Throttle Body Size (post b30 manifold swap)

Wow, no point in me even continuing to mess with trying to frankenstein the two. Sign me up for the first ones available.

WOW, really cool. If it gets done before I do my M54 swap, I wouldn't mind a kit, though I hope I don't have to cut/splice anything. Not a big fan of electrical/wiring components.

Originally Posted by alexxander.foster

I've got something you guys might like...

I've finished a major chunk of R&D for a prototype M54B30 throttle body controller. I've been working on this thing off and on for about 6 months now and I'm pretty close to testing it in my e46.

Here is a youtube video showing the throttle body in action:



Sorry about all of the shaking and poor video quality, I did this with my phone one handed.

The operation of the throttle body is extremely smooth but still very very responsive and precise. The throttle plate is accurate within +/- approx. 1% of the pedal's location. The controller software is progressive; i.e., it becomes progressively smoother with small movements (less than 2%) but quickly shifts to full speed for rapid changes in position resulting in near instantaneous throttle response. Its also has a calibration function to compensate for e-gas pedals and throttle bodies that are past their prime -which reduces the cost for other parts.

I'm designing it to be a complete replacement for the M52TU's throttle body. As of now its programmed to work with a BMW e-gas pedal from an e46 as well as an M54B30 electronic throttle body -which means all of the parts will be a direct bolt on. It will deal with the multiple POT signals, cruise control, traction control, throttle body manipulation, and several safety redundancies to protect the driver.

When I'm done I plan on offering complete kits with all the harnesses, wiring, and tools necessary for installation. I'm not completely certain on the price of these modules since PCB's are expensive to order in small quantities, but my goal is around $150 for a plug-n-play kit. If I can sell them for less I will.

Tell me what you guys think!!!

Very cool - also like how it demonstrates that an electronic throttle can be just as responsive as a mechanical throttle body

Thanks for the support guys!

Originally Posted by Hornung418

Err Mah Gerd!! Dude that is everything I've been hoping it would be! Add me to the list! Don't even care about the price.

Haha! When I woke up this morning your response was the first thing I read. I nearly fell out of my chair laughing! Thanks man, you'll be top of the list!

Originally Posted by jared_wiesner

Wow, no point in me even continuing to mess with trying to frankenstein the two. Sign me up for the first ones available.

Will do! I'll be sure to keep everyone posted.

Once I feel confidant in my first prototype I'll need to do some beta testing with the adapter in other e46's. If you guys dont mind helping me sort out the problems I can have you guys receive the first batch...

Originally Posted by Iceman00

WOW, really cool. If it gets done before I do my M54 swap, I wouldn't mind a kit, though I hope I don't have to cut/splice anything. Not a big fan of electrical/wiring components.

Yeah, I feel ya. Wiring is not fun. I'm doing my best to make the wiring easy but I can guarantee some level of cutting or DME brain surgery will be involved -thats just the way this mod is going to have to be.

Unfortunately, the M52TU's throttle body cam-lock harness has no counterpart in the BMW parts catalogue. I would have to source the part from whoever BMW bought the harness from -which could be an endless number of possibilities since BMW doesnt make their own connectors, pins, wires, or throttle bodies... but I am looking.

So instead, right now I'm looking to have the end-user go into the DME wiring harness and physically replace the pins that go to the throttle body. Its not as bad as it sounds, but if you wear glasses you'll definitely need them for this task. There will then be a separate wiring harness which will run from the adapter to the throttle body. I'm not really seeing any more reliable ways right now. But this will allow the kit to be completely reversible.

Originally Posted by TerraPhantm

Very cool - also like how it demonstrates that an electronic throttle can be just as responsive as a mechanical throttle body

Agreed. That was my biggest concern when I started this project, but I quickly realized that the throttle motor is way faster than the engine can change RPMs. I'm actually shocked at how fast this thing moves.

Originally Posted by alexxander.foster

Once I feel confidant in my first prototype I'll need to do some beta testing with the adapter in other e46's. If you guys dont mind helping me sort out the problems I can have you guys receive the first batch...

You got it. whatever you need regarding making this work. You have only to ask.

Status Update...

Alright guys, I popped open the hood today and did a basic experiment regarding idling. I was trying to determine if the throttle motor needed to be driven completely closed, or if it is fine resting at the detent position. I pulled out the M52TU throttle body, kept it connected to the DME, set it to the side, and installed the M54 throttle body.

Note: there were no electrical connections made with the M54 throttle body, this was simply an experiment to see if I could trick the car into starting and idling.

