alloy 5.7 block, high comp and boost
Thread Starter
Staging Lane
Joined: Nov 2012
Posts: 89
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alloy 5.7 block, high comp and boost So i was talking to a friend on the week end about our set ups and where we want to go with them and i mentioned to him i wanted to boost my 383 stroker once i can afford to do it properly and decompress it from 11.5:1, his response was why?
he told me he is running his 408 with twin 66mm borg warners at about 11.8:1 or so ( the thing is an animal that will light up the rears after he has put 4 or 5 car lengths on me while he is doing around 160 km/hr ( excuse the aussie measurements) ) now he is running an lq9 block, obviously much stronger then my ls1, but im looking to find any body out there who has done this before, and how it ended up for you?
I would only be looking to put around 10 - 15 psi in, and run it on e85
he told me he is running his 408 with twin 66mm borg warners at about 11.8:1 or so ( the thing is an animal that will light up the rears after he has put 4 or 5 car lengths on me while he is doing around 160 km/hr ( excuse the aussie measurements) ) now he is running an lq9 block, obviously much stronger then my ls1, but im looking to find any body out there who has done this before, and how it ended up for you?
I would only be looking to put around 10 - 15 psi in, and run it on e85
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
I certainly wouldnt want to be pushing 15psi in a 5.7 alloy block at that CR with any fuel.
That isnt to say it couldnt be done and you may make it last for a while. But it is a lot to ask with the thin liners.
That isnt to say it couldnt be done and you may make it last for a while. But it is a lot to ask with the thin liners.
alloy 5.7 block, high comp and boost That's a lot to ask with any block. Can it work? Sure. Max CP is max CP.. the manner in which you get to that point is your prerogative. With that said, know that your margin for error with that setup is extremely small. Never would I consider anything this extreme but there are guys in this section that would and do.
At the end of the day what is more important to you? Reliability or max effort? That will tell you what to do with your CR
At the end of the day what is more important to you? Reliability or max effort? That will tell you what to do with your CR
TECH Fanatic
Joined: Jun 2013
Posts: 1,163
Likes: 16
From: Avon, Ohio
Honestly if your running E85 and keep the boost mild, it should work great. That crap loves compression. But, its also will not knock before it torches a head or sends a rod threw your block. I have seen E85 cars melt the house down, and toss rods with CLEAN logs before the damage occurred.
Tread lightly.
Tread lightly.
Thread Starter
Staging Lane
Joined: Nov 2012
Posts: 89
Likes: 0
mixed responses are exactly what i was afraid of haha, thanks for the input though,
i did have a thought this morning of sleeving the block, the rest of the bottom end is forged so it shouldn't have any issues, but if i do that i may as well just decompress the engine anyway once it is pulled down that far. i like the alloy blocks as far as weight saving goes as they are a heavy enough car to begin with and i dont really want to spend the cash on a new engine anyway, this one has enough of my money in all ready. So who's in favour of sleeve's??
i did have a thought this morning of sleeving the block, the rest of the bottom end is forged so it shouldn't have any issues, but if i do that i may as well just decompress the engine anyway once it is pulled down that far. i like the alloy blocks as far as weight saving goes as they are a heavy enough car to begin with and i dont really want to spend the cash on a new engine anyway, this one has enough of my money in all ready. So who's in favour of sleeve's??
Depends on a bunch of different variable
I sprayed my 11:1 6.0...on top of 10# of boost
But it was also on 116 and the plugs still didn't look ideal
On a race care, sure, it could be tuned for a decent amount of boost with a good fuel and that compression ratio
If it's something you drive on the street a decent amount, make highway pulls in, idle in town getting warm, etc, I'd take the peace of mind and larger tuning window the lower compression ratio gives you
I sprayed my 11:1 6.0...on top of 10# of boost
But it was also on 116 and the plugs still didn't look ideal
On a race care, sure, it could be tuned for a decent amount of boost with a good fuel and that compression ratio
If it's something you drive on the street a decent amount, make highway pulls in, idle in town getting warm, etc, I'd take the peace of mind and larger tuning window the lower compression ratio gives you
Your friend might also have a large cam that will reduce dcr quite a bit as his setup is on the larger size. My 383 was 11.8 and I dropped it to 10.1-10.2 or so with cleaned up 317's and saved some money after selling my CNC 243's. Your tuning window will be quite small with the high compression setup.
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Thread Starter
Staging Lane
Joined: Nov 2012
Posts: 89
Likes: 0
Depends on a bunch of different variable
I sprayed my 11:1 6.0...on top of 10# of boost
But it was also on 116 and the plugs still didn't look ideal
On a race care, sure, it could be tuned for a decent amount of boost with a good fuel and that compression ratio
If it's something you drive on the street a decent amount, make highway pulls in, idle in town getting warm, etc, I'd take the peace of mind and larger tuning window the lower compression ratio gives you
I sprayed my 11:1 6.0...on top of 10# of boost
But it was also on 116 and the plugs still didn't look ideal
On a race care, sure, it could be tuned for a decent amount of boost with a good fuel and that compression ratio
If it's something you drive on the street a decent amount, make highway pulls in, idle in town getting warm, etc, I'd take the peace of mind and larger tuning window the lower compression ratio gives you
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