Does anybody have a water injection system on their car? (meaning water injection, not an intercooler sprayer)
What kind of boost did you run before?
What kind of boost were you able to run after? Difference in EGTs?
Thanks!

Dave,

I don't use WI but from what I gather, spending money on improving the intercooling is a much better way to go if performance is the aim.

WI works well at suppressing detonation but doesn't do much for power allegedly.

Having said that, a fair number of people in the UK use it - favouring ERLs system http://www.waterinjection.net/aquamist.html which is used in the WRC Imprezas.

Apparently, the WRC cars run 2.1 bar boost with WI (and a front-mount IC)...

It might be worth posting a question on Scoobynet http://bbs.scoobynet.co.uk to get some owner's opinions?

Thanks

Gavin

[This message has been edited by GavinP (edited April 29, 2001).]

I installed a WI system on my turbo SVX. I run 10.1:1 compression, so I am very close to detonation. The WI seems to have helped to calm down the detonation sensors, so I have more timing. It would probably help a turbo 2.5 rs as well due to the high compression. I'm not sure if it would be worth it for the WRX, but it is cheap and I may try it. I got mine from spearco for 200 bucks.

cdigerlando,

What type of engine management are you running on your turbo SVX? I have an acquaintance who has a custom turbo 88 Fiero GT. He runs WI to help combat detonation as well...

IMO, that's bandaiding the problem. A fairly simple ECU, like an SDS, or something a bit more involved like a Wolfe or TEC-2 would do wonders for power, drivability and engine longevity.

Digital_Boy,
Now imagine you are running 8.5:1 compression, have a completely built motor, and just can't get more boost without detonation. Might be time for water injection, no matter what your engine management is.

bsquare,

I'd imagine you might want to take a look at your compressor and see where you're making boost most effeciently .

Absolute boost isn't as important as compressor effeciency. The turbo I'm getting is a T3/T4 with a 60-1 wheel with a .63 AR housing, and it can make 350HP, and still be 80% efficient, and running 15ish PSI. Bumping boost up nets me 400HP, and I'm at the limit of the compressor's effeciency., Any more boost and I heat the air so much that I begin losing power.

Plus, if you're going to run that much boost, you can run race gas, or do the home brew octane boost like the guys on the GNX board. http://www.i-club.com/ubb-files/smilies/biggrin.gif

I'm not knocking water injection, but IMO, it's a safety mechanism to keep your motor from becoming shrapnel.


Exactly HOW much boost are you running, and how much power are you expecting to make? My short block, at 9:1 w/JE forged pistons and Crower rods, will be able to reliably make 400-ish HP with the stock heads and cams. You aren't going to see 600HP on 92 octane gas. Period. Byron can't do it, ASR can't do it. AT that power level, you're looking at HUGE turbo's and 110 octane and up, or methanol/alchohol or nitromethane as your fuel source, and HUGE injectors and fuel lines.

I'm planning on fitting a water injection, either an Aqua Mist, or that other one mentioned from Summit. I'm not knockiung it, but I personally won't factor water into normal horsepower figures. It's there as a last line of defense, and it does a great job of cleaning the combustion chamber... http://www.i-club.com/ubb-files/smilies/biggrin.gif

(edited for context and some technical gaffes)


[This message has been edited by Digital_Boy (edited April 29, 2001).]

So in Turbo'd RSs when you start to get detonation around 7 or 8psi (stock fuel system except for high flow fuel pump, 4:1 RRFPR, TCII), is it because of the lack of fuel, or the high temps?
If its the high temps, then by adding water injection to bring the temps down would enable you to run higher boost, correct?
Thanks for the replys so far. http://www.i-club.com/ubb-files/smilies/smile.gif

yes, you could run higher boost, to a point, but water injection can only do so much.

If you're running much over 5PSI, you really need a big fuel pump, dual feed fuel rails (So you don't lean out #3 and detonate), big injectors and an ECU.

I am only running 5 psi boost. The SVX is a 3.3 liter flat 6 running 10.1:1 compression for the '92. 10:1 '93-97. I figured since I am not running a lot of boost this would be the best way to intercool.

As for the comment regarding engine softeware. YES! You are right. That is my next step. An A/W intercooler, Nismo injectors and electromotive Tec II pem (electronic WG control). SVX has direct ignition. My goal is 400 HP at the flywheel.

As for the comment regarding when WI is good, I think it is always good if you are running on the edge of detonation. Whether you are at 8:1 compression and 20 psi boost or you are at 10.1:1 compression running 5 psi boost. It helps quiet the detonation sensors for full timing advance. It is also much cheaper than race fuel.

