Speeduino build for M20B25

[Digitalwave]

One thing I found with two-step on my car is that the stock clutch switch is not well suited for it. If you have the clutch depressed AT ALL, even a little bit, the switch will activate. What I found is that unless I took my foot fully off the clutch pedal between shifts, I was frequently activating two-step when I didn't want it active, just by applying the slightest pressure to the pedal. During autocross, when it's not really practical to take your foot off the pedal (because you are shifting very often), it was a pain in the ass.

For track use and flat foot shifting, that might work fine.

For autocross and two-step, you probably want a bottom mounted switch that will only be active when you really want it to be; clutch fully depressed to the floor.

[McGyver]

Overthinking.

MS simply has an open to closed, or closed to open parameters. The type of switch is irrelevant. When doing launch/traction, the ECU simply needs to know the condition specified, and act upon it. In the end, it is user-defined.

Ok, so you're saying that I use my stock clutch switch, which is grounded with the clutch engaged and open with the clutch pedal pushed. Then I set it in MegaSquirt to say, "turn on Launch control when you see an open circuit, turn it off when you see ground".

That's so simple. I overthink stuff way too often.

[JehTehsus]

Overthinking.

MS simply has an open to closed, or closed to open parameters. The type of switch is irrelevant. When doing launch/traction, the ECU simply needs to know the condition specified, and act upon it. In the end, it is user-defined.

Yeah, I figured it shouldn't matter. What does matter, from my understanding, is where the switch is 'tripped' relative to clutch position (and it being adjustable). The factory switch is adjustable. What I don't like is that the bracket holding it seems rather 'floppy'... for example, my switch wasn't working, took a look at it and realized the bracket was bent and it was sitting way back, bent it back and now it seems fine. Not really what I want for a setup beyond basic validation/screwing around, so I will need to fix that.

[ForcedFirebird]

Overthinking.

MS simply has an open to closed, or closed to open parameters. The type of switch is irrelevant. When doing launch/traction, the ECU simply needs to know the condition specified, and act upon it. In the end, it is user-defined.

[JehTehsus]

How did you use the clutch switch for MegaSquirt?

As you said, any manual transition car with cruise control has a switch on the clutch pedal. Unfortunately, the circuit is grounded when the pedal is up and the circuit is open when the pedal is pressed (the opposite of how MegaSquirt needs it). I'm looking into the following options:

• Switch to a single pole dual throw (SPDT) switch: cruise control gets grounded until I press the clutch, then MegaSquirt gets grounded. I bought a switch, but it seems too small and I don't like it.
• Add a second switch that closes the circuit when the pedal is pressed
• something else?

I don't think the MS cares, does it? I have not actually configured it yet but I can see the I/O switching. Worst case I should be able to invert it with a loop. (I am running an MS3 ultimate).

[McGyver]

I actually just wired in my clutch switch with my megasquirt build, as well as got most of the pieces into place for traction control, launch control and flat shifting as well. It will be a little while before I actually test it though, lots of other items on the list at the moment.

How did you use the clutch switch for MegaSquirt?

As you said, any manual transition car with cruise control has a switch on the clutch pedal. Unfortunately, the circuit is grounded when the pedal is up and the circuit is open when the pedal is pressed (the opposite of how MegaSquirt needs it). I'm looking into the following options:

• Switch to a single pole dual throw (SPDT) switch: cruise control gets grounded until I press the clutch, then MegaSquirt gets grounded. I bought a switch, but it seems too small and I don't like it.
• Add a second switch that closes the circuit when the pedal is pressed
• something else?

[JehTehsus]

I actually just wired in my clutch switch with my megasquirt build, as well as got most of the pieces into place for traction control, launch control and flat shifting as well. It will be a little while before I actually test it though, lots of other items on the list at the moment.

If your car had/has cruise control, and is manual, there should be a clutch switch.

[sk8]

Thanks a bunch! Looking forward to this project. I just started buying parts for my build. They'll probably come in month or so.

Am also pretty interested in launch control/flat shifting. Although not entirely sure what are the benefits but will probably look into it later on. I heard you could use the brake switch for it.

Apart from that, am actually quite interested in the capabilities of the HC-06 bluetooth module.

I have never tuned a car before (will have to get myself educated more on that later as well. Could you share more details about this timing light please? I thought there is a Crankshaft Position Sensor (CPS) that will be converted to something the Arduino can read by using the VR Conditioner and this would tell timing?

No worries, you've helped plenty!

For flat shift/launch control the clutch switch is used. Haven't had a chance to play around with it on my car because I never added a clutch switch when I swapped it from auto to manual.

The timing light is needed to set your trigger angle properly. This is how the ECU knows the position of your engine. For example if my trigger angle is off 30 degrees. Everything in my ignition table will be off by that much. So you typically want to set the trigger angle right at TDC so that your ignition table is accurate. You use a timing light to see if the setting you configured in your ECU is accurate to actual TDC.

[ecnerettee]

Thanks a bunch! Looking forward to this project. I just started buying parts for my build. They'll probably come in month or so.

Am also pretty interested in launch control/flat shifting. Although not entirely sure what are the benefits but will probably look into it later on. I heard you could use the brake switch for it.

Apart from that, am actually quite interested in the capabilities of the HC-06 bluetooth module.

I have never tuned a car before (will have to get myself educated more on that later as well. Could you share more details about this timing light please? I thought there is a Crankshaft Position Sensor (CPS) that will be converted to something the Arduino can read by using the VR Conditioner and this would tell timing?

No worries, you've helped plenty!

