I have an question for all the racer's/carbureation experts out there.
I have a friend who races a TR4 that won't pull past 5500 rpm in long
(i.e. 1 mile) straights. Incidentally, He posted the question to the
TR***ph list but got no response. I'm hoping someone racing with twin
SU's will be able to lend some insight to the problem. The symptoms seem
to point to a lean condition. Here's the facts:
1. He recently switched from a Stromberg to dual 1 3/4 SU's. The car
used to pull steadily to 6500 rpm with the Stromberg. The SU's have the
richest needles installed.
2. The Exhaust Gas Temperature reads 1500F at the end of long straights
versus 1350F with the Stromberg.
3. The SU's have two modification ala Vizard's book. The throttle
shafts have been tapered and the bridges have been built up with epoxy.
Both mod's are supposed to improve air flow.
4. It has a Holley electric fuel pump running about 5 psi.
Any insight to why the car won't pull or any experience with Vizard's
recommended mods (or how to contact Mr. Vizard) are appreciated.
Thanks,
Chris Barnhart
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