83 Crossfire TA

iTrader: (2)

I have a MS (2, pcb3 running MS2 Extra) in an '87 TA with a digital dash that I'd like to get the VSS signal into so among other things I can display MPH, compute MPG, I would like to trigger things using MPH (like turn off the fans over a certain rpm)...

I keep seeing something like with a MS3 you can just wire the signal in but for MS1/2 you need to add a circuit to convert frequency to voltage, but i can't seem to find any examples or instructions out there.

Has anyone out there done it or know how to do it? Is there a box or circuit I can use to do the conversion? Where/how do I wire it in?

If it helps I'm probalby going to be adding a Dakota Digital SGI-5
http://www.summitracing.com/parts/dak-sgi-5/
to compensate for a gear change, it would be nice to do it all at once if possible.

I'm also working on a TIOx canbus board to add additional PWM outputs for things I want to experiment with, and I'm getting the impression that I can use that to input the signal also, but to be honest, not being the biggest electronics guy I already have my head swimming with trying to work my way around that (though if that is the best way of doing this maybe I should do it all at once)

anesthes

iTrader: (12)

The MS2 doesn't have any frequency based inputs (other than ignition and MAF) that can be used for this purpose. You need to convert the VSS signal into voltage if you want to read it directly using a spare ADC.

I know what you are thinking, use the MAF input since it reads frequency.. Yes it does, but the way the main loop is written in the MS it could be interrupted and as such you would get erratic speed logging. (since a reliable timer is required).

I'm not aware of an 'off the shelf' VSS converter, but guys on the ms-forums have built a small circuit using an LM2917.

If you pick up a Microsquirt for transmission control, and load the e-trans/megashift code, you'll get VSS output for logging/shift logic. The Microsquirt will communicate over CAN with your MS2, so Tunerstudio will show everything in one place AFAIK.


The other option is to get a CAN based VSS/speedo/gps. Link it to your MS2 via CAN BUS, and the speedo will show as an extended i/o input in tunerstudio.


I was originally going to make a LM2917 based VSS to voltage converter and stick it in my ECM case, but then I realized I don't need VSS in my logs, that I have no tuning conditions that are speed related since I'm running a non-lockup TH350, and my converter is so loose I don't need a throttle follower.

If I decide to go e-trans eventually, I'll go the microsquirt route.

-- Joe

-- Joe

83 Crossfire TA

iTrader: (2)

Huh...

So megashift would get that info into my MS via can bus? I wonder what I could sell a new in box TCI box for... and if I can get my hands on the correct connector for a 4L80e (the JY's around here SUCK). What scares me about this is I keep hearing how atrocious the megashift forums, support/info is.

I'm actually very surprised that no one seems to make an aftermarket conditioning/buffer box that outputs 0-5VDC.

83 Crossfire TA

iTrader: (2)

Barring going megashift, what I was thinking about doing is grabbing the signal (I'm not sure if before or after the factory conditioning box, so far I think it's an AC signal 40x/driveshaft revolution before the box and 4000pulses per mile after the box), and trying to find a commodity frequency to voltage converter that will work or build something (unless I'm badly mistaken with my math it looks like I'd need something that could read about 0-6000hz before the box or about 0-250hz after the box (in both cases should be in the 200some mph range) and convert it to 0-5VDC and then get that into the MS...

I'm really surprised that it looks a lot like no one has done this (at least and documented it) and that there isn't an off the shelf part to do this.

83 Crossfire TA

iTrader: (2)

megashift question (running options around in my head)- it looks like it can be used to replace the conditioning box and drive my spedometer.... is there any issue with putting it in there, using it to drive the speedo and get the VSS input into the MS but not controlling a transmission with it (use it with the T5 that's in there till I finish the 4L80e and have time to swap it)?

anesthes

iTrader: (12)

Well, like megashift. I'm actually endorsing:

https://www.thirdgen.org/forums/tran...crosquirt.html

Which isn't exactly "megashift", but if I said something else you wouldn't know I meant using a Megasquirt/Microsquirt.

I don't know enough about how other vehicles do the VSS. I know on most GM's it's a AC wave.

