I spent the whole weekend fabricating a new adaptor throat to link a HIF44 to
the turbocharger in place of the 1.5" SU I've been using up to now. Welding,
grinding, drilling, (insert Tim Allen grunting noises here). The turbo inlet
is 1.75" and has always been choked down to a smaller carb with an adaptor
since the turbo was first installed. Now it has a carb to match the inlet
size. No rubber bowl seals to rot in MTBE and the throttle and choke linkage
is now much more accessible.
I didn't notice any power gain as the BCX needle that came with the carb was
waaayyy too lean. Judicious use of a needle file eventually yielded a decent
performance. I'd just watch the O2 sensor gauge as I ran throught the gears,
then back to the bench and the file until the readings stayed slightly rich
throughout the throttle range. I have no idea what the resulting needle is
equivalent to, but I'm interested if anyone else is running a single HIF44 on
a modified 1275 and if so, what needle you are using. What dome spring, and
why?
So far, the power feels almost as good as the old dialed-in 1.5", but boost
now doesn't go above 7 pounds no matter how hard I stomp it. It would easily
reach 10lbs with the 1.5". Still too lean? It may be that this is the carb
best matched to the motor I plan on building next and not to the one that is
in the car now. BIG valves and a turbo-matched cam are in the near future.
Glen Byrns
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