This is a direct response to Mike@AwdPerformance's post
http://forums.evolutionm.net/evo-eng...cracked+piston
I ran alcohol injection on my evo8 for
50,000 miles and here's what my pistons look like:
I have a lot of respect for Mike, but the point I want to get across to everyone that read Mike's
thread is that it is grossly generalized! There are two kinds of alky kits out there:
-ones that are cheap and could very well blow your motor up (especially if they fail)
-ones that will work well and serve you well for years on end and no they won't blow up your motor (if they fail)
EDUCATION is what keeps your motor healthy. Using the wrong kits is like playing with fire! There are really only three things you need to know about alky kits:
-precise, consistent spray pattern
-failsafes that work
-reliably add 50whp/50wtq
PRECISION
Ok from the top! Why do some alky kits cause pistons to crack? Because they do not consistently spray alcohol(and/or water) into your entire engine, evenly. The best way to have an even distribution is with consistent fluid pressure. This is NOT rocket science, right? Fuel pressure from your stock fuel system is consistent, so should the alky you're spraying in on top of it.
Most of the cheaper kits on the market are progressive pump speed kits, meaning as they start spraying on the pump kicks on, pressure builds up and then it starts spraying. Kind of hard for a nice fine mist to spray into the engine when its dribbling out of the pump eh? Then, when you let off the gas, the pump turns off and pressure slowly falls off in the line and fluid slowly stops spraying out.
Does this sound precise to you? (note: the pump mike pictured in his post is a progressive pump speed kit!)
The right way:
Other kits on the market have a pump that is *always* pumping (remind you of your fuel pump in your gas tank?) and output consistent pressure *all* the time. Sound good? Yup! Now, they also have a valve located very near the engine that turns on and off when you want it to inject (sound kinda like fuel injectors?). With the full pressure fuel pump running behind this valve, you can very precisely control the fuel injection.
Here's a few videos clearly demonstrating the difference between these two different types of kits. They were originally taken by Abner aka SlowCar but I can't seem to get a hold of him, so I rehosted them on youtube.
Note the difference between the nozzle on the left (high speed valve) and the nozzle on the right (progressive pump). Pretend the green lights are when you are WOT.
http://www.youtube.com/watch?v=c0FYGkMX1rg&hd=1
http://www.youtube.com/watch?v=KZRI7WZHggQ&hd=1
http://www.youtube.com/watch?v=8aoqhxQMtqA&hd=1
Think about those nozzles dribbling away when you're trying to run 30psi of boost (on onset) or just let off the throttle, might cause problems sooner or later eh? The kits that can accurately control when you want (and don't want) fuel injecting into your engine can reliably add power to your engine for years on end!
FAILSAFES
Ok next up, failsafes! This info has been a sticky in the
Water/Alcohol Injection forum for a long time, but its not like anyone reads those things anyways right?
Here's what happens when a well-setup alky kit with a well-setup failsafe when a problem happens (yup, even good kits have problems). This is a WOT run on a dyno, failsafe kicks in at ~5000rpm, AFR drops to a 100% safe pump gas level (and your pistons don't crack!):
Furthermore, boost drops to a safe level:
There is no question, lots of things can happen: too little flow, too much flow, zero flow, low fluid level, loss of power, etc etc etc and if your alky kit is setup properly, your engine will SURVIVE!
More info on failafes here:
http://forums.evolutionm.net/water-a...ther-last.html
http://forums.evolutionm.net/water-a...failsafes.html
POWER
Lastly, why bother running alky injection? +50whp/+50wtq, pretty easily.
Here's my stock turbo setup with and without alcohol injection (with tuning on both) 358whp vs 318whp:
Here's my BBK setup - 384whp vs 432whp:
SUMMARY
Alky kits don't caused cracked pistons, CHEAP alky kits cause cracked pistons. I used it for 50,000 miles with tremendous success, and so can you!
side note: e85 is pretty awesome (in some ways better, some ways worse than alky injection), but not everyone can get it, let's leave discussion of it out of this thread please
