Thoughts guys...4.09:1 gears or the FRPP Power kit for my 2020 Mustang GT PP1 manual

[Dave2013M3]

Just do both.

Oh I plan on it...

Can only do one for now.

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[PPstang]

Guess I’m a little confused. Did they change the ratios on the Getrag that much between 2015 and now? Mine is a 2015 PP1 and I have the FRPP2. I noticed a good difference in the power, but have always been disappointed in the transmission gearing as 1st always feel like a granny gear. Hard to keep traction and then it’s already time to shift to second.

 

[Dave2013M3]

Guess I’m a little confused. Did they change the ratios on the Getrag that much between 2015 and now? Mine is a 2015 PP1 and I have the FRPP2. I noticed a good difference in the power, but have always been disappointed in the transmission gearing as 1st always feel like a granny gear. Hard to keep traction and then it’s already time to shift to second.

Huge difference, the new gearing in the D4 Getrag basically neutered alot of the power advantage from a the Coyote 2 to Coyote 3.

 

[PPstang]

Huge difference, the new gearing in the D4 Getrag basically neutered alot of the power advantage from a the Coyote 2 to Coyote 3.

Now I understand the references to D3 and D4. Thank you, didn’t know!

 

[Brazos609]

Now I understand the references to D3 and D4. Thank you, didn’t know!

Well, not really. The post on page 1 where refers to D4 that is for direct 4th, the 1:1 gear ratio in the MT82D4. D3 is incorrect as there is no direct 3rd version of the MT82. He meant D5 to refer to the direct 5th 1:1 gear ratio of the MT82.

 

[Dave2013M3]

The ratios are actually much closer with the MT82 than the MT82D4, here are the ratios.

MT82

• 1st - 3.66.
  
• 2nd - 2.43.
• 3rd - 1.69.
• 4th - 1.32.
• 5th - 1.00.
• 6th - 0.65

MT82D4

1st - 3.24
2nd - 2.10
3rd - 1.42
4th - 1.00
5th - .81
6th - .62

As you see the torque multiplication on the 2015-2017 MT82 is quite a bit more than the D4.

 

[Elp_jc]

For street use, the D4 on my Bullitt (with 3.73 Torsen) is just about perfect for me.

 

[Mikepol2]

Dealer quoted me $1100 which included 2hours for the computer re-flash (which may or may not be needed). Installing ring and pinion properly takes some finesse and effort but that seemed high to me. How much have you guys paid for this job?

Not sure why they said you need a computer reflash. After changing mine to 4.09's, no computer work needed and the car reads the correct mph. But if $1100 includes all the parts that's probably a decent price. There's a lot of labor to remove the differential to be able to get to the gears. The guy who did mine is a Ford service writer and said most of the labor cost is the diff removal and reinstallation.

 

[PPstang]

Well, not really. The post on page 1 where refers to D4 that is for direct 4th, the 1:1 gear ratio in the MT82D4. D3 is incorrect as there is no direct 3rd version of the MT82. He meant D5 to refer to the direct 5th 1:1 gear ratio of the MT82.

Thank you! Now I know the difference. I realize this bucks the trend, but I wish I had the new ratios.

 

[Brazos609]

Thank you! Now I know the difference. I realize this bucks the trend, but I wish I had the new ratios.

I have to ask why. With the MT82D4 the gears you want to be closer ratios, 1st through 4th, are spread wider than the MT82 and the double overdrive gears are close ratio, which is pretty pointless. Out of the MT82, the Calimer/GGforce level 3 rebuilt MT82, the MT82D4, and the Tremec TR3160, the TR3160 has the closest and most usable ratios.

RPM drop between gears, regardless of what RPM you shift at

MT82D4
1st to 2nd 35% 2nd to 3rd 32% 3rd to 4th 30% 4th to 5th 19% 5th to 6th 23% 4th to 6th 37%(double overdrive)

MT82
1st to 2nd 34% 2nd to 3rd 30% 3rd to 4th 22% 4th to 5th 24% 5th to 6th 35%

Calimer/GForce level 3 MT82
1st to 2nd 34% 2nd to 3rd 30% 3rd to 4th 22% 4th to 5th 21% 5th to 6th 39%

TR3160
1st to 2nd 31% 2nd to 3rd 28% 3rd to 4th 23% 4th to 5th 19% 5th to 6th 37%

 

[kz]

Thank you! Now I know the difference. I realize this bucks the trend, but I wish I had the new ratios.

You don't - my '18 with 3.73 feels slower than '15 with 3.55 - and I jumped from one directly into the other so had a direct comparison. at least 1st and 2nd are too tall. Which is why OP in this thread wants 4.01.

 

[Dave2013M3]

Thats the whole point of the 4.09 gearing it gives you some of that torque multiplication back...some of it. The Gen 3 Coyote has a wider and longer power curve that the Gen 2 so it would just be a win/win situation.

 

[MRGTX]

Not sure why they said you need a computer reflash. After changing mine to 4.09's, no computer work needed and the car reads the correct mph. But if $1100 includes all the parts that's probably a decent price. There's a lot of labor to remove the differential to be able to get to the gears. The guy who did mine is a Ford service writer and said most of the labor cost is the diff removal and reinstallation.

This is great to hear.
I agree about the price if it includes the parts... but I don't believe that it did.

The local repair shop that rebuilt the beleaguered 7.25" rear axle in my Dart (it has long since been replaced by a 8.75" with a torsen style limited slip..thank God), that has been doing drivetrain work since the 1970s at least, quoted me $700 with "no computer stuff or anything like that..." ( ) The owner is a curmudgeon but a cool guy who runs a good shop.

So before I pull the trigger... does anyone disagree that the computer does NOT need a reflash to function properly with the new ring and pinion? The stealership thought that it would.

 

[Superspirit]

You will need to change the ratio in the pcm to make it work correctly. That can be done with forscan. It's a simple procedure with a laptop and a forscan approved cable.

 

[Mikepol2]

You will need to change the ratio in the pcm to make it work correctly. That can be done with forscan. It's a simple procedure with a laptop and a forscan approved cable.

To make what work correctly? The speedo automatically adjusts without any programming.

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