Moving the IAT Sensor for S/C & Turbos

[TooManyFords]

For those of you who do not run under boost, this thread will probably be good 411 for when you do, but does not apply to you yet. (yet!)

While at the Chicken Run yesterday (6/12/05) we got to look at the IAT sensor kit that Mac brought along. The discussion came up because we were looking over the ProCharger kit and I did not remember that this sensor was in fact moved from the MAF (where it is in the factory MM) to just after the Intercooler down below the car.

Why is this important, you ask?

Because the computer reads your incoming air temperature to know how much fuel to use as part of the complicated math it does to make everything run right. When running boost, the air is compressed and heated as a byproduct of the compression. As such, the engine will require the fuel charge to be modified accordingly to get the most hp and tq.

In my case, I've plumbed up the ZEX kit to flow a 25 spray which should have the effect of cooling and condensing the air charge into the motor. But, without the IAT -after- the n2o fogger, the engine will not know I've done this. We discussed drilling and tapping the upper plenum for moving the IAT so it will be informed of the changes made by the n2o.

So, the ground rules to this thread are:

1. If you have any technical input on this, good or bad, please share and be specific why it is a good or bad idea.

2. If you disagree with the logic of someone's post, please share the technical reasons why and hopefully suggest a better way to accomplish the goal.

3. No "I think" kinds of posts. Let's try to keep this on target and worthy of a "Sticky"

4. No "one-liners" take that to the buttermilk thread. Please.


I'll be the first to throw out a question or two on this procedure. I've contemplated moving the IAT to the upper plenum, but on the drive home I wondered if "engine heat soak" will affect the operation of the IAT under normal driving conditions. This especially applies to that stop-and-go traffic, run into the store for 15 minutes and come back out and start the car. Will the engine heat up the sensor so it gets confused? If so, what type of insulator should be used? Should the IAT -always- remain before the TP so it is isolated from the heated intake?

You may now type until you see the yellow light. When you see the yellow, you will be given 30 seconds before the red light and then your time is up.

John

[MarauderTJA]

For those of you who do not run under boost, this thread will probably be good 411 for when you do, but does not apply to you yet. (yet!)

While at the Chicken Run yesterday (6/12/05) we got to look at the IAT sensor kit that Mac brought along. The discussion came up because we were looking over the ProCharger kit and I did not remember that this sensor was in fact moved from the MAF (where it is in the factory MM) to just after the Intercooler down below the car.

Why is this important, you ask?

Because the computer reads your incoming air temperature to know how much fuel to use as part of the complicated math it does to make everything run right. When running boost, the air is compressed and heated as a byproduct of the compression. As such, the engine will require the fuel charge to be modified accordingly to get the most hp and tq.

In my case, I've plumbed up the ZEX kit to flow a 25 spray which should have the effect of cooling and condensing the air charge into the motor. But, without the IAT -after- the n2o fogger, the engine will not know I've done this. We discussed drilling and tapping the upper plenum for moving the IAT so it will be informed of the changes made by the n2o.

So, the ground rules to this thread are:

1. If you have any technical input on this, good or bad, please share and be specific why it is a good or bad idea.

2. If you disagree with the logic of someone's post, please share the technical reasons why and hopefully suggest a better way to accomplish the goal.

3. No "I think" kinds of posts. Let's try to keep this on target and worthy of a "Sticky"

4. No "one-liners" take that to the buttermilk thread. Please.


I'll be the first to throw out a question or two on this procedure. I've contemplated moving the IAT to the upper plenum, but on the drive home I wondered if "engine heat soak" will affect the operation of the IAT under normal driving conditions. This especially applies to that stop-and-go traffic, run into the store for 15 minutes and come back out and start the car. Will the engine heat up the sensor so it gets confused? If so, what type of insulator should be used? Should the IAT -always- remain before the TP so it is isolated from the heated intake?

You may now type until you see the yellow light. When you see the yellow, you will be given 30 seconds before the red light and then your time is up.

John
Good info John. Glad you posted this. I will be installing my methanol injection system this week before the big tune over at Diablosport on Saturday. Will have to do the same as you I presume. Thanks.

