It is my understanding that Rootes contracted with Holbay to produce a
performance version of the fastback Alpine. The prototype that was
delivered to Rootes was very fast but had lousy low end performance. This
was deemed not acceptable for a road car by the Rootes people. This was
communicated back to the Holbay people and they reconfigured the engine with
the smaller intake ports. The effect was that the velocity of the intake
charge remained high at lower RPMs resulting in better low end performance,
i.e. torque.
Last year I built a Holbay engine for my SV Alpine complete with an NOS
Holbay head, a Holbay replica camshaft from Sunbeam Specialties, and the
correct Weber setup. The engine was tested on the dyno and made around 125
peak hp but the torque curve was absolutely flat (about 120 ft/lbs, need to
check notes) from 2500 RPM to redline. So I would imagine if a "stock" head
was modified by reshaping the combustion chamber and polishing the intake
and exhaust ports like the Holbay, then the result would be a high RPM
(relative to Rootes) engine.
The flowbench results comparing the Holbay head to stock can be found at
http://www.tomhill.freeservers.com/custom.html. (sorry for the popups, its
free)
tom hill
-----Original Message-----
From: owner-alpines@autox.team.net
[mailto:owner-alpines@autox.team.net]On Behalf Of
Jay_Laifman@countrywide.com
Sent: Monday, May 19, 2003 7:53 PM
To: alpines@autox.team.net
Subject: Torque or not more torque
"Together with the Holbay camshaft and the correct Webers and right air
filter (look up! the carb set-up is very sensitive to the air filter) you
get a torque engine. Its not a high RPM engine! This suits the 3.77 rear
end with overdrive gearbox."
I do not think this is 100% accurate. In general, if you take two
identical sized engines and try to increase power to one of them by better
breathing and carberation, that brings on power at the higher rpms at the
expense of the lower rpms. On the other hand, if you take otherwise
identical engines and increase the size of one of the engines, you will
gain that power and torque at the lower rpms. So, by going the Holbay
route, you generally lose torque and power at the lower ends.
Jay
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