Trilogy IAT measurement

[JohnE]

Does anyone here have data logs of a Trilogy with a good working IAT in the lower intake. I tried both the revised mounting in the blower plate and then later in the back of the lower intake. Nether of these seem to be reading the actual air charge temperatures though.

When I get into the throttle heavy, my air charge temps drop. That's right my IAT starts high and then cools off. Basically the sensor gets heat soaked when there is not much airflow. And then when there is a lot of airflow, it doesn't register the actual rise in charge temps that I know is going on. This makes the car very sluggish in summer time. I commonly see 150F air charge at low throttle and then drop to 130 at wot on hot summer days.

I tried changing to a new sensor. But saw the same results. Actual temps seem accurate. It seems that the sensor locations I've tried are not really in the airflow path.


John

[sailsmen]

Those IAT readings that vary on/off throttle should not make the car sluggish.
Others with Eatons have had reports of sluggish in Summer. Some have switched to a bigger heat exchanger.

[SC Cheesehead]

Does anyone here have data logs of a Trilogy with a good working IAT in the lower intake. I tried both the revised mounting in the blower plate and then later in the back of the lower intake. Nether of these seem to be reading the actual air charge temperatures though.

When I get into the throttle heavy, my air charge temps drop. That's right my IAT starts high and then cools off. Basically the sensor gets heat soaked when there is not much airflow. And then when there is a lot of airflow, it doesn't register the actual rise in charge temps that I know is going on. This makes the car very sluggish in summer time. I commonly see 150F air charge at low throttle and then drop to 130 at wot on hot summer days.

I tried changing to a new sensor. But saw the same results. Actual temps seem accurate. It seems that the sensor locations I've tried are not really in the airflow path.


John

I'm not running a Trilogy set-up (have an Eaton swap), but will see a momentary (i.e. couple of seconds) slight drop in IAT when I go WOT, have always attributed it to influx of air into the intake system and the resultant lag in sensor reading.

150*? May want to consider retrofitting with a FrozenBoost Type 100 HE, I rarely see over 140* on my IAT, even during hot weather. That, or a Killer Chiller.

[sailsmen]

Research the KillerChiller. In their FAQ they say it saises cabin temps 7-8*.

[RacerX]

That's odd. It should read the same wether on Tilogy or Eaton. The setup is similar. My IAT temps under boost hit up to 136 deg. A relay went bad last Friday for the intercooler pump and at the track under WOT (didn't realize it was off) I was hitting 210 deg+.

New England Dragway, no intercooler:

http://www.mercurymarauder.net/gallery/data/579/medium/NED.jpg (javascript:;)

Dyno with intercooler working:

http://www.mercurymarauder.net/gallery/data/579/medium/Dyno2.jpg (javascript:;)

[BODYMAN]

210 I would be flippin out( iam sure you were). 90* day usually 120-130ish, at most if running it hard 140ish. As for getting sluggish thats cause computer is pulling timing when temps get high.

[RacerX]

210 I would be flippin out( iam sure you were). 90* day usually 120-130ish, at most if running it hard 140ish. As for getting sluggish thats cause computer is pulling timing when temps get high.
Yeah, I was when I realized days later when I noticed fluid wasn't running around when the key was turned. Still pulled a 12.96 with wheel spin, belt slip and high IAT's.

DO NOT BUY CHEAP RELAYS FROM AUTOZONE!!!

My 40amp, brand new auto relay lasted 1 month. I took it apart (Easily since it wasn't weather sealed) and it was completely rusted out.

[BODYMAN]

Yeah, I was when I realized days later when I noticed fluid wasn't running around when the key was turned. Still pulled a 12.96 with wheel spin, belt slip and high IAT's.

DO NOT BUY CHEAP RELAYS FROM AUTOZONE!!!

My 40amp, brand new auto relay lasted 1 month. I took it apart (Easily since it wasn't weather sealed) and it was completely rusted out.

Listening for I/C pump when I turn the key is one of a few things I ck each time. 12.96 with all that going on isnt to shabby:beer:

[RacerX]

I'm learning to listen for all the new noises. ;) Notice the run at NED, the computer pulled timing and commanded 10.5 afr to cool it. No where in my tune is richer than 11.7 commanded. That was all due to high IAT's!

