Stock Fitment 3 Bar Map Sensor Upgrade

[JumpingJackson]

The stock T-MAP sensor is a 2.5 bar map sensor that also has an integrated temperature probe for getting boosted air temperatures, which can only measure up to about 22 PSI depending on your elevation before it gets maxed out.

The current "solution" is to buy a AEM 3.5 bar map sensor and splice it in tandem with the stock MAP sensor so you keep the stock map sensor's temperature probe functionality. (Requiring you to drill another hole in your intake manifold or adding more vacuum lines, and its just not a very elegant solution in my opinion, and some people seem to have issues getting it to work the way it should)

So after many many hours researching a more suitable replacement i found it!
My first clue was the Bosch logo on the stock T-MAP sensor. At first this didnt yield much because i couldnt find any map sensors Bosch or otherwise that had the temp probe in it. Turns out they are mostly used in european turbocharged cars and not typically sold in the US and hard to find on a Google search because most of the pages referring to it are in italian. I ran across some internal Bosch documentation describing a map sensor with the temp probe (T-MAP) and what do you know it looks *exactly* like our OEM t-map sensor besides the plug on it. So i went and found a few sources you can buy them from. (very few places)

Obviously it will not work with a Stock ECU as the 0-5v scaling is different so you will need Cobb Accessport + Access Tuner Race or CP-e Standback + Flashes to adjust for this change in scaling.

The 3 bar unit should be fine as i doubt anyone is going to run more than 30 PSI.

Bosch Part Number:
0 281 002 437 3 bar (20 kPa @ 0.4V , 300 kPa @ 4.65V)
0 281 002 845 3 bar (11 kPa @ 0.25V , 307 kPa @ 4.75V) This one is used in GM Stage 2 Sky / Solstice GXP upgrade kits sold by GM, i got this one from a forum member very hard to find for sale
0 281 002 456 3.5 bar (50 kPa @ 0.5V , 350 kPa @ 4.5V)

Documentation on the MAP sensor itself:
http://www.ontronic.com/products/doc/Sensors_mapt.pdf

Where to Buy:
$121 Volkswagen Golf V 2.0T > Search > 0281002437 > ES#3417 - ECS Tuning Inc

or

$83 (but its special order 2-3 week wait) Bosch 0281002437 - Bosch Computers, Chips & Programmers – SummitRacing.com

If you find some other vendors that keep them in stock please post!

You will also need a connector pigtail as the connector is different than whats on the mazda harness. This includes the connector,pins, and wires all ready to go so all you have to do is cut the stock connector off of the wiring harness (Leave plenty of slack incase you have to put the stock one back on!) and then wire/solder the new connector to it. (The pin-out is the same as the stock one)

$25 Home » Shop » Connectors / Harnesses » Bosch » 4-way sealed Plug Bosch BSK Connector Pigtail for Bosch MAP Sensor


Here is how we think you adjust the ECU with ATR, also Jordan @ CP-e said they can make the standback/flashes work with these as well as the AEM 3.5 bar as long as there is a consensus on which of these MAP sensors people are going to use, id suggest sticking with an 0 281 002 437 as its the easiest to find)

OEM Bosch 2.5 Bar T-Map Sensor / 0 261 230 129 :
Scalar A - 230
Scalar B - 0.235
Offset - 1.647

Bosch 3.0 Bar T-Map Sensor / 0 281 002 437 (fitment verified, but not tuning):
Scalar A - 65.88
Scalar B - 1
Offset - 6.353

Other Bosch 3.0 Bar T-Map Sensor / 0 281 002 845 (fitment verified, but not tuning):
Scalar A - 279.5555528
Scalar B - 0.23529412
Offset - 5.44444 (repeating)

Here are some pictures of the OEM 2.5 bar T-MAP (left) next to the upgraded 3.0 BAR T-MAP (right) and the connector pigtail for the new T-MAP sensor

[whoosh@Realtune]

