On Friday I had the opportunity to do some water injection testing on the dyno. The thermocoupler probes were placed so that both probes were reading after the intercooler, one before that MAS and the other after the water injection nozzle about 14" before the throttle body. The pressure switch setting was set at 4, 5 & 6 psi but there was no noticable difference between these settings.

Ambient temp: 87f
First Probe: 105-110f
Second Probe: 70-80f

The water injection dropped the intake temp to below ambient temp, but I think a large part of this is due to the effectiveness of the APS intercooler. I have not yet taken temp readings before the IC, but the bottom of the IC (air in from turbos) was very warm to the touch and the top (air after IC cooling) was cool to the touch.

In the near future I will take readings before the IC to determine how much heat is being removed by the IC and I will be slowly raising the boost in conjunction with the Unichip water injection map to see where we can safely go. Also I will be emplementing a variable solenoid controller that will increase the volume as boost increases.

Finally, we ran the car all weekend in 90+ degree temps at the NOPI drag event at the Alabama International Dragway and only used about 1/4 of the washer fluid reservoir. With no other changes to the car the ET dropped from 12.59 with a 1.89 60' to a 12.44 with a 2.03 60'. I can't say if it had anything to do with the water injection, but the ET's were so consistant that we were able to take 1st in the 14 and under bracket

 

Congradulations!! Car looked great!

 

Thank you! I was very suprised to take 2nd in the show when we had been running it all weekend and could not keep it as clean as I would have liked.

 

coo;, wondered when someone was gonna do some water injection on the z!

 

its about time someone started playing with water injection. any plans on running alcohol in there?

 

Well as a VP race fuel dealer it just so happens we have a 50 gallon drum of methanol here at the shop.

I want to complete testing with water before adding methanol so it will be easier to identify what is causing the changes.

I think at the current 8.5psi level and with the stock APS tune that the water injection acts mostly as a safety factor and deterant against heatsoak, but as the boost is raised and the A/F is leaned out there should be safe power to be had as well.

 

I've tuned a few cars with water injection and highly recommend it. Its like getting 100 octane gas for the price of 93. Correctly tuned with water injection you can make some very good gains. The only unfortunate downside is that you must make sure you never run out of water or alcohol!

-Tuan

 

We have had great success with WI on the Z32 so I figured I would put something together for the 350Z. By using the washer fluid reservoir we can use the stock low fluid indicator on the dash to help prevent running out of fluid.

I think if I lived in any state that only had 91 octane like Cali I would definately use it even for lower boost applications.

 

Why would it matter if you ran out of water?? Is that because you would be aggressively tuning the A/F and without water it would compromise the tune?

 

Tuan is talking about tuning the car aggressively with WI, which involves advancing the timing and running very lean A/F which would be a problem at high boost if you ran out of water. Also, it is not particularly good for the pump to run dry.

 

Any pictures or how-to for the water injection kit?

 

As a matter of fact there is an excellent one, but until Mike gets back to me about renewing our Vendor status I don't want to get into it on the forum.

 

Mike hasn't replied to my email either in becoming a Vendor.

 

i saw you posted ET's, but what was the change in MPH before and after the water injection?

 

I think it was 111.xx before and 113.89 after, but I cannot find the before slip. :-(

 

Tuan, was your .76 bar wastegate limited?

 

I have ran both of my cars using WI. (Aquamist systems)

and absolutely loved it. on the black car, combined with the A/W IC i can hot lap on 95° days for almost an hour, ***** to the wall without noticing any real heat soak.

i ran tunes both with WI and without WI, but they were not that much difference.

by the way, you can use Windshield washer fluid. contains the correct mixture of alcohol and water, or you can use just plain water (not as good as alcohol). I ran the black mr2 for about 25,000 miles of normal driving, autocross, track and drag events before i sold it using washer fluid with no problems. I had my systems set to come on at 7-10 lbs of boost, depending on the weather outside.

 

We have seen the same thing at the 1/4 mile track, 5 passes back to back with no noticeable heatsoak. Washer fluid is also my fluid of choice, at least until I open that drum of methanol which I will mix with plain water to make sure the % is right.

 

I would recommend using/mixing distilled water but it might not make any practical difference.

--Steve

 

these is always debate going back and forth about using Distilled vs undistilled water. logic says that undistilled water will leave deposits, but i ahve never heard of anyone having problems from using undistilled water. (myself included) . i just pretty much used washer fluid and that's it. leaves a nice blue tint on the throttle body too. i was always too cheap to go out and by a drum of methanol when the washer fluid was the same thing.