Here is the proof....our suspicions were correct....two broken pistons, and two others that were pretty badly damaged also.

This comes as a result of tuning the car on the dyno with inlet temps at 40 degrees, and then racing with inlet temps that reached 95 degrees at some points (earlier in the year with no intercooler)

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Luckily piston #3 is not too bad. I will be sending to JE in the states to have some copies made.

Why would you attempt to do this with no intercooling anyway ? Fitting a good one such as a Ralliart Evo 4/5 type could have prevented this and saved much agro . Detonation from high charge temperatures is what killed those pistons .

Also why would you send a sample to the US when you can get pistons made here from better Cosworth blanks ? I think Tomei used to make pistons for these engines at +2mm .

The std late intercooled pistons with drilled oil returns are better than many give them credit for as is the std ring pack . Detonation will destroy forged pistons easily enough if gets out of hand .

Thanks for stating the obvious....... We were experimenting with water injection, which on the dyno was great, but on the track could not control the temps well enough on partial throttle/boost.....hence the high inlet temps.

We now run a small-medium size PWR intercooler as well as the water injection..... inlet temps at the track 2 weeks ago did not exceed 32 degrees at the end of the straight...and averaged around 25-27 degrees. The cooler controls the temps on the partial throttle stuff, with the water assisting in the top end stuff. Obviously the damage had already been done, and the psitons started to fail at the track 2 weeks ago.

My business sells JE pistons...... so why would I not use the products that we sell? I'm happy to put my money where my mouth is.

Mark.

Thanks for posting the pics. Its nice to see people actually posting their experiments/results. Most are too arrogant to admit failure and hence why you always see high-powered: cars, engines etc but never hey I went through 10 engines.

One thing I dont get, did you test every load point on the dyno with the water injection setup? It should work very well at light throttle. What type of injection system do you have? Your water injection should be as customisable as your fuel injection with increasing water with increasing load.

What AF ratios did you run?

Just questions, no doubting you did the right thing, just didnt have any info.

With WI, you should be able to get away with AF ratios of 12.5 at 28 psi on 98 ron. There is a track car in the UK which has this setup on a CA and has been running like this for years now. This is a CA is unheard of. So the FJ has more to come if youre willing to playt with it.

In australia, people havent really caught onto WI, but lets just say, 400rwhp reliably (reliably I say) is easy on street fuel with far more in the taking if you build it right to run more boost on a ported head.

Sorry for blubbering on, but please let us know how you go with some dyno results of your with WI and without on the fj.

Include ign figures at what boost and rpm if you can.

Cheers

What ever you reckon Mark , you stay with pre historic controls such as water injection and much good may it do you . Still can't work out why you want to advertise how you damaged your own equipment - not good advertising .

Thanks boosted for the feedback. The WI system we use is triggered from it's own internal MAP sensor. It increases water as boost rises through a user defined range. For my car it comes on at approx 4psi and reaches maximum injection at around 14psi.

We have seen huge gains through the use of water injection, and are currently able to run an additional 8 degrees of timing in the engine. AFR's are set at about 12:1, so still conservative.

The problem I believe from looking at the Motec data on the car came from the fact that because I was on and off the throttle very quickly(wakefield park) and the water was not actually on for long enough periods of time to effectively keep inlet temps down. As a result, inlet temps would gradually rise throughout the lap, however by the time we reached the end of the straight temps were back down to 44 degrees (from 95 degrees on some laps). Even this would not have been a problem if the car was tuned for these conditions, but it wasn't. We tuned it on the dyno where it is pretty difficult to simulate a lap as far as throttle postion etc goes. subsequently the car was tuned for inlet temps of around 50 degrees, with a little extra buffer margin also - just not enough.

Annon - WI has certainly been around for many years, and is still achieving great results. I don't see this as bad PR at all. If anything, this shows that we are not about blindly following the pack, and in fact actively looking at other avenues to try and gain performance. Sometimes they work...and sometimes they don't...... either way, if we can share that information - it may prevent someone else going down the same path.

As an aside, we have our WI kits running on a number of non intercooled supercharged V8's (Harrop, PWR & Vortech installations). All are in steet cars, and all have reported excellent gains in HP and in detonation supression (up to 25%gain in HP in one application). PWR are quickly becoming one of our biggest customers, recommending them with installs of their supercharger kits - both LS1 and LS2 applications.

Everyone is entitled to their own opinion, but our failure was due to user error, not product failure....we pushed the limit and got bitten - but that's motor racing.

As most who go down the WI road find its not much good for charge temp reduction , detonation supression yes , charge temp no . Water droplets displaces air and fuel and unless there is a huge difference in temperature all you do is lose power unless the engines detonating and its survival becomes the priority . Equal distribution of water to each cylinder is diffucult unless you are injecting into each port . I am curious as to why your charge temps are so high anyway particularly if you have an intercooler and it works effectively .

If you re-read my post...the charge temps were high due to the fact we were NOT running an intercooler at that time.

You are correct about inlet temp reduction - to a point. Obviously when injecting water post intercooler, the reuction in temp will not be as dramatic as in a non-intercooled application, however as previously stated - inlet temp reduction is not the only benefit.

With our old intercooler we saw a reduction in inlet temps of approx 20degC on the track by adding water. The new intercooler & Turbo set-up is more efficient, therefore I expect the reduction would be less.

There are a number of advantages to WI, it's not all about inlet temps. Good distribution of the water is essential - that is why you must have a system which atomises the water into the smallest possible droplets. The finer the mist, the beter chance you will have for more even distribution. The positioning of the Nozzle is also important for even distribution.

Mark.