[Biginboca]

Ok just to see I did a quick check. Sitting in a parking lot for a few mins waiting for my wife I pulled out my Carly and pulled the IAT. Then I looked at my dash.



I just ordered the IAT relocate kit. For $100 it’s not going to break me lol

[23psi4age]

Originally Posted by Biginboca

Ok just to see I did a quick check. Sitting in a parking lot for a few mins waiting for my wife I pulled out my Carly and pulled the IAT. Then I looked at my dash.



I just ordered the IAT relocate kit. For $100 it’s not going to break me lol

Very nice car you have! I lucked out with my car as it is nicely modded with MILV's / Tune / SuperSprint Headers / Euro Intake / Scoops. I put a thin amount of FIPG on the accordian section of the front snorkel so that it forms a bit of a better seal around the air box snorkel. I also put a big tie-strap around it. Just to make sure that as the engine bay heats up and the plastic heats up it doesn't flex and suck in hot air. Trying to keep all intake actually coming from the snorkel in front of the radiator support - and not let any hot radiator air in.

Post up your results!

[Biginboca]

Originally Posted by 23psi4age

Very nice car you have! I lucked out with my car as it is nicely modded with MILV's / Tune / SuperSprint Headers / Euro Intake / Scoops. I put a thin amount of FIPG on the accordian section of the front snorkel so that it forms a bit of a better seal around the air box snorkel. I also put a big tie-strap around it. Just to make sure that as the engine bay heats up and the plastic heats up it doesn't flex and suck in hot air. Trying to keep all intake actually coming from the snorkel in front of the radiator support - and not let any hot radiator air in.

Post up your results!

I’ll definitely post up my findings. I’m going to put some thought into where to place that sensor. I like what you did but I worry about it not getting a ton of airflow there. I also have 2 intake pathways, one from the fog light area and one from the snorkels in the grill. So I’m thinking maybe better on the front side of the airbox for my set up to get a combined reading from both intakes where they mingle. Plus the airbox will act as a huge insulating barrier between the sensor and the engine. Still, I have a feeling in the end I’ll probably do what you did.

Also I did some research this morning. A lot of guys doing this mod on the e46m3 and saying it helped. One guy put the sensor in the brake cooling duct

[rjahl]

Do you have the ability to log ignition timing, RPM and engine load with a reasonable frame rate?

TestO is free and will do these parameter and more at about 100ms. Just need to have a laptop running. I think Dylan managed to get the BimmerGeeks Andriod App running the same frame rate.

With these tools, you can also monitor the Knock sensor values, hint hint.

There is no way I could have managed without these tools.

[PhaseP]

Originally Posted by 23psi4age

The thing is im not arguing - I'm just posting my findings and feel that the modification, and how I installed it, worked. I put some graphs and temperature logs now to help justify what I felt.

Why everyone is mis-understanding what I am saying is beyond me - they are reading into it all way past what I wrote.

Your test and data measurements are not taking into account that air is going to get hotter while moving inside the hot ducting. Your data can't tell if the MAF reading is higher than your relocated temp reading because of MAF sensor itself has heat soaked, or the air as it flew through the air ducts got hotter, or how much of each.

To be able to quantify that, which I had written in a post of my above, you need to keep a separate MAF outside of the car in a cool place. After you warm up the car and got reading of the MAF inside the car, you need to shut down the engine very quickly replace that MAF with the cool MAF you had and then very quickly start engine close hood and read the MAF values now.
This would still have error due to cooling of the engine bay during shut down open hood remove the MAF put the new cool one close hood start engine and read. But it would a better picture of what you are trying to proof, or it may disprove it. You would be getting two different measurements, one with hot MAF one with cool MAF, from as much as possible same air temperature because the location is same. You need to change only one thing to be able to determine what you are trying to show: hot MAF vs cool MAF, at same location. In your case the location is different, air temperature will be different, and you don't know how much. Without that you cannot conclude anything.

I have two functional MAFs, one in the car one on the shelf, but I don't feel like spending time on such experimentation. I don't think that tiny bead sensor element will heat soak while air is passing through it all the time.

[Biginboca]

Originally Posted by rjahl

Do you have the ability to log ignition timing, RPM and engine load with a reasonable frame rate?

TestO is free and will do these parameter and more at about 100ms. Just need to have a laptop running. I think Dylan managed to get the BimmerGeeks Andriod App running the same frame rate.

With these tools, you can also monitor the Knock sensor values, hint hint.

There is no way I could have managed without these tools.

I have a pro tool and a Carly, well and a laptop with all the free softwares/bimmergeeks cable but I’ve never used it. If pro tool will monitor those parameters I’ll check them out.

I’m interested in testing this mod out to see if it’s snake oil!

[Biginboca]

So getting ready to install this and I’m debating between 2 locations. Wanted to see what others thought...



One potential location is on front side of airbox where my 2 intake tracts merge (one intake comes from lower bumper by fog light and other is stock intake from the snorkel in grill area).

