new install, pre turbo water injection
 

I've been reading lots on Pre compressor water injection and I want to give it a shot. Currently I see air charge temps around 130 C before the intercooler and 60 C after. (This is running around 20 psi)

I'm hoping I can reduce this with water injection.

I don't have a lot of time to spend on my own car (as always) this is a last minute install, and I'm on the rolling road Tuesday to test the install.

I was planning installing the smallest jet which came with a kit I had given to me. The jets in the kit are 130cc/min, 315cc/min & 550cc/min

The engine is currently fitted with 500cc injectors, running at around 60% duty (batch fired, 4clyninder if that makes a difference)

My plan was to use the smallest jet and aim it at the compressor wheel (I have a 90deg bend on my air intake pipe so it should be pretty easy to weld a boss into the intake pipe aiming directly at the compressor wheel)

I wasn't planning on changing the map for the water injection, currently my map is pulling off a lot of ignition advance as the Air temp increases, so hopefully I should see gains once the ACT are lower.

What mix of meth and water should I try?
Will one jet before the compressor be ok, or do I need one after the intercooler too?

any tips or advice would be great

cheers

Codey

Re: new install, pre turbo water injection
 

You could try the small or medium jet before the compressor wheel, or the small before and the medium or large after the IC. Water before the compressor works good, after the IC we would typically use 50/50. Is the air temp sensor after the IC? If so, methanol sprayed after the IC and before the sensor will give the biggest effect on the charge temp and the sensor. The down side to cooling with methanol is how much it will affect the AFR's.

Re: new install, pre turbo water injection
 

Thanks for the info the origonal plan was not to change the the map so sounds like I don't want to use to much meth so not to affect the AFR.


My air temp sensor is after the intercooler just before the throttle body.

So adding meth improves the cooling affect on the water? Could I simply reduce the meth but add more water (up to a point) to get the same effect but not change AFR's?

Also where can I can a 'T' connector and another jet delivered to me by the morning? (Friday today).

Assuming I can't get another jet in time, and I only have the one, should I inject pre turbo, or post intercooler??

Re: new install, pre turbo water injection
 

Where are you located?

The water will only evaporate up to a point, and not as low as the meth, so continuing to dump water to lower IAT doesn't always work. You can certainly give it a shot as all applications differ a bit.

As for jet position, the traditional spot would be post IC, but you can give anything a shot.

Re: new install, pre turbo water injection
 

I'm in the UK, nowhere near you unfortunetly,

hmm, I plan to mount the jet tonight, but really on the fence on where to mount it

Re: new install, pre turbo water injection
 

The safe bet is after the IC.

Re: new install, pre turbo water injection
 

Thanks for the info guys. In the end I resulted in running one jet after the intercooler.

I ran the car on the rollers, and my ACT after the intercooler dropped from 60 degree's ot around 25 degrees, I was running 50/50 meth. We found we lost around 4bhp everywhere. We tried advancing the timing a few degrees but it made no difference.

Any ideas why I lost power?

I have since got my hands on the parts required to add another jet, which I plan to add pre compressor.

I've only got one check valve will I need another when running two jets?

Thanks

Jim

Re: new install, pre turbo water injection
 

What model of kit do you have and which size jet did you install? When was it set to come on?

Re: new install, pre turbo water injection
 

I have the AEM Kit, using the medium size nozzle which came in the kit, (I think 315cc??) coming in at 7psi, up max flow set at 28psi, and running 26psi. The other nozzle i have is an aquamist jet, I think .6mm but not 100% sure, I'll check when I get to the workshop

Re: new install, pre turbo water injection
 

digging through old emails I think the aquamist jet I plan to put pre turbo is .4mm

Re: new install, pre turbo water injection
 

Doh I was wrong again, the jet is .7mm is that going to be too large??

Re: new install, pre turbo water injection
 

There are a couple things to consider. 1) A pump speed kit is not linear. I'm not sure about the AEM,. but another kit I just tested had the pump starting at 30%DC at the cut in point,7psi in your case. Then at 50% signal they are spraying 70%. With the pump already starting at 30%, you are already behind the curve.

2) Now reality. These pumps can push up to 1600-1800cc. When using a smaller jet such as an M6 (378CC rating at 100psi) You reach 90% for the spray at 50%DC on the pump. So what is happening is you essentially have a single stage system with a variable controller forgoing some consistency. Thta's not to say it won't work, you just have to know it's limitations.

What PSI is the pump rated for? You may have to re-adjust the jetting based on the performance of the system.

Do you have AFR and logged timing curves for the dyno run? Do you know what the max timing is for the open loop run?

