Thats pretty much what I told Walt this afternoon.
Ron
Walts engine builder
On Mon, 17 May 2004 20:34:55 -0500 "Jack W. Drews" <vinttr4@geneseo.net>
writes:
> This is a problem most TR vintage racers run into when an engine like
> this
> is run at full throttle for an extended period of time. The less
> expensive
> fuel pumps will simply not supply enough fuel to an engine like this
> on
> full song. When you have a pump like this, and have an in-cockpit
> fuel
> pressure gauge, or if you are brave enough or stupid enough (that's
> me) to
> stand and watch a fuel pressure gauge while a car with a hi
> performance
> engine is run up on a chassis dyno, you can see the pressure drop
> off at
> higher rpms, sometimes down to near zero.
>
> One fix is simply to get a Holley fuel pump and regulator. The pump
> by
> itself puts out too much pressure so you do need a regulator to get
> it down
> to a pressure that our carburetors like.
>
> Unfortunately, that is not an ideal fix either, because the Holley
> regulators may (or may not) fail after a period of time and get
> erratic. No
> one seems to know why because there's nothing to the innards of
> these
> things, just a ball, diaphragm, and spring. The ultimate solution is
> to get
> a $100 bypass regulator and run a return line to the tank, all of
> which
> seems like real overkill, but it fixes the problem once and for
> all.
>
>
>
> At 07:40 PM 5/17/2004, Walt Hollowell wrote:
> >I could use a little help from some FOT members that drive TR6s
> with triple
> >Webers.
> >In hard street use and SCCA autocross events I have no problems.
> However,
> >this past weekend I was club roadracing
> >on our Albuquerque, New Mexico 14 corner 1.65 mile road course.
> After the
> >4th or 5th lap on full throttle the engine started falling flat as
> if I
> >dropped a couple of cyclinders due to lack of fuel (110 octane
> racing gas).
> >I had to fall back in the pack and not push too hard (not difficult
> with my
> >driving skills) or things would just run flat. I suspect I do not
> have the
> >volume of fuel I need for this racing application.
> >My engine is putting 155 hp to the ground (just did a chassis dyno
> last
> >week) with a few more ponies to be found with some more tuning. We
> are
> >racing at 5,500 ft. above sea level. I have 10.5:1 compression,
> ported
> >heads, stiffer valve springs, 286 cam, headers and triple Weber 40
> DCOE
> >carbs. My main jets are 200 air and 115 fuel. Emulsion tubes are
> F7. Idle
> >jets are 55, acelerator jets are 40 and the bleed off is set at
> zero. I am
> >using the cheap electric fuel pump you can get at Pep Boys which
> has
> >performed OK up till now..If it is the higher volume of the two
> types they
> >sell. A fuel pressure gauge shows I am getting between 2.5 and 3
> PSI of fuel
> >to the carbs. I am not using the stock mechanical TR6 fuel pump at
> all.If my
> >problem is in fact not enough volume things now get difficult. Do
> you think
> >I can just hook up a second (same type) fuel pump in line to
> increase the
> >volume a little or am I going to have to find a high volume, low
> pressure
> >fuel pump with a return line back to the gas tank.
> >Has anyone else came across a similar problem?
> >Any suggestions?
> >
> >Thank You
> >Walt Hollowell
> >Albuquerque, New Mexico
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