i'm just wondering how much compression i could run. ideas/suggestions welcome

 

I ran a water injection in the late '80s on my iron head big block to help out on hot days. It was not very reliable, but it worked. I've also considered using it in forced induction applications. All the experts who write books are down on it, but I still think it has a place. I've also wondered about using a knock sensor to trigger it. Maybe the knock sensor could light a dash light, then the operator could adjust a dial to keep the motor out of detonation, rather than using the sensor as a switch.

 

years ago i had 2 tanks, one came on a 8 psi boost, #2 at 18 psi. it worked very good.
it's easy with a blower/turbo.
Much harder with a high compression engine as it could ping under slight acceleration. Octane knock can break the piston skirts.
Just kicking around ideas. i was thinking of a port system like on NOS, so the lean cyl's could get as much as they need. Maybe a big cam designed to bleed off pressure under 2500
then trigger with a TPS and knock sensor.

 

Matt,

Check out this site. This will probably be my next engine mod to help live with the 12:1 compression of my L88. http://www.aquamist.co.uk/ The cost is about $800+; but it is a mapable injection system much more sophisticated than the old windshield washer systems (i.e the Edlebrock system) converted to water injection. Another side benefit is that it should keep the complete combustion chambers and associated induction parts absolutely clean.

Chuck

 

with 12:1 yours is the perfect candidate.
that site is good; appears port WI is NOT necessary.
for $800 it better work! i think a clever guy with a timer circuit could build something effective for less, but including development time, maybe not

 

Take a look at http://www.carrollsupercharging.com/

They run a water/alcohol injection system instead of an intercooler.

 

I fiddled around with it on my 12/1 street engine but then was talked into using avgas. One problem I found was appropriate atomisation of the water/methanol. I reckon a good idea would be to use a nitrous fogger type nozzel but inject gasseous N20 not liquid N20 with the water. That way you will still get good atomisation but little N20 and a small bottle would last ages. I made up a vacume switch out of an old set of points and a dizzy vacume canister to activate the system. The switch worked.

 

years ago when GM used water injection with alcohol in the turbo charged olds engines they saw excess top ring groove wear. i also saw this on supercharged BBC boat engine when we tried water/alcohol injection. it come from washing the oil off of the cylinder wall.


[Modified by clem zahrobsky, 1:22 PM 6/24/2004]

 

that's interesting, clem. the grooves in the piston wore with excessive side clearance, but the ring was ok? or the ring wore fast too, as evidenced by an increasing gap?
how many miles did they last?

 

i have no idea about the milage on what GM found but the boat engines it showed up after a couple of summer as the engine lost power and that was the cause. this was years ago and maybe now with better injection control of the H20/alcohol mixture this may not be a problem i m sure that both parts wore causing the excess side clearance


[Modified by clem zahrobsky, 3:03 PM 6/24/2004]

 

Clem, could that be due to the alcy, not the water, washing the oil off (like an overly rich mixture does)? Reason I ask is that we've got a '79 Saab 900 Turbo that was fitted with aftermarket water injection by Saab, or somebody in with them (I think they were experimenting with it?). It's been running since '79 or '80 with the water injection & 3 or 4 years ago I had a lot of it apart for the 1st time. Couldn't detect any serious wear to the bores or pistons (the chambers were also remarkably clean). In fact, there was less wear than I've seen in engines with 1/2 the mileage on them. It's a real pity the bodywork is on the way out as that car leaves my Vette for dead (& a lot of modern performance cars - which is fun, they don't like it one little bit ).

 

The test your referring to is on Buick turbo motors. The only cylinder wear occured on the endurance dyno testing. This test ran the motor in cycles from max tq to max hp...continuously for the erquivalent of 100,000 miles!!! No other test showed any appreciable wear.

Their test conclusion is the following quote "Many people have successfully used alcohol injection on Turbo Buick engines hundreds of passes with no damage to parts, seals, or cylinder walls. GM did implement alcohol injection on a few durability test engines run on a dyno. During the durability tests the engines were cycled between the peak torque RPM and the peak horsepower RPM for the equivalent of 100,000 miles. Afterwards they were tore down and examined. They noted significantly more cylinder bore wear in the alcohol/water injected engines. It was believed to be from unburnt alcohol and water washing the oil off the cylinder walls but they could have also been running higher boost levels. This wear problem was only found on engines run through the durability dyno test and not on any other tests. The alcohol kits for Turbo Buicks only turn on during boost situations. So, I guess if you plan on having your foot to the floor for 100,000 miles with the alcohol injecting this could pose a potential problem for you otherwise there is no worry.
Alcohol does not cause any problems to your engine. It actually "steam" cleans the inside of your throttle body, intake, heads, valves, and exhaust! I know some list members that have taken their engines apart after using alcohol injection for a long time. Everything is very clean and no damage to any engine parts. No problems with washing the cylinders out. "

Alcohol injection is safe and does not cause excess wear...unless you drive 100,000 miles at WOT

 

Can a 'fuel' injector be used to spray water?
What about using a carberator to add water/alky
to the airstream. The carb could be put upstream of the blower. Doesn't have to be perfect. A carb might
have one psi of pressure drop, but with boost,
who cares.