Combustion chamber L98
Thread Starter
Racer
Joined: Sep 2000
Posts: 337
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Combustion chamber L98
What sizes are the combustion chambers on my stock L98 (91)?
When you change to aftermarket heads do you get heads with bigger combustion chambers?
What is the stock compression ratio? (L98 –91)
Thanks in advance
Best regards
:cheers:
When you change to aftermarket heads do you get heads with bigger combustion chambers?
What is the stock compression ratio? (L98 –91)
Thanks in advance
Best regards
:cheers:
Team Owner
Joined: Sep 2001
Posts: 62,146
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From: Athens AL
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Re: Combustion chamber L98 (Raistlin)
yes, you have D-ports and i thought the compression on the late L98's was 10 or 10.25
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Re: (scorp508)
90/91 are 10.25:1 with a different piston design.
I thought my '90 pistons looked just like your '87 pistons. Comparing the pictures, I can see they're not....
here's mine all dirty:
and yours:
That might be where the extra compression comes from.
Cool!
[Modified by Marcho Polo, 11:02 PM 9/9/2002]
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Re: (Cratzy)
But the chambers are 58cc no matter what year? If (when) I change heads do I change to heads with 58cc or bigger?
:cheers:
:cheers:
The D-ports are good for 350hp untouched, so if you need to change heads it all depends on what you want out of the motor and the compression ratio you want.
Thread Starter
Racer
Joined: Sep 2000
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Re: (vader86)
I can't change head for the moment because of money (or lack of money). If I can use my old heads that is good.
But in the future I will probably change heads to be able to put out more than 350hp. I will also put on a Superram in the future. For the moment I will only do the bottom end, 383”
Problem is if I should chose pistons to go with the 58cc or to go with bigger chambers (for the future mods) and compensate the higher compression with thicker head gasket? Is that possible?
:confused:
:cheers:
But in the future I will probably change heads to be able to put out more than 350hp. I will also put on a Superram in the future. For the moment I will only do the bottom end, 383”
Problem is if I should chose pistons to go with the 58cc or to go with bigger chambers (for the future mods) and compensate the higher compression with thicker head gasket? Is that possible?
:confused:
:cheers:
Pro
Joined: Jul 2000
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From: Vancouver WA
Re: (Cratzy)
Quote me if I'm wrong... but if you go with a larger chamber the compression ratio will be less which is good for twin turbos. With the 58cc and flat tops pistons that came with your 91, your compression should be good like Scorp says. Now I'm not positive about this, but from what I learned in Physics this should apply.
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Re: (daddydahlin)
Since I have iron that have a bigger combustion chamber could I replace them with afr 190 heads since their combustion chamber is 64cc
Melting Slicks
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Re: (vader86)
stock for a 90-91 is 10:25-1, keeping a 57-58cc chamber, using a similar piston, a .039 gasket and decking the block will have a person at 11:1, that's the number you want to figure if your rebuilding.