323Ci (M52tuB25) to M54B30 Complete Conversion, with MS43.0 DME and Drive By Wire
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fix picture please
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Pics show for me.
I think the posts I've made do a good job of summarizing the swap. What else do you need to know? Maybe I missed something.
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Based on the MS42 documents, it's the other way around. The motor overrides the cable unless a fault is detected
Also according to Tool32, the unit the MS42 and MS43 for throttle position use is degrees, not %. I don't know if the 81º limitation is because the "0" position is actually 9 degrees or something along those lines
when ignition is on the throttle is fully closed- not like without ignition - and the idle speed is regulated via idle valve. the throtte body is only open at 9 degrees or so when without ignition or voltage.
but independend if you open the throttle to 75 degrees, or 81 degrees or 90 degrees (with modified dme) the full load airflow is the same. so most likely the throttle is big enough...
but independend if you open the throttle to 75 degrees, or 81 degrees or 90 degrees (with modified dme) the full load airflow is the same. so most likely the throttle is big enough...
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323Ci (M52tuB25) to M54B30 Complete Conversion, with MS43.0 DME and Drive By ...
Yes ve is a much more accurate measurement of the power an engine is making. Air flow requirements change depending on weather and you will see variances in the peak maf readings. I still think that 80mm throttle bodies are much bigger than what is necessary on an m54b30
Yes ve is a much more accurate measurement of the power an engine is making. Air flow requirements change depending on weather and you will see variances in the peak maf readings. I still think that 80mm throttle bodies are much bigger than what is necessary on an m54b30
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323Ci (M52tuB25) to M54B30 Complete Conversion, with MS43.0 DME and Drive By ...
Hmm, that's not what I have experienced during testing. Pressing the gas pulls the cable which has direct mechanical connection to the throttle butterfly. The motor is on a second linkage arm and doesn't seem to operate throttle except in overrides. Just by inspecting the linkages this is how they seem to operate and how I have seen it work in practice. I would think the ms42 systems would suffer from the same lag issues as the ms43 users if it worked the way those documents suggest. This hasn't been the experience of the community. I wonder if the motor operates continuously to finely tune inputs from the cable but the mechanical linkage functions as an immediate coarse input.
Edit*
Found the following excerpt in a BMW document regarding MDK throttle operation.
It seems to suggest what I'm thinking where in the MS42/MDK systems, the motor acts as an override/modification to the drivers mechanical commands on the throttle. Frankly, as I alluded to above, when inspecting the linkage this is what it seems to be as well.
"MDK: The throttle cable (foot
pedal controlled) is connected to
a pulley on the side of the MDK.
The pulley is linked by springs to
one end of the throttle shaft
(springs also return the accelerator
pedal to the rest position).
With the pulley linked by springs
to the throttle shaft, this allows
ASC intervention to override the
driver’s set throttle position.
As the pulley and shaft are rotated,
the dual potentiometers (integral
in the MDK housing = driver’s
wish) monitor the requested load
for the ECM. Dual potentiometers
are used for request plausibility"
From page 12 of: https://www.google.ca/url?sa=t&rct=...=cIxtXESrLpFjGgulRmJmng&bvm=bv.83829542,d.cWc
Hmm, that's not what I have experienced during testing. Pressing the gas pulls the cable which has direct mechanical connection to the throttle butterfly. The motor is on a second linkage arm and doesn't seem to operate throttle except in overrides. Just by inspecting the linkages this is how they seem to operate and how I have seen it work in practice. I would think the ms42 systems would suffer from the same lag issues as the ms43 users if it worked the way those documents suggest. This hasn't been the experience of the community. I wonder if the motor operates continuously to finely tune inputs from the cable but the mechanical linkage functions as an immediate coarse input.
Edit*
Found the following excerpt in a BMW document regarding MDK throttle operation.
