LS3 HP Potential

[whipitVR74]

Anybody suggest what sort of HP I can get out of an LS3 with FI (turbo/blower) before I have to open it up and get it built?

Have bought an LS3 crate, just trying to get my head around what its capable of once its in...

[dijm8]

your probably looking around 400+ rwkw really cant get an exact figure all depends what you get without FI your looking around mid 300's

[Vt_vic]

i have seen some ls3 supercharged that are around 600rwhp

[Darcon666]

A stock engine is anything between 220-240rwkw, depending on the tolerances and how the motor has been treated/run in/thrashed when new.

I have seen with just bolt ons & tune >250-275rwkw... Add FI(turbo) as said >420rwkw depending on boost, (Supercharger) from 395rwkw, again depending on boost as the stock cam image is not that good for supercharging I have been told.

FI on the other hand WILL shorten the life of the aluminium motor and many don't go this way if you're wanting serious power(Chasing numbers/rwkw) with an LS1/2/3...they get a LSx or LQ9 iron block and got from there.

Personall I LOVE blowers or what I am doing to my recently purchased GM L92/3 Engine Block... a stroked & cammed N/A motor.

[whipitVR74]

Thank you.

[SirNemesis]

FI on the other hand WILL shorten the life of the aluminium motor and many don't go this way if you're wanting serious power(Chasing numbers/rwkw) with an LS1/2/3...they get a LSx or LQ9 iron block and got from there.

I would like to hear more on this theory. I cannot see how FI specifically (tuned correct) will have any effect on engine life depending on what material the block is made out of.

[GRPABT1]

Jakstas sees 400rwkw exactly out of his LS3 crate motor with stock pistons and big cam on 100 shot of nitrous and a good tune (auto+big stallie). Any more gas than that requires better pistons. I would say (depending on the form of FI) that would be close to the limit give or take a bit before requiring forged pistons at least. Some forms of FI are easier on the motor than others with nitrous being one of the harshest.

[whipitVR74]

Thanks, so its seeming that 400 rwkw is about it for the engine as is. My engine is brand new, I am in the process of pulling out the 5L and then doing a trial fit before the car goes off for paint.

Any thoughts on the benefit of getting some internal mods done (e.g. pistons, valve springs?) while the car is painted and while the engine is brand new Or would I maybe be better off driving it stock for a while to bed everything in before pulling it out and doing the modifications?

My end goal is a genuine 500 rwkw, I am thinking of a twin turbo set up, no nitrous, tricked turbo 400.

I have heard a rumour of someone doing a 9" centre assembly for a VR/VS independant rear, anyone know if that's true and who does it?

[SirNemesis]

If you are aiming for serious power you may aswell pull it down now and put some decent forged pistons in it. They will be your limiting factor. You will need to do valve springs for boost, but you can do that at any time.

[dijm8]

do what your budget will allow.. you wanna do it once and once only, and if the engine is out now you might aswell do it, cause it will save you money down the track ripping it all out again

if you cant afford it..push it back a few weeks to get the money, plenty of time m8

[GRPABT1]

Jakstas motor has arp rod and main bolts/studs too. But as mentioned you may aswell do it all and chuck some pistons in. Eagle auto parts interestingly sell a 376 cube GMPP LSX motor with low comp forties and LS3 heads for under $8000 now. Bargain I reckon.

[dirt drifter]

check harrop for the 9 inch irs centre, pretty sure they make one

[strgas]

Give MATT a call at HORSE POWER FACTORY hes got the answers your looking for

[whipitVR74]

Harrop make a 12 bolt complete centre, rated to over 500 rwkw, looks like the go.

[agrsv8]

now ask them for the price mate... hexy bit of kit. convert over to a 8 inch diff. VT-VZ LSD and case, get a good LSD centre, diff gears and the Harrop cover. Will cost a bit less than what they will quote you.

[whipitVR74]

Dont want to sound like a tosser, but money is not really the object. I have had the car in storage for 8 years waiting (and saving) to do the build, now I have the money I am doing it, do it once, do it right The diff is $5,500 without drive shafts. To be honest for something guaranteed to handle 500 rwkw, and able to take 750, and as a bolt in thats pretty good value. I am looking at a custom twin turbo set up, the paint job alone will cost me more that 3 times that. Maybe I am just old, but no point thinking you can do this sort of conversion on a budget then running out of money. Certainly dont want the car to end up for sale in unique cars as a 90% finished project car....

[SirNemesis]

If money isn't an issue why didn't you get an engine designed for boost in the first place?

