Will WI give intake sensor false readings? - Miata Turbo Forum

SKMetalworks · 07-25-2009, 05:22 PM

Im deciding where to put my nozzle and wondering if injection is pre IAT sensor will it supercool the sensor and give lower temps than the actual charge? How many inches should i inject before the sensor. Here is where my sensor is

SKMetalworks · 07-25-2009, 06:31 PM

Also is this how the nozzle is suppose to be mounted to the pipe?

If not can somone post a pic of the correctly installed way?

turbobluemiata · 07-25-2009, 07:17 PM

That's how my nozzle is installed and mine is about 10 inches before the IAT and it still reads correctly

Full_Tilt_Boogie · 07-25-2009, 07:17 PM

nozzle looks correct

i would recommend putting the nozzle upsteam of the IAT sensor for the reasons you described, some will have it downstream of the sensor in order to 'trick' the ecu into throwing more timing at it, but i would imagine that you already have some way of tuning the timing properly.

SKMetalworks · 07-25-2009, 07:19 PM

Another question

I was reading the DO site and they said that the place that lowers the intake temps the lowest is in the intake manifold. Since this is the primary reason im adding WI i figured i might as well do it right the first time right?

"6 Intake manifold
This location can be the most complex area to install. Usually requiring that he intake be removed for access. Injecting here is going to yield the largest water/methanol droplets. And with the closer proximity to the combustion chambers is going to provide a larger amount of mixture into the cylinders. Doing this usually requires more fuel from the factory system be removed. This option is best for max cooling.

The water here is being injected in a manner much like port fuel injection and it is the bigger water molecules being injected here that have a more direct effect of in cylinder cooling and injection here has more of an effect of altering the flame front of the combustion charge in a way much like a higher octane fuel. To take full advantage of this nozzle location it is suggested that trimming away some of the factory dumped fuel be done. In other words, in order to take advantage of the better properties of water over fuel for cooling and injecting water at this location, you want to remove the dumped fuel and actually REPLACE this with water. This injection point with a pretty sophisticated WI control method allows for the most advantageous use of water injection. The drawback for nozzles located heres is kit/component complexity, install complexity, additional labor, possible machine shop costs, and possible additional parts costs." - Devils Own WI
Where to locate your alcohol-water injection nozzle

I was thinking the best place to mount it and came up with a few deductions.

1. Minimize obstruction as to not throw off the air flow.
2. Easily tightened if my previous picks show it correctly mounted.
3. Even (as possible) span across all 4 runners.

I am a fabricator rather than an en⋅gi⋅neer. Maybe somone can chime in?

Mouglie · 07-25-2009, 07:43 PM

this is just an opinion but the whole part about trimming the dumped fuel so its replaced by the water/meth is corrected by your mspnp. in other words you can install this nozzle after the ait sensor and check your tune.
which size nozzle are you using?

SKMetalworks · 07-25-2009, 08:26 PM

5 i believe. Is there any special place to put it? or just right behind the butterfly valve

devilsown · 07-30-2009, 12:21 AM

No, its not giving it a false lower reading. Water methanol injection is really lowering it that much.

dvcn · 12-24-2009, 08:28 AM

Yes, spraying water on the IAT does give false readings. Seems that no one here really cares. I've had a concern about this but have gotten over it and just use the wideband as the bottom line.

Someday I'll mount the IAT halfway down the manifold plenum to get a more accurate reading and possibly control fuel/ignition better.

If the water is fully vaporized before the IAT there is a good chance of it reading correctly. Most of us hit the hit the IAT with a blast of water that isn't even atomized very well. A wet IAT cannot read correctly. If the AFR's are good I'd try not to loose sleep over it.