"IAT = Intake Air Temp sensor" on the Focus?

[JeffN]

Btw, in case anyone is wondering the SCT software allows you to add or remove spark based on the IAT/ACT temp reading... so as air charge temp increases you can back off the advance a bit.

With the IAT/ACT located on the MAF, on a blown car, you have to make some assumptions about how much heat your blower will contribute to the air charge temp, and that change may be non-linear. You can actually vary the spark advance as a function of load, RPM, and IAT/ACT temp, so you could develop a pretty good table keeping the sensor located at the intake IF you had good specs on the temperature contribution of your blower at various load/rpm combinations. But it would still be easier and more accurate to just MEASURE the IAT/ACT measurement as it enters the engine.

Now all I have to do is figure out how to mount one of those things on my JR intake.

This company makes all kinds of temperature sensors, mounting hardware, and insulators for preventing heat soaking: http://www.tempco.com/Sensors/temp_sensing_hub.htm.

Note that all we need to do to adjust the voltage range is add a resistor so there is no need to buy a Ford sensor. Just need to figure out the current running through the stock sensor (which can be measured with a voltmeter at the MAF) and then take some readings of actal temperatures to calibrate the sensor. The resister value can then be selected to produce comparable voltage ranges in the sensor you buy. I am hopeful that I can slide one of these sensors into the small vacuum inlet hose opening in the JR intake that was previously used for the JR fuel management unit (which fuel management unit is now unused thanks to SCT).

[Hypnotic]

I found it on a late 90's(I think) Taurus.

And just as an update for anyone considering the SCT software. They are now saying that for proper tuning, it is a MUST to re-locate the IAT sensor to after the blower.

Just a tip for all of you messing with the IAT, ANY massair equipped F150 has that sensor also.

[sct]

We have actually refused to tune cars without the IAT in the discharge. It's that important!!! You really really need to know the air temp post compressor so you can control spark if the inlet air heats up due to outside temp increase, heat soaked cooler, etc. Otherwise you have to tune for "worst case" scenarios and leave lots of power on the table, or take a chance of letting the smoke out of the motor when it gets hot.

The easy way to do this is with a Lightning sensor. It's brass threaded and has a standard IAT connector. Just drill and tap a 3/8's NPT hole somewhere in the discharge piping or manifold if necessary.

By this time you've spent $3000+ on your Focus for the blower/turbo/etc. Spend the extra $40!!!!!

[Penguini66]

I looked at the brass NPT sensor. And was concerned about heat soak. So I went with an all plastic one even though it was a little more difficult to mount for a pressurised application. Sorry I don't know much about the Lightnings. But is the sensor you're talking about designed for a blown application? Do you know if its resistant to heat soak?

[Hypnotic]

The easy way to do this is with a Lightning sensor.

LOL...didnt I say that in the post before his?

[P-51]

Yup, I don't like these metal bodied ones... I'd have to have a look at the head design tough. All I know is this Bosch sensor form Pectel sucks.

[Hypnotic]

I looked at the brass NPT sensor. And was concerned about heat soak. So I went with an all plastic one even though it was a little more difficult to mount for a pressurised application. Sorry I don't know much about the Lightnings. But is the sensor you're talking about designed for a blown application? Do you know if its resistant to heat soak?

These same sensors are used in the new (99-03) Supercharged Lightnings. There are several of these trucks pushing over 14-16 lbs of boost on the eaton, and some as much as 18-20 lbs with the Autorotor (Kenne Bell). While the stock, and even upgraded, intercoolers work very well, the piping is still in "hot" locations. I asked around, and no one has mentioned ever having any issues with the sensors.

[Hypnotic]

What do you guys think of this:

Thats the same sensor that is used on the 1994-1996 F150's with the massair setup. I have only sprayed mine, so I wouldnt know about it handling the heat, but with it being plastic, probably not.

[P-51]

These same sensors are used in the new (99-03) Supercharged Lightnings. There are several of these trucks pushing over 14-16 lbs of boost on the eaton, and some as much as 18-20 lbs with the Autorotor (Kenne Bell). While the stock, and even upgraded, intercoolers work very well, the piping is still in "hot" locations. I asked around, and no one has mentioned ever having any issues with the sensors.

Well, this all leads back into what we are saying. The Lightings probably are getting head soaked, but they were tuned conservatively to avoid problems.

That's why I did. I mean, I have a similar sensor, and you can watch it... go from 80 degrees while on the freeway, then climb to 180degrees in one minute sitting in traffic. I have data logs.

The result is, I have to fuel and time it for the worst case scenario. When I put on a better one, I can add a little more timing when cool, and pull it at high temps.

[Hypnotic]

The Lightings probably are getting head soaked, but they were tuned conservatively to avoid problems.

You evidently dont know who Jim D'Amore of JDM, Sal of PSP, or Johnny Lightning are. These guys are tuners on the wicked edge of new Lightning performance. THESE are the guys that still use these sensors, and have new L's in street trim running 18-20 psi with 1/4 mile times in the low 11's to high 10s IN DAILY DRIVER STREET TRIM!!!!!
Heat soak? with that much power and those times? I sincerely doubt it.

[P-51]

Ah....ok. What does a timeslip have to do with heat soak?

If they had a better sensor, maybe they'd be running 9's. The point is, you CAN'T tune for maximum power if your sensor isn't measuring the right air temp.

[sct]

Having datalogged literally hundreds of blown cars with the threaded sensor we've never seen heat soak like you describe. The Saleen blower has a bit of a problem but it's because the sensor is not threaded deep enough to get the sensor itself into the air stream and instead it measures the temp of air in the boundary layer along the manifold surface. The bottom line here is that the Lightning sensor works very well. The range is up to 250 degress which should be good enough for most blown vehicles. If you are blowing air hotter than that into your engine you need a cooler!!!!

[Hypnotic]

Having datalogged literally hundreds of blown cars with the threaded sensor we've never seen heat soak like you describe.

Thanks for the backup sct. Did you get the PM I sent you btw?

[Hypnotic]

Ah....ok. What does a timeslip have to do with heat soak?

If they had a better sensor, maybe they'd be running 9's. The point is, you CAN'T tune for maximum power if your sensor isn't measuring the right air temp.

What I was trying to get acrossed was this, those 3 guys, along with many others, have logged countless hours of tuning on the dyno, and passes at the strip using these sensors. IF there was ANY way to squeeze MORE power/ e.t out of the vehicles they work on, they would use it. If the sensor was not a viable and solid working piece, THEY WOULDNT USE IT.

[P-51]

Maybe I'm a little wierd but my idea of fun is a high horsepower car that I can drive every day, pass emissions with, and still race on the weekends ...

I guess I have very little faith in most "tuners" out there. Very little. I've seen more absolutely clueless "tuners" than good ones, by far.

I have datalogs from 3 different positions that showed massive heat soak from conduction. First was in the metal elbow feeding the throttle body, second was the charge pipe near the coil, and third is the metal elbow attached to the FILTER, which is located in the fender well.

The air in that location is NOT 160 degrees, but that's how hot it reads when sitting for a minute.