I am in the process of expanding my WI system to include twin pumps and a two stage twin jet set-up, the smaller of the jets is to spray some where around 2-5 psi into the (single ) turbos suction (to aid in cooling of the turbo as well as the charge) and the other larger jet to operate at higher boost of 18 + psi when it's needed.
I recently came across an article saying that the optimum intake temp for any internal combustion gasoiline engine is 40 deg C (? ) , I was planning on using the intercooler fan output on the E6K to activate a solenoid valve and bring the larger jet in service to get the intake temps as low as possible when in high boost , now I dont know what to do , can anyone say if there is any merit in that statement.

 

i have seen 20+ deg C before, and usually 30+ deg C. The lower the intake temp, the more power you make....

 

40*C sounds too high to be 'optimum'. Because if that is the case, then my IC is too good

 

Anything above 3*C = 37*F should be fine for H20 injection. Anything lower and you should add methanol to help prevent freezing. Other substances can be used but methanol is the most common. Check with the nozzle manufacturer to verify recommended operating temps. The colder your intake charge the better under most conditions.

 

If you are running H20 injection, you should be running methanol anyway.

I run a 50/50 mix with mine and it seems to work great!

 

40 deg C sounds like some carburation rule of thumb- probably needed the heated air to atomise fuel properly. Or maybe for best combustion emmisions- but certainly not for engine reliability.

My intake temps don't hit 40 C untill I have idled in the garage for over 1/2 hour heat soaking!

My HMIC FC runs ambient at cruise (15 C last night) and w/ the brake and gas floored in 4th (to get full boost) for a couple of miles the intake temps creep up to 26 C.

Coolant temps go from 82 C all the way to 84 C during this test

I'm pretty happy w/ that- I epect even better results when I finally get a hood w/ vent for my HMIC.

Temps are from Haltech- don't know how accuate that is...

 

Anything over - 20% methanol 80% H20 - will start to separate. Not a good idea.

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40 deg C sounds like some carburation rule of thumb- probably needed the heated air to atomise fuel properly. Or maybe for best combustion emmisions- but certainly not for engine reliability.

My intake temps don't hit 40 C untill I have idled in the garage for over 1/2 hour heat soaking!

My HMIC FC runs ambient at cruise (15 C last night) and w/ the brake and gas floored in 4th (to get full boost) for a couple of miles the intake temps creep up to 26 C.

Coolant temps go from 82 C all the way to 84 C during this test

I'm pretty happy w/ that- I epect even better results when I finally get a hood w/ vent for my HMIC.

Temps are from Haltech- don't know how accuate that is...

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Where did you locate your air intake sensor? Very cool readings. I wish mine were that cool.

 

I heard that water droplets in the path of the turbo will cut just like a waterblaster !! ..not good !

 

Thats a crock!
I store my water in a fuel cell that is easily viewable.
Water mixes with methanol just fine and it does not seperate.

 

The Aquamist system sprays a VERY fine mist. No droplets.
Rice Racing injects his before the compressor with great results. I am going to start doing that as well.
If you stop and think about it, your turbo is sucking in water all the time!
Have you ever seen water coming out of somebodys tailpipe?
The engine is sucking in dense air (water) and expelling it out the tailpipe.

 

Those are quite impressive numbers.

On a cool night 20C ambient, I can usually get about you have, ie 26C cruising, 30C or so at WOT.

But, on a hot day 35C, my intake temps are pretty high. Usually over 30 and as much as 40 during cruising on the highway. Don't change to much at WOT.

My IC piping does run over the UIM though (similar to what RXTASY had before), which I'm sure is part of the problem.

I'm still debating whether less bends is better than rounting it slightly away from the heat with more bends

 

Thats a crock!
I store my water in a fuel cell that is easily viewable.
Water mixes with methanol just fine and it does not seperate
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Good for you. I am just quoting what has been said and proven time and time again. I am not a chemical engineer. I did quite a bit of research back in the 80s and spoke with many experts in this field. Jim Mc Farland, Cris Kaufman, Mark Sanchez, Vic Edelbrock just to name a few. 50 / 50 mix will not be consistent. You will be sucking up more meth or water at any given time and throw your tuning off. I said it wasn't a good idea. I just didn't want to see your motor go POP. No need to be rude.

 

Sorry if I came off rude.
I am going to investigate this theory of seperation a little more.
Maybe some water based dye like food coloring mixed with water and methanol in a clear jar.
I will post my findings here.

 

Marcel

The RX-7 engine management system is OEM tuned for 40 degrees C.

IAT intake correction maps available through datalogit screens indicate that at 40C the fuel injectors provide 100% of the fuel required by the maps. At 30C the fuel injectors are instructed to provide a higher percentage of fuel than the base maps require and at 50C the injectors are instructed to provide a lower percentage of fuel than required by the base maps.

Although lower IATs are always nice for power (cooler temps=denser air=more available O2 and leaner AFRs), the OEM correction tables should compensate. The only caveat here is that if you retune the base maps when the IAT is not at 40C (or if you relocate your IAT sensor) you may want to consider recalculating the "O" point for the IAT calibration data.

 

Actually I am using the HALTECH and I also read this on a SUBARU forum where they were speaking about water injection.

 

Marcel

Sorry if my post wasn't clear enough. The 40 degree C reference point is not ECU dependent (Stock, Haltech, Wolf, AEC, or PFC doesn't matter). All standalone aftermarket ECUs build in some Correction Table based on the Mazda formula. 40 degrees C is the OEM reference tuning point from Mazda.

In other words, Mazda tunes the FD for a 40C Intake Air Temp and programs the ECU to make adjustments to the the amount of fuel actually delivered based on increases or decreases in the IAT. Since Mazda tunes for 40C, it would seem to add credibility to the belief that the optimum Intake Air Temp for an internal combustion gasoline engine would be 40 C.