Brining compression down?
Jan 12, 2014 | 12:32 AM
#1
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Brining compression down?
How can I bring compression down for boost
I have a rebuilt 355 with approximately 28,000 miles upgrades in the motor include:
9:1 speed pro forged pistons
54cc heads with 2.02 intake
and 1.90 exhaust valves
Making the overall
compression around 10:5:1
Air gap edlebrock performer intake
Edlebrock 650cfm carburetor
465 465 lift hydraulic camshaft
Moly push rods and new
Headman headers
I have a rebuilt 355 with approximately 28,000 miles upgrades in the motor include:
9:1 speed pro forged pistons
54cc heads with 2.02 intake
and 1.90 exhaust valves
Making the overall
compression around 10:5:1
Air gap edlebrock performer intake
Edlebrock 650cfm carburetor
465 465 lift hydraulic camshaft
Moly push rods and new
Headman headers
Jan 12, 2014 | 01:52 AM
#2
Why bring it down? The out of boost power is much better with the extra compression. You shouldn't have any issues at 10.5:1 however to answer your question the easiest way would be to swap your heads for some with 59cc chambers.
Jan 12, 2014 | 08:30 AM
#4
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Well it doesn't make enough won't it make more with boost
Jan 12, 2014 | 12:42 PM
#6
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From: norcal
What kind of forced induction are you going to run? If it is something with a linear boost curve, (Centrifugal SC, turbo to an extent) I would keep the compression where its at. If you are thinking about a Roots/Twin Screw set up that shoves in a ton of boost at low RPM's, I would probably change the heads out for something with a slightly larger chamber, or at the very least install some thicker head gaskets.
The reason is, when you lower the compression ratio and you are driving around NOT in boost, the engine will feel lazy. If you run a Centrifugal SC, this will happen most of the time. If you run a Roots, it will get into meaningful boost soon enough that you won't notice it nearly as much.
Just my .02
The reason is, when you lower the compression ratio and you are driving around NOT in boost, the engine will feel lazy. If you run a Centrifugal SC, this will happen most of the time. If you run a Roots, it will get into meaningful boost soon enough that you won't notice it nearly as much.
Just my .02
Jan 13, 2014 | 09:02 PM
#7
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What kind of forced induction are you going to run? If it is something with a linear boost curve, (Centrifugal SC, turbo to an extent) I would keep the compression where its at. If you are thinking about a Roots/Twin Screw set up that shoves in a ton of boost at low RPM's, I would probably change the heads out for something with a slightly larger chamber, or at the very least install some thicker head gaskets.
The reason is, when you lower the compression ratio and you are driving around NOT in boost, the engine will feel lazy. If you run a Centrifugal SC, this will happen most of the time. If you run a Roots, it will get into meaningful boost soon enough that you won't notice it nearly as much.
Just my .02
The reason is, when you lower the compression ratio and you are driving around NOT in boost, the engine will feel lazy. If you run a Centrifugal SC, this will happen most of the time. If you run a Roots, it will get into meaningful boost soon enough that you won't notice it nearly as much.
Just my .02
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Jan 14, 2014 | 06:28 AM
#9
Joined: Apr 2004
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From: In a van DOWN BY THE RIVER
Boost has came a long way since the 8.1 days. Electronics are here now so that you can run higher compression with boost. As said more comp makes out of boost driving much better. Some run 11-1 with lots of boost. All out race car, maybe drop it down, but not for a DD purpose. The prob with a carb set up is the carb tuning. You better plan to have meth, a good IC if you plan to slap it with a good amount. Also a good boost built carb.
Jan 14, 2014 | 07:50 AM
#10
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Boost has came a long way since the 8.1 days. Electronics are here now so that you can run higher compression with boost. As said more comp makes out of boost driving much better. Some run 11-1 with lots of boost. All out race car, maybe drop it down, but not for a DD purpose. The prob with a carb set up is the carb tuning. You better plan to have meth, a good IC if you plan to slap it with a good amount. Also a good boost built carb.
