FI : more gains with cams or with heads?
 

I've searched to no avail. even on ls1tech...

Most searches come up with head AND cam not heads OR cam.

I have a lq9 and my friend is giving my his Procharger d1sc for free! I just have to have it rebuilt.

My question is, will I see more gain more from just a FI cam and ls6 mani or with ported l92 heads and l76 manifold at 8-9 psi?

I understand the cost difference is significant.

If the cam route is better, I'll port the stock heads.

Thanks.

Too many variables to say honestly. However, I would go with the cam change. You're forcing air into the engine while under boost versus trying to suck it in running N/A. Changing how long the valves stay open to compliment the supercharger would be a better route in my mind. That and your stock heads are good to begin with. Porting them later is a solid and easy option that will only compliment the cam more.

I don't see the variables...you're basically increasing the airflow either through the heads and intake (since If I go L92, I have to go L76 mani) or through a cam through the stock Lq9 heads.

I guess one variable would be the spec of the cam. Let's say an aggressive FI cam that's streetable. It won't ever see the track as it will be a weekend cruiser.

Thanks

What are your horsepower goals? You can make a lot of power with a boosted motor with stock cam and heads.

I'd like to hit 550rwhp on 91 octane and will never see the track so I'll be on street tires.

That's an easy goal to hit. I'd go cam change with supporting mods like intercooler, headers, and full exhaust and then call it done. The cam will help give it good sound which I think is important to the overall goal/attitude of a good street cruiser. It will also help you target where you want the power to an extent as well.

For reference, a stock C5 Z06 with nothing more than headers and high flow cats into the stock Ti exhaust made 540 rwhp with Pro-Charger's Stage 2 system. The Stage 2 system utilized larger intercoolers, better air intake, and slightly higher psi than a "normal" C5 kit. Given the packaging restraints on a car like the C5, I see no reason you couldn't get good intercoolers and a clean free flowing air intake into the head unit itself on a classic car with an open engine bay. Your 317 heads are basically lower compression LS6 heads.

I talked with ECS about supercharging my ls2. They said 550 rwhp was very doable on a completely stock motor. If you have the cash I do a cam.

Thanks for this. As you can see I have PLENTY of room in the engine bay and in front of the radiator as well. My friend who is giving me the SC-1 also has a 4 core intercooler by Procharger but he was running 14 PSI...I probably can get away with a smaller unit since I'm limited to about 10 PSI with 91 and my compression ratio, not to mention unnecessary pressure loss. I've been around FI for a while but somewhat new to LSX's so I'm still learning the nuances of these engines :wacko: I think I'm also forgetting how large (though we get used to it) these engines are so FI on them is just nuts. Took me 13 psi from a Gt35R on a 3.2 to achieve 420rwhp on my old car...6psi on an ls2 is 600 to the engine:confused18:

Looks like I may not even need a cam after all. I'm going to get the SC1 running then decide if I want to do a cam but thanks for the info guys. Looks like cam over ported heads.

Do a cam/dual springs/pushrods and rebuild the rocker arms with the Comp Cams trunion kit.

Brian Tooley Racing can custom spec you a cam and provide all these parts.
Get your throttlebody ported as well. Great bang for the buck.

If you have e85 in your area or can do a meth injection kit... get it tuned that way. 91 octane pump gas is garbage and can vary on octane levels for boost.

A cam actually makes waaaay more sense than heads for my goal not to mention that the stock Lq9 doesn't rev to 7K which I realized. This will help with a centri.

I'll do a preliminary set up with about 8-9 intercooled psi with 91 and with cams then later do a water/meth injection later with a few more psi if I need the power.

There's a 69' Corvair with a stock lq9 bottom end, ls6 inatke and a cam making 617 to the wheels! Granted it's running a D1SC but I talked to tech at Procharger and he said at the boost level I want ( 8 - 12 ) I won't see much of a difference (just a bit more mid range) going from a P1SC to a D1SC so I found out I have no reason to spend $1500 for a upgrade!

here's the link below if anyone's interested. Doesn't say PSI level but I'm guessing below 11...

http://www.dragzine.com/features/car...air-of-chevys/

Well, that's always good news. Save money and still making your goals. Good luck!

both

Both Cnc heads and new cam..

i am very late to this party but if it is cam OR heads get the cam and do the springs.

The 317 heads work pretty good with FI.

google/youtube stock48 nova. A stock lq9 with a cam and a newer s476 turbo went 8.39@160+ in a Nova on pump e85 and a truck intake manifold.

He is pushing that motor hard but those numbers suggest he is pushing the 1000hp threshold.

So how much power did you want to make?

Wow thanks for the info. Had no idea the stock bottom end on the lq9 can handle that much power.

No upgraded rod bolts?

The tune must be incredible!