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Water injection finally fitted..
Posted: Wed Jul 14, 2010 4:17 pm
by tartan_rob
So I finally got around to it.
I have fitted water injection and an oil cooler spray. Oil cooler spray operates manually only from the 'RS4' button. The WI is armed via the 'Pursuit Mode' button and activated via a WOT switch - crude but effective.
The car has NOT been mapped but MRC will get her soon to fine tune the WI. I am currently running quite a small WI Nozzle - D02. I tried D03 but the car felt a little lumpy. I think a remap will work well with this size nozzle.
First impressions:
Oil Cooler Spray: Is only really effective if the oil temps are above about 102degC. It does nothing immediately but the oil temp recovers very quickly and within a few mins it does drop off to 97/98 degC.
WI: On the D02 nozzle I can accelerate from idle in 6th without any spluttering. She pulls stronger the high the revs go and car feels a little quicker. The big difference is that the oil temp also remains low and the inlet manifold never really gets above warm - even after a spirited drive.
I'll only know if there is a real performance differance once MRC have her on the RR but if nothing else I will have helped reliability. WI reduces burn temps by approx 300degC...!
All my components are Devils own kit.
Re: Water injection finally fitted..
Posted: Wed Jul 14, 2010 4:21 pm
by Sims
Tartan_Rob wrote:..
All my components are Devils own kit.
Excellent stuff, look forward to heating updates.
Like all the dash switches.
RE: Re: Water injection finally fitted..
Posted: Wed Jul 14, 2010 4:36 pm
by ShouldveBeenAGerman
Loving the switches!!
RE: Re: Water injection finally fitted..
Posted: Wed Jul 14, 2010 4:46 pm
by pippyrips
Great work - this would have been the next step for me had i kept the car. Is the WI going into the inlet manifold? if so it will be interesting to see if any associated 'cleaning' takes place.
RE: Re: Water injection finally fitted..
Posted: Wed Jul 14, 2010 4:51 pm
by rs4v8
How trick is that?

Well done that man!!
RE: Re: Water injection finally fitted..
Posted: Wed Jul 14, 2010 4:56 pm
by tartan_rob
The WI injects immediately before the MAF and the plan to get MRC to clean the valves, remap and see what the valves are doing in a year or so...
RE: Re: Water injection finally fitted..
Posted: Wed Jul 14, 2010 7:04 pm
by sonny
Does this actually increase performance, I know the effects of a water spray on a intercooler but a oil cooler?
Now methane injectors would be interesting, would you consider that? Great set up any how, looks good. like the buttons.
RE: Re: Water injection finally fitted..
Posted: Wed Jul 14, 2010 7:24 pm
by lengster1
Well done Rob,switches look factory quality,could you pm or share costs/suppliers as this little mod is high on my list as ive just had de coke etc
Posted: Wed Jul 14, 2010 7:54 pm
by P_G
Rob, where have you located your tank; in the boot or near fuse box? And are you using stage 1 or stage 2 kit?
Posted: Wed Jul 14, 2010 11:50 pm
by ArthurPE
lol, switches, niiiice
for an hour of running time how much water is injected?
I'd be curious to see the valve testing
Posted: Thu Jul 15, 2010 8:44 am
by Blue_Thunder
ArthurPE wrote:for an hour of running time how much water is injected?
Depends how long he is at WOT I would imagine.
Posted: Thu Jul 15, 2010 10:06 am
by tartan_rob
Sonny - the Oil cooling is just to help control oil temps. I know normal running temps can be high but I prefer them circa 100degC
I made a box out of CF and it now sits in the large storage space in the boot in front of the battery (but within the polystyrene). Holds about 12litres and fills from a pipe located beside the BOSE electronics.
As for costs:
The switches are circa 40Euro each
The WI parts from Alcohol-Injection were about $300 inc postage
Throttle switching and wiring etc from Maplin are circa £30
Then you need a water box and about 4 hours fitting
As for Nozzle size, Alcohol-injection do nozzle sizes (in size order starting small) D.75, D01, D02....D14. I used 03 and it felt a little lumpy and i suspect needs a remap to benefit properly. D02 seems the best fit for my current set-up.
I have no idea how much water is used for continious running as I use WOT only but you can work it out from the nozzle flow rates on the website.
Posted: Thu Jul 15, 2010 10:47 pm
by RS_Y4Z
Sorry for sounding dumb....but what the helll are u doing injecting water into the inlet manifold???? Engines run on air and fuel not WATER.
Posted: Fri Jul 16, 2010 9:37 am
by tartan_rob
RS_Y4Z - you should do a little research on this. The water is injected in the form of a very fine mist. The mist absorbs heat as the fuel and air mist is compressed and reduces pre-ignition. In addition it reduces the burn temp by approx 300DegC and slows down the flame front therefore giving a more effiecient burn.
On a NA car there are significant reduction in temps to be had + increased reliability.
Turbo/SC cars benefit much more and this tends to yield significant gains whilst increasing reliability.
Posted: Fri Jul 16, 2010 9:51 am
by PetrolDave
RS_Y4Z wrote:Sorry for sounding dumb....but what the helll are u doing injecting water into the inlet manifold???? Engines run on air and fuel not WATER.
Ever noticed how much better your car runs on cold damp days?
That's because of the cooling effect of the water vapour in the air.