bcrx7

iTrader: (5)

Since I ended up installing the MS3/3x I had on an ITB sequential Ford engine, I will need to purchase a new one and the MS3Pro is looking mighty good. Anyone here has ordered one yet? Experiences?

18psi

iTrader: (76)

Brain has one
Joe has one

bcrx7

iTrader: (5)

I thought Joe was playing around with it on the bench. I wonder if he has it in the car yet.

18psi

iTrader: (76)

its in his car.

his timing thread is a direct result of it being in the car

bcrx7

iTrader: (5)

I guess I need to pay more attention, eh?

18psi

iTrader: (76)

LOL I spend way too much time on here

bcrx7

iTrader: (5)

Didn't want to say anything... haha

Joe Perez

iTrader: (8)

Haha.

Yeah, I've been running it in the car since last November- so far as I know, mine was the first Miata with the MS3P installed. And it's a great box.

This was also my first MS3 in general, so a bit of a learning curve there. I'm still coming up to speed on some things, and the fact that the code is still changing makes life interesting. I recently upgraded from the pre-1.2 alpha 2 code to the "stable" 1.2.0 release, and as soon as I did, my idle (which had been rock-solid) started oscillating just a bit. So little **** like that is still cropping up, but on the whole, I have no complaints.

bcrx7

iTrader: (5)

That's good to hear. No issues with sync losses and such though. Idle I don't care too much about since it's going in the race car and no idle valve. But good to know.

Joe Perez

iTrader: (8)

Nope, that's one thing they really got right on the MS3P. It uses a MAX9926 IC as the signal conditioner for the crank / cam, similar to what I built several years ago with my crankwheel setup. It's been rock-solid for me thus far.

Braineack

iTrader: (62)

I've been running it since Jan, but I've been running ms3 since it came out in march of 2010.

bcrx7

iTrader: (5)

Have you guys been using the knock system at all? I guess Joe is N/A and Brain is turbo, right?

Braineack

iTrader: (62)

no, i dont have a knock sensor yet, but I prewired my harness to accept one easily. lol.

Scamby

What is the difference between the VR conditioner on the standard board vs on the MS3pro?

What I want to know if there is a significant advantage or benefit between them.

I got the standard MS3+MS3X box and besides adjusting the pots and the pullup resistor at first, so far no issues of sync loss all the way to 8000 RPM.

I was considering to sell my MS that I got to buy the MS3Pro. But unless is there a real advantage to justify the switch (besides the AMP connectors).

Joe Perez

iTrader: (8)

1: The MAX9924/9926 chip (used on the MS3Pro) has a differential input(s), rather than a single-ended (unbalanced) input on the VR circuit of the regular mainboard. This is of interest only to those using actual VR sensors (which tend to have balanced outputs), an in those cases it significantly increases immunity to common-mode noise.

2: The 9924/9926, in general, seem to have better immunity to false-triggering. This is contingent, in part, on the design of the filter circuit which is implemented by the board designer around the IC.

3: The 9924/9926 are inherently auto-setting for threshold and hysteresis, rather than requiring fixed values to be set via resistors or trimpots.


All in all, if you already have an MS3/X, and it is working reliably for you, it is probably not worth spending the money to upgrade to the MS3P. If you are building a new car, or have been experiencing chronic problems with the MS2/3/X inputs circuits (as 949 Racing had been when using NB sensors) then the MS3P is a very nice box if you can afford it.

Scamby

So because I am using the OEM CAS (which is a Hall effect sensor) it will make no difference based on what your saying. The advantage will be if you are using a VR sensor.

But I was reading in the MS3 pro manual that you have still to put a pull up resistor in the CKP cable if you want to use the OEM CAS or any other hall effect sensor.

I though that with the MS3Pro you can setup the pull up via software like Haltech. I was guessing with that new VR board on the MS3Pro will be the same but it is not.

Thanks for the clarification.

Joe Perez

iTrader: (8)

Or if you are using OEM (or OEM-style) hall / opto sensors and find that you are having difficulties with noise, false-triggers, low thresholds, etc. As an example, on my very first MS (an MS1 on my '92) I had infrequent but persistent misfire issues due to loss-of-sync on the stock CAS, and none of the common cures helped. I used this as an excuse to fabricate a whole 36-1 crankwheel setup for the car, although I could have saved a lot of time just by implementing a circuit such as this. And for the past several months, 949 Racing has been having problems with the OEM cam sensors on NBs getting flakey when they become heat-soaked during a race. They don't fail totally, they're just experiencing a degradation in their output which is enough to cause problems with the old-style MS input circuits. A well-filtered circuit with good noise immunity and hysteresis overcomes this problem.


Correct, the MS3P is universal in nature. If you want to use it with open-collector sensors, a pullup is required. I believe that they supply these as standard with the production-level units, as a little "pill" that is spliced into the wiring.

They certainly could have implemented a soft pullup, by using one of the MS3's general-purpose output pins to drive a pair of transistors to gate the pullup voltages. I think they made a better decision by not wasting an I/O pin for this. It's something that only needs to be touched once, at the same time that you are assembling the rest of the harness.