It seems to suggest what I'm thinking where in the MS42/MDK systems, the motor acts as an override/modification to the drivers mechanical commands on the throttle. Frankly, as I alluded to above, when inspecting the linkage this is what it seems to be as well.
"MDK: The throttle cable (foot
pedal controlled) is connected to
a pulley on the side of the MDK.
The pulley is linked by springs to
one end of the throttle shaft
(springs also return the accelerator
pedal to the rest position).
With the pulley linked by springs
to the throttle shaft, this allows
ASC intervention to override the
driver’s set throttle position.
As the pulley and shaft are rotated,
the dual potentiometers (integral
in the MDK housing = driver’s
wish) monitor the requested load
for the ECM. Dual potentiometers
are used for request plausibility"
From page 12 of: https://www.google.ca/url?sa=t&rct=...=cIxtXESrLpFjGgulRmJmng&bvm=bv.83829542,d.cWc
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Page 11 says this...
And Page 20 says this:
Page 26 does say this though:
So it becomes a "normal" throttle body after around 60% throttle. Below that it behaves like a DBW system
• The accelerator position potentionmeters (PWG = driver’s wish) are integrated in the MDK housing.
• A throttle cable is used to actuate the accelerator pedal position potentiometers and also serves as a backup to open the throttle plate (full control) if the MDK system is in failsafe."
• A throttle cable is used to actuate the accelerator pedal position potentiometers and also serves as a backup to open the throttle plate (full control) if the MDK system is in failsafe."
And Page 20 says this:
Air flow into the engine is regulated by the Throttle Valve and/or the Idle Air Actuator. Both of these air “passages” are necessary for smooth engine operation from idle to full load. On the MS42/MS43 system, the Throttle Valve and the Idle Air Actuator are electrically controlled. All of the ECM monitoring, processing and output functions are a result of regulated air flow.
Page 26 does say this though:
MDK: In the upper PWG range (approximately >60%), the MDK is switched off. The throttle valve is opened wider exclusively by the pulley via the spring linkage. At the full throttle position, “kickdown” is obtained by depressing the accelerator pedal fully. This will overwind the pulley, but the spring linkage will not move the throttle plate past 90 degrees of rotation.
So it becomes a "normal" throttle body after around 60% throttle. Below that it behaves like a DBW system
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323Ci (M52tuB25) to M54B30 Complete Conversion, with MS43.0 DME and Drive By ...
I noticed it said that earlier (on page 11, I had my quote incorrectly referenced, it is from page 12). However it conflicts with what is said on page 12 where it describes the linkage as a hard mechanical linkage to the pedal and an overriding pulley for the motor driven portion. And when you think about it, this is the only way it could work for using the hard linkage as a mechanical fail safe. If it was only engaged when told to, it could fail to function in the case of general malfunction of the throttle body. I don't disagree that the mdk has more function than simply traction control and cruise control but I do think it functions as more of a modifier to driver mechanical inputs vs a fully electronic system with only mechanical backup and override over 60% throttle.
I noticed it said that earlier (on page 11, I had my quote incorrectly referenced, it is from page 12). However it conflicts with what is said on page 12 where it describes the linkage as a hard mechanical linkage to the pedal and an overriding pulley for the motor driven portion. And when you think about it, this is the only way it could work for using the hard linkage as a mechanical fail safe. If it was only engaged when told to, it could fail to function in the case of general malfunction of the throttle body. I don't disagree that the mdk has more function than simply traction control and cruise control but I do think it functions as more of a modifier to driver mechanical inputs vs a fully electronic system with only mechanical backup and override over 60% throttle.
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The graph on page 26 makes it pretty clear. Upto around 60%, the motor overrides driver input constantly. After that it lets the mechanical linkage do its thing
Oh and also, after investigating the 325i vs 330i throttle curves, I don't think the 81 degree limitation is simply because the 330i TB is large
330i
325i
The 325 restricts the throttle body more at low RPMs, but otherwise the curves are essentially the same
Butterfly Throttle Cross Sectional Area Plots
In case anyone was wondering what the cross sectional area of a butterfly throttle is with respect to throttle angle, here is a plot of that.
