[tech]: compression ratio: 9a vs. pl

[Josh.Hignight@phoenix.edu (Josh Hignight)]

So what does the compression wind up being when you mate a 1.8 head to a 2.0
block? 



Joshua Hignight
Student Services/IT Services Coordinator
(505) 821-4800 ext. 2116


-----Original Message-----
From: Michael Abatzis [mailto:abatzis2@hotmail.com] 
Sent: Tuesday, May 07, 2002 3:34 PM
To: scirocco-l@scirocco.org
Subject: RE: [tech]: compression ratio: 9a vs. pl

>From: "Scott F. Williams" <sfwilliams@comcast.net>

> > how high a cr can you
> > run w/o blowing headgaskets/pinging,
>
>I'd be nervous to run anything more than 11.5:1 on the street. Ability to
>reach even that point requies some high-octane fuel. A healthy combustion
>chamber (no glowing carbon deposits or other problems), proper engine
>fuel/ignition mapping, and adequate cylinder head cooling should permit 
>this
>CR on 94 octane.
how much needs to be taken off a stock head to get this cr?

>
> > hmmm--this is actually a thread that hasn't been beaten into the
> > ground before, has it?
>
>I don't think that the CR topic has been beaten into the ground at all. In
>fact, I was just sweating about the same thing. See the recent thread
>entitled "Cincy: hotrod plans/what to do? ACK!". I was considering the
>purhase of a motor that supposedly had a 12:1 CR. It turns out that the
>ratio is actually higher. Thus, I'm passing on the deal.
>
>P.S. The difference in CR between PL and 9A motors is due to the different
>bore and stroke -not a larger combustion chamber volume in the PL. The 9A
>bottom/1.8l head combo is demonstrably faster than a 9A bottom/2.0l head 
>set
>up.

i've got a 2l/1.8 that begs to differ--are there any actual dyno reports 
showing a difference, or just that flow graph (at tt?) that shows 
intake/exhaust flow?
-michael

>--
>Scott F. Williams
>NJ Scirocco nut
>'99 Subaru Impreza 2.5 RS
>Mazda 323 GTX turbo "assaulted" vehicle
>Golf GTI 16v "rollycar"
>ClubVAC: "Roads found. Drivers wanted."
>
>


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