Propane injection kit?

Jon Pennington cowboydren@yahoo.com
Tue, 19 Mar 2002 11:11:01 -0600


--- mike kojima <choaderboy2@yahoo.com> wrote:

[water vs. propane]

> They are two opposite things that don't equal the same
> result.

Clearly not.  Water is used to cool the incoming charge (the water is
around 70-80*?) and keep the fuel from burning too quickly, as this
monkey understands it.  Propane should be quite a bit more effective
at cooling the charge, as the phase change from liquid to gas when
it's injected would cause a *dramatic* reduction in the propane's
temperature, which should also be more effective at cooling the air
coming into the manifold.  The only thing I'd be even slightly
worried about is oxygen displacement, but that's where this all
started; too much hot air coming into the manifold, too hot to be
efficeient and not enough fuel to burn with it!

> Propane has a high research octane, I don't think the
> motor octane is very high meaning it has high
> sensitivity.

A dedicated propane engine should have a static compression ratio of
around 12:1 or 13:1, IIRC (which I often don't), which would lead me
and others to believe that it it would live very well under the
conditions of a boosted gasoline engine.  It's used in turbo deisel
engines almost commonly (static compression ratios of more like
14:1), supporting this idea at least at a cursory level.

Propane has a very distinct advantage over water; it's combustible.
After the cooling benefits have been taken advantage of, it would
also mean that you would consume less of your high-SG (not to mention
expensive) race gas, since the gasoline wouldn't have to be enriched
as much to compensate for all of the extra air that overgrown hair
dryer is already introducing.  If this monkey's thoughts are at all
in line with reality, once harnessed, LPG would be an *excellent*
additon to a high-boost gasoline engine.  Much tuning would be in
order to make sure that your combustion chambers and EGTs are
reasonably safe, which is the biggest single roadblock.

I have neither the turbo nor the other resources to prove or disprove
this idea on a dyno, but Jason has already thrown the gauntlet down
in my place.  If he had an old N2O kit with very adjustable jets and
a propane tank, we could settle this once and for all.  Imagine the
power potential combined with Ben Davis' LBBBT.  Thirteens for under
two grand, anybody? :)

=====
--
-=|JP|=-          Need a good geek?  I'm unemployed!

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