IAT position with alcohol injection

[Lastyear4gt]

I don't know how many people have any experience with alcohol injection, but I am thinking of relocating the IAT to a port on the upper intake manifold about 6-8" after the injection nozzle. Will this cause any problems with the sensor being in the stream of alcohol mist? Should I just leave it before the alcohol injection?

[driftnpow]

dare say youll be opening a can of worms
id only presume you will get fluctuation of temperature readings having sensor contact with fuel and air both which would have different temps, or possibly a "windchilled".
id suggest sticking to an airstream before the injectors.

[e85grandprix]

I don't understand why you would do that?

[Lastyear4gt]

The alcohol injection is in place to cool the intake charge in addition to raise the resistance to knock when in boost. The way I see it, with the IAT at the outlet of the blower before the injector, the IAT is not reading the actual temp at the intake, therefore not really getting an accurate reading for fueling purposes. In actuality the way the set-up is now, the Alchy is only raising the octane, not actually cooling the intake air as far as the PCM can see.....

[Lastyear4gt]

Looking back, I think you guys are not understanding what Im talking about here. I am talking about a water (meth) injection system, not placing my IAT after my fuel injectors.

[driftnpow]

Dont mean to come across having a dig, in my opinion tho introducing avoidable variables having the sender after alch injection. from what i see theres possiblity of quenching the sender beyond actual intake temperature from accumilation/saturation. not to mention whos to say the sender is going to be quick enough to respond when injection starts and stops.
my suggestion is tweek with the ignition timing when injection is underway and leaving the sender where it is.

[oldskool]

The alcohol injection is in place to cool the intake charge in addition to raise the resistance to knock when in boost. The way I see it, with the IAT at the outlet of the blower before the injector, the IAT is not reading the actual temp at the intake, therefore not really getting an accurate reading for fueling purposes. In actuality the way the set-up is now, the Alchy is only raising the octane, not actually cooling the intake air as far as the PCM can see.....

my thoughts exactly.

If you have the correct flow rate (nozzle) for your application, and the correct trigger (MAP or TPS), then you should not have problems relocating the IAT sensor. I would prefer that my car "knows" that its getting a cooler charge as well. As long as there is a reasonable distance between the nozzle and the sensor, the water/meth will evap quickly and flow by the sensor in the gas phase rather than liquid.

My 2 cents...

[RWTD]

One issue is that ultimately the meth will kill your IAT sensor, and/or reduce it's ability to monitor properly. The other issue is when not in meth the IAT will read higher if you locate the IAT into the manifold. If you insist on spraying meth over the IAT, then put the IAT after the meth, but before the TB.

[CTX-SLPR]

What are you are talking about is a MAT (Manifold Absolute Temperature) sensor not an IAT (Intake Air Temperature) sensor. If you are spraying your alky before the blower it would likely be so vaporized by the time it got the MAT that it wouldn't cause wild swings due to droplets forming on the sensor but it would still be a corrosive environment and the temperature sensors are all thermocouple based and the responce curve changes with oxidation.

[AleroB888]

..............If you have the correct flow rate (nozzle) for your application, and the correct trigger (MAP or TPS), then you should not have problems relocating the IAT sensor. I would prefer that my car "knows" that its getting a cooler charge as well. As long as there is a reasonable distance between the nozzle and the sensor, the water/meth will evap quickly and flow by the sensor in the gas phase rather than liquid.

My 2 cents...

X2..... I used to run alc injection (w/o an intercooler) into the TB, I found the best place for IAT sensor was in the upper intake manifold. The charge temp could get down to 38 deg F. at the TB on a hot day, as low as 28 deg on a cool day, by the time it got to the UIM it was 20-40 deg above ambient, at the end of a pass. Never had the sensor fail from the alc.

[Lastyear4gt]

So where you spraying into the blower with the alcohol? Is that OK for the rotors? What size injector did you use? Im going with a 4gph. Looking at my best run to date, the scan showed my IAT without the alcohol is 50-55 degrees celcius before the run and hitting up to 70 degrees at the end of the run, and this was at night when it was about 8 degrees out. Definately need the alcohol.

[AleroB888]

So where you spraying into the blower with the alcohol? Is that OK for the rotors? What size injector did you use? Im going with a 4gph. Looking at my best run to date, the scan showed my IAT without the alcohol is 50-55 degrees celcius before the run and hitting up to 70 degrees at the end of the run, and this was at night when it was about 8 degrees out. Definately need the alcohol.

I was spraying into the blower, and I would say it is not good for the coating on the rotors, since much of mine has worn off. There was a lot of wear on mine when I first got it, though.

I used a low pressure atomizer that worked off boost pressure, not an injector nozzle. The system you have should be better. I would start with the lowest size you have, just a light mist. At some point, the amount of alcohol will be too much, and displace/restrict the incoming air.

I can't convert the temps from Celsius in my head, but if you can keep the temp rise in the upper intake manifold to within 10-20 deg F. above ambient, that would be close to what most intercoolers can do. That's assuming a pretty good cool-down between runs, and ECT to 180-190 deg or so at the line. Depending on what ECT you start with, it may or may not be good to have the alc on during the burnout.

[Lastyear4gt]

Yeah, the nozzle it came with was 9lb/hr, and you could feel the car bog when it came on, more than likely flooding out the spark. I have done the calculations and for the approx power output and boost level, a 4gal/hr nozzle should work perfect.

Lets put this in perspective for you. The night I ran, it was 47*F ambient temp. The IAT at the line was about 113*F, and through the trap it was approx 154*F. So that is where my power loss lies. Cool that IAT down and I should run significantly better times.