[BODYMAN]

I'm learning to listen for all the new noises. ;) Notice the run at NED, the computer pulled timing and commanded 10.5 afr to cool it. No where in my tune is richer than 11.7 commanded. That was all due to high IAT's!

lol. I know what ya mean.. Also a whole diff set of noises then a centri also. How long U been eatonized now?

[SC Cheesehead]

Yeah, I was when I realized days later when I noticed fluid wasn't running around when the key was turned. Still pulled a 12.96 with wheel spin, belt slip and high IAT's.

DO NOT BUY CHEAP RELAYS FROM AUTOZONE!!!

My 40amp, brand new auto relay lasted 1 month. I took it apart (Easily since it wasn't weather sealed) and it was completely rusted out.


Had the same issue, installed a new one, wrapped it in tape, and repositioned it from a horizontal to a vertical postion (I think it was getting some water whenever I'd clean the engine bay), no problems since, 2 1/2 months so far.

[RacerX]

How long U been eatonized now?
One fun filled month.:D


Had the same issue, installed a new one, wrapped it in tape, and repositioned it from a horizontal to a vertical postion (I think it was getting some water whenever I'd clean the engine bay), no problems since, 2 1/2 months so far.

Yeah, using a Tyco relay, sealed it with rtv jic too.

[SC Cheesehead]

One fun filled month.:D



Yeah, using a Tyco relay, sealed it with rtv jic too.

Prolly is something I oughta do, too.

[JohnE]

Take a look at the temperature readings with load.

It's a trend of down with airflow and up with less airflow.


John

[sailsmen]

Why is your coolant temp so high?

The Trilogies I have driven have lower coolant temps.

Is your car running lean? Have you ever had a Dyno Tune or AFR check?

Your IAT should be 140* or less.

[justbob]

My ECT will hit 198 for a couple seconds on these 95* days but immediately go down to 92/94*

My Iat's have always been consistantly 26 or so over ambient moving, never once been over 40 idling. Even on hot days I can see as little as 19/20 above moving at 40 MPH with my HAI JLT minus the crappy good for zero shield they sell you.

Sent from my Ally using Tapatalk 2

[JohnE]

It was about 98F ambient that day. Did a lot of idling as well. So everything was well heat soaked. But then again that would be a normal drive in Houston during summertime.


For comparison, here's a log from my other car. It's an intercooled Eaton M90 on a 2V. This is what the temp log should look like.


John

[sailsmen]

I drove a Trilogy 1 week ago in the same conditions. Your coolant and IATs are 15* higher. Something ain't right.

[SC Cheesehead]

I drove a Trilogy 1 week ago in the same conditions. Your coolant and IATs are 15* higher. Something ain't right.

^^^^^^ What he said ^^^^^

Are you sure the I/C pump is working properly?

[Siege]

IAT temperatures are 20-30 degrees over ambient at steady speed. The IAT temperature drops as the throttle is opened as greater amounts of ambient temperature air replaces the heat-soaked air in the lower intake.

At steady speed my coolant temperatures hover around 192 degrees peaking at 198 after a WOT run. The highest IAT and ECT temperatures I've seen were when I was stuck in stop and go traffic on a 97 degree day with the A/C on. That day I saw 145 degree IAT temperatures and 202 degree ECT temperatures.

[JohnE]

I'm going to review the sensor wiring. I think it's just a thermistor, so polarity should not matter. The temp does start at ambient on first crank.

I have visual flow through my degassing tank. I have one of the old Panther style tanks that's mounted to the fender, like what DR liked to use. I opened up the baffles inside it as well.

The variable speed fan is set to control to 190F engine temp when below 50mph.

[SC Cheesehead]

IAT temperatures are 20-30 degrees over ambient at steady speed. The IAT temperature drops as the throttle is opened as greater amounts of ambient temperature air replaces the heat-soaked air in the lower intake.

At steady speed my coolant temperatures hover around 192 degrees peaking at 198 after a WOT run. The highest IAT and ECT temperatures I've seen were when I was stuck in stop and go traffic on a 97 degree day with the A/C on. That day I saw 145 degree IAT temperatures and 202 degree ECT temperatures.

That's the same for me. ^^^^^

[JohnE]

Here's some temp numbers sitting for an extended idle after fully heated up.