Originally Posted by JumpingJackson The stock T-MAP sensor is a 2.5 bar map sensor which also has an integrated temperature probe for getting boosted air temperatures, which can only measure up to about 22 PSI depending on your elevation before it gets maxed out. The current "solution" is to buy a AEM 3.5 bar map sensor and splice it in tandem with the stock MAP sensor so you keep the stock map sensor's. (Requiring you to drill another hole in your intake manifold or adding more vacuum lines, and its just not a very elegant solution in my opinion, and some people seem to have issues getting it to work the way it should) So then I spent many many hours researching a more suitable replacement. My first clue was the Bosch logo on the stock MAP sensor. At first this didnt yield much because i couldnt find any map sensors Bosch or otherwise that had the temp probe in it. Turns out they are mostly used in european turbocharged cars and not typically sold in the US and hard to find on a Google search because most of the pages referring to it are in italian. I ran across some internal Bosch documentation describing a map sensor with the temp probe and what do you know it looks *exactly* like our OEM map sensor besides the plug on it. So i went and found a few sources you can buy them from. (very few places) Obviously it will not work with a Stock ECU as the 0-5v scaling is different so you will need Cobb Accessport + Access Tuner Race or CP-e Standback + Flashes Bosch Part Number: 0 281 002 437 (3 bar) 0 281 002 456 (3.5 bar) Documentation on the MAP sensor itself: http://www.ontronic.com/products/doc/Sensors_mapt.pdf Where to Buy: $121 Volkswagen Golf V 2.0T > Search > 0281002437 > ES#3417 - ECS Tuning Inc $83 (but its special order 2-3week wait) Bosch 0281002437 - Bosch Computers, Chips & Programmers – SummitRacing.com If you find some other vendors that keep them in stock please post! Also need Connector Pigtail as the connector is different than whats on the mazda harness $25 Home » Shop » Connectors / Harnesses » Bosch » 4-way sealed Plug Bosch BSK Connector Pigtail for Bosch MAP Sensor I have ordered this stuff and will verify fitment once i get it in about a week. Here are pictures of the OEM 2.5 bar T-MAP

wow
good job
much better than the AEM map sensor bandaid

[SSinstaller]

Great find!!

Have you been able to determine if the BAT scaling is different from our OEM sensor as well?

[JumpingJackson]

I wouldnt think so. But i could be wrong.

[06Speed6]

Nice work bro =) Anything that makes this car easier to work on is great.

This needs to be a sticky

[aaronc7]

awesome...mega reps.

do you know how to properly scale this in ATR? or perhaps you are going to be the first to try a 'larger' MAP on ATR?

[SPD6Tuner]

Would the 3 bar map still work with the boost cut defender.

[aaronc7]

if you're running a boost cut defender then you certainly dont have any sort of tuning....so no, this will not work on stock ecu tune. i guess if you got some cpe flash for this MAP and that was it, it would work. I didnt realize people still used boost cut defenders..LOL

[SSinstaller]

Originally Posted by SPD6Tuner Would the 3 bar map still work with the boost cut defender.

Your already limiting the boost the ECM sees from the OEM MAP when you use your boost cut defender. Why would you pay for a map that can register more boost, just to clamp the output anyway.. This is for people who want their ECM/piggyback to be able to see the higher boost levels so they can tune properly...

[JumpingJackson]

I know christian said he could tune an AEM 3.5 bar so i dont see why he couldnt do this.
There are a few BAT sensor settings in ATR but i dont know the specifics

[phailerider]

Originally Posted by SPD6Tuner Would the 3 bar map still work with the boost cut defender.

absolutely!!! upgrading the factory sensor so you can continue to fool it with a bcd, is just the kind of unnecessary modification i love. ive done a dozen mods like this, and the car still runs great, and makes the exact same power as before!

[aaronc7]

Originally Posted by JumpingJackson I know christian said he could tune an AEM 3.5 bar so i dont see why he couldnt do this. There are a few BAT sensor settings in ATR but i dont know the specifics

i linked him to the threads I made about calibrating the MAP...but he has not responded for weeks....ghey. i didnt know the BAT sensor tables were even included in atr hmm

[JumpingJackson]

Someone should remove the word tuner from his name. LOL

[SSinstaller]

Originally Posted by palerider absolutely!!! upgrading the factory sensor so you can continue to fool it with a bcd, is just the kind of unnecessary modification i love. ive done a dozen mods like this, and the car still runs great, and makes the exact same power as before!

Hell Yeah!

[SPD6Tuner]

Originally Posted by JumpingJackson Someone should remove the word tuner from his name. LOL

Lol. I was never that clear on the entire function of the map sensor so I just needed some info. All my other cars had maf sensors and not map so I didnt have much of an incentive to figure them out.

[JumpingJackson]

Well there is MAP scalar - Component A, Map Scalar - Component B, and MAP Scalar - Offset.

I would assume that is how one "scales" for a different MAP sensor.

edit: Oops just read your post on Cobb forums LOL

[JumpingJackson]

Aaron read the PDF file i linked in the OP look at the scaling graph for this MAP sensor it might answer some of your questions.

[aaronc7]

Originally Posted by JumpingJackson Well there is MAP scalar - Component A, Map Scalar - Component B, and MAP Scalar - Offset. I would assume that is how one "scales" for a different MAP sensor. edit: Oops just read your post on Cobb forums LOL

Yeah, it's very simple compared to MAF calibration...but the fact there are 2 scalars throwing me off. Unless Cobb just did not name the tables appropriately or something. We need to get christian to comment on this. I asked the guys at plano (or I had someone ask for me), but they were not sure, and said to ask christian.

[JumpingJackson]

Yeah which is really weird because according to "Characteristic Curve 1" the scaling is linear..

