Learn me- megasquirt differences.

For my Celica with the late 22re (vast ignition). Mainly trying to decide between ms1 v2.2, v3, or ms2. I want the following: delete air flow meter, control air/fuel (duh), retard ignition for boost, low impedance Honda injectors. Nothing fancy! I repeat, no fancy stuff, no frills. I don't need traction control or two step, crank trigger wheels, or etc.

Which is why I don't believe I need ms2. This will eventually be a low boost, high comp motor. 7psi max. Maybe 14 after a full rebuild.

So. Learnt me mega-yodas.

I actually just wanted to know this myself and diyautotune has a good comparison on their site. From what I know you can get away with ms1 but ms2 is likely worth the extra cash.

You don't NEED MS2. But you want it.

Low impedence injectors are a pain on either MS1 or MS2. I would suggest finding high impedence injectors that will work.

A brand new (assembled) MS2 is $279, how much of a cheapass are you?

Definitely v3. Swank is right about ms1 vs ms2.

Microsquirt may be an option.

Just reading up here: http://www.megamanual.com/ms2/vast.htm looks like microsquirt could work well. Just need to source a map sensor. The one from the v2.2/v3 boards would be the easy button.

Definitely ditch the low-imp injectors.

calteg wrote: A brand new (assembled) MS2 is $279, how much of a cheapass are you?

No, that's the v3 board kit price.

The cheapest possible assembled ecu is that price, but only ms1/v2.2.

I have a MS1 v3 board running MSnS-extra code on my Datsun turbo conversion. I've been running it for years and the whole thing has been really reliable. I'd say that you can definitely accomplish your goals with a MS1 setup.

I don't know what MS2 provides over MS1 with Extra firmware. If you're not already comparing MS1-Extra to MS2, do. As far as I know, MS1 without Extra is fuel-only.

Swank Force One wrote: You don't NEED MS2. But you want it. Low impedence injectors are a pain on either MS1 or MS2. I would suggest finding high impedence injectors that will work.

I went for years (YEARS years, like 2008-ish to 2014) on MS1 on my RX-7. Then I went to MS2 for various reasons.

MS2 rox teh sox, in the vernacular that I assume the cool kids use. Much more precise, as it measures RPM in single-digit increments instead of 100-RPM increments, does injector pulsewidth to more decimal places than a tenth of a millisecond (tenth makes things VERY granular when you're down in the 1.7ms opening-time range)... I can cruise at 14:1 now wherease with MS1 I had to cruise in the 12.5-13:1 range to avoid lean misfires. (It's kind of a finicky engine)

I have low impedance injectors. I used PWM on my MS1 box until I fried the flyback transistor from too much time near static duty cycle. I hear that was a common problem on the flyback hack on the 1.01 board. It was a LITTLE odd that I had to initially set the PWM to 75% instead of the 25-30% that the Internet said was correct for peak and hold injectors... anyway, I mounted inline resistors and eliminated PWM and kept on truckin'. The MS2 is also set up with resistors instead of PWM for three important reasons.

1. I had enough tuning issues to deal with, without determining what the correct and hardware-friendly PWM was for my new injectors (many Internet searches yielded zero useful info)

2. The car was already wired for resistors, engineering inertia rules the day

3. There is NO.... reason 3

So you can't run imp inj on ms1??? I can run high imp. The later (late late) 22re had high imp inj. I could run some 7m, 2jz, etc then.

One other question- can anyone explain the microsquirt hook up? http://www.useasydocs.com/details/vast.htm

Does this meani have to use a Hall effect? Or is it just saying "if you're using Hall effect- this is what you do"

I'm just using the stock dizzy and ignitor for ignition signal.

Have to see if the innards of your distributor is supported by the ms you choose otherwise you strap a toothed wheel and hall sensor to the motor and crank pulley. Also regarding injectors, because you will be using megasquirt you can use almost whatever injector you want, no sense in sticking to older style pintle injectors when theres loads of 4 hole disk style (ev6) injectors all in the junkyard for the taking, ahem turbo 5cyl volvos ahem.

Based on the link to the VAST ignition setup above, it looked like the VAST module puts out a hall style (square wave) signal you should be able to tap easily for crank reference. Run wasted spark and you won't need a cam sensor, either.

Once you get down to all the things you end up needing over the base board (sequential injector, any sort of real spark support, etc) its almost cheaper to build an MS3 than an MS1. And if you thought the MS2 was better the MS3 is like almost a real big boy ecu. IMO the MS3P is worth the money over all the rest to get the proper powersupply, better circuit design, and really the real electrical connectors instead of those stupid DB connectors.

Trackmouse wrote: One other question- can anyone explain the microsquirt hook up? http://www.useasydocs.com/details/vast.htm Does this meani have to use a Hall effect? Or is it just saying "if you're using Hall effect- this is what you do" I'm just using the stock dizzy and ignitor for ignition signal.

The MicroSquirt is a good option if you don't need a ton of I/O or sequential injection. It delivers many of the extra features of MS2 at an assembled MS1 price. There's an alternate set of documents for it here that many people find a bit easier to use:

http://www.msextra.com/doc/pdf/Microsquirt_Hardware-3.3.pdf

Trackmouse wrote: So you can't run imp inj on ms1??? I can run high imp. The later (late late) 22re had high imp inj. I could run some 7m, 2jz, etc then.

Yes, you can. With resistors and some mods on the board (depending on the version of board you're running) or an add-on board like the Peak&Hold board along with a small amount of board modification:

http://www.jbperf.com/p&h_board/

This board will also work with MS2 (since that is more or less, merely a CPU replacement for MS1)

MS1 is vintage.

MS2 has more features and less limitations.

v3.57 for an out of the box install (surface mount components, can be difficult to mod)

v3.0 for a custom tailored purpose built install with options.

v2.2 ick

MS3 is overkill for a banger.

IMO, MS2/Extra has more features than many "real" computers that run 3-5x as much.

Some days I wish I stuck with being a computer geek. I keep envisioning a CAN add-on box that does drive by wire control.

I'd like to see a dedicated MS3 main board.

Fly_by_wire would be very cool

bentwrench wrote: I'd like to see a dedicated MS3 main board. Fly_by_wire would be very cool

They've said multiple times they wont do it. Really its an H bridge driver and a bit of software away from being a thing. E36 M3, the MS3s have an H bridge driver.

I would prefer that it be a separate controller, myself, so that we don't have to worry about a Toyota stack-overflow fiasco.

The beauty of drive by wire is that you can divorce pedal position from throttle position. You push the pedal down a certain amount to make a certain amount of torque. Maybe the engine is more efficient at making that torque with more throttle and less ignition timing, and when you want more torque than that it changes timing instead of throttle position.

Yeah, we gettin' complicated here. But throttle position to determine engine torque is almost as archaic as determining ignition timing by weights and springs and a vacuum can.