I believe a MAF converter (with minor mods) would work.

https://www.thirdgen.org/forums/dfi-...t-voltage.html

I started thinking about this back in 2012, but I lost interest. If I had kept the manual trans in the car, I'd probably want to use VSS for DFCO and maybe a throttle follower/stall saver, but then again nobody else does.

-- Joe

anesthes

iTrader: (12)

So again, I'm talking about using the Micro shift firmware not the actual Megashift, but the Microsquirt ($299) will take a AC signal. (it has to, otherwise it wouldn't support a dizzy). When loading the transmission firmware, the main timer loop doesn't have an interrupt so it's reliable for VSS measuring.

One could re-code the main loop on MS2 (they did, MS3) but it would be a lot of work just to read a frequency based VSS.

To answer your question, yes you can use a Microsquirt to grab the VSS signal and display it in tunerstudio. It doesn't have to control anything. But $299 is a lot of money for a VSS decoder unless you do actually use it eventually to control an E trans.

I had a schematic to do a frequency to voltage conveter for like $20 in parts.. I'll have to dig it up.

I'm going to run the TH350 this season, but do a e-trans next year. I can program WOT shift points and the MS will shift a heck of a lot faster than I can.

-- Joe

83 Crossfire TA

iTrader: (2)

Well, I do actually have a 4L80e, a PI 3 disk clutch converter for it and a TCI box sitting in the garage for it... I plan on dropping it in, I just don't need it yet and don't really have the space to do it right now...

Yea, it would be a very expensive way of doing what I want to do with it right now, but the car will be setup for the 4L80e when I get to it and I'm wondering if it will be cheaper in the long run... (though I'm not convinced that I'm going to do this or find a cheaper short term solution)

I guess what I'm not sure about right now is will the second Mega_____ connected via CAN bus to the first be programmable/tuneable through the first one (like will I be able to just plug into my MS and tune my engine and trans) or will I have to plug into that second box separately to tune it?

I'm assuming that I can plug in multiple CAN bus devices, right? I haven't looked into it but that is the point of a bus...

anesthes

iTrader: (12)

You cannot program the TCU (trans controller) while connected to the ECM. They can share data via CAN (Tps, map, mat, vehicle speed, etc) but you cannot change the logic on either device from the other device.

You can plug in multiple things on the CAN bus, like guages and such.

-- Joe

83 Crossfire TA

iTrader: (2)

Huh (wheels turning)...

I can't seem to find anything about connectors, is there a connector standard? it seems like a couple of MS sites show a sterio audio connector, but I'm not seeing any of that just doing a search (just twisted blue and red wires). How do you chain/loop more than one device?

anesthes

iTrader: (12)

For the micro? Yes, a ampseal connector. You can buy the 12" one from diyautotune which comes with the small headphone jack for tunerstudio.




-- Joe

83 Crossfire TA

iTrader: (2)

I meant for CAN bus.

between being tired when I skimmed through the trans control pdf and posted some of this stuff and leaving words like CAN bus out of the posts I think I made myself look like a tard... :-/

83 Crossfire TA

iTrader: (2)

Not that I'd so something as crazy as order a microsquirt just to got a vss signal into the megasquirt... Of course, if you look at some of the other parts and some of the other things I've mentioned I'm working on for the thing...




What's the first thing you would do if you were presented with a neat little package?

anesthes

iTrader: (12)

Hah. That stuff is so cool isn't it.

I was thinking of putting a microsquirt on my boat. Might be a good project for next year.

-- Joe

83 Crossfire TA

iTrader: (2)

Yea, I figured that I'm at about 90% sold that I'll end up doing this for the 4L80e, and if not, well I'll likely use the micro in my '71 Mach 1, so it's not a loss either way. I feel like 'Squirting everything

I don't know, for some reason I am leaps and bounds happier with 'Squirts than I ever was with tinkering with GM ECM stuff (which I honestly hated)

anesthes

iTrader: (12)

It's like an Iphone vs a rotary phone.. Both make phone calls, but one makes your life easier.

-- Joe