Other potential location is where OP put his up front inside snorkel.

Thoughts?

[freakystyly]

If the purpose is only to trick the car into thinking colder air is going in, why put it in the engine bay at all?

Try running it with it behind your front bumper intake vent as a placeholder location before cutting into anything?

[Biginboca]

Originally Posted by freakystyly

If the purpose is only to trick the car into thinking colder air is going in, why put it in the engine bay at all?

Try running it with it behind your front bumper intake vent as a placeholder location before cutting into anything?

The purpose isn’t to trick... it’s to be accurate and not get heated by external sources outside the intake tract.

[freakystyly]

Then I would think the front of the intake box would be best / most accurate if there are 2 varying temperature sources into your airbox. Some sort of thermal insulation to keep the sensor body from touching the hot plastic box may help also.

A crazy impractical way to avoid heat soaking the airbox would be something like a thermos, double walled and an air gap in between with little or no thermal bridging. Kindof giving me flashbacks to the burrito mod thinking about this now.

[CRE]

If the MAF gets heat soaked then the entire housing and plenum (which has a MUCH greater surface area) is getting even hotter. That heat is transferred to the incoming air. At best, your engine is running just a couple percentage points richer as it believes the air charge is that tiny fraction denser (which the closed loop operation of the computer would quickly kill as it strives to maintain a stoichiometric mixture of 14.7:1)... not enough to make an appreciable difference from a stop or while cruising. At WOT it may stay a little on the rich side due to the open loop operation of the ECM, however at that point you have enough mass moving through the manifold that the temps would drop to pretty much the same in either sensor location making it a moot point.

[hassmaschine]

The N52 *never* runs in open loop. Just get that out of your head.***







***Okay, never say never - if something is broken (like a sensor failure, or you're using an ESS tune, lol), it's possible. But with modern widebands, the engine always runs in closed loop - even at WOT. Always!

The only exception is cold start. But it only takes a couple seconds at cold start for the sensors to warm up and enter closed loop mode, which (hopefully) it never leaves.

People really underestimate how much control the O2 feedback has on these engines. While your post is technically incorrect, I agree with the overall premise - the DME is *always* going to reach it's targets regardless of what the IAT is telling it (which, btw, any heat soak is already built into the model).

[PhaseP]

Originally Posted by CRE

If the MAF gets heat soaked then the entire housing and plenum (which has a MUCH greater surface area) is getting even hotter. That heat is transferred to the incoming air. At best, your engine is running just a couple percentage points richer as it believes the air charge is that tiny fraction denser (which the closed loop operation of the computer would quickly kill as it strives to maintain a stoichiometric mixture of 14.7:1)... not enough to make an appreciable difference from a stop or while cruising. At WOT it may stay a little on the rich side due to the open loop operation of the ECM, however at that point you have enough mass moving through the manifold that the temps would drop to pretty much the same in either sensor location making it a moot point.

Just a note, MAF being Mass Air flow sensor, i expect that it is measuring not the volume but the mass of air flowing in. With mass value from sensor, DME has what it needs for air fuel ratio adjustment, without needing to know current air density and so intake air temperature.
From what i read with maf providing amount if air flow, dme uses iat value to adjust timing to prevent knock with hot incoming air inside the cylinders.
In a MAfless euro mode, iat maybe more critical for calculating amount of oxygen mass entering the engine.

[hassmaschine]

Originally Posted by PhaseP

Just a note, MAF being Mass Air flow sensor, i expect that it is measuring not the volume but the mass of air flowing in. With mass value from sensor, DME has what it needs for air fuel ratio adjustment, without needing to know current air density and so intake air temperature.
From what i read with maf providing amount if air flow, dme uses iat value to adjust timing to prevent knock with hot incoming air inside the cylinders.
In a MAfless euro mode, iat maybe more critical for calculating amount of oxygen mass entering the engine.

yes, the MAF reads mass, not flow.

Interestingly, the MAFless mode mostly relies on the wideband feedback loop - although of course the IAT is used to correct density. An interesting property of controlling valve lift is the engine already has a pretty good idea of what the air mass inside the engine already is, corrected with wideband feedback and the IAT (for plausibility), of course. There's also a MAP sensor, although mostly it reads 100kpa.

Cutting the MAF wire just sets it into limp mode, it's not the same as the OEM MAFless mode. You can enable the MAFless mode without touching the MAF or any wiring. It just doesn't use the MAF signal (only the IAT).

Thinking about this again, I haven't run a MAF in a couple years now and I have never noticed an issue with IAT heat soak.

[Phyrexia]

I think your IATs are normal to begin with and not really indicative of a need to relocate the IAT sensor.

On the highway with no heat soak, my car with the BMW PI saw IATs of as low as 3 degrees F over ambient. If I sat in traffic I would heatsoak and IATs would increase.

[Biginboca]

Ok so I got this project wrapped up and will be doing testing this week. It will be easy to do testing because you can just pull over and swap the ECU plug from one sensor to the other, both are mounted and stay in place.

