xpost from: http://e30performance.info/viewtopic...p=34204#p34204
I got a lot of feedback from the last one so I decided to make a writeup for the MS3. This will be written from the M50 point of view and side note that it's a turbo motor. Shouldn't make a difference.
MS3 vs MS3x
The difference is simple. The MS3 processor has the USB port and SD card reader on it and it's a much faster processor than the older models. The MS3x is an extra card (on top of the processor) that gives you tons of outputs. If you want to run sequential or even just spark, I would recommend it. In fact, if you run an MS1/2 now and don't want the MS3x card, don't really bother going MS3. In short, get MS3x or just don't bother.
Why Go MS3?
If you're reading this, I'm not going to sway you to get an MS. You know enough to make your decision. If not, pm me? The big advantages of the MS3 is the full sequential fuel/spark, SD logging, USB cable, TONS of outputs, faster/bigger fuel calculations, and more resolution for your tables. If you have an MS1/2 setup now and you don't want most of this, stick with what you got.
Basics
As always, I advocate getting the stim (http://www.diyautotune.com/catalog/m...unit-p-33.html) and for good measure the adapter so you don't have to use 9v batteries (http://www.diyautotune.com/catalog/m...ply-p-168.html). Yes this is $80 you don't NEED to spend but you can fiddle with your msq, verify you didn't fry your MS, and other things. There is also the MS3X stim but if you get yours prebuilt, I wouldn't bother. My opinion.
For the love of GOD buy one premade. http://www.diyautotune.com/catalog/m...led-p-435.html Yea it's $650 but you save yourself the time and effort of soldering it. DIYautotune will warranty it if there are any defects and have great customer support. Spend the damn money!
I also recommend a starter harness. Many people make an adapter for the stock ECU connector so they can go back to stock but why not redo the whole harness while you're in there? The rest of this article will assume you are making your own full harness and not messing with the stock one. There's too many variants and I'm far too lazy to go into it.
Other hardware
Sensors! Your stock sensors will all work with the MS3 easily. The stock coolant temperature sensor simply requires calibration in tuner studio (MS3 doesn't use megatune anymore). I don't have the calibration as I used a GM sensor (http://www.diyautotune.com/catalog/g...tail-p-58.html)
Also, we need an idle air temperature sensor (IAT) since our stock system didn't have one we can use. http://www.diyautotune.com/catalog/g...tail-p-62.html
If we want to have spark output and use the stock BMW M50 coils, we will need coil drivers. You can make these out of bip373 chips and 330ohm resistors (one per cylinder) http://www.diyautotune.com/catalog/b...kit-p-230.html ($9 each) OR if you break them and can't solder chips to save your life like me, you can buy 2 of the 4 cylinder driver boxes DIY makes (http://www.diyautotune.com/catalog/q...ule-p-481.html). If you don't want to worry about coil drivers, you can get LS2 coils as they don't need the drivers. http://www.megamanual.com/seq/coils.htm . The coils are AC Delco D585
For an O2 sensor, I suggest the Innovate LC-1. You can tune with a narrow band but it's like threading a needle with your mouth. It won't work and people will look at you funny. http://www.diyautotune.com/catalog/i...3769-p-41.html
The last thing you will need is a 10k resistor! The BMW stock crank sensor for M50s (not sure about M20s) requires a 10k resistor in line with the crank signal. Without it, your car will crank/start but not rev very far.
Wiring
I never did get the hang of the stock harness enough to be able to make a plug and play harness out of the stock ECU connector. Basically, the megasquirt takes in all the sensors and spits out spark and fuel. The only other thing you need is power for the megasquirt and anything else. Below is my relay diagram for my car.
Main relay - The red dot means it's always receiving 12v. The 6 pin from the c101 gives a signal when the key is in the on/run positions. Otherwise, pin 85 grounds when you turn the key on giving the MS full power.
Fuel pump relay - This relay will be hot all the time (like all the others) but only receives power when the megasquirt is on. This powers the fuel pump (pin 13 on the c101).
O2/Coil relays - These parasite off of the fuel pump output pin. This means, they will only trip when the fuel pump is on and thus only when the car is running (aside from a priming pulse). This will keep your O2 sensor from being on for no reason and keep your coils from over charging. I recommend keeping these two separate relays as the coils pull so much power that they will interfere with other signals. You want a clean O2 signal, why not give it its own relay? The stock harness does it.
Grounds - This will trip many people. Do not ground to the chassis and do not ground things where convenient. Ground everything to a ground block and ground that to the engine block. This will prevent grounding loops. MS3 is great and has grounds back to the ECU. Use them! These will keep all of your sensors grounding together and stable.
