Ls2 396 Stroker... Boost?
Thread Starter
Teching In
Joined: Aug 2005
Posts: 30
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From: Asheboro NC
Ls2 396 Stroker... Boost? I recently had a ls2 shortblock built. Forged bottom end 3.9 stroke, 4.020 bore. Should be around 12.5.1 compression.TEA cnc 243 heads, Cam motion cam 251/259 dur @.050", .689"/.672" lift, 110 deg LSA. Lsxr 102 intake and tb. It runs mid 6s on motor but I want to go high 5s. It's a full interior street car and I want it to remain that way. My engine builder told me that he doesn't recommend forced induction on this motor because of the .020 overbore on a aluminum block. He said it will be fine on a small shot of Nitrous. I trust my engine builders advice since he has the fastest h pattern car In the world but with very conservative tuning and meth would I be asking for trouble running fi on this engine?
Joined: Jul 2007
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From: ELSA, South TEXAS (956) 802-7700
My honest and best bang for the buck opinion, as good as TEA heads are, I would sell.
They are better suited for LS1 or LS2 Non Stroked.
Stock Rectangle Port Heads and stock LS3 Intake would do better. If they are Ported even better.
They are better suited for LS1 or LS2 Non Stroked.
Stock Rectangle Port Heads and stock LS3 Intake would do better. If they are Ported even better.
I recently had a ls2 shortblock built. Forged bottom end 3.9 stroke, 4.020 bore. Should be around 12.5.1 compression.TEA cnc 243 heads, Cam motion cam 251/259 dur @.050", .689"/.672" lift, 110 deg LSA. Lsxr 102 intake and tb. It runs mid 6s on motor but I want to go high 5s. It's a full interior street car and I want it to remain that way. My engine builder told me that he doesn't recommend forced induction on this motor because of the .020 overbore on a aluminum block. He said it will be fine on a small shot of Nitrous. I trust my engine builders advice since he has the fastest h pattern car In the world but with very conservative tuning and meth would I be asking for trouble running fi on this engine?
Thread Starter
Teching In
Joined: Aug 2005
Posts: 30
Likes: 2
From: Asheboro NC
Depends on what fuel you're running; it would have to be E85 at minimum and the tune would need to be spot on at that compression.
Or put some larger chamber heads on to bring it down some, still gonna need E85 but the tuning window will be wider.
What does your short track look like, post a time slip?
Is the chassis and suspension working effectively?
Or put some larger chamber heads on to bring it down some, still gonna need E85 but the tuning window will be wider.
What does your short track look like, post a time slip?
Is the chassis and suspension working effectively?
Change the heads to ls3 with large chambers do not mill them and run ls9 head gaskets. This will lower the compression ratio a bit then run E85 and a procharger D1x with 12 psi or so it should get you where you want to be.
I recently had a ls2 shortblock built. Forged bottom end 3.9 stroke, 4.020 bore. Should be around 12.5.1 compression.TEA cnc 243 heads, Cam motion cam 251/259 dur @.050", .689"/.672" lift, 110 deg LSA. Lsxr 102 intake and tb. It runs mid 6s on motor but I want to go high 5s. It's a full interior street car and I want it to remain that way. My engine builder told me that he doesn't recommend forced induction on this motor because of the .020 overbore on a aluminum block. He said it will be fine on a small shot of Nitrous. I trust my engine builders advice since he has the fastest h pattern car In the world but with very conservative tuning and meth would I be asking for trouble running fi on this engine?
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I mean given all of the information in the post, it sounds like you just want some people to agree with you on disregarding the very sound advice from one of the best sources. I don't normally make posts like this, but you really should just listen to your engine builder, or pull the motor and build a different one that's made for boost.
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So it sounds like your builder is Jonathan Atkins with Tick Performance (or Nick Cole Mann in WI). In either case, I'd follow their advice.
Let's look at that compression. If you were running a class car you might run high compression because you are exploiting every aspect of the build you can so you can be competitive. There are class racers who are running 12.x:1 compresion on race gas of some kind. Keep in mind they are most likely running C16, Q16 or alcohol.
But the bigger issue with high compresion is it will limit the tuning window.
Let's say you add a supercharger, and let's say Jon is the tuner. He'll tune it as safe as he can for you. I think you'll find most folks like him will try to get you to at or under 11:1.
Back to the block, .020 over LS2. LS2 is not regarded as the best option for this, but if you only hit it with 10-15 psi to run high 5s maybe he can be convinced or he doubles down and says let's move your parts into an iron block. My boost range is just a guess. I ran 21 lbs with a Vortech YSI years ago but the engine was under 9:1 compression.
You could add a blower with race gas or E85 to your combo for high 5s the question will really be, will the block hold up for as long as you want to run it.
My path, iron 5.3 SBE with good head studs going to a gen IV LC9 (siamesed bores) all forged mid summer. Will be around 10:1. Going for 1100 and 5.40s @ 3100 raceweight on E85.
I have never used meth so I can't speak to that.
Let's look at that compression. If you were running a class car you might run high compression because you are exploiting every aspect of the build you can so you can be competitive. There are class racers who are running 12.x:1 compresion on race gas of some kind. Keep in mind they are most likely running C16, Q16 or alcohol.
But the bigger issue with high compresion is it will limit the tuning window.
Let's say you add a supercharger, and let's say Jon is the tuner. He'll tune it as safe as he can for you. I think you'll find most folks like him will try to get you to at or under 11:1.
Back to the block, .020 over LS2. LS2 is not regarded as the best option for this, but if you only hit it with 10-15 psi to run high 5s maybe he can be convinced or he doubles down and says let's move your parts into an iron block. My boost range is just a guess. I ran 21 lbs with a Vortech YSI years ago but the engine was under 9:1 compression.
You could add a blower with race gas or E85 to your combo for high 5s the question will really be, will the block hold up for as long as you want to run it.
My path, iron 5.3 SBE with good head studs going to a gen IV LC9 (siamesed bores) all forged mid summer. Will be around 10:1. Going for 1100 and 5.40s @ 3100 raceweight on E85.
I have never used meth so I can't speak to that.
Thread Starter
Teching In
Joined: Aug 2005
Posts: 30
Likes: 2
From: Asheboro NC
I mean given all of the information in the post, it sounds like you just want some people to agree with you on disregarding the very sound advice from one of the best sources. I don't normally make posts like this, but you really should just listen to your engine builder, or pull the motor and build a different one that's made for boost.
Thread Starter
Teching In
Joined: Aug 2005
Posts: 30
Likes: 2
From: Asheboro NC
Johnathan built the shortblock. I'm going to have him build a iron 6.0 that I have and play with a nitrous setup on this one spring of next year. Went to dig or die this past weekend and I'm itching for a turbo setup now. Thanks for the replies.