I am considering running WI on my JDM STI7. My aim is mainly to postpone the onset of det in our tropical heat, rather than to chase power.

I do know that WI on its own (without a mappable ECU) may result in some power loss. Aside from this, are there any other disadvantages it has? For those who have run the system on their cars, have you found that it corrodes engine parts or has other ill side effects?

tks.

EDIT: Forgot to say that I'm running the std exhaust with cat converter also. Does WI wreck cat's?

[Edited by RT - 8/7/2002 8:45:15 AM]

One downside....always try and be aware if it is actually working. Have some method of checking the pump etc is working, and any switching devices you are using for it. Make sure all pipes are secure, and cannot be blown off, and losing water.
If you are relying on it to protect your engine, you will always need to keep the system in good order.
I too have heard that methanol can be corrosive to some materials, although have used the mix on my mini turbo to good effect. Indy cars im sure will have their engine building materials designed to withstand methanol, as that is the fuel that they run on all the time..
Using fans to blow air through the intercoolers would maybe be beneficial at lower speeds, and preventing heat soak. Above 20-30mph, fans will no virtually nothing, as airflow through the car would be much greater than the fans could ever supply.
Another good option would be a good waterspray for the IC core. I havent tried it yet myself, but the Autospeed Intelligent Water Spray system looks very good, and should use a minimal amount of water.

[Edited by ustolemyname??stevieturbo - 8/7/2002 11:12:52 PM]

RT,

In your climate, WI should work VERY well, and I doubt you would lose any power.

The STi7 ecu is far more intelligent than the earlier ecu's, and will actively seek the knock point. So, if you have high ambient temps, and the ecu is retarding the ignition, WI will help prevent this, and give you far more consistant power.

There are no "downsides" that I can think of.

Mark.

Agrees with Mark - use a simple 1S system from ERL - don't go overboard on the injector size - say 0.4mm for normal boost levels and use the boost switch to turn it on at 0.6bar. Should do you very well with the Sti 7 ECU

Also as Sti 7s have water spray - I would go for an injector point just pre-throttle body. The alternative is pre-intercooler.

Trout :D

sorry david, but I wouldnt suggest pre intercooler, the nature of the air flow over the heat exchanger core means a lot fot he mist will recondense and effectively fill up the core giving it less volume and making it less efficient.

As for the corrosion aspect, its only really the minerals that could be a problem, and there are nastier things in fuel to worry about before that. If really concerned then boil the water before filling the tank.

Consider that complete combustion of fuel yields much more water in the cylinder than you are injecting anyway!

on the upside, it will be steam cleaning your cylinder for you on every stroke.

water injection just adds to the water vapour content of the inlet charge, and is basically ignored by the combustion process. Can't see why it would damage a cat,as it should pass straight through as vapour.

i would be wary of too much water if humidity is very high, you can't burn water vapour!

Adam,

clearly you can't read - I said I would recommend pre-throttle body - the alternative is pre-intercooler - as in Cossie - I am not recommending it.

Trout

few,
for a minute there I lost faith in you.

david you are still my hero.

Adam you are still my hero ;) :p

david,

all i did was apologise for the fact that I would not suggest it.

I dont recall saying that you suggested it.

Clearly it is you who cannot read baby puppy.

Inference is not the same as disclosure. If it were my job would be so much harder.

Tks a lot guys! Keep 'em coming!

RT

Sorry to hijack your thread, but do I recall correctly that you have fitted fans to force air through your intercooler? If so, don't suppose you could let me have some more details.

Thanks

Duncan ;)

Meanwhile, back on the subject of water injection... ;)

One "reputable" engine builder has suggested that the practice of injecting a 50:50 mix of water and methanol/ethanol will, over time, lead to erosion of the heads, as the mix is acidic in nature.

Moray

OK Moray, anything to keep you happy;):rolleyes:.

I think that you'll find that Methanol/Water and a combination of the two are fairly neutral in acidity terms. Running DFX and HB engines on Methanol for Indy racing (both "aluminium" heads) over a long period of time has not caused any corrosion problems, so I'm not sure where this idea originated.

Perhaps you could provide some more information? Is pure water or Methanol OK?

Duncan ;)

Regarding the Fans, firstly - its only one fan. Its a fairly biggish one, its diameter covers the intercooler pretty much "lengthwise" (measured along the car's length axis). It is mounted on a plate covering the bottom of the intercooler, on the left side.

It was impossible to get it mounted centrally, as the Y-ducts are in the way. Using a sheet of plain A4 paper on the intercooler top, I can see that the suction effect of the fan covers slightly more than half of the intercooler top surface. Its a pretty strong suction.

On the right side of the plate (just above the Y-joints and turbo), I drilled 3 biggish holes about 2 inches each, to allow some air to escape thru that route when the car's at high speed. The gap between the bottom surface of the fins and the top of this plate is about 1.5cm, so I would guess there's enough "crossflow" at the bottom of the intercooler (above the plate) when the car's at speed when the intercooler top is slightly pressurised by the ram effect.

At 100kmh with the fan off, I do agree that you're better off without the fan/plate, as there's a lower pressure under the IC. But at lower speeds, the combination of the fan AND IC water spray does actually help matters quite a bit.

I have a Defi water temp gauge tapped into the IC to read air temps pre throttle body. Get stuck in a 10 min traffic jam and you'll see 70degC with 30degC ambient conditions. With the fan and water spray, I can bring this down to 45-48degC. It gives a fighting chance in stop-go traffic.

