Tyzorg

Hello all,

let me start off by saying yes I did use the search. In fact, I've searched this issue and googled the crap out of this topic.

What I'm looking to find out is the maximum horsepower one would call 'reasonably safe' for a stock ls1 block. By stock I mean stock pistons, rods, bearings, all stock bottom end. Top end is stock 241's and I'm thinking of putting a tick turbo cam in there with springs, pushrods, head gasket and studs.

If it matters: I'm using a huron speed hot and cold side kit with a pt7675 turbo
I will be running this on 93 octane and will buy a meth kit if necessary (for the added safety blanket)

Please reply if you have hands-on experience with boosting a STOCK ls1 and know the limits of the internals and block. I mean to not be rude but please if you do not have experience and you are just going to repeat what you read on ls1tech or any other forum, then don't. I say this because there is SO much misinformation being spewed about this topic online.. I have seen anywhere from 500whp as a safe number to over 800.


Second question. What would be the limits of the BLOCK if one were to replace all internals with a forged assembly? I ask this because I want to compare the cost effectiveness of that vs a 5.3 swap.


For what its worth the block has 20k miles on it (just 13k on the clock 4 months ago)

Thanks for any and all replies!

VTC_WS6

iTrader: (9)

If you truly researched this like you say, then surely you must know that there is no singular number that exists as a "safe" power level aside from the stock output at which the engineers designed it to operate.

Nismo Kid

iTrader: (3)

I'd start by viewing these.

https://ls1tech.com/forums/forced-in...lity-list.html


https://ls1tech.com/forums/forced-in...end-lsx-s.html

gnx7

iTrader: (28)

those rods tend to bend at around 600-700rwhp..... Safe I'm thinking 550rwhp.... the 2004.5+ rods are much stronger. Those seem to take over 900rwhp before bending.

Taxman20

iTrader: (11)

^^^^^ What GNX7 said.

That's why I am putting Gen4 rods in my Gen3 block. Going for 1000rwhp. I know it may not live long but hey, hehehe.

oscs

iTrader: (19)

What's the block by itself good to?

IronBlocked

They've been 850 stock headbolts and cam, so I'd guess 600 is a safe number on a good fuel, all bench numbers of course lol

Tyzorg

Gnx7, Taxman20 and IronBlocked, Thank you!!!

Anyone know what power level splits the block? can this thing hold ~1k with forged assembly?

Nismo Kid

iTrader: (3)

https://ls1tech.com/forums/forced-in...-2004-ls1.html

6669camaro

iTrader: (1)

[QUOTE=Tyzorg;18962594]Gnx7, Taxman20 and IronBlocked, Thank you!!!

Anyone know what power level splits the block? can this thing hold ~1k with forged assembly?[/Q

I have a forged ls1 That's stroked to 383 That I will be using to replace my 5.3, I plan on putting 20psi of boost to it and Will be shooting for the 900 to 1000whp goal. Just getting ready to start swapping them out. Should be on the dyno in a couple of months. I believe several years ago Harlan was making over 1000whp with a nonfilled stock block and it was holding up.

LS6427

iTrader: (2)

Tyzorg,

According to Steve Darmijian who owns RED and developed the sleeves for LSx motors.......the LS1 block from 1997-1998 is actually the strongest, or the next strongest behind the LS2 block.

So you're off to a good start.

I wouldn't go over 600 RWHP with a bone stock LSx anything......

Stock crank is good to 1,000 RWHP plus. But you if you do a forged rotating assembly you can easily make 1,000 RWHP +

Re-sleeve it and go more.......

.

IronBlocked

I'd just buy a 500$ 4.8 to be honest, the alum block is way too nice to crack a sleeve

JoeNova

Record for the highest power stock LS1 is in the mid 800s to the wheels. We all agree that he is on borrowed time.

Gen 4 rods and pistons will take much more power. The LS1 block itself is questionable as far as power goes. Lots of mixed results. It seems the only safe aluminum block for big numbers without modifying the block at all is the 5.3 blocks.

ls1curt

iTrader: (31)

With a stock ls1 aluminum block (forged internals) I went 8.70s@160 at ~3350lb. Ran this setup for years with no issues.

coltboostin

As far as the stock LS1 goes, I have 4-5 pulls on the dyno over 870whp, and one Mexican run that lifted the head (this was at 22psi). Pistons still look great. I turned it down and will be running around 800whp for the foreseeable future. Many runs on the street and a few track days so far at this power level.

I cant comment on splitting the block, but I dont think you would have an issue with that on the stock bottom end. Real question-what is your goal? Is it a power goal or an ET goal? My set up was designed to come on late to keep the motor alive. If you make full boost much earlier, your torque spike will be harder on the motor and you stand a better chance at bending a rod. That being said-I think a fast spooling 600whp will last forever on a bone stock Ls1. If you are willing to take it to 7000 RPM and put a GT55 on it, I bet it would see close to 1000whp, but the set ups would not at all be comparable.

Its all relative.

LSX Power Tuning

iTrader: (4)

Splitting the block isnt the issue. Keeping the motor sealed and it not flexing is the issue. It will push water, get a head gasket or eat up bearings from everything moving around before the block breaks 9 out of 10 times. I have made a 1k plus on with a ls1 block but the harder we leaned on it the more it would push water and eventually got a head gasket. I would use another block before investing a lot of money into a ls1 block build.

BC178

Interested in the forged block limits as well. Have a built 347 hoping to reach 1k and 900+ whp.

Kmspeedie

iTrader: (1)

i boosted a bone stock ls1, only mod was dual valve springs, and i sprayed 100% meth. On 12lbs through an auto i made 565 wheel, and i would probably push 13-14lbs if i was feelin reckless, but for longevity i wasnt gunna push it past that power/boost level. Also used a 75mm turbo

BC178

Found 4 guys that are making 9xxwhp from a forged ls1, turbo, 6 speed. My setup is almost the same as a guy making 950whp from twins. Said he has ran the setup 3 years with no problems but a turbo rebuild.

Ls1curt you have any details on the setup?

denikena

I know it may not live long but hey, hehehe.