TOM

[Dennis Reinhart]

The IAT placement is very important, it tells the EEC what the actual air temp is entering the TB, thats why its always added on the discharge of the SC, on roots blowers you can put it in the intake Trilogy does not but they compensate for this in there tuning. Now with a wet shot you are adjusting AF with the gas Jet so this is not as critical as with a normally SC car plus you do not run nitrous all the time, but it would be a good idea to install the IAT after the nitrous point but not to close to where the IAT could freeze up.

[Smokie]

Have you considered installing it on the last rubber connector before your throttle body? I believe the upper plenun's absorbing engine heat is going to throw off the temp. reading and read temp. of metal instead of air intake temp.

[HookedOnCV]

I'll be the first to throw out a question or two on this procedure. I've contemplated moving the IAT to the upper plenum, but on the drive home I wondered if "engine heat soak" will affect the operation of the IAT under normal driving conditions. This especially applies to that stop-and-go traffic, run into the store for 15 minutes and come back out and start the car. Will the engine heat up the sensor so it gets confused? If so, what type of insulator should be used? Should the IAT -always- remain before the TP so it is isolated from the heated intake?



Not knowing exactly where it is that the N2O is being dispersed, I would shoot for a place where there is a steady air stream while the car is running under heavy TP / load.

The one way (there may be others) the IAT affects the programming is in controlling spark. Higher air temps will remove timing to prevent detonation/knock. The actual temperature where it starts removing and amount of spark removed can be adjusted through the programming. Obviously, it is safer for your engine to run less spark and lessen the chance of engine knock than it is to run at higher power levels and damage the engine. This is the main job the IAT.

Can you find out how much temperature drop you should have with a given 25HP shot and a known volume of airflow (lbs/min) at WOT? If you know that information, then you can program in an "offset" as to what temp the IAT starts removing spark.

What I would avoid is a potential dead spot (i.e. at bends in the airflow path). I would go for the intake pipe coming off the intercooler and up to the throttle body. Keep in mind that Ford designed the IAT to go in a steady airstream (remember where the MAF is/was located), not at a bend in the airflow. That should be your first criteria, with sensing the temperature drop from the N2O secondary.

I wouldn't worry about heat soak from the engine. As soon as the IAT sees good air flow, it will respond quickly to the change in incoming air temps.

Good Luck!

Todd

[HwyCruiser]

My IAT was relocated to the underside of the aluminium throttle body elbow during the ProCharger install as shown in the attached pic. I thought yours was the same location, but after discussion with Greg they made the change to get a better indication of the intercooler charge than I get with the "older" version.

Greg tells me that I my IAT reads 10 degree's hotter than where yours (and his) down low right after the intercooler. So this 10 degree's comes from heat soak of the aluminium elbow? Sounds reasonable.

You're chosen ZEX nozzle location might be a reason to locate the IAT where the original design had it, up near the throttle body.

[TooManyFords]

Dennis brought up a good point about using a wet n2o system as I have. So I called ZEX to get the skinny.

Per ZEX: When running a wet n2o system, the IAT should be -before- the fogger nozzle, and -after- the supercharger / turbo. By cooling the air with n2o, the computer will sense abnormally cool air and increase the timing. The fuel (as Dennis pointed out) is the correct offset for the n2o and the IAT should handle the compressed / boosted air.

Now, this does not mean that it cannot be adjusted for in a custom tune (ala Trilogy), but by taking the above approach you do not have to worry about heat soak in tapping the upper plenum.

With that said... Tom, with your methanol injection system, I am not familiar with the mixing ratio. When you get a minute, can you call your supplier and run this by him as well? I bet the Methanol will act as the additional fuel to the atomized water so you can put your fogger after your AIT as well. Keep us posted, K?

Good comments and suggestions everyone! ;)

John

[HwyCruiser]

Per ZEX: When running a wet n2o system, the IAT should be -before- the fogger nozzle, and -after- the supercharger / turbo. By cooling the air with n2o, the computer will sense abnormally cool air and increase the timing. The fuel (as Dennis pointed out) is the correct offset for the n2o and the IAT should handle the compressed / boosted air.


All this was just a quiz then? :poke:

Sounds good to me... but why offset the IAT? The additional cooling with the small whiff of N20 would be safety margin to your benefit instead of letting the PCM increase timing accordingly. Wasn't the nozzle after the IAT when you were running it before the s/c? The revised IAT location on the Procharger kit is in the coolest spot it is going to see anyway.

