We did not modify the Strombergs much, but they did give excellant power.
We used them primarly on the GT-6 and made 186 real BHP at 8200 with those
little 1.5" devils. I did as said before enlarge the needle and seat bore.
As I remember the main problem was getting float height to be high enough to
flow the fuel and low enough to not flow over the jet tube bore. Also I
remember the fuel pressure to be more particular with the Strombergs. (lower
semed to be better) Also with the GT-6 engines I made we used a velocity
stack that added a nice little 6-8 bhp. I would pull then off then push
them back into place on the engine dyno as the engine was revving away. You
could see the needle drop a considerable amount when the stacks were
removed. Not the type as used on the Webers but with a much bigger flair and
a nice rolled edge. Probably didn't answer your question but .....there you
are.
----- Original Message -----
From: <N197TR4@cs.com>
To: <kaskas@earthlink.net>; <vinttr4@geneseo.net>; <fot@autox.team.net>
Sent: Monday, January 24, 2000 2:22 PM
Subject: SU carb fuel flow
> Kas, et. al.
>
> RE: Jack Drews quest for carb improvement.
>
> Although I have a set of SU's on the shelf, I have elected to continue to
run
> the older style Strombergs. For whatever reason, I never encountered the
same
> problem to the extent that Jack did, I have a little bit of it.
>
> I am running the SU needles per your instruction in the little black book
by
> wrapping shim stock aroung the needle shaft. All modifications to the
carbs
> are quite modest, mainly getting rid of the sharp edges. I run with a fuel
> regulator and the engine is 87 mm with about 10.5:1 CR. Head flows nicely.
>
> What's two or three things that I can do to improve the Stroms with out
going
> bonkers about it. Recommend a needle with these specs?
>
> Any opinions between the two carbs. I feel I have had great success and
> reliability with these carbs...and many folks kind of turn their
collective
> noses up at them.
>
> Regards,
>
> Joe
>
> << Interesting problem that I have encountered before. The Strombergs
have a
> diaphrame so the piston is ruled by an accurate depression while the
S.U.'s
> have a static clearance that can vary. Its not likly BUT the clearance
may
> be too large on the SU's between piston and dashpot. More than likly
though
> the needle and seat are too small for the flow demand. I have almost
always
> needed to increase the flow of the needle and seat by drilling out
slightly
> (sorry don't remember those numbers). I also drilled the main jets as
you
> have suggested. I have used a #38 drill .101", and a #37 drill which is
> .104". The #37 more than does the job so I would use the#38 first and
see
> if there is any improvment. Do check the float levels though as this
puppy
> just might be not be able to flow the dmeand of the engine. >>
>
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