The car did start with the throttle body resting at its detent position, but it was extremely poor idle quality. The idle air control valve compensated from time to time and the idle would smooth out, but then it would try to reduce the idle speed and the engine would sputter. It eventually triggered a CEL regarding the poor idle conditions.

I then wedged a tool in the intake track to shut the throttle plate completely and restarted the car. The car idled much better but it still didn't idle right. When I went out to the engine bay to see what was going on, I noticed that the M52TU's throttle plate was moving slightly. The DME was working in conjunction with the idle air control valve to smooth out the idle.

This is a setback. I will have to re-evaluate my throttle motor control designs to deal with this.

Hmm. Progress in either direction is still progress

Originally Posted by alexxander.foster

Status Update...

Alright guys, I popped open the hood today and did a basic experiment regarding idling. I was trying to determine if the throttle motor needed to be driven completely closed, or if it is fine resting at the detent position. I pulled out the M52TU throttle body, kept it connected to the DME, set it to the side, and installed the M54 throttle body.

Note: there were no electrical connections made with the M54 throttle body, this was simply an experiment to see if I could trick the car into starting and idling.

The car did start with the throttle body resting at its detent position, but it was extremely poor idle quality. The idle air control valve compensated from time to time and the idle would smooth out, but then it would try to reduce the idle speed and the engine would sputter. It eventually triggered a CEL regarding the poor idle conditions.

I then wedged a tool in the intake track to shut the throttle plate completely and restarted the car. The car idled much better but it still didn't idle right. When I went out to the engine bay to see what was going on, I noticed that the M52TU's throttle plate was moving slightly. The DME was working in conjunction with the idle air control valve to smooth out the idle.

This is a setback. I will have to re-evaluate my throttle motor control designs to deal with this.

Hmm, looking at the wiring diagrams, I think it would be possible to get the MS42 DME to control the M54 throttle body, but the MS42 is somewhat more complex. If you can "translate" the pedal position sensor (M54) values to what would be expected from the "driver wish" sensor (M52TU), I don't think the DME would know any better.

Wiring diagrams:
M54 Throttle Body
M54 Throttle Position Sensor
M52TU Throttle Body

DME Wiring Tables:
M54
M52TU

edit: sorry about my post 20 minutes ago TerraPhantm, I wasn't paying attention to what you wrote and just started making up this imaginary response -haha!

I completely agree with your thoughts, thats exactly how I want to try and tackle this problem.

The MS42 sends out data to the M52TU's throttle body via Pulse Width Modulation (PWM). I'm preparing to do another experiment soon where I will measure the PWM duty cycle. The problem is that the M54's throttle body doesn't really work too well with PWM so the signal will have to be converted.

I sincerely hope that when I do this experiment the PWM duty cycle is consistent. If it is, that will allow me to simply measure the time the PWM is active and compare that time to a coefficient that corresponds to how much the throttle flap needs to be opened.

Originally Posted by TerraPhantm

Would it not be possible to simply have the DME control the M54 throttle? The M52TU throttle bodies aren't exactly cable driven - the cable action is more a failsafe than anything (the throttle body moving in your experiment also proves that). Looking at the DME wiring tables and diagrams, it looks like the MS42 and MS43 have the same pins powering the throttle body... If BMW happened to use the same sort of signal to control the servo, then it might just work.

Getting the MS42 DME to play nice with the electronic pedal looks like it would be the tougher part.

Status Update...

Okay, I've pretty much dealt with all potential problems associated with running the M54 throttle body. Since the video posting I've reconfigured the software so its much smoother and processed much faster. I've cooled down the microchip controlling the throttle motor actuation through some changes to the coding. I have added numerous safety loop programming into the system as well as a hardware reset. The controller has the ability to detect a jammed or failed throttle body, a hardware failure, a frozen software condition, and can self reset for all of the above. There's several programming loops that allow for "soft failure" conditions such as a single failing sensor at the pedal or the throttle body. This will allow the controller to identify a long-term failing sensor and switch to the second supplied sensor. And lastly, I've pieced together a calibration mode that can be activated at start up via a safety switch. It will allow each owner to pair their pedal and throttle body to the controller regardless of the quality or range of the sensors.

Since I've finished everything associated with driving the throttle body, interfacing between the pedal and TB, calibration, and safety, I've moved onto altering the sensor signals going to the M52TU DME. This is the last step before testing the part in the car. Tonight I tried to perform a simple test to both measure and synthesize the existing signals going from the stock throttle body to the DME. It didn't go so well. The car took the signals, but it gave me multiple CEL's regarding plausibility, motor failure, potentiometer failure, etc. I'm going to take another stab at this tomorrow and Sunday, but if it doesn't work I'm going to have to shelve the project until I can get my hands on a healthy 100MHz oscilloscope... cross your fingers!

