TimChiaretto

I am currently running a mild setup on my 97 Camaro A4 with an intercooled Vortech S-trim, 6 lbs of boost, 64cc AFR 190 heads and thin head gaskets. The cam is a very mild 212/224 @.050". It is nice BUT more is better. I don't want to go bigger on the cam as this is my daily driver (I know, it is too small etc, etc) so I have decided to go the cubic inches and blower pressure route.

Finally my questions
1. With that cam and 383" can it live with 12 lbs of boost if I go with JE 22cc dished pistons, 0.039" Felpro head gaskets. 0.00" deck and California 91 octane gas (my calculations show about a 9.3:1 compression ratio)?

2. Since the horsepower peak should be around 5000rpm, how forged should I go on the crank and rods or would cast work forever?

3. Will forged pistons create any false knock (ODBII system)? And the real crazy one - Would KB hypereutectics work at all?

Thanks for any help

rskrause

You didn't post the cam lift, but I am very happy with my 214/224 cam and the results speak for themselves. I bet others won't agree, but I would go lower on the CR with your crappy gas. Use the 31cc dish JE blower piston.

With an auto, the stock crank is probably ok. I'd worry about the rods though. Even with relatively low rpm, good forged "blower" pistons are quite heavy.

Lots of things can cause false knock. I couldn't find the source of mine and deactivated the knock sensor two years, 8,000 miles, and many runs at the track (using nitrous as well) ago. Just got the motor out last week for an upgrade/refresh and there is NO sign of detonation related damage. It's all in the combo and the tune, as far as I'm concerned.

Steer away from anything other than a forged, purpose designed "blower" piston for a high boost application.

Rich Krause

TimChiaretto

Thanks Rich. It is unusual on this forum to see someone else that likes using a small cam. Most of the advise seems to be "put a 306 in it and it will be so good". Lift on my cam is 0.520/0.536 with the 1.6 Comp rockers. Is your cam a Crane? I was looking at one like that but couldn't find a source to get it on a 114 degree lob center.

Those -31cc dishes would lower the compression to just about 8.5:1. Would that have any negative affects when I just put put around in daily traffic?

Does anyone know what effects lower the static compression has on emissions, just curious.

rskrause

I think your cam will work fine. It will be better than 9:1 or 9.5:1 with a big cam off boost. The dynamic CR (what really counts) will be higher than with a cam having lots of overlap. My current cam is a "custom" using Comp Cams XE lobes #3190/#3192 on a 114lsa with a 114icl.

Not sure about emissions, probably better with higher CR. But I'm pretty sure dynamic CR is what's important.

Rich Krause

TimChiaretto

Yes, now I remember your lobe profiles. Those are some good lift numbers, gives you the area of a bigger cam without the high duration. If I hadn't already bought my cam when I saw your profiles I probably would have copied you as my heads are setup for a lot more lift. Am I correct in reading your numbers that you don't have the common 4 degrees of advance built into the cam?

rskrause

Yes, it's ground straight up.

Rich Krause