[aaronc7]

Just looked at the pdf....yes it has important spec data that is needed, but i still don't understand how to use that to input the correct data into ATR. Usually specs of a sensor are given as.... at .5 volts it sees -14.7psig and at 4.5 volt it sees 32 psig or whatever. Then you can just use those 2 points to create the scalar/slope of the linear line. The fact that we have 2 tables that you multiply together to get that scalar makes it weird. All we know that is the two multiplied together will give you the scalar/slope... we have no idea how the two tables are related. If that makes sense... lol either way i hope christian can/will help us.

yeah MAPs are 'always' linear. here's specs on the AEM

http://www.bmotorsports.com/shop/pro...roducts_id/663

[JumpingJackson]

at .4 V it starts at 20 KPA , and at 4.65 V where it "maxes out" is 300 kpa (3 bar)

[JumpingJackson]

I know these stock map sensors adjust for temperature.. you can see scalar B being a relatively minor multiplier in comparison to scalar A. I betcha scalar B is the adjustment for temperature.

[aaronc7]

well, based on that...the final scalar is 65.88235 Kpa/volt. Final scalar as in (Scalar A) * (Scalar B). The stock one is like 54.11765. Offset is easy to calculate... we still just need to know how the A and B scalars are related. B might be constant, but I have no way to test it.

[JumpingJackson]

Yeah who knows.. it would help if we had the data sheet for the stock MAP sensor.

[aaronc7]

if B scalar is constant... make Scalar A 280 and offset 6.353. Based on the volt/pressure relationship pressure u posted above those are the numbers u want in the tables.

[aaronc7]

based on the stock MAP sensor ATR/table values, this is the plot i created for it... also on the left side i just put in the stuff for the 3 bar i just computed lol.

[JumpingJackson]

Wouldnt the offset be .5v according to the datasheet i posteD?

[aaronc7]

offset is basically just the b.... in the slope of line equation y=mx-b. y being pressure (kpa), m is slope (scalar A x scalar B), x being volts.

you just need to have so that when x=.5 volts... y is 20, and when x=4.65, 7=300. I used my graphing calculator to figure up the offset, lol.

i discovered this by working backwards with the stock ATR/table values and created a plot to represent the line/calibration

[JumpingJackson]

Sorry im retarded i keep on looking at the 2nd graph, i meant .4V (but how does that relate to the offset? 4.0 ?? 40??

[JumpingJackson]

Wait i think i get it.. the lowest the 3 bar map sensor can read is 20 kpA and it reads that at .4V

I think the offset would be 20 kpa

[JumpingJackson]

Im going to stop now, i think im just spinning my wheels. LOL

[aaronc7]

here is a plot created using the 6. whatever offset...

notice at .4 volts, its 20 kpa, and same for 4.65 volts and 300kpa.

notice also that at 0 volts its -6.3 kpa... that is the offset

[JumpingJackson]

that makes sense. i think we are on to something.

[aaronc7]

im at the same place as i was when I posted that thread on here and cobb forums, lol.

If you get it hooked up soon and we have made no progress....I say try teh values I posted and see how it goes. worst case it sets off a CEL and wont idle right and you can flash back. I hope the B value is just a constant though and it works out.

[JumpingJackson]

Well your graph lines up perfectly with the data sheet. What were your scalars?

[JumpingJackson]

Also, assuming both the scalars are static, it doesnt matter what 2 numbers you use for scalar a and scalar b as long as the "final scalar" is the same. (250x2 is the same as 500 x 1, etc etc)

because both the scalars are being multiplied together.

[aaronc7]

Scalar A - 280
Scalar B - .24 (it's actually .23-something...this is untouched though)
Offset - 6.353

[aaronc7]

Originally Posted by JumpingJackson Also, assuming both the scalars are static, it doesnt matter what 2 numbers you use for scalar a and scalar b as long as the "final scalar" is the same. (250x2 is the same as 500 x 1, etc etc)

i am guessing that it does matter how they are related (or one is constant)...again this is where we just need to test it or have christian chime in or someone who has messed with this. If it did not matter at all, as long as the product came out to what it needed to be...what is the point in having 2? thats how i see it anyway.

[JumpingJackson]

I bet the stock MAP sensor uses the same characteristic curve.. You could apply our methods here and see if it lines up with what we would expect?

Assume .4V is 20 kPa and 4.65 V is 250kPa

And im saying it doesnt matter mathematically because they are multiplied together. I dont know what that property is called. like i said before 280 x 0.24 is exactly the same thing mathematically as 67.2 x 1.0

Although im sure there is some reason for breaking it out into 2 scalers, obviously the 2 numbers come from somewhere

[aaronc7]

Originally Posted by JumpingJackson I bet the stock MAP sensor uses the same characteristic curve.. You could apply our methods here and see if it lines up with what we would expect? Assume .4V is 20 kPa and 4.65 V is 250kPa

you are absolutely correct. if you plug in the stock MAP values in the tables and plot what the curve looks like.... its exactly what you said. we still just dont know if the B scalar is constant or how they are related to each other.

at this point i guess we just need to wait until u get your stuff in and you can try it out