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Stromberg carb fuel flow

To: fot@autox.team.net
Subject: Stromberg carb fuel flow
From: "Barr, Scott" <sbarr@mccarty-law.com>
Date: Mon, 24 Jan 2000 17:53:29 -0600
Joe, et al.,

If you've found a way to make the Strombergs work when cornering, I'd
sure be curious to hear about it.  I don't mean to turn my nose up at
them, but I think the Strombergs may be a little smarter than me.

If I understood Jack's description correctly, I've had the same problem
with my Strombergs as he's describing -- fine performance as long as you
don't ask them to corner.  After this list correctly prescribed an
increase in fuel pressure (maybe up to 2.5 or 2.75 lbs. now, and I'll
experiment with a little higher pressure), my GT6 has shown quite a bit
of improvement on the straight sections -- it seems as if it was just
running out of fuel when asked to go WFO for more than 10 seconds at a
time.

But it still refuses to run when cornering, specifically left-handers.
For those of you familiar with Blackhawk Farms, that means from the
turn-in between 3A and 4 all the way down to 6, the car runs on 3
cylinders, if that.  Smells like gas, too.  Also makes the climb from
turn 5 at Road America less fun than it might otherwise be...

Maybe I WILL just go to the movies and forget the whole thing (and
replace them with the Webers)... ;-)

Scott



> -----Original Message-----
> From: N197TR4@cs.com [SMTP:N197TR4@cs.com]
> Sent: Monday, January 24, 2000 4:22 PM
> To:   kaskas@earthlink.net; vinttr4@geneseo.net; fot@autox.team.net
> Subject:      SU - Stromberg 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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