Torsen gear ratios

[GigaHz]

What are the available ratios for the torsen? Do you only get a torsen with the PP?

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[Black6gGT]

3.73 and yes

 

[ilkhan]

Torsen is only on the GT/PP, so 3.73 only.

 

[GigaHz]

Will other ratios fit in it?

 

[foghat]

Will other ratios fit in it?

Yes.

 

[GigaHz]

What are the other ratios?

 

[Schu]

ratio... or final drive?

 

[GigaHz]

3.73 is one. What else is available?

 

[DJGold]

3.73 is one. What else is available?

http://www.ebay.ca/itm/OEM-NEW-Ford...Parts_Accessories&hash=item3f4709c63c&vxp=mtr

Here's one for sale for 2015 Mustang and if you look lower down in the add it says you can reuse 3.31, 3.55, or 3.73 gears.

 

[esacteksab]

A car with 3.15's will need gears _and_ torsen?

 

[Grintch]

The Ford Racing site says the Torsen diff (M-4204-MT) -
"Fits 2015 Mustang GT, V6 and I4 with 3.31, 3.55 and 3.73 ratio gears only".

I am not sure why it wouldn't work with any of the 8.8 final drives.

 

[EXP Jawa]

The Ford Racing site says the Torsen diff (M-4204-MT) -
"Fits 2015 Mustang GT, V6 and I4 with 3.31, 3.55 and 3.73 ratio gears only".

I am not sure why it wouldn't work with any of the 8.8 final drives.

Simple. There are two cases for the Super 8.8" axle - one for high numeric, one for low numeric ratios. This practice is common in axle design, though Ford never used it before with the 8.8". However, this axle is pretty far removed from the 8.8 of old. The cars that have lowest numeric ratios have a different ring gear flange position, so they require a specific differential case. The Torsen is only made for the higher-numeric ratios, 3.31:1 and up. If someone has a car with a ratio numerically lower than the 3.31 set, they'll have to also change to a higher numeric ratio to allow the Torsen to be added.



FWIW, the reasons for splitting the ratios up is also pretty simple, if you stay with me here. As R&P ratios go up (numerically), there are typically some combination of more teeth on the ring and fewer on the pinion. Fewer pinion teeth means the diameter of the pinion head decreases, and that means that the ring gear has to reach over farther to mesh with it. The consequence is that ring gears get progressively thicker as the ratio goes up.

The manufacturer will tolerate this to a point, but if the spread of available ratios is wide enough (say, from 2.74 on one end to 4.10 on the other), then the difference in thickness is a lot. Since the ring position is determined by the biggest pinion head (on the 2.74:1 gearset), the ring gear in the 4.10 set has to carry a lot of extra mass to fill in the gap. So, at that point, they might elect to tool two different diff cases, which have two different ring gear flange positions. This allows them to split the range of gears, and minimize the thickness across the line. Other axle manufacturers (Dana, for example) have always done this. Ford, less so. But in this case, that is what they choose to do.

 

[marcoinpb]

Am I the only one that would really prefer a 3.55 rather than the 3.73 on the PP. the mustang 6th trans gear is also low making me wonder if the 3.73 is going to be not a great choice. Any opinions? Thanks

 

[OzS550]

Our Australian Mustangs will all be PPs with non-Torsen 3.55 LSDs.

I think the ratio will be a good choice but we're getting short changed not getting Torsen.

 

[GigaHz]

I would like the 3.31 with the Torsen. What is the normal Mustang limited slip? Does it have clutches instead of a Torsen?

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