Hi Dick,
On the advance issue, high spark advance numbers required for nitro (and
alky) are the result of slower burn rates (flame front). You must start the
fire burning earlier in the combustion cycle with slower burning fuels.
This is a topic that I have a lot of interest in but no data!!! Does
anybody have flame front data for the fuels that we use in racing today? I
remember data in a late 50s or early 60s Hot Rod mag. I think it was Hot
Rod......but I cannot find it. If we had the data, we could do some more
testing........read "playing". I know it works with alky at 60 degrees in a
SBC unblown.....instead of a "lean out" device.....burns more fuel and
makes more power.
Contacting fuel companies has not worked so far....
Skip (Curious as always)
At 02:37 PM 1/3/02 -0800, you wrote:
> Dave Dahlgren <ddahlgren@snet.net> wrote:
>I would suspect they 'tolerate' the ignition advance because the design is so
>poor thermally.. It is not the sign of a good design, it is the characteristic
>of a poor one though. \
>
>
>
>Fact of the matter is, the Chrylser hemis only like around 28 - 35 degrees,
>until fuel loads get above 80% Nitro. Once you get up that high in nitro,
>then they like 55-70 degrees. When you get that high in nitro, it's my
>opinion that you are no longer dealing with flame propogation, etc, you are
>dealing with true explisions in the cylinders, and the time of travel of an
>explosive charge is much different than a flame burn. But I'm really out of
>my realm here, this is engineering stuff. I'm just an old shade tree
mechanic.
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