I did some baseline testing with the stock setup last week. It was 93 degrees and I monitored the intake temps for about 30 mins driving around under various conditions. What I found is on a WOT pull the stock sensor would drop 5 degrees in about 3 seconds but it never really got any closer to ambient than like 6-8 degrees and really wanted to be around 10-12 over ambient most of the time.


Cruising 60mph for 2 mins it was steady at 10-12 degrees over ambient.

Then at the next red light (after cruising at 60 for 2 mins) it rose to about 30 degrees over ambient.

Then leaving the red light at 2/3 throttle running back up to 60mph after I hit 60 it had dropped 15 degrees but was still about 15 degrees over ambient and took about 2 mins to drop back to 10-12 over ambient.



So that got me thinking as long as we are taking measures to address heat soak and pulling everything apart, why not go whole hog. I remembered this pic:



I ordered a single roll of that DEI gold heat shielding tape. It was about $35 on amazon prime. The end result is I combined 2 projects into one. Mounted the sensor here right between both my intake tracts to the airbox:



This location is on the front of the airbox. When I was debating where to put the sensor I pulled over and started feeling around under the hood. This location was the coolest option I found:



And then I heat taped every part of the snorkel to airbox connection that faced the engine and radiator, and the same on the airbox:







Now with both sensors in place I can conduct some real testing. I can swap the plug between both sensors in 30 seconds on the side of the road and see what the behavior of each is back to back. Will update once I’ve done some testing.

I can also just run the stock sensor and see if the heat tape has any effect. Will be testing that also.

[Biginboca]

BTW if anyone is not familiar with the DEI heat tape here’s a cool 2 min video I found on YouTube...

[Biginboca]

So after doing some testing I prefer the stock sensor in the MAF and have disconnected the Turner sensor. The stock sensor “behavior” seems to be better, responding to changes in temp very quickly and I believe it’s more accurately relaying the temperature of the incoming air charge than the Turner relocation kit does. (At least on my car with my install, which it turns out is in the location recommended in the Turner info by the way.)

For the guys who like data, here are some of my observations and why I’m choosing stock over this kit.

Test 1:

Shut the car off and come back in 5 mins, the intake temps for both sensors were about the same approx 30 degrees over ambient, in this situation with no intake airflow and the hot engine having been shut down for 5 mins they are equal. With the motor freshly turned off they were both heat soaked equally on start up.

Test 2:

I parked and idled the car for 3 mins with each sensor to heat soak and let the IAT rise to about 125*. Then drove the same route same speeds and checking temps after 1/2 mile and after 1 mile. Here were my findings:







So as can be seen in this test theres a consistent ~3 degree difference on the OEM vs Turner. I think in this test both sensors were actually accurate! I think it’s reasonable to assume that the oem would read approx 3* higher since it's deeper into the intake tract and the air would be warming as it passed deeper through the tract.

Test 3:

Here’s where the differences really show. I took back to back videos of the stock sensor and the Turner on acceleration from a red light.

What can been seen here is that in my car the OEM sensor sheds the heat much more quickly and is very responsive to changes. In these videos the stock sensor sheds 10 degrees in 20 seconds and Turner sensor sheds only 3 degrees in a 50% longer time of 30 seconds. The end result is after 20 seconds the stock is actually responding much more quickly to adapt to be closer to ambient than the Turner is after 30 seconds.

My conclusion after testing is this.... The Turner sensor is slower to get hot and then slower to shed that heat. I can only guess why the Turner is so slow to respond to changes. My gut says the fact the OEM sensor is a tiny 1/8” diameter bulb in a high flow area of the MAF chamber makes it quick to adapt, vs the Turner sensor which is a large (~2.5”) and thick plastic wand which sits inside a lower velocity of flow area (inner chamber of airbox).

Only scenario where I can see the Turner being an advantage is if you come down from steady cruising (having gone a 1/2 mile or more) to a short redlight. During your time at that red light the Turner will not grow to be as hot as the OEM, and ecu will not pull as much timing for the first 2-3 seconds of throttle with the Turner. So in this specific scenario I believe you have a 2-3 second advantage for the Turner for 2-3 seconds only.

After that 3rd second the OEM will react quickly to shed heat and soon be showing a temp that is likely to be cooler than the Turner and for the remaining time of your pull away from that light the OEM will likely give you better performance.

[gT-BMW]

that was really interesting experiment i watched the video just only to hear intake and exhaust noises. sounds so epic! can you make a ripper vid?

Originally Posted by Biginboca

[Biginboca]

Originally Posted by gT-BMW

that was really interesting experiment i watched the video just only to hear intake and exhaust noises. sounds so epic! can you make a ripper vid?

I had the windows up so that was all intake noise! and a little diff whine lol

[Phyrexia]

Excellent work! There's nothing like hard data.

I might have to get some of that tape for the 335...

[hassmaschine]

Soooo.... I told you so?