I want a general list of advantages of propane injection and another of the disadvantages.... All I'm wondering is if it's worth the $400+ that IPO online is offering? Like how much more gains would I get? And I know it's like running Race Fuel but at a fraction of the cost.... I am just wondering too see if it is worthy enough to seriously consider.... I do know however if All I'm looking for is power just go Wet Nitrous. But I want something that i can run all the time or just part of the time and see some gains... Let me know on this one guys.

Woody

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~Woody...

I won't do anything for you. It is used for extra fuel/knock suppresant for turbo cars. If you have a built motor (higher compression) and many other mods it might be helpful but race gas still may not be needed then either.

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'94 vr4- Now with extra slowness

http://www.3si.org/forum/showthread.php?t=217433

Will explain things a lot better than me...

Greg linked to the appropriate thread on 3SI.

Propane is a knock suppressant just like water/alcohol injection. It allows you to make more power safely on pump gas. Is it as good as race gas? No. Is it cheaper? Yes. Do you need it for an N/A motor? No.

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Any internal combustion engine needs air, fuel, and compression. To get more horsepower you can increase any of those three, but you must keep a balance in the equation.

Nitrous oxide adds air to the equation, because the atmosphere has 3.76 "peices" of nitrogen to every "peice" of oxygen. In the bottle you have 2 "peices" of nitrogen to every "peice" of oxygen. Oxygen is what reacts, and nitrogen just piggybacks the equation and robs energy. So for more horsepower the bottle is desirable.

Propane is a fuel, much like the gas you put in your car from the pump. you can run 91, 94, or 100 octane in an NA, but it will not make you go any faster unless the engine needs that amount of octane to keep off predetonation. Just like spraying more fuel will not add any horsepower, as you must have the right amount of air to react with the fuel.

You can also run a high compression motor, and squeeze the whole mess more, which will yeild more power, but also requires more octane, because higher compression will be more knock prone.

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Well, Reading what you guys wrote and that link to that thread on 3SI my knowledge on this stuff has greatly increased. Sure, If I had a TT setup I woudl probably buy it but I'm not soo... So one thing I have a question about is: From what I understand If I put 95 octane in my SOHC It will make No difference performance wise at al in a N/Al? compared to say 89. But you would get a cleaner burn though with higher ocatane right?


Woody

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She's my baby!

~Woody...

Engines have static and dynamic compression ratios. In a N/A motor, your dynamic (actual) compression ratio will only change based on elevation, hence the reason you must adjust your carb when you drasticly change alt. In a forced induction motor, you are taking the density of the ambient air, compressing it, then throwing it into the motor. This obviously effects the dynamic compression ratio, hence our need for more fuel with a denser air charge. Your static compression ratio is what the motor "should" be on paper, it never changes.

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cleaner burn would depend on the additives in the gas. the higher octane will just slow down the explosion in the cylinder. to much octane will actually take power away, as you are not pushing the piston down with all the force of the gas/air mixture exploding.

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Bad decisions make good stories.
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okay... Now I am confused... The lesser the octane the faster the explosion, which moves piston faster which equals more power, or atleast rev quicker? But you guys run high octane becuase you have higher compression. Like what would 89 octane do to say a car that requires 95 octane (premium)? So the slower the explosion the better than?

Woody

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She's my baby!

~Woody...

No, I run higher octane as a knock suppresor only. See, the higher the octane, the less easily it ignites thus making it a knock deterrent. Knock is ingition happening when it shouldn't (igintion when the pistion is traveling UP the cylender). Higher octane, when you don't change anything else, lowers horsepower because it requires more energy to ignite.

The idea is to run as low of octane as you can get away with without knock. That will give you the most power.

okay, Now i get it... That's why they dont' sell anything under 89 octane otherwise I'd probably start getting knock in my SOHC then? Now the octane levels change when they refine it then i take it? Can somebody explain how they do that please.

Woody

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She's my baby!

~Woody...

octane is changed by addatives that they put in the gas.

_________________
Bad decisions make good stories.
Look at it! LOOK AT MY @SS AND TELL ME IT'S PRETTY!