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These calculations are taken from a simple projection of a circle onto a plane. They do not account for the throttle shaft, which will remove a little bit more area from the flowpath, but it is fairly negligible.
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It looks as though you would lose about 17.4% of the cross sectional area when opening to only 80 deg throttle.
P.S.: Interestingly, cross sectional area is pretty linear with respect to throttle angle after about 40 deg.
In case anyone was wondering what the cross sectional area of a butterfly throttle is with respect to throttle angle, here is a plot of that.
These calculations are taken from a simple projection of a circle onto a plane. They do not account for the throttle shaft, which will remove a little bit more area from the flowpath, but it is fairly negligible.
It looks as though you would lose about 17.4% of the cross sectional area when opening to only 80 deg throttle.
P.S.: Interestingly, cross sectional area is pretty linear with respect to throttle angle after about 40 deg.
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For whatever it's worth, the throttle body curves on the S54 seem to assume that the throttle shaft area is negligible. I haven't checked the in-between values to your equation though
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qmm = mm^2
KL_AQ_ABS_WDK = Throttle % vs Total TB Area
KL_AQ_ABS_LLS = ICV % vs ICV Effective TB Area
K_AQ_ABS_MAX = Maximum throttle area (TBs + ICV)
K_AQ_ABS_MIN = Minimum throttle area
S54 has 6 50mm diameter throttle bodies.
qmm = mm^2
KL_AQ_ABS_WDK = Throttle % vs Total TB Area
KL_AQ_ABS_LLS = ICV % vs ICV Effective TB Area
K_AQ_ABS_MAX = Maximum throttle area (TBs + ICV)
K_AQ_ABS_MIN = Minimum throttle area
S54 has 6 50mm diameter throttle bodies.
Dyno Graph
Guys, I went to the dyno last night. Just hopped on one here at work (I work at a NASCAR shop - Richard Childress Racing). They let me use the one in the dirt shop, which is just an old Dynojet inertial dyno. But they wouldn't let me use the really nice load cell one (which also happens to have a wideband O2 sensor).
Since there was no O2 sensor on the dyno I used, I had a friend ship me his handheld wideband unit, which I hooked up and just watched as I was doing some pulls. It runs lean, somewhere in the 14.3 - 14.8 range at WOT. Also, I hooked up my EOBD scan tool, and watched ignition advance (the laptop with INPA on it was left at home). I am seeing anywhere from 23-26 degrees of advance, which to me is really low. I think the old MS42 DME on my old M52tuB25, with an AA tune, was running around 35 degrees of advance. That being said, I think there's a good 20-30 HP left in it, also including some cam timing tuning. Maybe some more experienced folk could give a better estimate.
So here's the dyno graph. Max HP = 223, Max Torque = 213 (Uncorrected HP = 228, Torque = 219).
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I went ahead and digitized the data and plotted it in Excel. First, I plotted it against my old setup, an M52tuB25 with M54B30 intake, AA tune, K&N intake, Turner pulleys, lightweight flywheel, same custom headers and exhaust, and 255,000 miles.
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First thing to notice is that the displacement increase (all others held equal) is almost a perfect offset in torque, as was my suspicion. However, the torque has a more rapid decrease at higher RPM. To me, this indicates either insufficient flow through the ports, intake manifold, or not enough valve lift, or not enough overlap. Maybe some input from the more experienced guys would help.
Also, I went ahead and plotted it against another guy on here, who installed an M50 intake on an M54B30 (John). He is making about 12 ft*lbs more peak torque, but he also has a pretty aggressive tune (from what I understand, he uses a standalone). This huge lump in torque tells me his intake manifold and headers are more tuned to eachother's length; his engine has better scavenging in the exhaust.
