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by Dave Koehler
1/7/05
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How can an
rpm-limiter work in a fuel motor? If this is true
(and, it's generally accepted as fact: it's all
over the Internet, and has been for a while.)
To wit: "Spark
plug electrodes are totally consumed during a
pass. After 1/2 way, the engine is dieseling from
compression-plus the glow of exhaust valves at
1400 degrees F. The engine can only be shut down
by cutting off its fuel flow." So, you're
going to limit the rpm by cutting off the spark?
I don't think so.... IF this is (the above statement)
is true. If it's NOT true, why hasn't it been
challenged and de-bunked by now? I'm just asking...
Ray Alley is nobody's fool...
Bill Dedman
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Bill,
Ahhh, the internet. It is kind of like today's network tv
news. Take it for what it is worth until you see it for yourself.
I have thought about this from time to time. I will concentrate
my thoughts on the spark plug and exhaust valve issue. Nitro
ignition via compression is a whole 'nother can of worms.
"Back in the day" there was a much talked about
case of the mag exiting the engine and the car still ran.
This was not a common occurrence however. This hot valve scenario
was deemed logical at the time but I know of no one that went
out of their way and pocket book to verify this scenario.
If the mag stays put and the plugs were toast at the end
of the run who can say when they actually croaked. Also, if
the plug strap burned off did the spark just move to the next
available ground like the ring/threads of the plug?
We all have seen on slo mo TV where a fuel car drops a hole
and then picks it back up. This can only be happening if there
is a controlled spark available. It cannot be due to that
cherry red exhaust valve. It would have already been cooled
off by the previous flying fuel.
All the above is moot anyway since fuel car crew chiefs have
been advancing and retarding the ignition via chips for a
few years now, and the only way that can happen is if spark
is available for manipulation, therefore, rev limiting with
electronics is also possible.
Sooooo… I say that in today's fuel car the plugs are
still firing until it drops a cylinder and the raw fuel flies
into the stands.
Have a safe race
Dave Koehler
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Fuel
for Thought [12/8/04]
Dave Koehler answers your nitrous & fuel-injection related questions |
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