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Re: Cam bearing bore size

To: "Robert M. Lang" <lang@isis.mit.edu>
Subject: Re: Cam bearing bore size
From: Don Malling <dmallin@attglobal.net>
Date: Sat, 23 Nov 2002 08:49:56 -0500
"Robert M. Lang" wrote:

> > If I shave my TR250 head to 9.5:1 CR would I still be able to use an M62
> > or similar supercharger? Your web site hints that the answer is no.
> 
> WHoa!
> 
> If you're going to add forced induction, you don't want to start with a
> H.C. engine. Au contraire! The point of a blower is that _it_ increases
> the cylinder pressure. If you start off with 9:1 or more, you will have to
> worry about detonation.
> 

Oooppps...a little disconnect between the brain and the keyboard on that
one. Wasn't thinking.

If I'm close to detonation at 9.5:1 at atmospheric pressure, then
boosting the pressure won't help the situation. Must be the value of the
supercharger is to keep a low compression ratio at atmospheric pressure
(more volume in the head), and then pack it tight with air/fuel, with
the compressor, to about the same "density" as the atmospheric 9.5:1
would have been. Now we have more volume at the same "9.5:1" density 
and a bigger bang... ? 

Probably don't to spend a lot of money on head flow bench work
either...  :-) 

Don

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