compression question
12-28-2004, 10:06 PM
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compression question
I'd like to lower my compression so I can run a blower. Is it possible to add a spacer between the head and block? Where can I get such a spacer? If I install a spacer, will everything be OK? TIA
12-29-2004, 01:02 AM
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Re: compression question
You need to post some info on your motor to answer your question properly. What motor do you have? Whats the existing compression? Do you know the thickness of your existing
head gaskets? What kind of a blower do you want to run? How much boost do you want or need? Whats your existing HP and what HP are you shooting for?
Dumb Questions are easier than dumb mistakes!
Ray @ Raylar
head gaskets? What kind of a blower do you want to run? How much boost do you want or need? Whats your existing HP and what HP are you shooting for?
Dumb Questions are easier than dumb mistakes!
Ray @ Raylar
12-29-2004, 05:30 PM
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Re: compression question
Originally Posted by Raylar
You need to post some info on your motor to answer your question properly. What motor do you have? Whats the existing compression? Do you know the thickness of your existing
head gaskets? What kind of a blower do you want to run? How much boost do you want or need? Whats your existing HP and what HP are you shooting for?
Dumb Questions are easier than dumb mistakes!
Ray @ Raylar
head gaskets? What kind of a blower do you want to run? How much boost do you want or need? Whats your existing HP and what HP are you shooting for?
Dumb Questions are easier than dumb mistakes!
Ray @ Raylar
12-29-2004, 08:27 PM
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Re: compression question
174 blower sort of runs into an efficiency wall around 550hp. Can't generate much boost at those flow rates without whipping too much heat into the charge.
A 454 with 119cc chambers, .020 deck, .038 gasket, and 30cc popups will net a 10:1 static CR. To drop to 8:1 CR, you'd have to add a spacer 1/8" thick tween the heads and block. Obviously, this would cause issues (the bolt holes and ports on the intake manifold will no longer match up - custom pushrods will need to be used - studs would be necessary for the heads, as std head bolts would no longer work - and you would have NO squish area in the combustion chamber, to name a few of the more obvious barriers to doing this).
Do yourself the biggest favor imaginable:
don't use spacers on the heads
do get a set of 8:1 flattops
notch the bores for flow under the valves
and run a 250/256 blower at 5psi.
A 454 with 119cc chambers, .020 deck, .038 gasket, and 30cc popups will net a 10:1 static CR. To drop to 8:1 CR, you'd have to add a spacer 1/8" thick tween the heads and block. Obviously, this would cause issues (the bolt holes and ports on the intake manifold will no longer match up - custom pushrods will need to be used - studs would be necessary for the heads, as std head bolts would no longer work - and you would have NO squish area in the combustion chamber, to name a few of the more obvious barriers to doing this).
Do yourself the biggest favor imaginable:
don't use spacers on the heads
do get a set of 8:1 flattops
notch the bores for flow under the valves
and run a 250/256 blower at 5psi.
12-30-2004, 09:33 AM
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Re: compression question
I'm with mcollinstn.
If you lower compression and add a 177 blower, you'll go from a 527hp NA motor to a 550hp SC motor. You really spin those little blowers to get more than 5psi on a 454.
If you lower compression and add a 177 blower, you'll go from a 527hp NA motor to a 550hp SC motor. You really spin those little blowers to get more than 5psi on a 454.
