Well Five-Valve technology doesn't mean it's the best. After all look at F1
that TRIED 5-valve heads but after they found out they couldn't get as good
of cam profiles and the cylinder filling wasn't that good they went back to
four-valve heads. Regardless if whether the 20v was built for turbo or not
I believe the head isn't THAT great for anything other than turboing...like
you said :)
Mark
From: John Caldwell <[email protected]>
To: Mark Radelow <[email protected]>
CC: <[email protected]>, <[email protected]>
Subject: Re: OT: 1.8T stuff(my project-for those interested)
Date: Wed, 27 Jun 2001 12:08:24 -0600 (MDT)
On Wed, 27 Jun 2001, Mark Radelow wrote:
> I think the jury is still out as to whether the Five-Valve head is really
> that superior to the 4-valve design. In Europe the normally aspirated
> 5-valve 1.8 liter makes approx. 130hp (72hp/liter) compared to the 150
made
> by the 2.0 (75hp/liter). The 5-valve head has a lot more reciprocating
mass
> in the head along with the rocker design which limits cam profile design.
I
> doubt the costs justify the end result. For me, if I were to turbo a VW
I
> would use a G60 head. Same thing, designed for boost and you can easily
get
> 250 HP out of that motor with a turbo.
>
That motor wasn't built to be naturally aspirated.. in the great tradition
of giving people 9,000 engine choices to put in their golf, some dudes at
vw and audi said "wouldnt it be cool if we made a NA 20v?" With the same
displacement, as you approach max efficiency for a head on the motor, the
gains arent going to appear that big. If you could rev a 20v to 10krpms
or above, I guarantee that it would make more power than a 16v. That
whole game changes though when you start cramming air into the motor...
you don't need to rev it to 10k to get the power out of it.
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