I'm have issues again with my vette.I think my compression is too low. After motor was installed the compression was too high ( built to stock LS7 compression). the installer felt it was too high so lowered boost and used a .120 head gasket.It runs rough ect. Here is what that guy that tuned the car told me.
"Typically you wouldn't have any drive ability issues with and cam that size. There is something about you setup that makes it not want to burn good with a lean mixture. I can only guess that it has to do with the head gasket / quench situation as I see they same problem on late 90's low compression big blocks in the trucks.

You can should want to drive down the road at 14.7:1 afr (stoich). At that afr you car wants to surge and not run lean, especially with a little more than flat ground load. When your at 13.5 afr your car happies up and runs smooth. The problem is as soon as your car goes into closed loop and utilizes the stock o2's, the afr automatically goes back to 14.7.

Since the car does ok at 14.7 under some conditions I left the o2's on. To combat the load induced breakup and fight the throttle tip pop I set the tps value very low to let the car go into power enrich mode early and give it extra fuel.

I have a plan but I don't know how good it is. Right now I'm just going to leave it alone, because of winter coming.Plus I do not drive it much.

1. First change out the head gaskets to some thinner ones. Maybe .08 or .09 to get some quench back. I think that the motor is running like 9.2 - 9.4 compression right now. That would be .04 -.030 decrease. I read somewhere stock were .051-.053. Do you think this would be ok?

2. I know why the motor was valve floating, because the springs only go to .650 lift. I called Texas Speed and performance to conform this. The cam is bigger because of the LS7 1.8 rocker arms. I figured out to be somewhere in the .660 range.While I have heads off change valve springs to Precision Race Component .700" Lift Spring Kit.I don't like the cam that is in it so change it also to one of these cams
215/247 .629/.656 121 CL With 1.7 rockers

224/248 117 .625 - LS7 With 1.8 rockers


232/256 114 .660 - LS7 With 1.8 rockers

Which one looks the best? I like the first one.

3.Keep boost the same.

4. LSx ported fast intake

Then after all this have it re tune. Are the intakes worth it? Do you think its a good plan or not?

 

Pull the 1.8 off the car. some guys have had problem with using them. May cost you now but better safe than more money down the road.

 

1-Find a new tuner that knows how to tune LS cars very well.
2-Put stock LS9 MLS head gaskets on it and ARP studs.
3-Add Alky Control Meth kit to cover the higher compression from thinner HG's.
4-Cam something like 232/246 .630/.630(calculated for current rockers) 118 LSA.
5-Don't spend money on ported Fast, put that $$$ toward Meth kit instead.
6-Find a new tuner that knows how to tune LS cars very well.
7-Get some M/T Drag radials and enjoy that beast.

 

Forgot to add I have Alky control meth kit and M/H drag radials. The motor was built by texas speed and performance so its a forged motor and has ARP studs, Eagle crank, rods,ect. Going back to 11.4 compression will be ok? Cool!

 

I would fix the springs and change the rockers and see how it runs then.

 

Only if you can find a very well known boosted-LS tuner. Also, I wouldn't shoot for 1000rwhp with that much compression, but run straight meth with a really good tune and you can make more than the DRs can hold and be happy.

 

How thick are the LS9 head gaskets? They are 4 layered right?

 

Let me know if you go with the first cam, I think that is the new LPE cam. I would like to find someone running that cam. Good luck.

 

7 layers ~.053" thick