![]()
It would be nice to see what my torque curve looks like after a tune. Does anyone have any suggestions on tuning myself? I have read some of Terraphantm's, HakkenTT's, Thaniel's, and Daniel_f's threads, but I'm unsure whether the full amount of information is available for one to be able to tune the engine themselves. Any information regarding flashing my own DME would be helpful. I have a Galletto 1260, tunerpro, INPA, and some other software, but am not sure the exact process to adjusting the maps (I'm not asking how to tune - I've tuned many standalones in the past, I've just never tuned a stock DME on a BMW before) Is there a DIY tune thread that someone could make me aware of?
The four things I'm wanting to adjust are:
(1) Fuel injection pulsewidth at WOT
(2) Ignition advance at WOT
(3) Intake and exhaust cam timing
(4) Throttle response of the electronically controlled throttle valve
Guys, I went to the dyno last night. Just hopped on one here at work (I work at a NASCAR shop - Richard Childress Racing). They let me use the one in the dirt shop, which is just an old Dynojet inertial dyno. But they wouldn't let me use the really nice load cell one (which also happens to have a wideband O2 sensor).
Since there was no O2 sensor on the dyno I used, I had a friend ship me his handheld wideband unit, which I hooked up and just watched as I was doing some pulls. It runs lean, somewhere in the 14.3 - 14.8 range at WOT. Also, I hooked up my EOBD scan tool, and watched ignition advance (the laptop with INPA on it was left at home). I am seeing anywhere from 23-26 degrees of advance, which to me is really low. I think the old MS42 DME on my old M52tuB25, with an AA tune, was running around 35 degrees of advance. That being said, I think there's a good 20-30 HP left in it, also including some cam timing tuning. Maybe some more experienced folk could give a better estimate.
So here's the dyno graph. Max HP = 223, Max Torque = 213 (Uncorrected HP = 228, Torque = 219).
I went ahead and digitized the data and plotted it in Excel. First, I plotted it against my old setup, an M52tuB25 with M54B30 intake, AA tune, K&N intake, Turner pulleys, lightweight flywheel, same custom headers and exhaust, and 255,000 miles.
First thing to notice is that the displacement increase (all others held equal) is almost a perfect offset in torque, as was my suspicion. However, the torque has a more rapid decrease at higher RPM. To me, this indicates either insufficient flow through the ports, intake manifold, or not enough valve lift, or not enough overlap. Maybe some input from the more experienced guys would help.
Also, I went ahead and plotted it against another guy on here, who installed an M50 intake on an M54B30 (John). He is making about 12 ft*lbs more peak torque, but he also has a pretty aggressive tune (from what I understand, he uses a standalone). This huge lump in torque tells me his intake manifold and headers are more tuned to eachother's length; his engine has better scavenging in the exhaust.
It would be nice to see what my torque curve looks like after a tune. Does anyone have any suggestions on tuning myself? I have read some of Terraphantm's, HakkenTT's, Thaniel's, and Daniel_f's threads, but I'm unsure whether the full amount of information is available for one to be able to tune the engine themselves. Any information regarding flashing my own DME would be helpful. I have a Galletto 1260, tunerpro, INPA, and some other software, but am not sure the exact process to adjusting the maps (I'm not asking how to tune - I've tuned many standalones in the past, I've just never tuned a stock DME on a BMW before) Is there a DIY tune thread that someone could make me aware of?
The four things I'm wanting to adjust are:
(1) Fuel injection pulsewidth at WOT
(2) Ignition advance at WOT
(3) Intake and exhaust cam timing
(4) Throttle response of the electronically controlled throttle valve
Attachments
I can use it whenever I want now. What measurement are you asking that I can reproduce?
Sure, I'll do this after work.
Well it seems my galletto 1260 is broken. Does anyone have a link to a place I can buy the real cable? The cheap ebay one is known to have issues I guess.
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