Boost capabilities.

[71LS5Formula]

I've got a 6.0 LQ4 short block with L92 heads. How much boost can this combo reliably handle? 9? 10? Thanks.

[andrewb70]

I've got a 6.0 LQ4 short block with L92 heads. How much boost can this combo reliably handle? 9? 10? Thanks.

For how long is really the right question. Guys on LS1tech seem to run pretty high boost levels on stock engines, but they are drag racing or doing the occasional street pull. If you plan on using this engine for any sort of sustained time in boost, I would keep it under 8. There are a lot of variables of course, but that should be safe. If you have the engine apart, you might want to open the ring gap a little. This will keep the ring ends from butting together when they are very hot, which will pop a piston crown.

Andrew

[71LS5Formula]

Sorry. Guess I should've mentioned. It's pretty much just a street car. Probably won't ever see a race track. Thanks for the info andrewb70.

[Trevor @ Texas Speed]

Being a street car, the engine can handle quite a bit of boost. As Andrew mentioned, it will certainly vary according to intended use. You'll find quite a few guys running 15 psi (sometimes more) on their stock short-block engine, but your room for error is zero. Any little bit of detonation will shatter the stock, hypereutectic piston pretty quick. As Andrew also mentioned, it wouldn't hurt to open up the ring gaps a bit for boost. Some of the factory GM ring caps on non-supercharged engines can be pretty tight. If you're just looking at 7-8 psi, it won't be a big deal. If you're looking to run 10+ psi, I'd definitely recommend opening up the ring gaps. While it's apart, it also wouldn't hurt to throw a set of ARP rod bolts in it. Pretty cheap insurance for $80. Top it off with a set of GM LS9 head gaskets and a set of ARP head bolts or head studs, and you'll be good to go!

Give us a call if we can help you out with your build. We keep all of the parts mentioned above in stock, as well as the complete line of bolts, gaskets, etc. needed to complete your build. We can help you out with cam selection (if you're looking to change it) that will work well with your boosted application, as well as the other valvetrain upgrades. If you're looking at a larger cam, I'd recommend a Comp Cams trunion upgrade kit for the rocker arms, too. Again, cheap insurance against not finding needle bearings in your oil pan during an oil change!



Trevor

[WallaceMFG]

Anytime somebody mentions boosting an LS motor, this is what I think of hahaha

http://www.hotrod.com/how-to/engine/...g-bang-theory/

[71LS5Formula]

That is awesome. A 4.8 making 1200hp on a stock bottom end.