Ambient 95F (98F outside temp sensor between aftercooler and radiator)
Engine Coolant 194F
Degassing Tank Fluid 118F
Aftercooler radiator 111F

Intake Charge (IAT) 148F
Case of the M112 150F

*Notice how the IAT is just a bit cooler that the blower case. Guess what the temp sensor is measuring?

It has substantial intercooler fluid circulation and the radiator fan was running.



I still have the Trilogy intercooler hose routing though. Here the rundown:

Degas tank -> Bosch Pump -> Radiator -> Intercooler -> Degas tank.

The way it is now puts heated coolant in the degas bottle right way. So all of my spare capacity is heated instead of cooled fluid.



I'm going to change to this setup:

Degas tank -> Bosch Pump -> Intercooler -> Radiator -> Degas tank.

[JohnE]

I am looking for the root cause of poor air charge temperature measurements. So far the hardware all checks out. The location is still in question for me.


IAT signal goes to Pin 39 at the PCM. The return signal is pin 91 at the PCM. Both connections from IAT plug to PCM plug are 0.3 Ohms, so the wiring is GOOD. I have two IAT sensors, at ambient one is 22.64 KOhm and the other is 22.88 KOhm. Dropped in ice water they read 94 KOhm.


I used a combination of my extra one reading both ambient air and dropping it in ice water while running the car and data logging. Everything reads as expected. Now, this is a cold start situation as well. I even plugged the IAT on the back of the lower intake in and I agree with the readings. The temperature changes as expected.


Maybe the intercooler pump is cutting out during acceleration, but I doubt it. Seems to have great flow every time I open the hood. I think its time to look at yet a 3rd temperature probe location.



John

[dmjarosz]

Im doing an Eaton swap soon so I've been paying close attention to this thread to learn what I can.

I think it would be a good idea to somehow "float" an IAT sensor somewhere in the middle of the lower intake, away from any aluminum walls. I know this is easier said than done, but putting a thermocouple right in the air flow path, just under the intercooler discharge would be ideal. That way you're not picking up and stray heat from the intake itself.

Ive got the entire eaton assembly (blower, intercooler, LIM) sitting on a bench right now. Im gonna take a look and see if something cant be done. I like the resistance reading posted above. I think it might be possible to use a commercialy available thermocouple in place of the IAT since they come with all kinds of crazy mounting options. Just need to get the temperature/resistance correlation right. Can that be handled in the tune?

[JohnE]

The Cobra Factory MAP/IAT sensor works just fine. If you use a Cobra Blower, there is a provision for the sensor to be in the airflow. You have to intercept the MAP sensor signal from the EGR sensor and the IAT signal from the MAF sensor wiring. You do need to change the transfer function for using a Cobra MAP though, however any decent tuner can do that for you. The MAP signal is used in EGR, but not in fueling calcs. I use the signal to log actual versus calculated MAP. When they match each other, the MAF transfer function is correct.



Looking at the location I drilled a hole into the lower manifold I see some small differences from Reinhart's in the archives. His sensor screws all of the threads in and is slightly more outboard by one sensor diameter. I'm going to give re-tapping the hole and bottoming my sensor to see if it helps next.



John

[Vortech347]

So many variables about IATs. Speed, outside temp, humidity, heat soak, ect...

As long as you're under 150 you're doing just fine.

[JohnE]

29747

I took the blower off and looked at IAT alternatives. There was not enough room to drill and tap closer to the outside in the rear. I have mine about one half a hole diameter towards the center than Reinharts pic. Apparently that's just enough to be out of the flow.


I went for a modification to the Trilogy IAT mounting. Removed metal in attempt to flow air past the sensor. Also bent the element closer to to intake port. Need to data log to see if it helped.


John

[JohnE]

29790

Off topic, but is it ever hot in Houston!

Peak outside temp read 113 in traffic. It's actually 108 ambient.

[RacerX]

Ahhhh... Out of the flow of air. I put mine in the rear of the lower plenum. Like Dave did in his thread:

http://www.mercurymarauder.net/forums/showthread.php?t=67051&highlight=relocation

http://i2.photobucket.com/albums/y47/blaster250cr/blue%20car/IMG_1842.jpg