[sk8]

Hey guys,

Am new here and have been reading quite a bit on this, recently acquired an E30 couple months back and in the midst of converting it to manual. Am also very interested in tuning and have been looking at Speeduino vs tuning the EPROM chip (am aware there are readily available chips) but it's just fun to get started and learn, not so much about the cost but more on enjoying the process.

Speeduino seems the be the easiest way to get started, looking at the schematics done by Amila, I wonder if sk8 can share what are the things that will not work with this Speeduino? If i'm not mistaken, speeduino does not has CEL, am I right? so does that mean your Check Engine Light is always turned on? I believe the diagnostics and econometer will not work as well? Am hoping if you can confirm this and appreciate if you could share what other things that will not work with Speeduino.

Are there also any notable benefits of going wasted spark vs using the stock distributor?

Lastly, I am actually planning on making a M20b30 (starting with a block from M20b25 from a e34), with the increased stroke, are the base tunes for M20 engines the same across the different displacements?

Sorry if my questions sounds silly or have been asked before, but I have read as much as I could.

Thanks! :)

Yes CEL will not work with the speeduino. If you are planning to mess around with tuning, but not planning to turbo the car I can't really recommend and aftermarket ECU. You can get an eprom burner and a few chips and tune that way. With chip tuning I don't think you can adjust fueling, so you will mostly be tuning the timing tables.

The benefits of a speeduino on an na engine, is getting rid of the afm so that may make the car a little more responsive. You can also adjust fueling, timing, burble tune, etc.. a lot easier. With a chip you have to take it out, flash, put it back in. You can also setup launch control with the speeduino and no lift shift.

If you go with the speeduino it won't be as fast or easy to get everything setup. Also I would recommend buying a timing light. The typical setting people use for trigger angle using a megasquirt is different from speeduino. When I tried to verify my timing with a timing light, tdc was at 50 deg.

I don't really have enough knowledge to answer your other questions.

[ecnerettee]

Hey guys,

Am new here and have been reading quite a bit on this, recently acquired an E30 couple months back and in the midst of converting it to manual. Am also very interested in tuning and have been looking at Speeduino vs tuning the EPROM chip (am aware there are readily available chips) but it's just fun to get started and learn, not so much about the cost but more on enjoying the process.

Speeduino seems the be the easiest way to get started, looking at the schematics done by Amila, I wonder if sk8 can share what are the things that will not work with this Speeduino? If i'm not mistaken, speeduino does not has CEL, am I right? so does that mean your Check Engine Light is always turned on? I believe the diagnostics and econometer will not work as well? Am hoping if you can confirm this and appreciate if you could share what other things that will not work with Speeduino.

Are there also any notable benefits of going wasted spark vs using the stock distributor?

Lastly, I am actually planning on making a M20b30 (starting with a block from M20b25 from a e34), with the increased stroke, are the base tunes for M20 engines the same across the different displacements?

Sorry if my questions sounds silly or have been asked before, but I have read as much as I could.

Thanks! :)

[ForcedFirebird]

The AFM is more of a speed density (MAP) than it is mass air flow (MAF) in that it calculates the atmo pressure using the IAT, CTS and air vane position. So, punching in the stock numbers will get you close enough to run.

Aslo, here's a screenshot of the stock table to make things easier:



The WOT table is separated and is actiave when the WOT switch in the TPS is closed. This was done so that the ECU would revert to open loop and disregard the o2 feedback when in WOT.

EDIT: The MS kits are far less than the PnP's. The DIY kits are ~$200 for v2.2 and $250 for v3.0 MS1 boxes.

https://www.diyautotune.com/shop/megasquirt-kits-components/megasquirt-1/

[Tinkerer007]

I think we can convert the WOT map, since at WOT we should be right at atmospheric pressure. I will play around with these values when I have a chance. I haven't went for a drive with the car yet as I have just been messing around with idle for now. Thank you for sharing! These are the stock tune timing values right?

Yes, these are from the stock 173 BIN.

[bmwman91]

The "AFM" axis in the maps is actually "Load". The AFM is a primary input to the load variable, but the calculation also factors in intake air temp & coolant temp.

[sk8]

Here isthe ignition Low Part Throttle timing map. You might be able to extrapolate values to your Map sensor values. And atleast the changed by RPM should be consistent.

RPM in the left column. AFM value in top row.
14 38 48 60 74 90 110 130
680 20 20 21 24 24 16 7 2
800 21 21 21 24 24 16 10 6
1120 22 22 22 24 24 18 15 10
1440 31 29 26 24 24 20 19 15
1760 39 37 33 30 29 25 25 20
2080 39 37 33 31 30 28 28 24
2680 39 37 34 31 30 30 30 30
2920 39 37 34 31 30 30 30 28
3620 35 33 32 30 28 26 24 19
4000 35 33 32 30 28 26 24 19
4520 33 32 31 30 30 28 25 23
4820 33 32 31 30 29 26 22 18
5000 33 32 31 30 29 25 21 16
5220 39 38 37 36 35 33 30 27
5520 39 39 38 37 36 36 34 31
6000 39 39 39 38 37 36 30 27

High part throttle goes from:
130 150 170 175 180 190
Let me know if these values would be interesting.

Here is the WOT map:
RPM Deg. Advance
800 1
1200 8
1800 17
2400 21
3000 30
3800 30
4200 18
4360 18
4520 22
4800 22
5040 15
5240 15
5480 24
5600 29
5840 29
6200 24

I think we can convert the WOT map, since at WOT we should be right at atmospheric pressure. I will play around with these values when I have a chance. I haven't went for a drive with the car yet as I have just been messing around with idle for now. Thank you for sharing! These are the stock tune timing values right?