Fingers crossed!

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Well?!?!

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Ugh! It didn't work. I tried to reproduce the identical voltage signal that the stock M52TU throttle body was producing. I used an digital to analog converter to read two of the four sensor signals, I processed the signal, and pushed the exact same signal out to a digital to analog converter. The car was unhappy and threw a bunch of CELs.

I'm kind of at a loss right now. I suspect that my hardware is too slow. The MS42 DME doesn't have a super fast processor (especially compared to the MS43) but its a lot faster than the hardware I'm using. The DME might be catching the time difference of my hardware, which is on the order of 50 microseconds. Its not a lot of time but thinking about it now, that's a lifetime to a computer.

Its also possible that a can-bus signal is being sent through the sensor voltage feed line. BMW may have even programmed each sensor line to be slightly out of phase with one another to help identify a short between the two potentiometers. This would explain why there are four completely separate circuits for each sensor feed on the M52TU (5v,GND,Signal for each). I would need an oscilloscope to see if there's a hidden signal. I highly doubt I could replicate it though.

So here are the five options at the moment:
1 - try isolating all four signals using a second DAC and see if the dme is satisfied
2 - try powering the DAC's with the 5v supply going to the pots at the M52TU throttle body. perhaps, if there's a hidden can-bus signal, it will carry through the voltage supply of the DAC.
3 - switch from DAC's to digital pots to help better replicate what the DME is already doing
4 - reprogram the DME to ignore the back-up sensor pots
5 - remap the DME's throttle position sensor tables for the back-up sensor pots

If anyone has any other ideas or suggestions, they're absolutely welcome.

Damn

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You know what, now that I've had a chance to talk out the problem, I think I have a new way to tackle this. It'll be a couple more weeks before I can test this new theory, but it should work perfectly. Sit tight.

Keep at it, Alexander! We're pulling for you!

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thanks Hornung418, I really appreciate the support!

Originally Posted by Hornung418

Keep at it, Alexander! We're pulling for you!

Reviving this thread...

Has anyone considered using a Saab throttle body?

BMW subcontracted the manufacture of the M52TU throttle body out to Hella. Hella has produced throttle bodies for European cars for quite some time now for all sorts of manufacturers. Though just random google searches, I've noticed that Saab's have the same 50/50 (half electronic/half mechanical) throttle body configuration that the M52TU's do. They're also made by Hella and were produced for similar year ranges as the M52TU. Also, the number of pins look to be about the same as the M52TU's - 10.

All the Saab throttle bodies I've seen with the 50/50 setup look too small to be a viable alternative to the M52TU's stock throttle body, but perhaps there's a Saab sub-model that utilized a larger TB...

Originally Posted by alexxander.foster

edit: sorry about my post 20 minutes ago TerraPhantm, I wasn't paying attention to what you wrote and just started making up this imaginary response -haha!

I completely agree with your thoughts, thats exactly how I want to try and tackle this problem.

The MS42 sends out data to the M52TU's throttle body via Pulse Width Modulation (PWM). I'm preparing to do another experiment soon where I will measure the PWM duty cycle. The problem is that the M54's throttle body doesn't really work too well with PWM so the signal will have to be converted.

I sincerely hope that when I do this experiment the PWM duty cycle is consistent. If it is, that will allow me to simply measure the time the PWM is active and compare that time to a coefficient that corresponds to how much the throttle flap needs to be opened.

Ah I did not realize the MS42 sends a different type of signal; shame they didn't use PWM signals for both

Edit: hmm, I'm finding some documentation that indicates both the mdk and edk are controlled with pwm signals. The mdk signal has a 600hz base frequency; I cannot find what the frequency for the edk pwm signal is

The pedal position sensor on the dbw cars is a little different. Potentiometer 1 goes from 0.5-4.5V while potentiometer 2 goes from 0.5-2v (so that a short can be detected). I cannot find any reference to how the MDK does things, but I'll assume your explanation is correct. FWIW for some dbw cars, BMW did make a separate cable actuated sensor (13621407446); this can be found in the e39 m5 and s54 z3m. The signal is identical to that of the self contained pedal. Also the reason I was confused about getting the pedal to work above was because BMW moved the pedal sensor signals to x60004 for some reason. But since it's still a double potentiometer, it should be easy to get to work as long as you double the voltage on the lower voltage potentiometer.

I really do believe it should be possible to run everything off the dme with minimal extra circuitry. I wish I had an MS42 car to play with lol

Hey TerraPhantm,

Sound like you and I are more-or-less on the same page about this. And it sound like we found the same information as well.

