[Diy_efi] compression ratio

[Perry Harrington]

On Sat, May 11, 2002 at 04:15:34AM -0400, elcamino73 wrote:
> 
> > I'm running .037, so nyeh! :)
> >
> > I've got TFS TW heads.  With the piston .003 out of the bore, I still
> > have .280 valve clearance at .498 lift.
> 
> 
> my lift is .523 Sooooo,
> I'm happy to be right where I'm at!
> 
> 
> > I would start to be concerned at half the gasket thickness, .020 in my
> > case.
> >
> > BTW, have you sat down and calculated your CR?  It's unlikely that you
> > would gain anything splitting hairs over the squish, if that's your goal.
> 
> Sure have, filled the assembled chamber with dexron and ended up with 9.51
> compression.
> 
> > BTW, you're crescent is about 2.9 to 3.2cc as a quick figure.  A .040
> gasket
> > with a 4.100 bore is 8.4cc.
> >
> > My CR is 9.767:1.
> Are you running boost?
> 

Nope, but I had considered running a Procharger P1SC with intercooler at 8lbs.

That would've given me another 100-120HP.  I just didn't like the prospect of
having to upgrade the tranny, clutch, and bellhousing, seeing how I had dropped
$2500 on that stuff 2 years ago.

> I'm looking to run 15 to 16 psi. And started this thread with questions
> about amount of water for WI with my set up.

You also need to consider the basic efficiency of the head design.  Some combustion
chambers have almost no detonation (hemisphere and pentroof), and others are
overly prone (mostly stock heads with small volumes).

Generally speaking, the less timing you can run to make power, the more efficient
the head.  If you're dialing in 18 degrees base timing to get power (like stock
5.0s), you're prone to problems.  But if you can run 8 degrees and get decent power
on 89, then it's a better head (like the TW).

--Perry

-- 
Perry Harrington             Linux rules all OSes.               APSoft      ()
perry at apsoft dot com 			                 Think Blue. /\

Those who would give up essential liberty to purchase a little temporary safety
deserve neither liberty or safety. Nor, are they likely to end up with either.
                             -- Benjamin Franklin


_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi