LS1 Block reliability
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Joined: Sep 2020
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From: Fourways
LS1 Block reliability Hey there Guys
I have searched through the threads and can't seem to find anywhere about the amount of Boost and horsepower an LS1 block can handle.
Before someone says it, I'm from South Africa and we can't get Iron Blocks (would love to use LQ4 or LQ9) without importing from USA (crazy expensive). So I unfortunately can only use the LS1 aluminium block.
I have upgraded all the internals. Forged Crank (4 inch stroke), connecting rods and Pistons. BTR Stage 2 twin turbo Cam with new springs, Lifters, Trunion upgrade and pushrods. Going with a Holley Lo Ram LS modular intake. I've read these aren't good unless your running the car above 6000 RPM. Is the performance loss really that substantial? I like the intake alot for the look and strength of it.
This car will be a daily driven street car aiming to make 800 wheel horsepower, with the option to up the boost when I want a little more excitement.
My main question is, how much boost can I safely run on the LS1 block. It seems to now be my weakest factor? I've spent alot of time and money on the internals and turbo upgrades and don't want it all being blown up. This is my first engine and car build.
I have searched through the threads and can't seem to find anywhere about the amount of Boost and horsepower an LS1 block can handle.
Before someone says it, I'm from South Africa and we can't get Iron Blocks (would love to use LQ4 or LQ9) without importing from USA (crazy expensive). So I unfortunately can only use the LS1 aluminium block.
I have upgraded all the internals. Forged Crank (4 inch stroke), connecting rods and Pistons. BTR Stage 2 twin turbo Cam with new springs, Lifters, Trunion upgrade and pushrods. Going with a Holley Lo Ram LS modular intake. I've read these aren't good unless your running the car above 6000 RPM. Is the performance loss really that substantial? I like the intake alot for the look and strength of it.
This car will be a daily driven street car aiming to make 800 wheel horsepower, with the option to up the boost when I want a little more excitement.
My main question is, how much boost can I safely run on the LS1 block. It seems to now be my weakest factor? I've spent alot of time and money on the internals and turbo upgrades and don't want it all being blown up. This is my first engine and car build.
I have put 12 lbs to my 2001 with it only pushing water. Once or twice overboosted to around 15 and it survived. It's all stock except for valve springs. Anyway, I'd say keep it around 12 and that should be safe.
Not a forced induction owner but with good gas, good tuning I think a good 1999 and up LS1 block will live at 700whp for a while. I don't know beyond 700whp. Maybe others will have more insight. No experience with the 97-98 blocks but they are different and IMO slightly more fragile. My opinion is based on these experiences:
1) A friend pushed his Prochargered 2002 SS with a stock bottom end LS1 to ~680 whp for a while...the LS1 block was OK...the stock rings eventually gave up.
2) The take out LS1 I used for my NA 383 LS1 stroker was in a shop race car that had forced induction. The LS1 block survived in good condition and we used it for stroker. My understanding is it was pushing ~700 whp for a while. It wasted the stock rings and a couple of pistons.
I also think a 4 inch stroke 383 LS1 under boost will likely be more fragile than a stock stroke LS1. I may not say the following in exactly the correct technical jargon but I think it covers the basic issue.
To get correct piston taper, and this is critical to avoid piston rock at bottom & avoid an oil burner, for a 4 inch stroker LS1 the ring package has to shift upward. The piston is already shorter due to the stroker application so the area for the ring package is fairly small and compressed.
The result is the piston crown thickness ends up so it isn't that well suited for forced induction. With the stock stroke one a pick a better piston with a thick crown for forced induction.
1) A friend pushed his Prochargered 2002 SS with a stock bottom end LS1 to ~680 whp for a while...the LS1 block was OK...the stock rings eventually gave up.
2) The take out LS1 I used for my NA 383 LS1 stroker was in a shop race car that had forced induction. The LS1 block survived in good condition and we used it for stroker. My understanding is it was pushing ~700 whp for a while. It wasted the stock rings and a couple of pistons.
I also think a 4 inch stroke 383 LS1 under boost will likely be more fragile than a stock stroke LS1. I may not say the following in exactly the correct technical jargon but I think it covers the basic issue.
To get correct piston taper, and this is critical to avoid piston rock at bottom & avoid an oil burner, for a 4 inch stroker LS1 the ring package has to shift upward. The piston is already shorter due to the stroker application so the area for the ring package is fairly small and compressed.
The result is the piston crown thickness ends up so it isn't that well suited for forced induction. With the stock stroke one a pick a better piston with a thick crown for forced induction.
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Thread Starter
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Joined: Sep 2020
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From: Fourways
Thank you all for your messages. Really helpful stuff alot of mixed experiences. I think due to the lack of availability of iron blocks. I am going to run the car with aluminium block and see how long it lasts. If the cylinder walls crack at least I can just transplant all the internals to a new block. Won't be a total loss. I pray
Thanks all.
Thanks all.
TECH Apprentice
Joined: Jul 2012
Posts: 341
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From: UK
Might be a silly question butttt, when you all say ran at say 10psi, do you mean at the intake or pressure at compressor? I mean there may be 2 to 3 psi difference? Depending on intercooler drop etc etc....or shall i keep quiet.....
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TECH Fanatic
Joined: Dec 2019
Posts: 1,129
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Yeah, but either way you should be taking your boost readings from the map sensor, not the boost controller.
I agree but I don't think that was the intent of his post. He was just trying to understand does 10 psi max (which it isnt) mean 10 psi from the turbo or what the motor actually sees. They're different power limits. It's all inference from his post anyhow lol.
TECH Apprentice
Joined: Jul 2012
Posts: 341
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From: UK
Hi, that is what i meant. And on a stock bottom end 3psi with these i guess is quite a difference. I just dont want to go too high with mine and making sure of things as never done turbo before as you all can tell...i will be referencing the compressor pre intercooler for the wastegstes first...start low and see what psi i get in manifold...