[Atomic Ed]

I keep seeing a lot of comments on this forum concerning the high IATs on the Edelbrock E-Force vs. other FI kits. Comparisons did, and continue, to pop up regarding how much cooler the Magnuson supercharger runs compared to the E-Force. I too was concerned when I first got my E-Force and did some first time measurements. The E-Force IATs are indeed +40* F above ambient just cursing around town, while the Magnuson runs around +10* F above ambient.

I was baffled. Why the big difference? The rotor packs are the same, coolant pumps are the same, intercooler bricks are nearly the same size (a tip to Magnuson for a somewhat better design), and the E-Force heat exchanger is bigger. The other confounding factor is that the two units put out almost exactly the same power at the same boost level. For the most part, the two units are twin sisters.

So what is the big difference? IAT sensor location. Edelbrock choose to mount the IAT (TMAP) sensor right above the runner to the intake valve. As you can see in the picture below, the IAT sensor is masked in such a way that it not only measures the IAT, but is also affected by the temperature of the intake valve and not the intercooler above it.




The Magnuson on the other hand, places the IAT sensor in a more traditional location which is more influenced by the intercooler above it and very little influence by the head’s intake runner.



So do I think one is better than the other? Not really. If both companies set their tune up relative to their own design, it really doesn’t matter. Both are a great unit and will serve you well over time. So don’t sweat the IATs on the E-Force.

What would be an interesting experiment would be to move the IAT location of one unit to the location of other unit and see what the IATs are then. Anyone ready to try this?

[Daves1SS]

Thanks for the write up and pictures, Ed! It makes sense. I personally prefer the heartbeat's IAT sensor location simply because it's a more accurate representation of the true temp of the air entering the combustion chamber, and is not artificially inflated by the heat of the intake valve. Edelbrock designed theirs with financial protection for their company utmost in mind, since they are providing the 3/36 power train warranty. It's a smart design to really keep things conservative. Just not what we enthusiasts would ideally like to see with it being artificially inflated a bit.

[E-Ray]

Thank you Sir, for this information. Good write up on the two systems.

[cleoent]

Originally Posted by Daves1SS

Thanks for the write up and pictures, Ed! It makes sense. I personally prefer the heartbeat's IAT sensor location simply because it's a more accurate representation of the true temp of the air entering the combustion chamber, and is not artificially inflated by the heat of the intake valve. Edelbrock designed theirs with financial protection for their company utmost in mind, since they are providing the 3/36 power train warranty. It's a smart design to really keep things conservative. Just not what we enthusiasts would ideally like to see with it being artificially inflated a bit.

Dave,

Edelbrock doesn't back, or cover the warranty at all, that's a 3rd party. So I don't think that's why they put it where they do, I'm thinking there has got to be another reason.

I'd also love to understand at what temp the edelbrock stock tune starts pulling timing and effecting HP. Even here in CA with temps in the 50's my IATs (at least i think it's the correct sensor) were around 130 on the dyno.

[Daves1SS]

I believe the Edelbrock tune starts pulling timing at 130 degree IAT'S and higher......

[cleoent]

So I've been PM'ing a few of you about this issue over the past couple days, and I keep getting different answers from everyone. Time to figure this out!

A factory supercharged car, like a cts-v, or zl1, have an ambient temp sensor, an intake air temp on the MAF, and an IAT2 (TMAP) sensor inside the supercharger that measures the air temp of the air actually flowing into the engine, post intercooler.

From what I can gather, the IAT2 temps in a factory FI car, is what the ecu cares about and determines ignition and all that good stuff.

Now, for our cars, who aren't FI from the factory, where are our temp readings coming from? I have an aeroforce gauge that plugs into OBD2 port. It has the same 3 temp options. Ambient, Intake Air Temp, and IAT2. Where are these sensors located?

Here's a picture from the edelbrock install guide that shows the new wiring for the TMAP that comes with the edelbrock. From what I can gather, the TMAP sensor gets its readings from the location described in post #1, which replaced the stock TMAP sensor that's in the stock air manifold.



I took a slow, very slow easy trip around the block just to get the temps up in the engine bay to see how these sensors were reading.

Outside car temp (mylink reading) Ambient (not sure from what location) and Intake Air Temp -



And now, Outside car temp, ambient and IAT2 -



So this tells me there are 3 different temperatures being recorded, as all 3 of those values are different.

So my theory is this -

Ambient - temp somewhere underhood, maybe at airbox?
Intake Air Temp - At the maf sensor, stock location, BEFORE intercooler
IAT2 - comes from edelbrock TMAP location inside supercharger. (which replaced the stock map sensor thats no longer in car, and isn't capable of recording temp)

So, IAT2 temps I believe is what we should care about, and what the tuning is probably based off of? Right?

The MAF sensor most likely is what reads IAT1, as modern MAFs have temp functionality built into them. The factory MAP sensor, probably doesnt do temperature, which is why it is replaced by a TMAP in the s/c intake manifold.

This is my theory. If that ends up being true, then we need be watching IAT2 temps, not IAT 1.

