Forced Induction - Lq9/Lq4 safe limits for stock internals with a centrifugal supercharger




Spectre86
02-23-2009, 07:08 PM
Prett basic question. Whats a "safe" limit for the stock bottom end on a lq9 and lq4 engine? no spray. very mild cam, and a centrifugal supercharger. Not looking to run 15psi or make 900+hp.

Would 650rwhp be a safe "area" for it? I dont want to push it to the limit, but at the same time I dont want to have a ticking time bomb.

I see alot of people making 500-550rwhp on the stock ls1s. Iv read that the lq9 and lq4 rods and rod bolts are a lil bit stronger as well.

I know alot has to do with the tune, but assuming the tuner knows what he is doing.

Whats a comfortable whp level for a stock internal lq9 or lq4.


Jimmy P
02-23-2009, 10:47 PM
Most will say a safe level is around 550rwhp. Lots push it much farther than that, but they know the risk that they are taking.

Spectre86
02-24-2009, 12:17 AM
Most will say a safe level is around 550rwhp. Lots push it much farther than that, but they know the risk that they are taking.

hmmm so the lq9 isnt any stronger then the ls1?


hellbents10
02-24-2009, 06:21 AM
The Lq9 has stronger rods much like the ls2's and all the 05/06' newer engines (5.3,6l). Being that the rods will bend before anything breaks with a proper tune up and good fuel, I would say that the Lq9 is indeed stronger. 500whp is just the level they will tolerate with pump gas and a little detonation. Detonate at 600+whp and the pistons will blow to bits. Keep it from doing that and the rods bending/breaking has been the only limit I have personally seen. That and cam bolts backing out when shifting early under boost.

Spectre86
02-24-2009, 07:46 PM
The Lq9 has stronger rods much like the ls2's and all the 05/06' newer engines (5.3,6l). Being that the rods will bend before anything breaks with a proper tune up and good fuel, I would say that the Lq9 is indeed stronger. 500whp is just the level they will tolerate with pump gas and a little detonation. Detonate at 600+whp and the pistons will blow to bits. Keep it from doing that and the rods bending/breaking has been the only limit I have personally seen. That and cam bolts backing out when shifting early under boost.

sounds like you have a very good tuner:)