water injection?? any opinions?

[Guest needwaymorespeed]

Well ive been thinking about running a water injection system to help with detonation. I thought id see if anyones used it and how well it worked for them

Thanks

Curtis

[Scottie-GNZ]

Curtis,

 

give some more details on your setup. Unless you are running a turbo with high boost or an NA with high compression, there are many things you can and should tune before you need something like water injection. Some of the things that come to mind are: timing, fuel mixture/volume/quality, coolant temp, spark plug heat range, too much boost for the octane level, inneficient or lack of an I/C.

 

Even if you end up do needing water or alcohol injection, you should still check and correct the list first.

[Andrew Bayley]

Curtis,

I played around a little with water injection on a suck-through type carb turbo system. It was not worth the effort. The water inside the combustion chamber takes away a significant amount of energy. For instance, 10 psi without water injection was way faster than 14 psi with water injection.

 

Also, on the suck through system, I was spraying the water in before the compressor. Most people agreed that constant use would result in the little water droplets destroying the compressor wheel. I was worrisome about this too, but I could not get the correct air/water mix any other way.

 

I'm sure I could have dialed the system in a little better, but the initial results were disappointing. IMHO, water injection is a band aid fix. Unfortunately, people running carb setups don't have many other choices.

 

Three words: Fuel Injection + Intercooler ( = No need for water injection)

 

I don't mean to poop on your parade, but I just remember spending a lot of time and a few bucks making my own water injection system and I was very disappointed. There are kits out there for carb type setups, just keep in mind how water injection works.

It's not an intercooler, it's water...

that's getting dumped into your combustion chamber...

instead of air and fuel...

which makes power.

 

-Andy

 

P.S. got that roll bar mounted yet?

[Guest Fast Frog]

Andy's right!!

 

I used water and alcohol mix as a detonation preventer for several yrs when I was running a turbocharger. It works but there is a noticable loss of power! I didn't experience the loss that Andy describes but it's there. There are better ways to handle detonation-lower CR, intercooler or higher octane gas are a few! Or all three!!

[Guest Anonymous]

Andy and Scottie summed up my thoughts as well, it is a crutch to try and fix a problem that could be dealt with better with proper engine tune and setup. Its a pretty old scheme, first production use that I can remember was the Old's 215 turbo motor, they used it to try and keep detonation down under boost and they mixed it with alcohol. The system was'nt real effective and many of the turbo motors were changed over to normally aspirated because of the ineffectiveness and the lack of technology of the day. I'm sure it was probably used much earlier, probably a offshoot of WWII aircraft usage although I have no first hand information as to if that is so.

 

It might help to knock off a little carbon out of the combustion chamber due to the cooling effect, but as Andy said there goes your combustion energy and heat = reduced HP.

 

Make sure its all tuned to spec, retard the timing if necessary, add octane booster if your running to much compression for the octane available or run a higher octane fuel if your using regular, fuel mixture and cooling system can play a part too. Check it all out and you'll probably solve your problem.

 

Lone

[Guest needwaymorespeed]

thanks for the posts guys-I dont even have the engine in the car yet,my thinking was to use it to prevent detonation-use higher compression with lots of ignition advance and use the pooorer quality of fuel and still not ping,It sounds like from the experiences here that it sucks up more power than what the extra ignition lead or higher compression would net you.

andrew no the roll bar still isnt in, the cars up in the air about three ft and everything but the dash is stripped out of it

I've gone way overbord on this one never intended to go down this far but I keep saying"well im this far I might as well take a look at this" and bam the car is even more stripped down. everyone around here thinks im nuts!

Whats realy sad is that this thing will be totaly mechanically new with the underside and florboards all painted pretty but the exterior is still goona look like crap! just dont seem right.

 

thanks

Curtis

[pparaska]

Curtis, you pretty much described the major factor in how my "put some framerails and a V8 in the car" project turned into a huge "snowball". No worry, it was a fun and satisfying process. Hopefully, you have more time and are more efficient that I was in getting it done!

 

As for H2O injection, it might be nice to be able to turn it on from time to time to clean the combustion chambers .

Boost + carbon_deposits = detonation

[Scottie-GNZ]

Curtis, still do not know what type of combo you have. Hopefully it is not a turbo.

 

You made the following statement:

quote

my thinking was to use it to prevent detonation-use higher compression with lots of ignition advance and use the pooorer quality of fuel and still not ping

If this is a turbo, higher compression, lots of ign advance and poorer quality fuel is the exact opposite of what you want and in fact is a fine recipe for a major explosion .

 

[ May 25, 2001: Message edited by: Scottie-GNZ ]

[Guest needwaymorespeed]

Scottie-I totaly agree with you turbo motor or not if you get detonation youre in BIG TROUBLE!

Its not a turbo its n.a. has 10-1 comp. ratio

 

Thanks

Curtis

[Guest Anonymous]

Might try external water injection, in having water squirt directly at the intercooler WRX style during high boost situations using a cheap setup of an extra windshield washer pump, a few nozzles and a reservoir. Would help cool the intake charge a bit more, although you wouldn't want to always run high boost depending upon this, because you wouldn't know if you were outta water until you popped the hood and checked the reservoir. Might come in handy on a hot day or something though...

[BLKMGK]

Airplanes use this too - it's called "spraybar" if memory serves. The racing planes carry huge tanks of some mixture that they spray on the intercoolers during a race. It's a short duration thing obviously

 

With an electronic boost controller you could wire it such that if the tank went dry it reverted to low boost... Personally I'm not sure I'd want water going all over the place - like under my tires! You'd want a pretty fine mist I'd think - washer pumps aren't know for working long under constant use or for hainv high pressures so you might want to look for a heavier duty source as a pump. (shrug)

[Scottie-GNZ]

BLKMGK,

 

you hit the nail on the head with these systems. Water spray is most effective when it is applied as a fine mist that evaporates immediately. The problem with racing with that setup is the concern about it not misting and instead streaming water which drips right in front of the rear tires .

 

A more efective method of decreasing detonation is to inject alcohol in the up pipe just before the TB. It is still, however, a poor and more complex substitute for doing it the correct way which is properly sized injectors, an efficient I/C and octane.