What is the purpose of running alcohol injection on forced induction applications? I've noticed a few blower guys running them. I thought alcohol will make the engine run hotter=less power . Can someone help me out here?

 

The basis of the injections is to help prevent detonation to allow you to run more boost. The water or alcohol has a higher specific heat, I believe is the right term, than air does and when it becomes compressed sucks heat out of the air and into the liquid. I probably didnt' hit this right on the head but the short of it is it allows you to run more boost safely.

 

Alcohol burns MUCH cooler than gasoline, and has a nice high octane rating of 101.

 

Water injection has been used on piston engines since WW II aircraft.
Tractor pull guys use it to get those huge boost numbers.
The water and/or alchohol soaks up the heat generated compressing the air by expanding thus cooling and dampening the charge and preventing detonation.

 

Chosing between water, water/alcohol mixtures, and straight alcohol is an interesting question. What they all have in common is that they are inhbit detonation and also cool the air charge (which is one of the reasons for the anti-detonation properties). In and of itself, they actually may cost hp. That's because they are replacing fuel and air with either an inert material (water) or with alcohol (which has less energy density than gasoline). However, they do increase the density of the fuel air charge (which compensates for some of the gasoline and air displaced) and allow more boost and timing to be run without destroying engine components. AFAIK, I have one of the only hi-po SC setups running without an intercooler. It's possible for a variety of reasons, but use of water/alcohol injection is the most significant. I use the kit made by my friend Bob Kennedy at www.kennedysdynotune.com

Rich Krause