I don't know exactly the brand of the fan, but I can find out. I've seen some installations where this fan is mounted behind an oil cooler (like the std radiator fans). This is especially effective if the oil cooler is mounted in the fender.

can sopmeone please explain to me what the point of having low intake temps is in stop go traffic?

you dont need the power, and at just above idle you are hardly likely to det the engine to destuction.

The only problem with heat soak is idiots who boot it straight from standstill when the car has been sitting a while, but if you can remember not to do this, I dont see what the need is for this fan.

[Edited by Adam M - 8/8/2002 11:57:22 AM]

Perhaps conditions in other countries are different so that you might wait in traffic for a long time and then move onto a very high speed stretch of road?

The only thing with Water Injection is that if say a nozzle got jammed / blocked, then the water wouldnt get thru, without spending a fortune on the WI that has the built in warnings it could especially if you have had your car re-mapped to reap the rewards go serioulsy wrong.

Adam

Have you never had to crawl up to a roundabout in the heat of summer and then had to pull away quickly to get out?

When the temps have reached 60-70 deg in slow traffic, it usually takes 5+ mins to cool down once moving again. Junctions and roundabouts could be a problem in these conditions so I don't think it totally unreasonable to have an 'idle' cooling system, especially in hot countries.

F

5+ mins?

must admit I never monitored temps with my top mount, but with my front mount, temps came down in about 10 secs.

Yes I have crawled up to roundabouts, but I have seen thousands of other cars manage to pull away wiithout access to serious turbo boost type power levels.

I completely believe that you never need the power we have on the road, otherwise how would I survive in my humble peugeot 205?

A couple of weeks ago (hot weather), I'd been plodding round the North Circular & got to the turning for the M1. Sat at the traffic lights, eased off slowly, changes to 50 limit, lowered my foot when in 3rd (nothing excessive) & the ECU dropped the boost to 7 - this ordinary movement was enough for it to panic from the det.
Yes, the car's running a tad lean at the moment, but it shows there's a problem (standard TMIC this was with) and it can happen! And it hasn't done this under any other circumstance, other than doing 100 under full boost in 30C on a RR...

TBMeech,

a point well made - from experience I can say that even tuned to provide significantly more advance - my car did not fail me when the WI failed on track. Yes the knock count went up - and so I slowed down and then cut the boost.

It is useful tho to have both a knock link and ideally a WI light as well as a low water warning. It is a powerful mod, especially for heavily tuned cars - but not fatal if treated appropriately.

The other dimension is that RT will get a great benefit with a real time ECU that is in the STi 7 - at no risk as if the WI fails the ECU will compensate in real time.

Trout :D

Thanks Trout :)

It was one thing that worried me, especially that I have an STI-V (Choco engine and all!), plus my Link, so if I added WI, I would have to re-map the car to suit, if anything went wrong it would be a worrying, again having the knocklink like yourself it would show instantly....

Prob is price as well, its something like £300 for the basic WI kit, then £450 for one that looks more sensible or £650+ for the ideal system, seems extremely expensive!

But think of the fuel saving :D

TBMeech,

it is costly - however I would personally very strongly recommend it if you are out on track. It is a little less valuable on road - but still good. However if I was in a hot country I would do it just for road performance.

Also I have found that performance is MUCH more consistent. My RR figures are much less susceptible to atmospheric conditions than without it.

Trout :D

Trout,

Fair comment there m8, I hardly to track work (1 Track day in 8 Months!) so at present it's on the drawing board for the future, but after my Defi's are fitted am really going to have to think about a FMIC as still running std ic.

Fuel thought is a good one - on the road my car uses 3% less fuel with WI - and water is free.

Trout :D

Just curious for those who do monitor core/air temps, what temps did you see on sunday at Elvington?? You say heat soak isnt usually a problem. I totally disagree, obviously some countries are hotter than others, and the UK is usually on the cooler side of things. But take a day like Elvington on Sunday. It was a very hot day, and we were doing drag runs.. Flat out, stop. Queue for the next run. Here heat soak can be a problem as you will be pulling away, flat out, and the air flowing through by the end of the run, just has not had time to cool the core down. The core would only really be getting cool again after the run, when the car has come to a standstill again, ready to soak up a lot more heat.
Keeping the core temp down in these situations would be a major benefit, whether via waterspray, or a good cooling fan, or both.
There was a lot of heat build up on my car, partially due to the amount of hot metal around, and also not helped by having a black car. My air temps were over 50 degC most of the day, unless I parked up for an hour or so, with the bonnet open.
Heat soak can be a problem, and anything to reduce it, or cool the car, whilst stationary cannot be a bad thing.

[Edited by ustolemyname??stevieturbo - 8/8/2002 5:15:27 PM]

Good point Stevie, the same can be said for track days as you could be queueing for the session and temps can rise sharply. Then it's straight into blast mode on track (don't give me that take it easy on the first few laps crap as I've never seen anyone do that on session days - open pit different though).

Adam, it can really take 5+mins to cool down to the 30's as I've measured it real time. FMIC may be way different, but not many can afford or want to modify to that extent.

Oh, and BTW, I need all my power on the road (because my car is slow) so are you saying that you never need to use WOT on the road?

F

Need, or choose to use? I know that, on a private road (Honest Officer:rolleyes:), when I clear traffic it is not unknown to want to give it a good boot. This is the time that both Water Injection (agree with the benfits and the idea of post intercooler) and a fan (or Nitrogen/CO2 cooling as used by our Cousins over the Pond) to prevent heat soak in the intercooler.

RT. Any chance of a link to some pictures? Fan type? TIA.

Duncan ;)