Hey all.

I've got a stock(ish) 87 T2 powerplant in my 88 'vert and I've been strongly considering switching to a megasquirt instead of the N332, especially since they started doing ignition. Engine is internally stock except for S5 rotors and CWs; Turbo is S5 so no twin scroll solenoid. It has a cat and a sane exhaust. I've got an HKS EVCIII monitoring boost although not controlling it right now - it's steady at 6 psi.

I've messed with fuel-only MS before, I had one of the first FBs running MS with a TBI unit from a Chevy Blazer on an adapter plate. So I'm familiar with that part of the MS.

Anyone running this on a S4 car:
1. Are you still running the thermowax or using one of the fast idle solenoids to do cold idle?
2. Running the ACV or an electric emissions pump?
3. Doing the staged injectors with differently sized injectors? (I've got all 4 550cc now, I have a set of 720s I was going to put in there).
4. My injectors are low impedance. Stock ECU uses the resistor pack. When I had messed with the PMW control before I wasn't terribly happy with the results. Any thoughts?
5. Looks like I'd need to keep IAT, CLT, MAP, and O2 as well as the CAS input for spark. Anything else?
6. Doing launch or traction control with the ECU?
7. Which is the better ECU to start off with, V2.2 or V3?

I'm looking for maximum on/off transition drivability, not max power. This car is about half time daily driver. I just want to be rid of the 3800 hesitation, the AFM issues with starting it, and ditch the stock (crap) wiring harness. It's more patch than original wire now.

I'm also wondering about the wisdom of using an old ECU for the housing, and making more or less a replacement for the stock harness with aircraft wire and what connectors I can get - as opposed to ditching it all and using the normal DB37 flying lead harness.

 

The ms can control the BAC valve... I've still got the thermowax on mine, but only because I have not gotten around to taking it off.. I still have the MS controlling the idle speed once warm.

Nope, you might be able to do this with one of the spare outputs, but I've removed and blocked off all of my rat's nest stuff.

This is easy to do, and I've done it before. There are several people doing this. With ms1 you just enter the correct scaling factor, with ms2, you just enter the sizes of your primaries and secondaries.

Stick with the resistor packs. It's possible in ms2/extra (2.0 betas only) to control the PWM settings per injector bank, which you'd need to do with different sized injectors, but I prefer to just not mess with it unless the primaries are so large that they actually *need* peak and hold control to get the better opening time.

The MS has it's own MAP sensor, so you wouldn't need that... for O2 I'd recommend a wideband controller and sensor.

Both ms1 and ms2 support launch, although I don't know who's using them on rotary engines...

Only the ms1 supports traction control, and it's a very simple algorithm... I don't know of many people using it for any car, let alone the rx7

2.2 is easier to build, but the v3 is more robust, and contains a built-in VR signal conditioner.

The main thing to be wary of is that you must have good grounds for the MS to work reliably. I say that because one of the common causes of the 3800 rpm hesitation is bad grounds. The MS will have all sorts of problems, mostly related to the VR sensors in the CAS if you don't do a good job grounding everything. The stock ground setup works well for me with cleaned-up ground-points to the chassis and starter.

Some people have done that successfully.

Ken

 

I was planning on using the BAC valve for warm idle, I was wondering about cold idle. I'd like to ditch the coolant lines to the TB, and I figured in order to do that I'd need one of the AWS valves left on there. Will the newer MS boards support both cold idle and regular idle control? Alternately, does the BAC have enough command authority to get the idle up to 1k or so when cold?

When you say MS1 and MS2, you're talking about the chip difference, right? Not code or a board revision?

I don't like having the Map inside the box, so I mount it remotely. Since the outputs from the stock T2 MAP and the PCB-mount one are similar, I was going to use the sealed/weathertight one (ie, oem). All that should change would be the load bins in the map. I would use an Innovate to get it tuned, then probably go back to a narrow-band for normal function.

I have a few 2.2s leftover from the MS-on-FB project (I think - they might even be 1.0 boards). I've seen a V3 board in person, not too hard to build. I think I'd like to start from scratch.

I've already done that in a quest to make the stock ECU work better. 4 gauge from battery to chassis, chassis to engine, and negative to starter bolt. Also cleaned and grounded the ECU grounds inside the footwell.

So a v3 board with some mods would seem to be the ticket. What code should I be running for both staged injection and rotary ignition? Squirt-n-spark extra?

 

It has more than enough authority to get the idle up to 1k cold.


the ms2 is a daughterboard that fits where the ms1 chip would have. So it's really a chip difference AND a firmware difference. MT is the same, but configured with different settings in its ini files.

You'll have to recalibrate for the MAP sensor then, and I'm not sure anyone else has done that with that MAP sensor. That means you'll have to measure kPa vs voltage if you want the displayed kPa to be anywhere near reality.

Some of that might be the *cause* of some of the problems you had running the stock ECU. The stock ground points are not only adequate, but recommended... You just need to clean them up. When you start running wires all over the place, you can end up creating things like ground-loops, etc... which cause problems that are difficult to nail down.

Depends on which processor you go for. With ms1, you'll want the latest ms1/extra firmware. With ms2, you'll want to either go with ms2/extra 1.0.2, or wait a week or two and go with ms2/extra 2.0. The mods between ms2/extra 1.0.2, and ms2/extra 2.0 are slightly different if you're going to run a stock CAS.

MS2 basically just gives you easier configuration, more fine-tunability, and a smoother running engine (on my GXL, ms1 runs fine, but a bit rough here and there... ms2/extra on the same engine feels as smooth as my stock rx8).

Ken