[Darcon666]

FI on the other hand WILL shorten the life of the aluminium motor and many don't go this way if you're wanting serious power(Chasing numbers/rwkw) with an LS1/2/3...they get a LSx or LQ9 iron block and got from there.

I would like to hear more on this theory. I cannot see how FI specifically (tuned correct) will have any effect on engine life depending on what material the block is made out of.

Exactly my point as well SirNemesis, when the OP is asking about MAX HP/RWKW out of an up-opened LS3 with FI... my gut is telling me that it will self destruct. Now a LSx or any iron/LQx block is known for high HP(...and for the LQ9 - designed) for FI implementations @ >15psi of boost, something I know for a fact that many/most tuners, will not run more than >10-12psi or it will do things like, lift the heads and other problems.(UN-Opended remember).

Dont want to sound like a tosser, but money is not really the object. I have had the car in storage for 8 years waiting (and saving) to do the build, now I have the money I am doing it, do it once, do it right The diff is $5,500 without drive shafts. To be honest for something guaranteed to handle 500 rwkw, and able to take 750, and as a bolt in thats pretty good value. I am looking at a custom twin turbo set up, the paint job alone will cost me more that 3 times that. Maybe I am just old, but no point thinking you can do this sort of conversion on a budget then running out of money. Certainly dont want the car to end up for sale in unique cars as a 90% finished project car....

Wow... too late - If your serious about FI get yourself a LSx block and go nuts or stick with your LS3/Twin turbo setup, run it a 30psi and you will get easy 1000HP and watch how long it lasts(I say 10... maybe 20sec the bang)....

[one_and_only2004]

Forged pistons plus rods in the LS3 and it'll happily run 15psi. So much negativity!

[Darcon666]

Forged pistons plus rods in the LS3 and it'll happily run 15psi. So much negativity!

...and the OP's question was....

Anybody suggest what sort of HP I can get out of an LS3 with FI (turbo/blower) before I have to open it up and get it built?

[one_and_only2004]

Up further it says money's no option, plus a turbo setup is on the cards. Just offering advice.

Don't get me wrong, running 30psi on an unopened LS3 will probably last less than what you suggested...

[SirNemesis]

Exactly my point as well SirNemesis, when the OP is asking about MAX HP/RWKW out of an up-opened LS3 with FI... my gut is telling me that it will self destruct. Now a LSx or any iron/LQx block is known for high HP(...and for the LQ9 - designed) for FI implementations @ >15psi of boost, something I know for a fact that many/most tuners, will not run more than >10-12psi or it will do things like, lift the heads and other problems.(UN-Opended remember).




Wow... too late - If your serious about FI get yourself a LSx block and go nuts or stick with your LS3/Twin turbo setup, run it a 30psi and you will get easy 1000HP and watch how long it lasts(I say 10... maybe 20sec the bang)....

I still think you have too much negativity towards an aluminium block. RHS is aluminium and good for well over 2000HP. There are also plenty of people in the states running 8 second passes on LS2 blocks without a worry. Mines alloy and I give it a beating, it isn't a worry for me. When I suggest 'doing it right', I don't mean do it in iron. I mean do it with decent pistons and rods.

You will also find plenty of people running alloy blocks with LS9 headgaskets well over 15psi (well over 25psi even) without issues lifting heads. Mine did lift the heads at 15psi and LS2 gaskets, but that was more of a tune related issue than anything else.

[Darcon666]

I still think you have too much negativity towards an aluminium block. RHS is aluminium and good for well over 2000HP. There are also plenty of people in the states running 8 second passes on LS2 blocks without a worry. Mines alloy and I give it a beating, it isn't a worry for me. When I suggest 'doing it right', I don't mean do it in iron. I mean do it with decent pistons and rods.

You will also find plenty of people running alloy blocks with LS9 headgaskets well over 15psi (well over 25psi even) without issues lifting heads. Mine did lift the heads at 15psi and LS2 gaskets, but that was more of a tune related issue than anything else.

I have nothing against the aluminium block if you do set it up correctly for any FI, but the OP is asking.... "Anybody suggest what sort of HP I can get out of an LS3 with FI (turbo/blower) before I have to open it up and get it built?" and so if your going to do that with a fully built, off the shelf LS3 you might as well go with a LSX block from scratch.... but hey as the OP said money is no option, right.

To each their own and it's all good.

[SirNemesis]

I'd rather run an LS2 block than an LSX block.

[one_and_only2004]

I dare say an iron block LSX would weigh at least 50kg more than an alloy block LS3?

Edit - it's actually 100kg heavier than an LS1 block