I just had my 89 L-98 motor re-built and stroked to 383. The cam they put in is driving me nutz! I can't get a decent idle, the vacuum is very low, and I'm just not a happy camper. As I remember the cam has a .108 separation which I assume is why I have an idle problem. I want to change cams and get more performance but be able to tune the darn thing and drive it other than on the strip.
Here's what I have done so far. I would really appreciate some recommendations for a good performance cam.

383 cu. in. balanced 9.5.1 compression ratio
First Injection systems intake, plenum, fuel rails, runners, and throttle body.
Converted MAF sensor to MAP sensor and added new ECU with Dynamic EFI's EBL flash system for tuning.
Headman long tube headers -dual exhaust w/o cats.
1.6.1 Crane roller rockers
Corsa exhaust system
.308 gear
700R-4 trans beefed up w/ BM shift kit.
2500 stall converter.
added vacuum canister. (didn't help much!)
Nitto street radial.
stock aluminum heads. (I know better heads would help but $$$ is tight)
builder rates horsepower at crank at 375 hp.

the car runs fine as long as I don't have to sit at a light in gear, as it will stall.
The idle surges between 600 and 1200 rpm's at idle, which I believe is also related to the cam lobe separation.

My knowledge regarding cams is pretty limited. I have been looking at Comp's cams which list several choices for TPI systems with computers.

I'm looking for a solid low and mid range performance.

Thanks in advance for any advice!

Steve

 

Was the rebuild a turn-key job or did you get it get it built and do the removal and reinstall? If turn key why not take it back to the ship and have them diagnose the problem.

If not, are you sure it's the cam? You may have a vacuum leak or an idle setting issue.

Who selected / specified the cam? You or the rebuilder? If the rebuilder, make them responsible diagnosing and fixing the problem! If the cam is mismatch to the motor specs they should fix it!

If it's a 108 LSA then it's a little stout for the build you posted and you will have a lumpy idle.

Do you have the cam card? If not, get it and post it.

I did not see any info regarding a reprogrammed or custom chip. Was this done? If not, it should be to match the rebuild.

Just a couple of things to consider.

 

http://forums.corvetteforum.com/c4-t...right-cam.html

He has multiple threads on the same subject

 

Too much over-lap due to a combination of too tight LSA and duration. Go with 112 LSA and you'l be amazed at the positive improvement.

Oh, and you ABSOLUTELY NEED A ECM TUNE!!!

Jake

 

Sorry about the mutiple postings, but the first one didn't get any replies and went to page two. I thought I would try again. My Bad! Thanks to those who replied. any suggestions for lift and duration are still welcomed!

Steve

 

you gotta do what you gotta do.. just giving you a hard time