High humidity?

[rarson]

I'm looking to set up a WI system on either a non-turbo or turbocharged car, or possibly both. I'm not set on water, but I think I would like to run at least a 50/50 water/meth mix. I also might experiment with some nitromethane, but for now my question concerns water.

I am in Guam. Guam has quite a lot of humidity, probably an average of about 80%. I am concerned by this fact, and am afraid that even a small amount of water will saturate the air. The problem is, it is also rather hot here so I would like to take advantage of WI for detonation purposes.

I am thinking possibly a straight methanol system might be in order. Also, I am highly interested in pursuing testing of a pre-turbo system. I would be removing the intercooler in this instance and making the piping as short as possible. I am a little weary of injecting straight meth into the compresssor, or is this just unfounded? I have no experience with methanol whatsoever, so tell me if I'm just being unnecessarily anxious.

Thanks for all the help, there's a wealth of info here but I could not successfully find any information regarding high humidity climates.

[hotrod]

Having spent a couple years in Guam, ( I remember a speed run or two on an abandoned air strip on the north end of the island in a new 240Z ).

I would say your assessment is probably correct. Your humidities are very high and water evaporation will be nearly zero when you are off boost or at low boost.

On a turbocharged application, even with an intercooler, there will be some evaporation due to the high inlet temps. In my tests on a TMIC on a WRX, in 90 degree weather the charge temp out of the intercooler might be 135 deg F or so. That significantly drys the air so water injected into hot charge air will still cool things off.

I would suggest you use at least 50/50 water methanol, straight water would not be my choice in a tropical climate like that.

On the pre-turbo injection, water would still work due to the high air temps reached in a turbocharger under boost, you would still get the advantages of wet compression. I would how ever delay the spray turn on a bit more than stateside or temperate climate folks because your very high humidities will do some of that for you anyway.

Let us know how things work!

Larry

[rarson]

Hehe, Orote Point air strip... I've actually done a few speed runs in my friend's Skyline out there.

Okay, so I think I've decided on a setup that I would like to try. For pre-compressor injection, I'll probably do a 50/50 mix of water and isopropyl, with a goal of maybe 1.5-2% airflow I guess? I won't turn it on til I'm >13 psi of boost. The second stage be some kind of methanol injection (either pre-TB or direct, I'm not sure), and hopefully I could throw in a bit of nitro too. I'm willing to experiment with my car, but I'm going to have to start out slow.

My last question is regarding methanol injection pre-turbo. Is corrosion a real concern in this instance? Because I'd rather use meth than isopropyl, but not if I'm going to have to worry about corrosion. If I could use it though, then I would probably think about spraying a larger amount pre-turbo, with lower water mixture (say, 60/40 or 70/30) so that I won't saturate the air.

[hotrod]

I saw no evidence of corrosion, only the info, I've already posted about a bit of compressor blade tip erosion due to trying too high a water flow rate. Most likely due to dropplets running down the inside of the inlet pipe from turning the Pre-turbo injection on a bit too soon.

I'd go with the methanol as well if I were in your location.

Yeah me and a buddy almost stuffed a 240Z into the jungle up there on that strip. As you probably know wet crushed coral pavement is not the best braking surface. :shock:

Larry