1.8L head on 2.0L block

[jdbubb at ix.netcom.com (Dan Bubb)]

Couple thoughts:
Generally intake flow is more important for performance since the maximum
pressure difference through the port is only one atmosphere. The pressure in
the exhaust port is far greater as the initial slug of exhaust comes out
which is why exhaust valves and ports have been smaller than intake valves
and ports since the '30s.
But, there is some optimum ratio of sizes. Not sure what that is, but on the
1.8 head the exhaust flow is ~70% of intake and on the 2.0 head the exhaust
is ~82%. And bearing in mind the much higher pressure in the exhaust, the
2.0 head seems biased towards the exhaust.
IIRC, back in the mid-90's Techtonics was getting more power from a 2.0 with
a stock 1.8 head vs. 2.0 head.
So, anybody seen any dyno runs that confirm which head has more power or a
better torque curve?
Dan

----- Original Message -----
From: "Chris DeLong" <green536@hotmail.com>
To: <sfwilliams@comcast.net>; <marquez337@yahoo.com>;
<scirocco-l@scirocco.org>
Sent: Friday, June 27, 2003 2:42 AM
Subject: RE: 1.8L head on 2.0L block


> Yes, averaging numbers compared between intake and xhaust flow. Not to
> mention that when polishing and porting the head you have more material to
> work with on the intake side of a 2.0l head and by nature the exhaust
ports
> are larger. So basically this gives an all around better solution to the
> whole head issue.
>
>
>
> Chris DeLong
> Fine Tuning
> 206.367.5503
> www.finetuningperformance.com
> Seattle, WA USA
>
>
>
>
>
> >From: "Scott F. Williams" <sfwilliams@comcast.net>
> >To: Chris DeLong <green536@hotmail.com>, marquez337@yahoo.com,
> >scirocco-l@scirocco.org
> >Subject: RE: 1.8L head on 2.0L block
> >Date: Thu, 26 Jun 2003 18:57:13 -0400
> >
> >Mr. DeLong wrote:
> > > Uninformed people *think* the 1.8l head flows more air
> > > than the 2.0l head. Although, I have flow sheets here somewhere
> > > that depict a regular 1.8l head flows 14% less air than a 2.0l head.
> >
> >Chris, the 1.8l 16v head is reportedly higher-flowing on the intake side
> >whereas the 2.0l 16v is supposed to be better with the exhaust. What
> >exactly
> >are *you* claiming? Are you comparing intake or exhaust or somehow
> >combining
> >the two? If it is the latter, how are you doing it -averaging the numbers
> >for both?
> >--
> >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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