General wiring - I repurposed a stock M50 harness to keep the stock wiring colors. Do what you need to do but remember to shield what needs to be shielded and put that 10k resistor for the crank sensor.
Starting Settings
Note that my tune is not 100% but my car does run.
Required fuel will be your own value based on your injectors.
For sequential we want 1 squirt per cycle (lol).
The rest is self explanatory. M20s/M50s are firing order 153624
These are my cranking settings. Cranking PW are based off of a percentage of required fuel so your mileage will vary.
Here is the biggy. Copy everything exactly. minus what I say below.
Skip pulses is simply how many full rotations to do before the engine starts injecting fuel. 3-4 is fine.
Ignition input will always be rising edge.
Spark output will ALWAYS be "Going High (Inverted)"
M20s/M50s are dual wheels with 2 missing teeth. hence the 60 and 2
Tooth #1 angle will vary. M50s/M20s are ~84 degrees while the S52 and I think M52 use 324. Realistically, a timing light on your #1 cylinder and a friend should nail this exactly for you.
"Second trigger active on" and "Level for phase 1" I've seen multiple ways. They can just be rising edge. Both seem to work on my motor so I'm not sure on this.
Cranking dwell could probably be lower. ~5ms I'd say. Cranking advance is fine at 3 though.
Max dwell should be as low as you can get away with. I've seen 3-4.
Max spark duration is fine at 1
All of the rest of the MS settings will be up to you. I don't have any good base maps to share and my setup is an S52 bottom, M50 NV top, Dual intake cams, and low comp pistons so you wouldn't want to go with mine.
Troubleshooting/Tuning
Tunerstudio is an awesome tool. When you're trying to verify your cam/crank settings, crack open the composite logger and check for desyncs. The Megamanual will have an idea of what your signals should look like. The key is to get an rpm signal while cranking and no descyns while the motor is running or cranking. Tunerstudio can load logs of the composite logger (logs cam/crank syncs) but it requires the pay version. Megalogviewer cannot open the trigger/tooth/composite logs! and you HAVE to pay for tuner studio to review your logs in tunerstudio. I was annoyed but it's worth it.
Pricing
Stim/adapter - $80
MS3x prebuilt - $650
Harnesses - $105
IAT/CLT sensors - $41
Spark boxes - $180
LC-1 - $200
Total: $1256
Please let me know if there is any clarification needed or corrections. This is what currently works for me.
I got a lot of feedback from the last one so I decided to make a writeup for the MS3. This will be written from the M50 point of view and side note that it's a turbo motor. Shouldn't make a difference.
MS3 vs MS3x
The difference is simple. The MS3 processor has the USB port and SD card reader on it and it's a much faster processor than the older models. The MS3x is an extra card (on top of the processor) that gives you tons of outputs. If you want to run sequential or even just spark, I would recommend it. In fact, if you run an MS1/2 now and don't want the MS3x card, don't really bother going MS3. In short, get MS3x or just don't bother.
Why Go MS3?
If you're reading this, I'm not going to sway you to get an MS. You know enough to make your decision. If not, pm me? The big advantages of the MS3 is the full sequential fuel/spark, SD logging, USB cable, TONS of outputs, faster/bigger fuel calculations, and more resolution for your tables. If you have an MS1/2 setup now and you don't want most of this, stick with what you got.
Basics
As always, I advocate getting the stim (http://www.diyautotune.com/catalog/m...unit-p-33.html) and for good measure the adapter so you don't have to use 9v batteries (http://www.diyautotune.com/catalog/m...ply-p-168.html). Yes this is $80 you don't NEED to spend but you can fiddle with your msq, verify you didn't fry your MS, and other things. There is also the MS3X stim but if you get yours prebuilt, I wouldn't bother. My opinion.
For the love of GOD buy one premade. http://www.diyautotune.com/catalog/m...led-p-435.html Yea it's $650 but you save yourself the time and effort of soldering it. DIYautotune will warranty it if there are any defects and have great customer support. Spend the damn money!
I also recommend a starter harness. Many people make an adapter for the stock ECU connector so they can go back to stock but why not redo the whole harness while you're in there? The rest of this article will assume you are making your own full harness and not messing with the stock one. There's too many variants and I'm far too lazy to go into it.
