Simple Whipple IAT Relocation

Hello Whipple owners...

I was disappointed that Whipple did not relocate the IAT sensor to after the compressor. As you know, monitoring air temperature before the compressor underestimates the temperature of the air entering the cylinder, and could result in detonation on hot days if not compensated for somehow in the tune. The right way to solve the problem is to drill and tap a 3/8"-NPT hole in the intake manifold and install the DY754 IAT sensor. However, this requires removing the blower, which is a PITA. When I eventually swap the engine internals, I will do this. But I wanted a short term solution for now to ease my mind about the intake air temperature. So here's what I did.

Image 1 - Bought a DY735 plastic push-in type of IAT sensor, along with the connector, WPT420.
Image 2 & 3 - Used a Dremel tool to remove material until the OD of the sensor was 0.405" diameter. Bought a 1/8"-NPT die at the local hardware store, and threaded the shaft.
Image 4 - Threaded the sensor into the existing 1/8"-NPT hole in the intake manifold. Used Teflon sealant.
Image 5 - Cut the wires to the temperature sensor in the MAF sensor, and re-route to the newly installed IAT sensor.

I confirmed that the DY735 reads exactly the same as the MAF sensor prior to proceeding. I've been driving around for 6 months now taking data, and the numbers I'm getting all make sense.

I moved my boost gauge monitor pickup to the fuel rail pressure sensor vacuum hose. This works well, since that line senses pressure after the compressor.

Ultimately I'd like to replace the plastic sensor with the metal one, but the plastic was very hard, and feels strong enough to last the life of the engine anyway.

I did all of this with common hand tools.

thats a great idea. im sure it will last as well. Good job!!!!

Thanks for the post! This will save me about $500 to have it done or 5 hours of my time for me to do it the other way. Is the DY735 the part number for that sensor that you used and does it come with the plug to plug into it?

KIMMER said:

Thanks for the post! This will save me about $500 to have it done or 5 hours of my time for me to do it the other way. Is the DY735 the part number for that sensor that you used and does it come with the plug to plug into it?

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Yes, DY735 is the Motorcraft P/N for the sensor (it's used in various other Ford cars & trucks), and you need the WPT420 connector to plug into it. I got the parts from rockauto.com. The total came out to $50 or so.

One last question, which 2 wires did you cut from the maf plug for the sensor? Can't wait to get it done now!

i believe it is the grey and grey/red wires for the IAT sensor out of the Maf harness

Did you notice an improvement in driveability? I have a slight pre ignition problem bellow 3000rpm with my non intercooled Whipple and was wondering if this might help cure this condition.

i wouldn't expect improved drivability.. it's more of a safeguard measure for your engine, so it can properly read the intake air charge temps and pull timing accordingly, if needed.

are you running higher than 6PSI non intercooled?
what fuel octane are you using?
sounds like you need a better tune (with a bit more retarded spark)
your spark plugs are probably busted

G.T said:

i wouldn't expect improved drivability.. it's more of a safeguard measure for your engine, so it can properly read the intake air charge temps and pull timing accordingly, if needed.

are you running higher than 6PSI non intercooled?
what fuel octane are you using?
sounds like you need a better tune (with a bit more retarded spark)
your spark plugs are probably busted

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Only running 6 PSI boost. It came shipped with a 93 octane tune and 91 is the highest we can get here. So I shipped my FRPP Pro cal tool back to Ford Racing to have it adjusted for a 91 octane tune(they pull out a bit of timing) But the courier lost my pro cal tool. I had to re-order one from Ford Racing which over writes the 93 octane tune to a 91 octane tune.

first thing. don't use octane booster.

second thing. DON'T USE OCTANE BOOSTER!!!

you can still have a custom tune done, you don't need your original unit if the tuner is good hes a level 4. he can unlock the car.

94tbird said:

you can still have a custom tune done, you don't need your original unit if the tuner is good hes a level 4. he can unlock the car.

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It's a FRPP/Whipple strategy that's not yet supported.

KIMMER said:

One last question, which 2 wires did you cut from the maf plug for the sensor? Can't wait to get it done now!

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Sorry it took so long to reply. The IAT sensor is on pins 1 and 2 of the MAF sensor connector. The wires are gray and gray/red, respectively. The polarity does not matter - it is just a thermistor.

Cdvision said:

Did you notice an improvement in driveability? I have a pre ignition problem bellow 3000rpm with my non intercooled Whipple and was wondering if this might help cure this condition.

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The PCM will start to pull timing at high IAT readings, so the car will seem sluggish when it is really hot outside. That should be the main effect - and it is definitely desirable, to keep the engine in one piece. The IAT is used by the PCM in some other calculations as well, so it would be good to have that reading as accurate as possible.

Sounds like you need to pull a bit of timing yourself at low RPMs...I'd get a custom tune and resolve the issue ASAP. I had a detonation issue >5,000 RPM, but wrestled with Whipple until I got control of the PCM, and now the engine is running great.

Iat sensor

Hi I have a 2004 Saleen S/C and i pulled out the sensor you guys were talking about the ford part number is FS6F-12A697-AB /2A16A OR F62F12A697-AA
and it does take the WPT420 plug and pigtail the kit is 35.50 at the ford dealer

MAF with IAT

As for the MAF with the Iat together 2003 and newer mustangs you need to find pin1 which is the gray/red wire is the ground and pin 6 solid gray is the return wire for the PCM you will need to put the gray/red wire on the pin 1 on the wpt420 and the gray wire on pin 2 on the wpt420 make sure you connect the splice right with connectors and heat shrink them.

RedFury said:

Image 2 & 3 - Used a Dremel tool to remove material until the OD of the sensor was 0.405" diameter. Bought a 1/8"-NPT die at the local hardware store, and threaded the shaft.
Image 4 - Threaded the sensor into the existing 1/8"-NPT hole in the intake manifold. Used Teflon sealant.

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I'm about to tackle this project. Is 1/8"-NPT for sure the correct die to use? That seems kind of small. I don't want to mess this up. How exactly did you reduce the diameter of the sensor? Which Demel attachment did you use? What is the final O.D. of the threads on the sensor?Thanks.

Yes, pipe threads are strange. The size doesn't seem to reflect the actual size of the stud you are threading. The 1/8"-NPT is the correct die. I reduced the diameter with a combination of dremel tools and files. It is rather hard plastic, so I think I was using the little grinding wheel, or one of the barrel sanders. Once I got close to the desired diameter, I was using small files to make it more round. Shoot for 0.405" diameter on the sensor before running the die on it.

Cdvision said:

I'm about to tackle this project. Is 1/8"-NPT for sure the correct die to use? That seems kind of small. I don't want to mess this up. How exactly did you reduce the diameter of the sensor? Which Demel attachment did you use? What is the final O.D. of the threads on the sensor?Thanks.

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Awesome!! Thanks for the speedy reply, I'll be picking up the die tomorrow.

I finally got around to grinding down the sensor (I worked my way around the shaft of the sensor with a 1/2" dia.,1/2" tall stone in the Dremel) and cut the threads.I cut it down another 1/8" after I took the pic then I wrapped the threads with teflon tape and she's ready to go. I'm in no big hurry to install the sensor as it's the middle of winter here(freezing cold and snowing). But I'll get around to it eventually sometime before spring. Thanks for all the info.

I installed the IAT into the intake with no problems. But the wires on the relocation harness are to short to reach. So I'll pick up the some wire and finish the project later.