T-uk

hi all,

I do not want to go as far as a front mount intercooler,so was wondering if either of the above are worth considering.I see that Scoobymania do a spray and PE do an injection kit,is there much difference between the two,has anyone running these got intake temps from say a trackday or similar with/without water.

I was also wondering if anyone had made up their own spray kit ?,could I disconnect my headlamp washers and plumb a hose from there,to the front of my top mount.scoobymania list water spray STI nozzles,so two of these and some piping,hit the h/lamp washer button and the i/c is sprayed.thing is the flow rate might be too high.

any input appreciated.

sorry if this has been covered before,but search off.

Cosie Convert

The water spray on my WRX RA (OEM) is just a windscreen wash set up.
It comes standard with only 2 single jets, apparently it's just there for homoligation purposes.

I have modified it and fitted 2 spray bars, the standard set up sprays for about 5 seconds for each press of the button.

I have monitored the with/without temps after the I/C and achieved a 3 deg C drop with the spray.

Not too impressive me thinks !
This was after a 30 to 120 MPH blast on each occassion.

Far more effective would be water injection. I used to run this on my Cossie and by advancing the timing I made 340 bhp at 19 psi boost.

I'm part way through fitting the system to my scoob. Let you know how I get on.

I hope to get a before and after power/boost/temp on the rollers. Any idea how much a RR run is normally ? Or rather 2 back to back runs ?

[Edited by Cosie Convert - 1/25/2002 12:21:18 AM]

T-uk

thanks CC,

did you make the injection kit up yourself or is it a kit you have bought?
I think john banks said Star take 60£ for r/r runs outside an organised day.

edid for spelling,is spell check coming back .


[Edited by T-uk - 1/25/2002 9:29:11 AM]

GavinP

To get the best out of an intercooler water spray, you need a high pressure pump.

I tried it with a windscreen washer pump and some nozzles normally used for garden watering - didn't work very well. Water pressure is the key to getting good atomisation (and better cooling).

I've read about a couple of people who have used the ERL water injection system and setup an additional nozzle to act as an intercooler water spray as well - pressure shouldn't be a problem.

If your like tinkering, obtaining a suitable high pressure pump and some nozzles is not hard - http://www.jabsco.com/spot.asp

Thanks

Gavin

john banks

I have been looking at water spray and it seems that the control system is very important. The greatest effect for the least water usage seems to be to measure core temperature and only spray when the core temperature is high AND there is high engine load. Spraying on boost is useless, and spraying when the intake temperature high has missed the boat.

The intercooler is acting like a heatsink. Spraying it whilst on boost unless for a very long time makes very little difference to intake temps. You can start the spray after it has heated up to allow it to heatsink better. But if you are only intermittently on the throttle such as on the road even pushing it it is reputed to make little difference. This was my understanding from an autospeed article on it.

http://www.google.com/search?hl=en&q...er+water+spray

john banks

I am also wondering about a high efficiency TMIC as CC described.

John you'll have to put the boost up before you need to worry about water going anywhere

BTW, does water corrode the intercooler? What is it made of?

That damn 406 of ours is slowly leaking coolant from I think a corroding radiator which looks like it is made of the same stuff as my intercooler in the Scoob and it is under 5 years old. Implications?

T-uk

will read the links later,all I am really after is something that I can use on track or at a r/r day,it does not need to be timed or anything fancy just hit the button,count to five and let go.

Adam M

It depends on your goal.

If you want power go for water spray, as when it lowers your intake temps, the denser air will mean more air in the combustion chamber and hense more power.

Water injection alone is the best thnig to do, it robs you of power, but it introduces a safety net by giving you a cushion of allowable extra ignition advance. if you dont employ this, you will lose about 10 to 15bhp apparently but you will have a car which is far less likely to det!

If you can alter ignition it is possible to increase the advance and recover more power than you lost, with this in mind you can therefore get back to original power but still have a buffer keeping you out of the det zone which is nice.

Cosie Convert

T

It is a hybrid system using a proper pump and atomiser with my own pressurised tank and control valves.

On my last car I had it switching on at 15 PSI via a pressure switch.
John's point on not controlling WI by boost is only valid regarding the charge temperature. The combustion temperature is what we are ultimately trying to control (as Gavin P states)

The sooner the combustion temp is controlled the less pressure rise you will get as the charge temp inevitably rises.

As we know, it is the increase in cylinder pressure & temp that promotes knock.

T-uk

as far as I know the cars not detting,(Knocklink on order),so do not think it is injection I need,especially if I'll loose 15bhp.if this car gets any slower I'll be buying a sport .I am just after a simple thing,to give me added piece of mind on track, to help the intercooler.at the moment I have no idea how high my intake temps. get on track.I have loads of nozzles kicking about so may try something spray wise and see if it makes a difference.3 dec.C drop is not much but if I or passenger use the spray every lap for 5secs on every long straight it might help enough,or am I wasting my time here?

Cosie Convert

No, you're not wasting your time. Every little bit helps, 3 deg C may be the difference between safe and bang.
I'd go for it ! My 3 deg C drop is with an ambient of 9 C. You may get a bigger drop in the summer.
It will also make your passenger feel more important too !
You can always blame them if it goes wrong !!

ski

CC is right,water spray will be more effective when there are higher ambient temperatures.I read in a tuning book that"there is greater efficiency of the intercooler when operating over a steeper temperature gradient"

T-uk

okay will try and rig something up with the headlamp washer hose,never used them anyway.

screenwash in the water won't make a diffrence will it?

[Edited by T-uk - 1/26/2002 6:29:35 PM]

john banks

I figured you wouldn't use water spray at times of the year when you needed much screenwash in so could use very weak or just water?

Trout...

A simple boost switch water spray kit - I used STI nozzles, a Halfords universal pump and an ERL boost switch set at 0.4bar - keeps intercooler temps below 40deg or lower with a standard STI topmount - this is improved with a much larger top mount. The difference is awesome. On a RR without intercooler airflow the power loss was around 25bhp - this was tested as the first and last runs differed by that much as the I/C heated up. On a RR with good I/C airflow the power was constant at the top number - if anything the power got better with each run.

Water injection pre-intercooler will give you better intercooling (a la Escort Cossie) but will rob you of some power as the charge is made up of water vapour.

Direct injection (post intercooler) will reduce power if nothing else is changed. About 6-10bhp. However you can more than get this power back by remapping the ignition. Even without a remap, on track you would feel the difference. Heat soak on track will cause the standard ECU to retard the ignition significantly more than 6-10bhp. With water injection this will stay constant and you will have a more consistent power output.

On a remappable car the gains can be had for the road/RR and retained on track. Det caused by heat soak is almost non-existent.

So Water Spray, even cheap and cheerful on a boost switch is good - boost and temp is even better as it will reduce water usage.

Water injection is a superb tuning tool for both power and track work. It has been the single best improvement on track that I have made to my car. Also - I would be very surprised if anyone could make a satisfactory water injection set up in their own. Buy one from ERL. An MF1 (non-mappable) should be run with the smallest jet possible otherwise there will be too much water. A mappable system is perfect. Fit the spray injector just before the throttle body - you can tap it into the base of the end-can on the I/C.

Trout

[Edited by Trout - 1/26/2002 11:00:20 PM]

Cosie Convert

Trout

Thanks for the information but I think T-UK is looking at a DIY system.

The ERL is fine but at 600 quid I could think of many other go faster bits I'd rather have !
My home made system was made successfully for less than 1/4 that price.

Yes it works properly, it was the same system I used to win a 15 race, Saloon Car Championship a few years ago. That's proper circuit racing, not just 'out to play' on a track day !!

CC