Hey all,
This idea stemmed from a discussion on the mye28 forum and I know a lot of you probably don't frequent that forum so I am posting here. I was turned on to the shortcomings of Motronic 1.0 when i bought a euro 325iX that ran Motronic 1.0 and a 073 ECU (35 pin). I started modifications and learned it did not come with all of the sensors necessary to upgrade to the later Motronic 1.3 in order to run a 55 pin ECU and/or a Megasquirt unit built into a 55 pin board.
I ultimately performed an engine harness upgrade and supporting sensor upgrade to make my car run the 55 pin M1.3 and Megasquirt for forced induction. I was and still am surprised nobody has made an adapter for the 35 pin ECU's to the 55 pin so they could plug and play a 173 or similar ECU (megasquirt). I also learned at that time that the M20b27 (325e/s,528e) uses the 35 pin board and is the basis for the 2.7i stroker engines that is common in e30 circles. Why not have the ability to fully tune spark and fueling without having to change engine wiring harnesses or buy multiple pricey EPROM chips?
So I decided to look into the adapter and found the correct 35 pin male connector that allows this possible and am currently waiting on the 55 pin connector to see if this will work. Assuming I found the correct adapter, the next step would be wiring the circuit up correctly and building a prototype to test. Also something to note is the db37 cable is not needed with this setup so the unit does not have unnecessary cables and should be able to fit in the factory space. Here is a simple graphic to show you how it would work.
In case you are unfamilar with Megasquirt, here is the DIYPnP 55 pin kit that you can buy unassembled, or you can buy prebuilt running the Microsquirt module and MS2/E v3.0.3 or later.
Some features of megasquirt if you are unfamiliar:
Speed Density, Alpha-N and Hybrid Alpha-N (both SD and A-N algorithms hybridized) Supported
Onboard 2.5 bar MAP sensor
2 Ignition Inputs (for dual wheel ignitions)
4 Spark Outputs (Up to 4 Cylinder Coil On Plug, up to 8 Cylinder Wasted Spark)
Natively support two fuel outputs for batch or bank-to-bank fueling. Optionally upgrade to 4cyl sequential or 6/8 cyl semi-sequential with this module.
Enhanced Acceleration Enrichment (EAE)
Boost Control
Knock Control
Launch Control
Flat Shift
Tachometer Output
Fully Adjustable Rev Limiter
Table Switching
4 General Purpose Outputs
4 General Purpose Inputs (2 analog, 2 digital)
Support for Flex Fuel
Optional Realtime Baro Correction
Closed Loop O2 Correction
Plenty of Proto Area, add your own customizations!
Some other suppliers of 55 pin Megqsquirt units include Sssquid Tuning (http://sssquid.com/v2/shop/tunes/bmw/megasssquirt/), Whodwho's 55 pin unit on R3vlimited.com (http://www.r3vlimited.com/board/showthread.php?t=202653), Dedericms.com (his site is down now though)
What will you need to fit megasquirt to your e28?
- Variable TPS off of an e34 automatic, or variable TPS from an e36 with adapter bracket (I found a supplier and maybe able to provide these also)
*Note one wire usually needs to be swapped to make this TPS work, so I am looking into a TPS to vTPS adapter as well)
- 60-2 toothed wheel/harmonic balancer and CPS/bracket from e30 with M1.3
- Intake Air temp sensor (GM, or the sensor in the factory AFM unit)
- Vacuum line to the ECU
- 55 Pin ECU (Megasquirt or BMW ECU)
- High Impedence Fuel Injectors (or i read low impedence injectors could possibly be used with certain megasquirt settings)
- 55 pin engine Wiring Harness OR this 35 pin adapter
- (Not necessary but a wideband oxygen sensor like the AEM UEGO or Innovate LC-1 is recommended.)
What cars will this theoretically* work on?
*this assumes the pinout will work and I have not yet verified all of the models listed below are 35 pin, but it should include m30b35 models through mid 1987 with the 35 pin ECU connector. This also assumes you can find a 60-2 CPS wheel/sensor which is available for the e23/e24/e28/e30. I believe you can use an m30b35 cps/wheel on the s38 and/or s38b36 cps/wheel on the s38b35 but i am not aware of an option for the s14. The m42 could possibly fit but I have not heard of anybody trying it yet.
