Water injection - first test

[johnf]

OK - someone explain WI

How it does what it does and why its better.

John

[sdminus]

I used to have stock clutch...... Past tense LOL I am exploring the alc injection part of the whole thing.

Gmogle. At 165 on that track the clutch was not loving it at all. And the 5000rpm launch on the same track was a no no LOL.

WI seems very good. Try this

http://www.rx7club.com/forum/showthread.php?t=202871&highlight=water+injection

Scott

[ScuttleRX]

Short and simple version: What it does- cools air intake temps, prevents detonation (forgot to mention knock meter didnt go above 29, on about month old optimax too)

How it does it - injects air as a very fine mist, atomises under combustion taking a lot of heat out of the reaction, basically doing the same as when you run slightly rich fuelling to prevent detonation, only water is much more efficent due to high specific and latent heat capacity. Obviously too much water will cause bogging, and too little will be ineffective.

Mix with methane, acetone and the like and ive heard things get even better For more detailed explanations check out this thread

[johnf]

Thanks

I\'ll look at the link.

John

[ozzyvelcro]

I just installed an aquamist kit last week and am very impressed with the results.
Aquamist also run a very helpful forum on there website which will tell you everything you need to know about WI.


http://www.aquamist.co.uk/

[ScuttleRX]

Had some more test runs today, gave it a much harder time this time, wot thru 1st 2nd 3rd 4th a few times. Temps did rise on these occasions, from low 30\'s to 40 on one run, but at a reduced rate to normal, would probably be hitting the mid 50\'s/60\'s without (really should have wired the switch in for better testing ). When driving on and off boost, ie twistys, or boost then cruise, temps stayed very constant. If the temp was above ambient before the run, a couple of boosts/coasts would see it come down again then stay down.

Might be just me but it seems to work more efficiently in the lower gears rather than the higher gears (on wot). Also think having a dual set-up with an extra injector coming on when almost at maximum boost would be benefical, as it could probably handle a bit more water, have not experienced any noticable bogging down whatsoever.

Conclusion at the moment (for set-up as a whole, not just WI) is a definate improvement overall, probably will exploit the benefits the most in circuit sessions. I can still see heat build up in the queue affecting drag races, obviously it will be much better than before (not to mention safer) but not perfect yet.

[sdminus]

I mirror the view about circuit racing. I think WI would be better suited to that rather than drag racing

Scott

[davegttph1]

Looks good, good results too, did you install it yourself? Doesnt need setting up along side the ECU then?

[ScuttleRX]

Yes took me ages but only cos ive never really worked much on a car before so was constantly double checking etc, someone with a bit of know how would do it very quick, think Scott done his in a day

No doesnt need setting up, you can get more advanced systems that are linked to ecu and inject a variable rate of water from a 3d map of boost, rpm, etc. Mines a simple boost activated one, wanted to start simple, and work up if I need to, working good so far

Think it might be one of them things where difference between a simple system and a more advanced one might not be that much except for the dent in your wallet.

Think my next step will be to play about with injector placement a bit see if that makes any difference, then go for the $99 dollar dual set-up pack and have a bit more water going in at high boost

[ScuttleRX]

Just doing the math, im injecting 246cc/min of water at the mo, and at 90% ive got 2520cc of fuel going in. That leaves me with an extra 132cc of water I can still inject to get 15% water to fuel ratio.

So a smaller injector (2.3g/h would be just about spot on, 144cc/min) that comes on near max boost would seem ideal, time to get ordering I think. Not sure where to put it though, maybe right up on the elbow.

[sdminus]

How about this !
Scott

[ScuttleRX]

Im torn, dont know whether to go pre intercooler or not...being as its not very efficent I think the water maybe \'wasted\' by being injected before it. If I had a nice FMIC like yours I reckon id think differently

BTW, is your injector near throttle a normal one or angled one

[sdminus]

I put it post ic as that was how it was recommended to me, I was also worried about the ic condensating. Maybe right after the turbo\'s it might be ok but I haven\'t found any evidence of this method?

I didn\'t have the angled injectors as I didn\'t like how big they were. Being thinking about running a 2nd system just to inject alcohol, instead of mixing it, been looking into this but isn\'t seeming likely at the moment  :chat

[ScuttleRX]

Just ordered it got the fast delivery so hopefully have it hear and installed by next sat now I know what im doing (just!)

[ScuttleRX]

I was reading a thread about mixing, methanol and water go together, and nitromethane and methanol do, but when you\'ve got all three they have to be mixed in right quantities or the nitromethane wont dissolve/dilute properly.

2nd system would be good, some of the threads I was reading the people said ditch the water!