A sidelight to flow reversal. Using headers that are 4-6 mm larger than
the exhaust ports at the head will cause trapping of gas and prevent
reversal and allow better scavenging, according to a UK book on head
flow I read last year.
Works for me....
Simon Favre wrote:
>
> An interesting question (FINALLY!). I have a similar problem with
> a Formula Junior motor, but I'm almost certain it's the crummy carbs.
> Mine does this, but only on right turns. Left turns seem to be no
> problem.
>
> As a thought to your question, there is a thing called "standoff"
> that is affected by the length of the intake runners, as well as the
> cam, etc. At certain RPMs, there is a kind of reversal that happens
> between the intake and exhaust that hinders flow into the motor. I'm
> probably not explaining this correctly. Perhaps opening the intakes a
> bit later prevents the standoff effect from choking the motor. Do
> you have an O2 meter on the car? I'm trying to get more info on my
> problem using one. If your motor is running lean when it stumbles,
> that may be a clue.
>
> >NOW the question is (and I really don't know the answer) what is
> >happening in those first .050" lift that is causing this breakup?
--
Jim Hayes Winchester, MA, USA
hayes@mediaone.net http://www.fotec.com/jim.htm
jeh@fotec.com http://www.fotec.com/
All generalizations, with the possible exception of this one, are false!
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