I was able to find a 35 pin connector and received it in the mail today. Here are a few (sorry for the poor quality) pictures of the connectors I received and the test fit into my 35 pin engine harness. One shows the connector next to my 35 pin 073 ECU.
As mentioned above, on top of this adapter, I am considering sourcing components to create a TPS to vTPS adapter. This would be a similar male to female adapter that could plug into the factory engine harness wiring for the TPS and would allow you to run the e36 vTPS without having to rewire anything. All you would need is the variable TPS from a later BMW.
I could do a similar adapter that would plug in to the factory AFM connector and could be wired to a GM open element IAT sensor. The benefit to all three of these adapters is that they would make everything reversible and you could install a 55 pin ECU, or 55 pin Megasquirt and if you decided you wanted to sell the car without it, or return the vehicle to stock for one reason or another, you could return it back to the factory electronics very easily.
With that said, I would like to gauge interest in this adapter circuit. Who would be interested in one, and if we have enough interest and this first prototype works as expected, maybe we can start a list for a preorder.
This idea stemmed from a discussion on the mye28 forum and I know a lot of you probably don't frequent that forum so I am posting here. I was turned on to the shortcomings of Motronic 1.0 when i bought a euro 325iX that ran Motronic 1.0 and a 073 ECU (35 pin). I started modifications and learned it did not come with all of the sensors necessary to upgrade to the later Motronic 1.3 in order to run a 55 pin ECU and/or a Megasquirt unit built into a 55 pin board.
I ultimately performed an engine harness upgrade and supporting sensor upgrade to make my car run the 55 pin M1.3 and Megasquirt for forced induction. I was and still am surprised nobody has made an adapter for the 35 pin ECU's to the 55 pin so they could plug and play a 173 or similar ECU (megasquirt). I also learned at that time that the M20b27 (325e/s,528e) uses the 35 pin board and is the basis for the 2.7i stroker engines that is common in e30 circles. Why not have the ability to fully tune spark and fueling without having to change engine wiring harnesses or buy multiple pricey EPROM chips?
So I decided to look into the adapter and found the correct 35 pin male connector that allows this possible and am currently waiting on the 55 pin connector to see if this will work. Assuming I found the correct adapter, the next step would be wiring the circuit up correctly and building a prototype to test. Also something to note is the db37 cable is not needed with this setup so the unit does not have unnecessary cables and should be able to fit in the factory space. Here is a simple graphic to show you how it would work.
In case you are unfamilar with Megasquirt, here is the DIYPnP 55 pin kit that you can buy unassembled, or you can buy prebuilt running the Microsquirt module and MS2/E v3.0.3 or later.
Some features of megasquirt if you are unfamiliar:
Speed Density, Alpha-N and Hybrid Alpha-N (both SD and A-N algorithms hybridized) Supported
Onboard 2.5 bar MAP sensor
2 Ignition Inputs (for dual wheel ignitions)
4 Spark Outputs (Up to 4 Cylinder Coil On Plug, up to 8 Cylinder Wasted Spark)
Natively support two fuel outputs for batch or bank-to-bank fueling. Optionally upgrade to 4cyl sequential or 6/8 cyl semi-sequential with this module.
Enhanced Acceleration Enrichment (EAE)
Boost Control
Knock Control
Launch Control
Flat Shift
Tachometer Output
Fully Adjustable Rev Limiter
Table Switching
4 General Purpose Outputs
4 General Purpose Inputs (2 analog, 2 digital)
Support for Flex Fuel
Optional Realtime Baro Correction
Closed Loop O2 Correction
Plenty of Proto Area, add your own customizations!
Some other suppliers of 55 pin Megqsquirt units include Sssquid Tuning (http://sssquid.com/v2/shop/tunes/bmw/megasssquirt/), Whodwho's 55 pin unit on R3vlimited.com (http://www.r3vlimited.com/board/showthread.php?t=202653), Dedericms.com (his site is down now though)
What will you need to fit megasquirt to your e28?
