propane and evaporative cooling

[300kGN]

Is anyone using propane injection? I see a lot of alky posts but nothing on propane. Seems to me injecting liquid propane before the IC could cause a radical charge temp drop due to the phase change from liquid to gas (like freon in the evaporator). But hell, I'm definitely not a chemist or physisist(?). :redface: Just wondering would it go bang good! or boom BAD. BTW 300K went 12.43 today on 23#, 1.65 60'. 2-3 shift is done Really need some more cooling!!

 

[TType84]

Is anyone using propane injection? I see a lot of alky posts but nothing on propane. Seems to me injecting liquid propane before the IC could cause a radical charge temp drop due to the phase change from liquid to gas (like freon in the evaporator). But hell, I'm definitely not a chemist or physisist(?). :redface: Just wondering would it go bang good! or boom BAD. BTW 300K went 12.43 today on 23#, 1.65 60'. 2-3 shift is done Really need some more cooling!!

i have the jay carter pro-pain kit on my car.

28psi, 93octane, no intercooler

think it works?

 

[Razor]

I think you need an update to your sig.
3125 curb weight, 13.6*98 mph at 28 PSI.. 28 PSI you should be running high 10's with that weight.

 

[Grumpy]

i have the jay carter pro-pain kit on my car.

28psi, 93octane, no intercooler

think it works?

28psi ??? BUT are you making power??? I had propain on another GN here ... changed it last year to ALKY ... there is a BIG difference in power

 

[300kGN]

so Grump, definitively, all things considered and the same, (ie. boost#, ambient temp, bolt-ons, etc...)more power from Alky than propane?
Not doubting you. Just looking for your experienced based opinion. I would figure the combustion temp of propane is higher than that of alchohol-which could negate any gains made by intake temp drop? Thanks for the input!!!

 

[Grumpy]

so Grump, definitively, all things considered and the same, (ie. boost#, ambient temp, bolt-ons, etc...)more power from Alky than propane?
Not doubting you. Just looking for your experienced based opinion. I would figure the combustion temp of propane is higher than that of alchohol-which could negate any gains made by intake temp drop? Thanks for the input!!!

difference of night and day plus we could run more boost with the alky "tuned" in this was on a mid 11 car

 

[Lonnie]

All propane injection that I have seen is in vapor form.

Injecting liquid as you stated could substantially cool the mixture, but the amount needed for cooling would equal a huge quantity of gaseous propane. This would be well in excess of the amount required to actually fuel the motor. It has an extreme expansion rate when it vaporizes.

This is fine when injecting liquid nitrous as a small volume of liquid turns to a large air portion "air" for your air/fuel mix. Injecting liquid propane would cause a very rich mixture. A .045 jet (in vapor form) could feed an appriximate 75 hp motor (depending on bottle pressure) as the only fuel supplied to the motor.... not as an additive fuel. I do not have the actual evaporation data handy, but it is likely well over 100 times this volume as a liquid.

Propane will detonate on overly rich mixtures, so this is not something to experiment with unless you have deep pockets.

Hope this generalization helps a little.

 

[468Chevelle]

The problem with propane vs. alcohol is the states the fuel is in. Alcohol is a liquid, propane is a gas. When you inject propane, it instantly turns to a gas in the intake. Much of the Alcohol will make into the cylinder as a liquid and this is important. In the cylinder, the alcohol will evaporate, pulling heat out the cylinder. This is called latent heat exchange. Pulling heat out, prevents the formation of oxides of nitrogen (a bad emission gas), but also prevents preignition (good for more boost and power).:wink: This is the problem faced by manufactures of the gas direct injection engines. They fire the injector fuel directly in the cylinders at different times for different effects. Firing the injector at TDC is called Stratified injected. It is a small amount of fuel, just enough to kep the engine running. (good for fuel economy, bad for power). Or they fire the injector on the intake stroke. (homogoneus). More fuel is added, latent heat exchange happens, more power is produced. The computer in the car decides when the injector fires, depending on what is needed at that time. I hope that helps.