RWTQ or so. The motor was built by LME in Houston. I do agree that these numbers are not bad in 96* weather but with this radical of a cam I was a little disappointed. I want to go with something a little more mild and pick up some tq down low and sacrifice a little HP's. What cam would be a good choice for this??

As far as compression....good question. The AFR's have not been milled, we are running flat top pistons, and GMPP head gaskets.

Thank you guys for your help!

JakeFusion

iTrader: (7)

That cam isn't radical. On a 112+2 it's perfect for your motor (don't know how much advance, but I'd recommend that). Near perfect VEs with a good IVC point (for a 6300 RPM Peak), equal IVO and EVC (to carry the power past peak), and an EVO that's not too late (for good midrange).

AFR 205s out of the box would have provided the power at the bottom of the curve that you are seeking. A good SD Tune will help with any drivability concerns. High compression would yield the best overall powerband and help with any laziness you feel on the street--also you need to watch the quench distance (which may be okay around .044", but closer to .030" would be better and would help increase compression and power while reducing any detonation).

Honestly, I think the heads being hogged out are what's hurting you. The AFR 205s and 225s do so well stock that all the results I've seen of aftermarket ported versions have been terrible, imo. Also, the AFR heads like it to be lean 13.6:1 A/F with some upper 20s timing, and lots of compression (out of the box versions). I can't speak for your heads as I don't know who ported them. Having a velocity ported FAST LSX 90 will help pick up a good 5-8HP as well uptop and a good 15-20HP down low.

Edit: I see they are unmilled heads with flat top pistons which is probably around 11:8:1 CR. High enough that you should see good power. I'd still try to run Cometics at .040" though.