[TooManyFords]

All this was just a quiz then? :poke:No, just because someone at ZEX says it's so doesn't mean it is. It sounds right to me but I want to hear what everyone thinks.


Sounds good to me... but why offset the IAT? The additional cooling with the small whiff of N20 would be safety margin to your benefit instead of letting the PCM increase timing accordingly. Wasn't the nozzle after the IAT when you were running it before the s/c? The revised IAT location on the Procharger kit is in the coolest spot it is going to see anyway.Yes, the nozzle was just before the J-tube and it makes sense that I should duplicate this regardless of whether or not it is boosted. But I am really not an expert by any stretch of the imagination so I will now listen to the others to see what they share with us.

And yes, I did go out and look under the car and find the relocated IAT sensor! Thanks Greg!

John

[HwyCruiser]

No, just because someone at ZEX says it's so doesn't mean it is. It sounds right to me but I want to hear what everyone thinks.

Good point. I yield to the man with the cat with a lime (?) on its head.

[David Morton]

Let common sense prevail. Having said that, if you don't have the right information to make a common sense judgement, you aren't using common sense when you go ahead and make a decision anyways.

N2O is a very powerful addition to the intake charge, cooling it and providing gobs of oxygen, hence the need for extra fuel delivery. Let's not fool the computer into thinking it can get away with more timing and less fuel by telling it the air is colder. Zex has figured out the amount of extra fuel needed in it's kits, I won't sandbag their research.

I fully agree with the concept of telling the computer that the air is hotter from the turbo or S/C and thusly that we need more fuel and less timing especially when more boost=more heat. A very good strategy, placeing the IAT after those devices.

Methanol is a fuel, yes but the main effect is for the 160 octane value it has. Methanol systems indicate placement of the IAT after the injection of the methanol, to inform the computer of the cooling (and by proxy the added octane value), but most importantly, because such a system is bound to run out of methanol and then less timing is needed. Tune program is the problem nut that doesn't seem to have a wrench on any of these water/methanol/alcohol injection systems. I wish the computer had an input to indicate the tank is dry to take advantage of the stuffs' capability and tune accordingly, but alas there isn't one, so tuning for it is dangerous, and for this reason alone I'm against using such a system on my car.

Could the methanol corrode the sensor? I have no idea.

[Warpath]

Similar to what Dennis mentioned, if the IAT is too close to the methanol injector, methanol may collect on it and alter the temp (likely read very low). So, it would be better IMO to put IAT before the injector and put some sort of safe gaurd on the injector system similar to N2O - Flip a switch and timing is altered. If methonal runs dry, the switch isn't flipped.

[Dennis Reinhart]

Let common sense prevail. Having said that, if you don't have the right information to make a common sense judgement, you aren't using common sense when you go ahead and make a decision anyways.

N2O is a very powerful addition to the intake charge, cooling it and providing gobs of oxygen, hence the need for extra fuel delivery. Let's not fool the computer into thinking it can get away with more timing and less fuel by telling it the air is colder. Zex has figured out the amount of extra fuel needed in it's kits, I won't sandbag their research.

I fully agree with the concept of telling the computer that the air is hotter from the turbo or S/C and thusly that we need more fuel and less timing especially when more boost=more heat. A very good strategy, placeing the IAT after those devices.

Methanol is a fuel, yes but the main effect is for the 160 octane value it has. Methanol systems indicate placement of the IAT after the injection of the methanol, to inform the computer of the cooling (and by proxy the added octane value), but most importantly, because such a system is bound to run out of methanol and then less timing is needed. Tune program is the problem nut that doesn't seem to have a wrench on any of these water/methanol/alcohol injection systems. I wish the computer had an input to indicate the tank is dry to take advantage of the stuffs' capability and tune accordingly, but alas there isn't one, so tuning for it is dangerous, and for this reason alone I'm against using such a system on my car.

Could the methanol corrode the sensor? I have no idea.

This is why a lot of guys run two programs one for water Meth one with out. With either N20 or water meth if the IAT is to close it will freeze up, by n20 or get by soaked by the water meth

[David Morton]

This is why a lot of guys run two programs one for water Meth one with out. With either N20 or water meth if the IAT is to close it will freeze up, by n20 or get by soaked by the water methIf the switch for the chip could be a level indicator and put inside the methanol tank, I'd consider using the system.