917/10 Throttle Bodies
(not for sale)
Recently we received some well worn
throttles from a factory 1972 917/10 car. The client's
instructions were to restore them functionally, but with
no attention given to appearance. No plating, no black
coating on the throttle housings.
Recall that the 917/10 was Porsche's
answer to the Lolas and McLarens which were dominating
the Can-Am series at that time. The 917/10 used a
turbocharged 12-cylinder 5 liter engine which was
capable of producing between 800 and 1000 horsepower.
Fewer than 20 of these cars were built and probably 12
These are the throttles as received:
developed an all new throttle for a small number of
engines, Porsche used what was already being produced in
large quantities for their 911 street car. Note the
casting number: 911 110 101 1R
started life as a second series 2.2E casting from 1971.
The only modification that was done to the throttle
housing in order to change them from 911E throttles to
917/10 throttles is an increase in bore size.
With forced induction no taper is needed.
Bores are 40mm straight through. Note the small groove
on the side of the bore from contact with the throttle
Removed rolled-steel bushings.
New brass bushings ready to install.
All hardware shown. Levers are different
than street MFI as well as two shafts (pictured on left)
which are longer than normal to accommodate throttle
One of the housings was a Sportomatic housing. Note the
two vacuum ports which are shown blocked off compared to
the non Sporto housing with no vacuum ports.
The Sportomatic housing also had its air
bleed holes buggered, including compression of the seats
from over tightening the incorrect screws. The Sporto
was damaged, and likely a replacement for the original
housing. After confirming with the client that the
vacuum ports are not being used for pressure measurement
or other reasons, and because of the damage to air bleed
holes and seats, we decided to swap out the Sporto
housing for a non Sporto. Fortunately these are readily
New bushing installed. Small
overbore....no more groove.
Bore is smooth. New throttle plates
machined to fit the new bore. Shafts were re-blued to
help prevent surface corrosion after polishing.
917/10 throttles all finished. Balanced
on a flow bench. All 12 air screws 5 half turns out +/-
1/4 turn. Target idle of about 1600rpm. Ready for
Return to top