Magnum XL wiring

[1ChillBoss]

Hello fellow Boss owners I have a question about the wiring on the my T56, I finally got it installed but i can'f figure out the 3 to 2 wire conversion, or find a diagram anywhere. If any XL owners chime in it would be greatly appreciated.

 

[Berol]

Do you have the appropriate conversion box?

 

[1ChillBoss]

Yes I do

 

[DaveW]

Old thread - I am converting my '12 S197 to T56 and being Covid times, everything is on backorder, including apparently the wiring harness adapter. I just tried to order one from Modern, but I bet it is on backorder too....Lethal kind of let me hanging by not telling me the harness was on backorder when I ordered the kit

I have an event in two weeks so I am trying to figure out plan B just in case. Is the speed sensor wiring on the transmission the VSS that the computer needs for the car to run, or is it for speedometer and cruise functions? If it runs ok without this hooked up and only the speedo doesn't work, then I really don't care for now, the car is rarely street driven.

Or other ideas to make it work? I see mention of hooking the T56 sensor to the wiring and using the tune to adjust the different number of pulses, but that seems sketchy.

Thanks,

DaveW

 

[Cobraaph]

Have you looked at this? https://lmr.com/item/LRS-85656/t56-transmission-sensor-connector-pigtail-kit I bought this for my T-56 (non-magnum) but have not installed it yet (trying to connect into harness for T-45).

 

[DaveW]

Have you looked at this? https://lmr.com/item/LRS-85656/t56-transmission-sensor-connector-pigtail-kit I bought this for my T-56 (non-magnum) but have not installed it yet (trying to connect into harness for T-45).

I just did, but I think there is also some sort of conversion box needed as well (for the speed signal). Here is the description that I found, doing it without the box sounds sketchy....

Mustang GT MT82 to T56 Magnum XL swap - info to fill in the gaps. | SVTPerformance.com

DaveW

 

[67GTA]

@DaveW, take a look at the attached instruction sheet for the Bowler all-in-one harness if you haven’t seen this already. This is likely the harness that you’re trying to get, and it’s the same one I used on my conversion from Modern Driveline. Page 3 is a good description of the wires and their purpose, and page 10 is where the specific S197 MT82 conversion information is. The Tremec VSS puts out 12 pulses and the ECM needs 36 to match the output of the MT82. Now I still think the biggest function this provides is a working speedo, however I’ve never found a clear answer on this and still feel like the VSS signal is feeding other systems. Cruise control won’t work until the trans gear ratios are updated in the tune - best explanation in the Bowler doc.

Since the Bowler unit is out of stock, I’ve heard of others using a Dakota Digital conversion box to convert the pulse count. This may be a decent stop gap to get you through your first few track days, but I would highly recommend installing the Bowler unit once its available for the reverse light functions and Bluetooth capability.

https://www.bowlertransmissions.com/wp-content/uploads/2021/01/All-in-One-Harness-Manual-010521.pdf

https://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=1192/mode=prod/prd1192.htm

 

[Equinsu]

Definitely get the Bowler harness if you can hold out. It has worked perfectly for over two years now on my T56 and I've always made sure others get it if I do their Tremec install. Everything said above from the post above by 67GTA is right on. The biggest issue being for the pulse output conversion.

 

[DaveW]

I think I lucked out, Modern Driveline had one in stock and it shipped to me today. Which makes me feel bad that I just didn't order the whole package from Modern as Lethal has been not terrible, but not great.

DaveW

 

[DaveW]

I think I lucked out, Modern Driveline had one in stock and it shipped to me today. Which makes me feel bad that I just didn't order the whole package from Modern as Lethal has been not terrible, but not great.

DaveW

So I think I inadvertently answered the question on whether aS197 *needs* the speed signal but putting the wrong signal pulse number in the Bowler setup and the car ran but limited itself to a certain low speed.

DaveW