- Variable TPS off of an e34 automatic, or variable TPS from an e36 with adapter bracket (I found a supplier and maybe able to provide these also)
*Note one wire usually needs to be swapped to make this TPS work, so I am looking into a TPS to vTPS adapter as well)
- 60-2 toothed wheel/harmonic balancer and CPS/bracket from e30 with M1.3
- Intake Air temp sensor (GM, or the sensor in the factory AFM unit)
- Vacuum line to the ECU
- 55 Pin ECU (Megasquirt or BMW ECU)
- High Impedence Fuel Injectors (or i read low impedence injectors could possibly be used with certain megasquirt settings)
- 55 pin engine Wiring Harness OR this 35 pin adapter
- (Not necessary but a wideband oxygen sensor like the AEM UEGO or Innovate LC-1 is recommended.)
What cars will this theoretically* work on?
*this assumes the pinout will work and I have not yet verified all of the models listed below are 35 pin, but it should include m30b35 models through mid 1987 with the 35 pin ECU connector. This also assumes you can find a 60-2 CPS wheel/sensor which is available for the e23/e24/e28/e30. I believe you can use an m30b35 cps/wheel on the s38 and/or s38b36 cps/wheel on the s38b35 but i am not aware of an option for the s14. The m42 could possibly fit but I have not heard of anybody trying it yet.
Code:
325e/es E30 M20/B27 (122hp) 9/84-12/86 0 261 200 027 Bosch Motronic Basic M1.0 325i/ECE E30 M20/B25 (171hp) 85-87 0 261 200 081 Bosch Motronic M1.0 M3 E30 S14/B23 (195hp) 86-08/89 0 261 200 071 Bosch Motronic M1.0 Motorsport M3 E30 S14/B23 (215hp) 09/89-90 0 261 200 091 Bosch Motronic M1.0 Motorsport M3 - Evo2 E30 S14/B23 (220hp) 88 0 261 200 090 Bosch Motronic M1.0 Motorsport M3 - Evo3 E30 S14/B25 (238hp) 01/90-05/90 0 261 200 092 Bosch Motronic M1.0 Motorsport 533i E28 M30/B32 84 0 261 200 008 Bosch Motronic M1.0 Basic 528e E28 M20/B27 9/84-12/86 0 261 200 027 Bosch Motronic M1.0 Basic 535i/is E28 M30/B34 85-87 0 261 200 059 Bosch Motronic M1.0 Adaptive (24 pin) 535i/is E28 M30/B34 88 0 261 200 059 Bosch Motronic M1.0 Adaptive (28 pin) 535i/is E28 M30/B34 (218hp) 85-87 0 261 200 061 Bosch Motronic M1.0 M5/M635CSI E28/E24 S38/B35 (260hp kat) 87-88 0 261 200 079 Bosch Motronic M1.0 Motorsport M5/M635CSI E28/E24 M88 (286hp) 84-87 0 261 200 055 Bosch Motronic M1.0 Motorsport 633csi E24 M30/B32 84 0 261 200 008 Bosch Motronic M1.0 Basic 635csi E24 M30/B34 85-87 0 261 200 059 Bosch Motronic M1.0 Adaptive 635csi E24 M30/B35 86-88 0 261 200 150 Bosch Motronic M1.1 733i E23 M30/B32 84 0 261 200 008 Bosch Motronic M1.0 Basic 735i E23 M30/B35 09/80-09/82 0 261 200 001 Bosch Motronic M1.0 Basic 735i E23 M30/B34 (218hp) 84-87 0 261 200 011 Bosch Motronic M1.0 Adaptive 735i E23 M30/B34 84-87 0 261 200 059 Bosch Motronic M1.0 Adaptive 745i E23 M102/B34 (252hp) 83--86> 0 261 200 013 Bosch Motronic M1.0
As mentioned above, on top of this adapter, I am considering sourcing components to create a TPS to vTPS adapter. This would be a similar male to female adapter that could plug into the factory engine harness wiring for the TPS and would allow you to run the e36 vTPS without having to rewire anything. All you would need is the variable TPS from a later BMW.
I could do a similar adapter that would plug in to the factory AFM connector and could be wired to a GM open element IAT sensor. The benefit to all three of these adapters is that they would make everything reversible and you could install a 55 pin ECU, or 55 pin Megasquirt and if you decided you wanted to sell the car without it, or return the vehicle to stock for one reason or another, you could return it back to the factory electronics very easily.
With that said, I would like to gauge interest in this adapter circuit. Who would be interested in one, and if we have enough interest and this first prototype works as expected, maybe we can start a list for a preorder.