Other hardware
Sensors! Your stock sensors will all work with the MS3 easily. The stock coolant temperature sensor simply requires calibration in tuner studio (MS3 doesn't use megatune anymore). I don't have the calibration as I used a GM sensor (http://www.diyautotune.com/catalog/g...tail-p-58.html)
Also, we need an idle air temperature sensor (IAT) since our stock system didn't have one we can use. http://www.diyautotune.com/catalog/g...tail-p-62.html
If we want to have spark output and use the stock BMW M50 coils, we will need coil drivers. You can make these out of bip373 chips and 330ohm resistors (one per cylinder) http://www.diyautotune.com/catalog/b...kit-p-230.html ($9 each) OR if you break them and can't solder chips to save your life like me, you can buy 2 of the 4 cylinder driver boxes DIY makes (http://www.diyautotune.com/catalog/q...ule-p-481.html). If you don't want to worry about coil drivers, you can get LS2 coils as they don't need the drivers. http://www.megamanual.com/seq/coils.htm . The coils are AC Delco D585
For an O2 sensor, I suggest the Innovate LC-1. You can tune with a narrow band but it's like threading a needle with your mouth. It won't work and people will look at you funny. http://www.diyautotune.com/catalog/i...3769-p-41.html
The last thing you will need is a 10k resistor! The BMW stock crank sensor for M50s (not sure about M20s) requires a 10k resistor in line with the crank signal. Without it, your car will crank/start but not rev very far.
Wiring
I never did get the hang of the stock harness enough to be able to make a plug and play harness out of the stock ECU connector. Basically, the megasquirt takes in all the sensors and spits out spark and fuel. The only other thing you need is power for the megasquirt and anything else. Below is my relay diagram for my car.
Main relay - The red dot means it's always receiving 12v. The 6 pin from the c101 gives a signal when the key is in the on/run positions. Otherwise, pin 85 grounds when you turn the key on giving the MS full power.
Fuel pump relay - This relay will be hot all the time (like all the others) but only receives power when the megasquirt is on. This powers the fuel pump (pin 13 on the c101).
O2/Coil relays - These parasite off of the fuel pump output pin. This means, they will only trip when the fuel pump is on and thus only when the car is running (aside from a priming pulse). This will keep your O2 sensor from being on for no reason and keep your coils from over charging. I recommend keeping these two separate relays as the coils pull so much power that they will interfere with other signals. You want a clean O2 signal, why not give it its own relay? The stock harness does it.
Grounds - This will trip many people. Do not ground to the chassis and do not ground things where convenient. Ground everything to a ground block and ground that to the engine block. This will prevent grounding loops. MS3 is great and has grounds back to the ECU. Use them! These will keep all of your sensors grounding together and stable.
General wiring - I repurposed a stock M50 harness to keep the stock wiring colors. Do what you need to do but remember to shield what needs to be shielded and put that 10k resistor for the crank sensor.
Starting Settings
Note that my tune is not 100% but my car does run.
Required fuel will be your own value based on your injectors.
For sequential we want 1 squirt per cycle (lol).
The rest is self explanatory. M20s/M50s are firing order 153624
These are my cranking settings. Cranking PW are based off of a percentage of required fuel so your mileage will vary.
Here is the biggy. Copy everything exactly. minus what I say below.
Skip pulses is simply how many full rotations to do before the engine starts injecting fuel. 3-4 is fine.
Ignition input will always be rising edge.
Spark output will ALWAYS be "Going High (Inverted)"
M20s/M50s are dual wheels with 2 missing teeth. hence the 60 and 2
Tooth #1 angle will vary. M50s/M20s are ~84 degrees while the S52 and I think M52 use 324. Realistically, a timing light on your #1 cylinder and a friend should nail this exactly for you.
"Second trigger active on" and "Level for phase 1" I've seen multiple ways. They can just be rising edge. Both seem to work on my motor so I'm not sure on this.
Cranking dwell could probably be lower. ~5ms I'd say. Cranking advance is fine at 3 though.
Max dwell should be as low as you can get away with. I've seen 3-4.
Max spark duration is fine at 1
All of the rest of the MS settings will be up to you. I don't have any good base maps to share and my setup is an S52 bottom, M50 NV top, Dual intake cams, and low comp pistons so you wouldn't want to go with mine.
Troubleshooting/Tuning
Tunerstudio is an awesome tool. When you're trying to verify your cam/crank settings, crack open the composite logger and check for desyncs. The Megamanual will have an idea of what your signals should look like. The key is to get an rpm signal while cranking and no descyns while the motor is running or cranking. Tunerstudio can load logs of the composite logger (logs cam/crank syncs) but it requires the pay version. Megalogviewer cannot open the trigger/tooth/composite logs! and you HAVE to pay for tuner studio to review your logs in tunerstudio. I was annoyed but it's worth it.
Pricing
Stim/adapter - $80
MS3x prebuilt - $650
Harnesses - $105
IAT/CLT sensors - $41
Spark boxes - $180
LC-1 - $200
Total: $1256
Please let me know if there is any clarification needed or corrections. This is what currently works for me.
