I've been following along here and at the MS forums, muthaiboxr, you rock! So I wanted to ask you advice, on a car that won't have to go through emissions checking, and is not a daily driver, should I go with the MS1 or MS2?

I know you've done a lot of work on the trailing, but your last response on this thread, https://www.rx7club.com/megasquirt-forum-153/megasquirt-s5-2nd-gen-fully-stock-ignition-works-455340/
seems to me that I should go with the MS2 for my application.
"I'm not even sure why mazda put trailing on there because it sure as heck didn't help power on tofuball's car... at full throttle it seems it didn't make any difference at all (at least on the "butt dyno")."

I'm planning on a lot of overlap and maybe a big turbo. So I believe that I'll need larger injectors to idle well (not a daily driver but still a "street" car). With the MS2's injector resolution, I think this will be OK.

I'll lose decoder wheel capability right? What's the other alternative, EDIS?

Thanks,
Owen

 

What I'd do is run stock primary injectors, and use bigger secondaries, and do this with msns-extra. My main reason for this is because ms2 also doesn't have staged injection, so you'd have to use the dual table code, which is a bit hard to tune (although it produces good results once you tune it).

You'll probably idle fine on stock primaries as long as you set the idle advance right (I'm working on code that'll allow a separate idle advance from what's in the table since the rotary seems to like idling at 5 ATDC, but the next spot over from idle in the map is like 20 deg BTDC), and run it fairly rich.

Later, when I (or someone else) get to writing the ms2 code, you can always upgrade to the MS2.

To directly answer your questions, there isn't a wheel decoder in ms2, so you'd want to probably use mike_robert's old HEI mod (cut all but 4 teeth from the CAS, and wire everything up with a GM HEI module. tofuball and I ran like this for a while before moving to stock leading) if you're going to run ms2.

But like I said, I'd run msns-extra on an ms1 chip, and use stock primary injectors, and then just cut in the secondaries as soon as the primaries get to a higher duty-cycle than you're comfortable with.... that'll allow you to have decent control of the idle AFR, and still have big enough secondaries to get the amount of fuel you need once you rev it up.

 

Hmm, that makes sense. I didn't know about the lack of staged injection, that's a big requirement for me.
Thanks again!
Once I get moving on this, I'm sure I'll be bothering you a lot more...so let me apologize now!
Owen

 

haha no problem... that's what the forum is here for. Hopefully if I answer your questions, people will USE THE SEARCH instead of starting new threads. (Not referring to you because your question was unique, at least on this forum).

 

Just trying to stay caught up here. My understanding is for rotary engines wanting leading and trailing I can,

1. Use V1 or V2 boards and use a daughter card, error*s or Renn's dual lm1815

2. Use a stock CAS with two teeth cut off

3. Use the V3 board's internal VR and add a single lm1815

Is this correct? I'm starting from scratch so the V3 board would be my choice.

When you do your write up, definitions or links to them of the different major components would help. I only know what the lm1815 is, what's a VB921, etc etc???

Thanks,
Owen

 

I don't know if anyone's used the v1 board, but the v2.2 board is alright. You're also correct about the options for the dual lm1815/daughter card.

The point of the dual lm1815 is that you don't need to cut any teeth off the stock CAS. You just use the CAS the way it is.... Cutting off 2 teeth is an option for those who only want to use a single vr sensor conditioner. For example, if you want to use the v3 board with its built-in vr sensor conditioner, and you don't want to build the lm1815 vr sensor conditioner in the proto area, you can just cut 2 teeth off the Ne wheel, and use that. That's what pmrobert is doing I believe.

correct

In my opinion, yes that'd be the best way to go, as it's a much more robust board than the 2.2 board. That said, the 2.2 board works fine, so if you want to save yourself some money, you can also do that.

Well, most of the rest of the components are just resistors and capacitors and jumper wires.... in fact all of them are. A vb921 is just a transistor that's meant to switch fairly high-current devices. People use them in the megasquirt to directly drive ignition coils. It's not necessary to use one for an installation using all-stock mazda parts.

Ken

 

Thanks again! I think I will go with the modded CAS, one less thing to mess up in the MS build :-)
Owen