Chevelle Ls3 twin turbo questions
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Chevelle Ls3 twin turbo questions Hello to all. This is my first post on ls1 and I'm sure I'll get a ton of answers and flack for my questions.. I'm in the process of building a 1970 chevelle and currently working on the frame and suspension. The old 307 and power glide are at the junkyard so I'm trying to figure my engine/ transmission set up. I would like to run a new ls3 twin turbo engine with new t56 tranny. Now I know what's involved with the engine and tranny swap but I don't know much about turbos or the engine needs to run them. I have seen some posts on guys wanting to twin turbo a stock ls3 crate engine but there doesn't seem to be much info there. I was going to put in GMs ls376/525 hp and call it a day but then I got on this twin turbo kick. Now is it possible to twin turbo a stock crate motor and get decent gains? Or is it going to need to be ripped apart and the valves,cam, rods, and pistons changed to make real power? It seems that a stock crate could make good power if set up right but I'd like to be in the 750Hp+ on pump gas and I'm not sure if it can make that. What internals would? Thanks again for any help
Phil
Phil
I think the weak link in a factory rotating assembly are the rods/pistons. The cranks are strong and plenty of guys have run them passed the 1000RWHP mark. I would replace these parts but then again some have made 700hp and gotten lucky.
Looks like you have a lot of searching ahead of you my friend. There are a million different variables, so you have to do a lot of research. Id say the basics are:
Stock shortblocks are usually run up to 500-600rwhp(at the wheels), past that you'll want forged rods & pistons. Stock crank is fine. Compression ratio under 10.0 is generally safe. You'll need a turbo cam..something around 228/228 .580/.580 with a wide LSA 114-116. Turbo motors will blow exhaust back into the intake valves on a naturally aspirated cam profile. You'll need bigger injectors (60-80lb), stiffer valve springs, and a heavy duty timing chain (single row is fine). You'll want to port your stock oil pump or get a high-flow replacement. You can run pump gas with methanol injection or switch to E85 to run more boost and timing safely. Most of all, you'll need a GOOD tuner who can recalibrate your settings to match all the changes, or buy HP Tuners software and learn it yourself (takes a LOT of reading). Anyway, most people who turbo stock motors start with a cam, valvesprings, injectors and a tune. Good luck!
Stock shortblocks are usually run up to 500-600rwhp(at the wheels), past that you'll want forged rods & pistons. Stock crank is fine. Compression ratio under 10.0 is generally safe. You'll need a turbo cam..something around 228/228 .580/.580 with a wide LSA 114-116. Turbo motors will blow exhaust back into the intake valves on a naturally aspirated cam profile. You'll need bigger injectors (60-80lb), stiffer valve springs, and a heavy duty timing chain (single row is fine). You'll want to port your stock oil pump or get a high-flow replacement. You can run pump gas with methanol injection or switch to E85 to run more boost and timing safely. Most of all, you'll need a GOOD tuner who can recalibrate your settings to match all the changes, or buy HP Tuners software and learn it yourself (takes a LOT of reading). Anyway, most people who turbo stock motors start with a cam, valvesprings, injectors and a tune. Good luck!
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Thank you very much.. The more I read the more I am leaning away from the crate engine.. Kind of a waste to buy it then tear it apart. I'm really not into half assing a build . So I'm back to the drawing board. I suppose I could just build a new ls. Unfinished blocks are around 1700.. But what's the advantage to building a turbo ls other then the weight? Is the tall deck lsx a better choice for a block? It is a big block but could be mighty strong with a smaller bore
Thank you very much.. The more I read the more I am leaning away from the crate engine.. Kind of a waste to buy it then tear it apart. I'm really not into half assing a build . So I'm back to the drawing board. I suppose I could just build a new ls. Unfinished blocks are around 1700.. But what's the advantage to building a turbo ls other then the weight? Is the tall deck lsx a better choice for a block? It is a big block but could be mighty strong with a smaller bore
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You won't need a huge block for your hp goals. Sometimes a larger displacement is harder to make power on with turbo applications. Something in the 5.3, 5.7 or 6.0 would be perfect for your needs. You can make 1000hp on a 5.3 block with a relatively small turbo. Put the same turbo on a 427 and you'll only make 700. You'd have to upgrade to a huge turbo, and then sacrifice some streetability. Search for posts from INTMD8 on his thoughts around turbo trends & setups.
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Brett Foote Thread Starter
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The 6.0 block can handle that kind of power ? Smaller is better in the turbo world I guess . I'm still stuck on the bigger cubes bigger hp ways? The ls7 isn't a boost friendly engine?
Last edited by bikerman9967; Oct 9, 2012 at 05:41 PM.
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Darts Iron Eagle block looks pretty tasty.. 4.125 bore 9.325 deck . Cam moved up .. Looks like a strong start. Drop in a Callie's forged crank and forged -20 pistons.. I think it would be a strong boost friendly block
A stock iron 6.0 block can handle 1200+ hp or more no problem. People are running 1200-1300hp all over this forum on stock blocks. Even 5.3s and 5.7s. They are bulletproof.
People run them up to pretty high hp levels too. I think your target of 750hp is well within the capabilities of an alum block. Especially if you're mostly street. If you're a racer, and plan a lot of hardcore, high-horsepower track duty, then you're better off with iron.
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Is it possible to make 1000hp on pump gas with a small block and still be safe? We do have e85 the next town over but I'd rather it stick to 93 just to drive . What is a good set up to start with? Forged crank rods billet piston, high flow heads. 9.5:1. And say 66mm turbos?
Is it possible to make 1000hp on pump gas with a small block and still be safe? We do have e85 the next town over but I'd rather it stick to 93 just to drive . What is a good set up to start with? Forged crank rods billet piston, high flow heads. 9.5:1. And say 66mm turbos?
