MegaSquirt 2 Embarrassingly Noob Questions

[MaxBell]

Hi Guys;

I've poured through Google and I want to confirm some questions with you guys. (assume I know nothing)

I'm getting ready to supercharge my M50B25TU and I'm looking at MSII for the engine management.

1. Can I use my coils with MS2?

I have 6 coil on plugs and I want to run them with MS2, rather than buying GM coils that some people have been buying?

(Although those GM coils may be for people who were using a distributor.)

Does the MS2 have enough drivers for 6 coils?

2. Which MegaSquirt do I buy?

This one? http://www.diyautotune.com/catalog/m...ase-p-119.html

2.a. Just to confirm, MS 2 "Extra" is firmware that I flash the ECU with after I've built it?

3. Is there an adapter board out there to fit the MS2 into a BMW M50 ECU case?

I'd love to not tear my wiring harness apart wiring in the MS2 plug.

4. Other components needed:



From what I can tell, other than the MS2, I will need the following to get the car running on MS2:

a. IAT: http://www.diyautotune.com/catalog/g...tail-p-62.html

b. Coolant Temp Sensor: the one in the M50 head I can use? Or do I need to put one somewhere else?

c. TSP: I can use the M50 one.

d. LC-1 Wideband

[Northern]

1. Can I use my coils with MS2?

Short answer, No.

Long answer, MS2 can have 4 ignition drivers installed to run COP on anything up to a 4-cyl. For 6cyl cars, it only has enough drivers to to wasted spark. I have no idea if it is possible to use the oem coilpacks with a wasted spark setup, but I don't believe it is.

MS3/MS3x can do COP for up to 8 cyl.

2. Which MegaSquirt do I buy?

MS3x:

http://www.diyautotune.com/catalog/megasquirtiii-ems-system-with-ms3x-expansion-v357-assembled-p-435.html

This will run COP, and sequential fuel, plus whatever else you want to do.

I have no experience building MS units, so I can't comment on your link.

2.a. Just to confirm, MS 2 "Extra" is firmware that I flash the ECU with after I've built it?

Yes, it just adds some "extra" features, also see here

3. Is there an adapter board out there to fit the MS2 into a BMW M50 ECU case?

Buy an extra DME case and gut it, use its connector as an adapter.

4. Other components needed:



From what I can tell, other than the MS2, I will need the following to get the car running on MS2:

a. IAT: http://www.diyautotune.com/catalog/g...tail-p-62.html This will work, not sure if the OEM M50 one doesn't work?

b. Coolant Temp Sensor: the one in the M50 head I can use? Or do I need to put one somewhere else? M50 sensor works.

c. TSP: I can use the M50 one. Yes

d. LC-1 Wideband or equivalent

[Northern]

I know a diy ms2 kit is very attractive because of the price, but I feel the price difference for the assembled MS3x is well justified. I wouldn't be opposed to chopping up an m50 harness either, there are over a million M50 cars made (only counting e36 m50b25 cars and e34s,) so it shouldn't be too hard to find another.

[MaxBell]

Thanks Northern. I'll definitely be going after the MS3, since I want to keep with my coils.

I don't have an IAT that I know of on my M50. I think there may have been one stock, but I don't have one on there right now. (Maybe on the stock airbox, I just have an air filter on there)

So which of these do I want?

http://www.diyautotune.com/catalog/megasquirtiii-ems-system-with-ms3x-expansion-v357-assembled-p-435.html

http://www.diyautotune.com/catalog/megasquirtiii-ems-system-v357-assembled-unit-black-case-p-420.html

http://www.diyautotune.com/catalog/megasquirtiii-wpcb-v30-unassembled-kit-with-black-case-p-419.html

[Northern]

The top of the 3 is the only one with the ms3x expansion board, which is the way I would go for the ~100 difference, but depending on what you need the others may fit the bill.

[Northern]

There should have been an iat in the manifold, otherwise the gm IATs are cheap as balls, so go for it.

[MaxBell]

Oh yes, I remember now. It is still in there.

[nando]

I know a diy ms2 kit is very attractive because of the price, but I feel the price difference for the assembled MS3x is well justified. I wouldn't be opposed to chopping up an m50 harness either, there are over a million M50 cars made (only counting e36 m50b25 cars and e34s,) so it shouldn't be too hard to find another.

having done it both ways - don't chop the harness. it will be a gigantic pain in the ass. Use an old DME and put your MS inside that, make the harness plug right in. much easier to build, easier to maintain, and easier to remove the DME if you want to test something.

[blasphemy101]

having done it both ways - don't chop the harness. it will be a gigantic pain in the ass. Use an old DME and put your MS inside that, make the harness plug right in. much easier to build, easier to maintain, and easier to remove the DME if you want to test something.

Exactly, if you ever have a DME-related problem, there will be very little question about where it's coming from.

Also, it turns out looking much nicer.

[Paradox]

um...some of this information isn't actually 100% correct.

You can run 6 coils off MS2 - you will have to use wasted spark
You can use all your stock sensors - you will have to configure the resistance curves

Its actually not that hard to make a ms - to 88 pin adapter I just did.

http://www.r3vlimited.com/board/showthread.php?t=310051

[MaxBell]

Is wasted spark difficult to set up? I love the stock look of the 6 coils on the M50. It's just those GM Coils and then distributor wires to each spark plug?

[nando]

um...some of this information isn't actually 100% correct.

You can run 6 coils off MS2 - you will have to use wasted spark
You can use all your stock sensors - you will have to configure the resistance curves

Its actually not that hard to make a ms - to 88 pin adapter I just did.
http://www.r3vlimited.com/board/showthread.php?t=310051

of course it can. but you're also limited to batch fire injection. it's basically a downgrade from the stock computer.

[Paradox]

Completely respect your opinion Nando, but let's do a thought experiment. Let's imagine an engine running at about 4000 rpm. Imagine every squirt per revolution is a flash of a LED light. At engine speeds anything above idle the light will almost be a steady glow. In other words constantly injecting fuel. Sequential will be almost the same, the only difference would be during idle. Sequential injecting doesn't help make more power it only improves emissions at idle

[nando]

not quite constantly. you never run the injector above 80% if you can avoid it. and you certainly shouldn't be at 80% dc at only 4000rpm.

also, there are other factors - like individual cylinder trims that you can't do with batch fire, and being able to run large injectors and still have an acceptable idle.

[MaxBell]

So MS3 I guess. Seems like sequential is probably a better enough system to warrent the $350 increase to MS3?