BTW, there are a lot of alternatives to insufficient fuel delivery. You
should check your float levels very carefully. The best way is to pull the
emulsion tubes and look down them with a flashlight. One of the tubes has a
feed hole on one side. Blow gently down the tube and see if the gas level
rises back up to where it just reaches the hole. That's perfect float level.
A quick check for weak spark (which can easily cause the problem you are
describing) is to narrow the plug gap to about .015". You don't want to run
there permanently because it's easy to foul that small of a gap and you want
a fatter spark, but voltage-caused problems will generally go away.
Likewise, if you open the gap to .050" it will get a lot worse.
Incidentally, a second pump in line will not increase the flow much, it will
increase the pressure. You want the pumps in parallel to increase flow--just
like batteries. Its funny, when people are explaining voltage, current and
resistance they use pumps and water as the analogy, and here I'm using
electricity to explain pumps.
-----Original Message-----
From: owner-fot@autox.team.net
To: fot@autox.team.net
Sent: 5/17/2004 5:40 PM
Subject: out of fuel- I think?
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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