Additional reading on IAT/MAP/MAF sensors - http://www.gmtuners.com/tech/MAF_MAP_IAT.htm

Anyone here with a non supercharged camaro that has an aeroforce gauge or similar that can see if you get an IAT2 reading?

[wnta1ss]

Are the Edlebrock and Magnuson kits actually running the same boost? Saw a dyno sheet on this site for an Edelbrock and the thing was over 10psi. That is higher than I've heard for the Magnuson kit. What have owners been seeing with these respective kits?

[Daves1SS]

Originally Posted by wnta1ss

Are the Edlebrock and Magnuson kits actually running the same boost? Saw a dyno sheet on this site for an Edelbrock and the thing was over 10psi. That is higher than I've heard for the Magnuson kit. What have owners been seeing with these respective kits?

Starts at 6.5, averages 8 to 8.5 and I've seen a peak at just over 10 on mine.

On the IAT'S, I only get one reading on my SCT X4 and I am confident it's the reading just prior to the air entering the passenger side head. That's the reading that I'm sure Edelbrock uses for fine tuning their calibration. If there's also a reading at the maf, I would think it would be lower.

[cleoent]

Originally Posted by Daves1SS

Starts at 6.5, averages 8 to 8.5 and I've seen a peak at just over 10 on mine.

On the IAT'S, I only get one reading on my SCT X4 and I am confident it's the reading just prior to the air entering the passenger side head. That's the reading that I'm sure Edelbrock uses for fine tuning their calibration. If there's also a reading at the maf, I would think it would be lower.

Edelbrock sent me an email today telling me they use iat2 for their tuning.

[Daves1SS]

Originally Posted by cleoent

Edelbrock sent me an email today telling me they use iat2 for their tuning.

And where do they say IAT2 is located? Post intercooler correct?

[JANNETTYRACING]

Originally Posted by cleoent

So I've been PM'ing a few of you about this issue over the past couple days, and I keep getting different answers from everyone. Time to figure this out!

A factory supercharged car, like a cts-v, or zl1, have an ambient temp sensor, an intake air temp on the MAF, and an IAT2 (TMAP) sensor inside the supercharger that measures the air temp of the air actually flowing into the engine, post intercooler.

From what I can gather, the IAT2 temps in a factory FI car, is what the ecu cares about and determines ignition and all that good stuff.

Now, for our cars, who aren't FI from the factory, where are our temp readings coming from? I have an aeroforce gauge that plugs into OBD2 port. It has the same 3 temp options. Ambient, Intake Air Temp, and IAT2. Where are these sensors located?

Here's a picture from the edelbrock install guide that shows the new wiring for the TMAP that comes with the edelbrock. From what I can gather, the TMAP sensor gets its readings from the location described in post #1, which replaced the stock TMAP sensor that's in the stock air manifold.



I took a slow, very slow easy trip around the block just to get the temps up in the engine bay to see how these sensors were reading.

Outside car temp (mylink reading) Ambient (not sure from what location) and Intake Air Temp -



And now, Outside car temp, ambient and IAT2 -



So this tells me there are 3 different temperatures being recorded, as all 3 of those values are different.

So my theory is this -

Ambient - temp somewhere underhood, maybe at airbox?
Intake Air Temp - At the maf sensor, stock location, BEFORE intercooler
IAT2 - comes from edelbrock TMAP location inside supercharger. (which replaced the stock map sensor thats no longer in car, and isn't capable of recording temp)

So, IAT2 temps I believe is what we should care about, and what the tuning is probably based off of? Right?

The MAF sensor most likely is what reads IAT1, as modern MAFs have temp functionality built into them. The factory MAP sensor, probably doesnt do temperature, which is why it is replaced by a TMAP in the s/c intake manifold.

This is my theory. If that ends up being true, then we need be watching IAT2 temps, not IAT 1.

Additional reading on IAT/MAP/MAF sensors - http://www.gmtuners.com/tech/MAF_MAP_IAT.htm

Anyone here with a non supercharged camaro that has an aeroforce gauge or similar that can see if you get an IAT2 reading?

Ambient is in the grille area typically inboard of the headlamps.

IAT is in the MAF.

The Edelbrock harness takes the Temp sensor wires out of the MAF and relocates them to the T-MAP, and extends the original MAP wires to the T-MAP.

IAT2 is not used in a Non supercharged application converted to supercharger.

Ted.

[cleoent]

Originally Posted by JANNETTYRACING

Ambient is in the grille area typically inboard of the headlamps.

IAT is in the MAF.

The Edelbrock harness takes the Temp sensor wires out of the MAF and relocates them to the T-MAP, and extends the original MAP wires to the T-MAP.

IAT2 is not used in a Non supercharged application converted to supercharger.

Ted.

Perfect info. So where is the mystery 3rd temp being picked up from?

[cleoent]

Originally Posted by Daves1SS

And where do they say IAT2 is located? Post intercooler correct?

Yeah. The temp is being read from location in post 1.

[JANNETTYRACING]

Originally Posted by cleoent

Perfect info. So where is the mystery 3rd temp being picked up from?

During data logging I have seen the IAT 2 report the same as IAT1 even though only one is used.

Ted.