Alright... I know a little bit about the different types of injection (water, propane, alcohol/water) but I've never found a platform where all three are being used. Therefore it's really hard to find out what the benefits of one system is over the other. On WRX's, water is used primarily with a few propane peeps walking around. I just want to know what advantages one system has over the others... I know how they work, and the differences between them scientifically, so you don't have to go into that. Just wondering the real world differences.

 

Water injecton will reduce cylinder head temps. You will actually make less power at teh same boost level, but you can run higher levels of boost without worrying as much about detonation. You will run at a lower BSFC. lemme dig up a good argument about water injection....

 

First read this: http://www.sr20deforum.com/showthrea...ater+injection

Then this: http://www.sr20deforum.com/showthrea...ater+injection

That should help you with the water injection thing
Sorry but I dont know anything about the other ones.

 

3000GT VR4 guys use propane alot. I've heard of a few GN guys running with it too. The GN guys use alcohol mostly though. As far as water injection, that's pretty widespread. You probably won't be able to find an example of each all on one car. You'll just have to mix and match opinions.
Alcohol is the best IMO, it won't rust the intake if any of it's left after running. You can cut it with water, getting double the effect and it's really easy to get either or both of the ingredients.

 

Propane is just a fuel forgot what octane it is. Like running race gas.

 

Well, I don't know anyone who has been running it for a long time... but I've heard prolonged use of propane is bad for your engine. Again, I have no idea if that's true. I'm pretty sure I'll end up with a alcohol/water or just water mixture... I'm thinking of making maps for both systems so I can just run whatever I feel like at the time.

A question about alcohol/water... I assume the mix has to be the same if you don't want to change your tuning. How much leeway is there? I wish Danny (MR2) was still around so I could pick his brain.

 

You'll find that propane injection is designed more as a seconday fuel and cooler than anything else, it is combustable so it enrichens your fuel air mixture which can reduce detonation and also expands at a very cold temperature so you end up with a denser air charge. The main point of water injection is to simply increase compression as water is non compressable. You're essentially decreasing the size of your combustion chaimber thus increasing compression ratio.

 

WRONG!

 

Water is compressable... but only under very high pressure. But, yah, I get what you're saying. Everyone always said water injection was just used for cooling... the WRX road course guys can do a 5-10 minute run and all points of their intake are cool to touch.

 

Check with some diesel people they have been using it for a while now.