Y'know, Smitty has a Holbay head and we were puzzling over the smaller
intake ports recently. He thought that going from a large carb opening
to a small intake port would increase the velocity of the air/fuel mix.
Wouldn't that contribute to better torque?
I think that somebody else (apologies for not remembering who) wrote
yesterday that the intent of the Holbay head was to make better low-end
torque rather than high-end horsepower.
Regards
David Sosna
56 S4 GT V6
Greg Locke wrote:
>
> I heard that holbay originally delivered the H120 powered rapier (or
> hunter?) with decent sized ports and rootes said... "No way. this is too
> fast, make it slower". The reduction in port size was holbays answer. I
> thought they only reduced the size of the intake manifold runners, and the
> head ports were standard, but I may be wrong here. Would take a lot of work
> to weld up the ports and re bore them.
>
> more information form vague sources.... The original engine did put out
> 120hp, but the port mods reduced it to about 107.
>
> Kindof defeats the purpose of the webers in the first place, but it was more
> of a sales gimmic anyway, as a result of the london-sydney win.
>
> Greg
>
> ----- Original Message -----
> From: Jarrid Gross <JGross@econolite.com>
> To: Tom Hill <tom.hill@att.net>; Christopher Albers
> <Christopher.Albers@bubbs.biola.edu>
> Cc: <alpines@autox.team.net>
> Sent: Friday, 9 March 2001 09:02
> Subject: RE: RE: More Power from the 1725
>
> > tom wrote,
> >
> > >I am referring to the port diameter at the intake manifold not the valve
> > >size. I think the valves are the same on the standard and Holbay heads.
> >
> > >tom
> >
> > CNA wrote,
> >
> > >Huh? That doesn't seem right. How does the head breath with an intake
> > >only, what, 1.2"? I can't recall the stock size, I seem to recall
> > >about 1.4" for the intake & 1.2" for the exaust.
> >
> >
> >
> > This is correct, the ports on the holbay are about 1.25.
> >
> > The valves are 1.30 and 1.52, the same and SV alpines.
> >
> >
> > Jarrid Gross
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