I would also like to program my pem with 2 programs. 93 octane street and 105 octane race for autocross. Should be able to run more boost and timing with race fuel.

Someday I will rebuild the engine with 8.7:1 forged aluminum pistons, strenghened rods, and copper head gaskets. But not until I have to. These subarus never die. (knock on wood)

On my last car (a 1998 Jetta VR6) which was supercharged (non-intecooled with 9 psi of boost and 10:1 CR) with a Vortech V1-S trim, I made an extra 25 wheel hp with the cheap Spearco water injection kit. I was shocked. I redynoed again to triple check the results. The same thing came out everytime, 260 wheel hp and 230 wheel ft lb, good enough to run low 13's @107-108 mph in a full weight street car (about 3100 lb)

Basically, the water injection (actually, I ran a mix of methanol (I also ran drug store variety alcohol) and water )did 2 things on my car. One, it cooled the intake air somewhat. Secondly, it allowed more ignition advance. I suspect this is what made the lion's share of the power gain. In fact, I used to get knock on very hot days when the engine was fully warmed. After the water injection, I never heard the "castinets" ever play a tune again.

That sounds like an incredibly cool street car. Probably no turbo lag due to the 10:1 compression. Low 13s is great. My goal is to run between 8 and 10 psi. I guess you didn't intercool? Do you think its necessary for this little boost? I have heard that it is uneccessary when below 8 psi. So 8 to 10 psi with WI might not matter for me or you.

The only negative thing I can think of is that methanol is extremely rough on engine parts. So is alcohol. I'm sure this improved your gains though. I too noticed more ignition advance with the WI.

Dave -

When I had the turbo on my RS, I was able to run 5-6psi without the water injection. With it, I was able to go to 7-9psi. Not earth shattering, but enough to make a noticable difference.

-Paul

That sounds like an incredibly cool street car. Probably no turbo lag due to the 10:1
compression. Low 13s is great. My goal is to run between 8 and 10 psi. I guess you didn't
intercool? Do you think its necessary for this little boost? I have heard that it is
uneccessary when below 8 psi. So 8 to 10 psi with WI might not matter for me or you.

The only negative thing I can think of is that methanol is extremely rough on engine parts.
So is alcohol. I'm sure this improved your gains though. I too noticed more ignition
advance with the WI.

The amount of methanol/alcohol being injected has little affect. In fact, the entire intake path and combustion chambers get incredibly cleaned!

I think at 6-8 psi, intercooling would still help. But, its much easier and cheaper to do it with WI.

That is the subject of argument. Heat exchange occures at a greater rate with two fluids of greater temp difference. So the most efficient way is to let the air cool through the intercooler first then water inject before the TB. However some argue that the mixing you get through the intercooler helps to better entrain the water and allow it to vaporize better.

Either way I think it would help if you wanted to push more boost.

Hello, I'm a ERL/Aquamist distributor and have some great experience with quality waterinjection systems. ERL has the best waterinjection systems in the industry, most WRC teams are using ERL pumps,valves and atomizing jets. I recommend a look at the Aquamist website>> <A HREF="http://www.aquamist.co.uk/" TARGET=_blank>http://www.aquamist.co.uk/<<</A> They have a bunch of great tech info on W.I. and turbo engines in general. If you have any questions feel free to E-mail me. I also fab trick aluminum tanks and can assist with mapping and/or jet sizing if you need.

Peter VanBogart www.cascadeautosport.com (http://www.cascadeautosport.com)

[This message has been edited by PVB (edited May 02, 2001).]

How much can you get the base kit for?
Any discount if we can get a few people to buy kits?
Do you recommend using a seperate water tank (how big should it be), or just tapping the windshield resevior?
I've checked out that site, and it does a good job of answering alot of questions.

Hello,
after living down under for a few years, I picked up a some good mags. Particularly Fast Fours and Rotaries. Quote: This is in regards to APS's 206 KW upgrade.

"The last part of the kit is the water injection. the kit is boost sensitive (adjustible, but generally above 12 psi) and injects water from the factory wshare bottle into the intake manifold post intercooler. Incorporating an anti blowback facility and electric pump , boost is used to pressureise the water line to allow it to be injected into the highly pressureiszed intake manifold. the ikt includes a samll bottle which mounts in front of the battery, which is used as the windshield wahser resevoir. ther larger facory windshield washer resevoir sole duty is now water injection. and briefly, water injec. sprays into the intake to supress detonation and cool the induction charge, a little like a second intercooler.
does this help? hope it come here soon

-mark

have you guys thought about doing a 20 or so shot of nitrous...its cooling effect would be very drastic, and could allow for lots more boost, i already have a system waiting to go in after break in.