Yes, the signals sweeps are exactly as you say they are -I can empirically verify that. And from what I've researched, the two systems appear to both driven by PWM, but I couldn't find any more information on the type of signal used with the MS43. It didnt really matter much though since I wasnt able to drive the M54 throttle predictably or reliably using only PWM.

As for that pedal assembly you mentioned, I'm not really sure why BMW made this completely external unit instead of just integrating it into a single pedal system. Perhaps they had a surplus of older style pedals and needed to use them up before switching to a self contained DBW pedal system (BMW has a long history of doing things like that). Either way, I did some research on this several months ago. Supposedly they're interchangeable, but there were changes to the physical sensors used between the two pedal systems. The pedal sensor assembly you posted a link to uses potentiometers, while the M54's e-gas pedal uses a pair of rotary hall-effect sensors. Supposedly they were having problems with dead spots on the tracks of the potentiometer style sensor you mentioned, so they switched to a non-wearing style sensor.

Also, modifying the sensor signals is not quite as easy as "doubling" the voltage as you're suggesting. Its going to be quite a bit of clever manipulation to rectify the differences between the two system's sensor outputs in high resolution and high speed. Additionally, the M54's throttle body uses a 0.5-4.5v sweep in conjunction with a 4.5-0.5v sweep. Its a very clever solution to simplify coding and safety checks, but there's no way to modify the second signal to match the sweep to the M52TU's counterpart sensor, that will have to be a completely synthesized signal. Also, the biggest problem isn't the signal, its producing a faux-signal fast enough as to not cause alarm to the DME. For example, if we do too many resistors or capacitors to modify the existing sensors on the M54 it'll slow down the signal rate to an unacceptable speed. It will also eat up small movements within the circuit. The MS42 wont be able to pick up rapid pedal position movements. Personally, I'm putting my money on a signal conditioner circuit I'm piecing together. I just hope its fast enough. The fastest rate I can process throttle plate and pedal position sensor data, remap it, and kick it back out is around 5 microseconds. I sincerely hope thats fast enough for the MS42.

And regarding coding all of this to the MS42 directly, I completely agree! From what I've read, it looks like the DME might be able to handle the extra task of full-time throttle body articulation. And, lets be honest, thats the easiest way to go. Recode the DME and wire up the new pedal/TB assemblies.

However, there are a couple problems that made me want to avoid digging into the DME:

1 - there are wwwaaayyyyyyyyy too many check sums to deal with for a major coding change like this
2 - trouble shooting code with an error would be a nightmare with all of the checksums
3 - the throttle motor driver on the MS42 was never made to run full time or respond with any sort of precision, the transistors may blow out
4 - the cost would likely be extraordinary

To be honest, the cost is my biggest concern with this project. Last time I checked, an MS43 swap is around $1200. That gets you a DME, wiring harness, pedal, throttle body, and some wide band O2 sensors. For that price you get a faster DME, DBW, and the option of wide band tuning. Thats more money than I'd like to spend, but its a pretty good deal if you really want a larger throttle body. Tuning these cars or modifying any code on these cars is extremely expensive. I'd be willing to bet a DBW reflash would cost at least $800. After someone buys their throttle body and e-pedal, that puts them pretty damn close to an MS43 swap -why not upgrade your ECU while you're at it and get the option of wide-band O2 sensors? Or at the very least, have the piece of mind that the DBW coding was factory proven. Ya know?

Anyway, if somebody can do it in a cost effective way, modifying the MS42 is the most ideal way of tackling this problem. However, if it cant be done for a reasonable price, then its not worth it... but thats just my opinion.

Originally Posted by TerraPhantm

Ah I did not realize the MS42 sends a different type of signal; shame they didn't use PWM signals for both

Edit: hmm, I'm finding some documentation that indicates both the mdk and edk are controlled with pwm signals. The mdk signal has a 600hz base frequency; I cannot find what the frequency for the edk pwm signal is

The pedal position sensor on the dbw cars is a little different. Potentiometer 1 goes from 0.5-4.5V while potentiometer 2 goes from 0.5-2v (so that a short can be detected). I cannot find any reference to how the MDK does things, but I'll assume your explanation is correct. FWIW for some dbw cars, BMW did make a separate cable actuated sensor (13621407446); this can be found in the e39 m5 and s54 z3m. The signal is identical to that of the self contained pedal. Also the reason I was confused about getting the pedal to work above was because BMW moved the pedal sensor signals to x60004 for some reason. But since it's still a double potentiometer, it should be easy to get to work as long as you double the voltage on the lower voltage potentiometer.

I really do believe it should be possible to run everything off the dme with minimal extra circuitry. I wish I had an MS42 car to play with lol