Re: 20V heads on 10V engines

[Andrew Duane USG/PE <duane@zk3.dec.com>]

Hairy green toads from Mars made AUDIDUDI@delphi.com say:

> > There's a company here in Briatin called "GTI Engineering", which 
> > specialises in tuning up VW/Audi engines in a professional manner - they 
> > are fully endorsed by V.A.G. and have a reputation here for being 
> > reliable, drivable and good value.
> > 
> > They can get at least 200 BHP out of the five cylinder by increasing its 
> > capacity, fitting new cams and poished, airflowed ports. On the five 
> > cylinder 20 valve they were offering a 240 BHP conversion - of course you 
>            ^^^^^^^^
> I've been curious about this for a while ... does anyone know how easily (if
> at all) this can be installed on a non-turbo 5000?  There's a nearby salvage
> yard that has one of these they're willing to sell cheaply, along with the
> intake and exhaust manifolds, etc.
> 
> I keep meaning to research this further but end up getting distracted by my
> existing projects each weekend and most weeknights... 

I researched this a while ago, when I picked up a 20V 90Q for Angela.
Suddenly, my 10V 100Q seemed a little lethargic.

Anyway, the news is bad. Here's the reply I got when I asked:

> From: bbell@csn.net (Bruce Bell)
> To: quattro@swiss.ans.net
> Subject: RE: 20V head upgrade
> 
> OK. But first I have a comment about grafting a 20v head from a 90Q onto the 
> 10v block in Andrew's 100Q. The 100Q has the 130hp engine, with 10:1 CR. The 
> pistons in this engine are dished, i.e. part of the combustion chamber is in 
> the piston. The 20v engine has a 10.3: CR and the pistons are flat with the 
> exception of a groove cut into the top for intake valve clearance. The 
> combustion chamber is almost completely located in the head. This means, if 
> you bolt on the head you will lose compression, my *rough* guess is that you 
> will be left with about an 8.3:1CR. You will also run the danger of crashing 
> an intake valve since your pistons are full height around the circumference. 
> Hence, you will need to either change pistons, or drop in the whole engine.   
> 
> A less expensive way to get a little more performance from your 10v is to 
> set the initial advance at 12 deg. BTDC to get your knock sensing computer 
> more involved. Getting a mild Schrick cam (the 268) will make it a little 
> softer on the bottom end, but should get you into the 145-148 hp range. 
>  
> Bruce Bell
> bbell@csn.org

I've been thinking about this advice, and am saving for a cam....


-- 

Andrew L. Duane (JOT-7)			duane@zk3.dec.com
Digital Equipment Corporation		(603)-881-1294
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Only my cat shares my opinions, and she's too heavy to care.