-grant

The way you make the nitrous work correctly, is first you use a toggle switch, then goes to a throtle switch, which finally goes to a RPM pill window switch. that allows the nitrous to only come on when your above, say 3000 rpm's and at full throtle.the map sensor will compensate for the drop in pressure and add more boost.at 20 shot you get no horse power from the oxygen in the NO2 mixture which usally is how NO2 is used, but in our case we gain from the cooling effect from the nitogen in it.i have talked to CDS racing here many times and he has alot of experience with nitrous and cars and at that level you can run a dry system without a fuel pressure riser or any extra injectors.its safe and i predict it will give good results, i will let you guys know after things have been tested.

-grant

If you run high boost(over 15psi on pump gas), have a heavy foot, or don't like checking the tank often, a nice aluminum tank with a cap of about a gallon is best. I'm prepping a WRX right now for SCCA pro rally and can fit the tank to the car, or a RS as I own one. Most rally cars use a larger 3 gal tank in the passenger compartment. A 2.0 at 15psi+ on pump gas is a prime candidate for W.I., especially with the location of the interwarmer on subarus.

In general, if the jet is placed AFTER the intercooler, it will suppress detonation caused buy heat build up in the C.C. buy removing heat in the conversion to steam.

If placed BEFORE the intercooler, the effect is to enhance the efficiency of the intercooler by further cooling the charge and making it even more dense. This makes more power, power=heat, heat is what causes detonation.

For both effects( detonation suppression and intercooling) a tee is placed in the line and both locations are used. I would suspect this is not necessary on the WRX running less than 20psi.

An engine running any given psi boost will make more power with water injection as the timing will not be retarded(with a closed loop ECU) in addition to the intercooling effects.

If ten people can get together I would consider a group buy.

Pete www.cascadeautosport.com (http://www.cascadeautosport.com)

[This message has been edited by PVB (edited May 03, 2001).]

When I had the turbo on my RS, I was able to run 5-6psi without the water injection.
With it, I was able to go to 7-9psi. Not earth shattering, but enough to make a noticable
difference.

Thats a 29-40% boost increase! Thats pretty impressive for doing nothing but adding water dont you think? :-)

As far as installing a WI on a WRX, where would be the best place to put the nozzel? Between the IC and the throttle body, or in the pipe from the turbo to the IC?
-Jeff

PVB,

I presume that in my situation, the "System 2C" would be the ideal choice, as I will be using a Motec M48 Pro ECU for controlling fuel, spark and boost on my red beastie.

As I said previously, I *like* water injection, or water/alchohol injection. http://www.i-club.com/ubb-files/smilies/biggrin.gif I feel that it's a great "ace in the hole", and an excellent safety backup.

For my purposes, I'll have a built 9:1 forged piston/rod EJ25 with a T3/T4 hybrid, running somewhere around 15+ PSI, mapped for optimal power on 92 octane pump gas.

Digital_boy,
The system 2c would be ideal for your application. Any aftermarket ECU capable of a pulse width modulated output signal can be configured to drive the system.

The system 1s has a simple adjustable boost switch that controls the injection start at a given boost level.

The system 2s is a fully mappable injection system in linear and 3-d with the addition of a MAP sensor output(on your car already).

The 2C system wont properly work with the Motec... or Tec II.. or Link (due to lack of spare/seperate maps). Assuming you want to fully map it, and not simplying turn it on and off based at specific TPS/Boost/Rev points

It is far easier to get the 2S (with MF2 controller) and use that.

J.

The way you make the nitrous work correctly, is first you use a toggle switch, then goes
to a throtle switch, which finally goes to a RPM pill window switch. that allows the nitrous
to only come on when your above, say 3000 rpm's and at full throtle.the map sensor will
compensate for the drop in pressure and add more boost.at 20 shot you get no horse
power from the oxygen in the NO2 mixture which usally is how NO2 is used, but in our
case we gain from the cooling effect from the nitogen in it.i have talked to CDS racing
here many times and he has alot of experience with nitrous and cars and at that level you
can run a dry system without a fuel pressure riser or any extra injectors.its safe and i
predict it will give good results, i will let you guys know after things have been tested.

On the car that I ran water injection on (see post above), I also ran a small nitrous shot. A window switch is also not really needed on any size system (unless you want the added safety), but on a 20-30 shot, you can spray at very low rpm, without any problems.

I can assure you, you will get extra power from only a 20 shot http://www.i-club.com/ubb-files/smilies/smile.gif I ran a 25 shot and picked up 40 hp to the wheels and made an extra 70...yes 70...ft lb at 2000 rpm.

wow!! i really can't wait to put that nitrous on, i can't belive that power increase, iknew it was gonna be significant but, wow! thanx for the in put.

-grant