Intake Air Temp sensor placement question

[ae86ma70]

Tried searching for this already. Here and on Google. And on the AEM forums.

I have a 7M. I am gettnig ready to install my EMS and convert to speed density. I wasa going to do EMS+AFM at first, but my tuner says "Why do it twice?". So, I'm trying to plan this out as best I can in advance.

Many people say that if the IAT sensor is placed in the plenum, it tends to get heat soaked. I have heard this about the Supra and also many other applications. My understanding is that the stock sensor is part of the AFM, and as such reads the temperature before it goes through the turbo, IC, TB, etc. If this is the case, why is it not a good idea to mount my GM sensor in the 4" intake before the compressor?

My actual second choice after the plenum would be in the IC piping just before the throttle body, but I still have the stock (PCV) breather setup that recirculates to the intake. And it looks as if this is a tight fit. I suppose my PCV setup might have to change with the new intake setup. Any input on this?

While I'm at it, I've also got a MAP sensor to mount somewhere. Does anyone have pics of a setup similar to mine?

7MGTE (stock intake manifold)
2.5" IC piping
big FMIC (same side inlet/outlet)
Driftmotion 60-1
4" SS intake (from ^ DM kit)

Any positive input will be appreciated.
Stock PCV system

 

[turbo87targa]

I'm wondering the same. Similair setup minus the turbo kit.

In for info.

 

[Enraged]

I have mine mounted about 8" in front of the throttle body. I'm running a FFI with a Maft Pro.

 

[IJ.]

I run one on each side of the IC Couplers.

All depends on what you're using to tune, standalone I find this works well as you can "adjust" to suit.

At a rough guess a stock ECU would have compensations for heatsoak and engine bay temps, 3P might have some data on this.

 

[Kckazdude]

My IC piping runs up the inner fender well on the outside of the shock mount. I mounted mine right at the bend at the shock mount before it goes across the turbo. I had read about heat soak concerns at the 3000 pipe and the intake.

 

[ae86ma70]

I run one on each side of the IC Couplers.

All depends on what you're using to tune, standalone I find this works well as you can "adjust" to suit.

At a rough guess a stock ECU would have compensations for heatsoak and engine bay temps, 3P might have some data on this.

IAN-

You mean that you run 2 sensors, one on the before the IC and one after? Does the AEM EMS have inputs for two AIT sensors? I am very glad that you posted a reply here, as I saw many replies from you while doing research on this topic. I resisted the urge to PM you, thinking that others might have similar questions.

 

[IJ.]

Yep I like to have pre and post IC temps just for my own curiosity

The AEM "should" have a bunch of spare inputs you can plug another sensor into (I don't know for sure but I'd be surprised if it didn't)

When I ran the sensors inside the engine bay and did my running compensations based on them it would heatsoak like a bitch if I stopped to refuel and be very difficult to restart, I got around this with the MoTeC by adding in a ground speed channel on that axis, but if I were doing it again I'd add a cranking axis instead so the compensation wasn't off when stopped at lights.

 

[ae86ma70]

My IC piping runs up the inner fender well on the outside of the shock mount. I mounted mine right at the bend at the shock mount before it goes across the turbo. I had read about heat soak concerns at the 3000 pipe and the intake.

And have you had any problems tuning it like this? I have a more-or-less stock routing on my IC piping. I don't particularly like the idea of mounting the sensor directly over the turbo, but maybe closer to the intercooler, like IJ suggests.

 

[turbo87targa]

Will the air temp change significantly after it passes over the turbo?

 

[TurboStreetCar]

Will the air temp change significantly after it passes over the turbo?

Depending on boost pressure and the turbo in question yes, it can increase GREATLY.

At 14.7 psi of boost, without factoring in the inefficiencies of the compressor wheel, temperature will double, This is from strictly compression alone. Add in the inefficiency of the compressor wheel, the temperature of the housing and anything else that may influence the temperature of the air and your looking at some REALLY REALLY hot air.

 

[Poodles]

Think he means where the stock piping crosses over the top of the turbo.

 

[Dirgle]

Indeed, temp can vary greatly. In a speed density setup the computer needs to know exactly what temperature is going in to the cylinders, this combined with pressure data from the map sensor give the air density of the intake charge. And this gives the volume of air expected inside the cylinder at a given stroke, so that the computer may provide proper fuel to meet target AFR's. And incorrect temperature reading will give an incorrect air density. Ideally you would take this measurement inside the intake plume, but as IJ has hinted at you have to combat heat soak.


On the JDM 2JZ the temperature is located inside the intake plume. So more than likely there is programing inside the ECU to correct for heat soak.

 

[ae86ma70]

If I am using the stock 7M-GTE intake manifold, and don't want to tap or weld on the actual intake plenum, what is the most optimal placement for the IAT sensor? After what IJ posted, I was thinking in the pipe on the cold side of the intercooler, but now I'm back to thinking somewhere above the valve covers. While we're on the subject, anyone using the AEM MAP sensor? How is it mounted/plumbed? Maybe someone has some pictures to post?

 

[ae86ma70]

Think he means where the stock piping crosses over the top of the turbo.

I'm thinking that adding a heat shield to this area would not be a bad idea.

 

[IBoughtASupra]

I Bought $180.00 worth of heat protection. Use heat protection on anything that you can, you will be very happy.

 

[paradox616]

My haltech manual says it should be placed as close to the cylinders as possible, the sensor its self needs to be in direct path of airflow, ie not just bunged in a weird spot in the plenum that wont see a constant path of airflow.

The buick 3.8L v6's mount them JUST before the valves in the plenum, i installed mine just before the crossoverpipe that passes ontop of the turbo to avoid heatsoak, its aprox 50cm from the throttle.

IJ you must get a good indication of how well your intercooler works! ill probably end up wiring in a few more air temp sensors etc,

 

[IJ.]

Started doing it back when I had the W2A IC in it just to get an idea how well it was working, don't really use the Hot side sensor to control anything just a curiosity thing

 

[paradox616]

Started doing it back when I had the W2A IC in it just to get an idea how well it was working, don't really use the Hot side sensor to control anything just a curiosity thing

=)

At fullboost what kind of temprature drop do you see across the intercooler?

 

[IJ.]

@ 10 psi on a hard pull I was seeing 100c discharge and 31c inlet temps, had to dig back through my old data logs to find this if I find some higher boost pulls I'll post em up.

It was August so probably mid 20c day.

 

[ae86ma70]

i installed mine just before the crossoverpipe that passes ontop of the turbo to avoid heatsoak, its aprox 50cm from the throttle.

Pics? (Please) Before meaning between the IC and the turbo, near the fender?I'd also want to add a bung for meth injection. would i mount that even closer to the IC? My thought was to mount the sensor on the backside of the pipe that connects to the TB. Between the valve covers. And then mount the methanol jet closer to where that pipe passes through the fender, and then wrap the whole pipe in exhaust insulating wrap. My turbine housing is ceramic coated, and I'm going to cover the dp in wrap as well. Thoughts?