LQ9 with TVS2300 safe limit?

[wormus]

Hi, back in April the engine in my 2006 Monaro (GTO) died. The forged LS1 couldn't take the torque, flexed and split. At the time it was was making about 820hp/900tq at the flywheel on 15psi boost from my TVS blower.

Since then all the internals have been swapped into a new LQ9 block with new, low comp pistons (9.5 CR), ARP studs etc for 402cid (4" stroke but standard bore).

My question is, how much stronger is the LQ9 block than the LS1 and what can it be pushed to reliably. Will it flex much less than the LS1?

[bluehawk2000]

Hi, back in April the engine in my 2006 Monaro (GTO) died. The forged LS1 couldn't take the torque, flexed and split. At the time it was was making about 820hp/900tq at the flywheel on 15psi boost from my TVS blower.

Since then all the internals have been swapped into a new LQ9 block with new, low comp pistons (9.5 CR), ARP studs etc for 402cid (4" stroke but standard bore).

My question is, how much stronger is the LQ9 block than the LS1 and what can it be pushed to reliably. Will it flex much less than the LS1?

Monaro huh that is freakin awsum always loved those cars, But a LQ9 block is iron, the ls1 is aluminum so you will be able to push a more substantial amount of boost to an iron block than you will an aluminum block.

I am no master mechanic but if its fully forged internal LQ9 block then it is pretty bulletproof from my understanding.

So I would say 15 psi would be a low boost setting, and on up to in the 20's is very easily achievable you dont have to worry about it breaking like the ls1 did.

[Frost]

It's time to get rid of that heat pump at >800hp.

I had a 2010 SS w/2300 blower get picked up today by the owner. [video [ame]http://www.youtube.com/watch?v=5metuXsWYMw[/ame] ] We left it strapped down to the dyno on Sunday to get a cold 'hero' pull out of the blower first thing in the AM. This is an over-built 427 (RHS 6-bolt block) at 15psi (rear cog drive) and a six-speed manual trans. We got the engine up to temp; IATs were showing 80degF. The first pull made 722 ft/lbs of tq from about 2K RPMs to almost 5K. It fell off up top making 707 rwhp. The IATs rose from 82degF to 158degF at the top of the pull, and that's only ONE GEAR on an unloaded DJ224. The second pull, it's soaked and it loses over 100HP (really) up top from the combination of heat and timing pulled for the heat. I've seen many stock cubed forged LS1's that make more that with a D1sc at just 15-16psi... I guess I am trying to say if you already made 800fwhp with that blower, I wouldn't think that there be much "meat left on the bone" blower-wise to be worried about making much more.

[squee]

I'd agree with frost. Not much left with that blower. I'd look into a better blower. I don't like the Prochargers though. The instant torque of a roots or twin screw can't be beat. You might want to look into the new Ken Bell. Supposed to be as badass as they come, and you should be able to make ALOT more power without having to worry about the heat soak so much.

[wormus]

Thanks for the info. Sorry if I wasn't clear, my goal is 700rwhp/700wtq which was very close on my LS1. Any more is a waste of time on the street IMHO and mine is going to be a daily driver.

Take a look at the dyno graph:


There was way too much torque which I think killed the block. I now have a lower compression ratio and my heads are 235cc intake runner volume which I hope will reduce the torque and lift top end.

Everyone says 1000hp from any alloy block is easy but I had no problem breaking mine, my question is will the LQ9 be as strong and reliable as I need it to be at my planned power level? I still worry about flex and the thickness of the cylinder walls.

[bluehawk2000]

700 pony's and tq, dude their is people that has twice that coming out of that block, you will be fine with what you are wanting to put down I am sure someone will agree with me on this one.

[wormus]

That's good to know, although I've also been told an LS1 one can make 1000hp no problem. Doesn't explain why mine broke though.

[gluon]

The LS1 has fairly thin sleeves, they have been known to crack even on stock engines. That is why the gen 4 engines (ls2 etc) moved to thicker siamese sleeves. Also, turbos are easier on the block/internals because the crank doesn't have to drive the supercharger, this could account for 100hp.

If i where you i would trust a LS2 to 1200hp, an LQ9 to 1500, and an LSX to 2500+. Overbores take away strength as well. Get a new LQ from GM for $800 or LSX for $2500.

[wormus]

Well she's running and just needs breaking in. I was surprised by what you said about the thermal efficiency of the TVS. I bought one because they are supposed to be over 70% which is about the same as any twin screw blower. Mine has never suffered from heat soak but I guess the weather is cooler in the UK.