Re: new install, pre turbo water injection
 

I am on the dyno again this afternoon. I have mounted a jet pre compressor, and I plan to log AFR, ambient air temp, pre and post intercooler temps, boost, ign timing, and injector duration, and RPM. anything else I should log?

Re: new install, pre turbo water injection
 

EGT and knock if possible.

Re: new install, pre turbo water injection
 

I don't have a knock sensor, and I've not yet mounted the EGT sensor, forgot all about it and only had the turbo off Monday night, :eek:

Re: new install, pre turbo water injection
 

I tried running with both injectors yesterday. Didn't have time todo everything I wanted todo on the rolling road, as a had problems with a cam change between runs (long story)

When running WI, with a 270cc jet after the intercooler and a .7mm aquamist before the turbine it was over fuelling, afr 10.1!!! I'm guessing these jets are far to big.

My WI pump is 150psi, how do I calculate what size jets I need?

I'm guessing woth fueling that rich the data I logged is going to be no good to anyone?

Going a bit off topic, in a turbo'd engine running 25psi boost what AFR's would you set your tartget to both with, and without water injection?

Re: new install, pre turbo water injection
 

You will have to lean the fueling maps to bring the AFR back where you need it. Various cars like different target AFR's some cars like 13.0 fine, in know it's a bit scary, and some cars like 11.5. What was you base AFR before turning the injection on?

Re: new install, pre turbo water injection
 

Afr target before water injection was 11.1, I think this was done to keep it cooler as ACT where over 60 deg C. I'm think with WI and afr target of around 12 should be safe. I've ordered an aquamist .4mm jet I think it may be better if I start small and work my way up. I'm thinking that it's better to run a small jet with more pressure than a large jet with low pressure?

Re: new install, pre turbo water injection
 

Not trying to complicate the issue, but keep in mind as you change jet sizes on a pump speed system, you change the flow curve. The smaller the jet run the more it resembles a single stage system. The pump ramps up speed behind the small jet orifice and makes near max pressure very early. While spraying less overall, the flow curve is very flat.

We routinely see 1 AFR drop running 100% methanol and about a 25% injectant ratio. If using the w/m for cooling add jetting until you reach the desired temp then start to tune the maps for the added fueling.

Re: new install, pre turbo water injection
 

ahh ok, I think I have been going about this the wrong way, is the aim to use as least water as possible to get the desired ACT, any more water after that will lose power?

I've just received my parts from ERL, so I can now start with a .4mm jet pre compressor and a 130cc/min jet post intercooler

Re: new install, pre turbo water injection
 

No offence to anyone , but I think you are doing too many things at once.You need to decide why you are wanting to use water injection .If its for cooling to control high IAT's thereby reducing detonation , then water ONLY is more effective at doing this.If you are at the limit of your fuel system and you need to use some methanol to "bring Back" your a/f ratios , then a 50/50 mix is good . What ever you decide to do , you have to consider that a bit of tuning is required to see gains , but the least amount of changes you make to your maps the safer you will be if your WI system fails (ask me how I know this). if you have to lean out your maps too much or run too much ignition, then you are spraying too much water.
In my experience , water works best because of its cooling properties ! Infact since water has four times the cooling ability of methanol , you would need substantially less (1/4 the amount compared to a 50/50 mix) !! All that is required is leaning out your maps to where they should be and advancing ignition timing not more than 2 to 3 degrees at any one point .I usually stick with the lower number for safety reasons. After you have played around with this you should see some decent gains ,if not then go bravely into the world of methanol injection .

Re: new install, pre turbo water injection
 

There many factors in play. Water's best attribute is detonation resistance. It will cool IAT's some, but the evaporation point is high relative to methanol. You will never get close to ambient temps in the inlet track with water.

Methanol on the other hand will cool to well below ambient temperatures in the inlet track. Yes, the latent heat is much less than water, but the flash point is much lower giving lower ultimate temps. We have run 40F less than ambient before in the inlet track with 100% methanol. The drawback is you are adding more fuel that needs to be accoutned for.

On many cars, just adding water will cool the inlet temps a little, then adding a bit more the car will loose power. If using water solely for inlet temp reduction on a near stock car, the numbers may not be dramatic.

There is no magic pill for setup with certain ratios and cars. Each application needs to be looked at for injection system capability, car use, tuning capabilities(ECU) etc. I have seen 100% water work great on some cars and applications and the complete opposite on other cars.

Re: new install, pre turbo water injection
 

Some good info here thanks guys, I'm in the process of installing an engine dyno so I can experiment and log things much easier. I doubt however that the waterbrake dyno I have will be able to handle the power of my engine on full chat for long, but it should give me an idea of whats going on.