2019-up 4.09 Rear Gear Swap

TnWHTMARE

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Dave2013M3

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Dave2013M3

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Did you get her back? If so...wellllll?

Shop got backed up and needed a different crush collar. Won't get it back until Monday. :(
 


paulmustangv6

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2020 Manual Euro GT here, I'm going to switch to 4.56 soon. Swapped from factory 3.55 to Torsen 3.73, feels little bit better but due to long geared MT82D4 still weak at low revs, so I hope with 4.56 will be better. Street use, no tracking. Hope I can mod with Hptuners / Forscan, (that if needed) if not, I will order a tune... here in Europe we have few modding opportunities
 
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NeverSatisfied

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2020 Manual Euro GT here, I'm going to switch to 4.56 soon. Swapped from factory 3.55 to Torsen 3.73, feels little bit better but due to long geared MT82D4 still weak at low revs, so I hope with 4.56 will be better. Street use, no tracking. Hope I can mod with Hptuners / Forscan, (that if needed) if not, I will order a tune... here in Europe we have few modding opportunities
when you get 4.56 to work in a rev match car please let us all know how you do it!
 

K4fxd

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If you tell the PCM through HPTuners and the BCM through forscan, I think it should work just fine.
 

NeverSatisfied

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If you tell the PCM through HPTuners and the BCM through forscan, I think it should work just fine.
Sounds good in theory. i have yet to see someone successfully exceed 4.09 in a ‘19+ car.
 

Dave2013M3

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Well it's Tuesday, do you have it back yet?

Where do I begin...car was all buttoned up, they went to the ProCal tool to adjust the gears and the tech try to rewrite the software bricking the ECU. A guy from a local Ford dealer is going to go out and reflash the ECU to stock and then back to the Ford Performance software as I have the Ford Performance Power kit. I am so frustrated. What turned out to be a 3 day job is now into 2 weeks. The tech that worked on the car has way to many projects going on in the shop. Then there was a race the shop had to close as the whole shop is at the F1 Race in Texas.
 

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Where do I begin...car was all buttoned up, they went to the ProCal tool to adjust the gears and the tech try to rewrite the software bricking the ECU. A guy from a local Ford dealer is going to go out and reflash the ECU to stock and then back to the Ford Performance software as I have the Ford Performance Power kit. I am so frustrated. What turned out to be a 3 day job is now into 2 weeks. The tech that worked on the car has way to many projects going on in the shop. Then there was a race the shop had to close as the whole shop is at the F1 Race in Texas.
Damn, that sucks! Another reason I am glad I was able to do this myself, took literally seconds to change the gear ratio with the procal 4. I've flashes hundreds of pcms in my lifetime and have yet to brick one. Guess I've been lucky ( or blessed) I'll take it either way.
 

Dave2013M3

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Damn, that sucks! Another reason I am glad I was able to do this myself, took literally seconds to change the gear ratio with the procal 4. I've flashes hundreds of pcms in my lifetime and have yet to brick one. Guess I've been lucky ( or blessed) I'll take it either way.

Yea, I saw him and I was like "what are you doing?!" He then admitted to me he never used the Ford Performance ProCal before just XCT and the like. I was like than ask!!!

This is an issue thinking you know everything and dont want to ask for advice.
 

Seanuf99

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Yea, I saw him and I was like "what are you doing?!" He then admitted to me he never used the Ford Performance ProCal before just XCT and the like. I was like than ask!!!

This is an issue thinking you know everything and dont want to ask for advice.
That sucks. One of the main reasons I have hesitated on the gear swap is I have only found one shop that I feel comfortable doing the work, but they are 2 hours away. The delay in doing it though, made my mind wander to other mods or swapping cars. Still may do it... I am curious to know how you like them once you get it sorted out.
 

Scootsmcgreggor

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4.3 would have been perfect for me but don't exist, so 4.09 it was. Still I'm surprised some say it wasn't a big difference, really made a difference for me. Gearing used to be so long it wasn't much fun despite the power, but now gears are short enough that there's not only more torque but also I get to shift more which is more engaging which is more fun.

My only complaint now is that 4th gear is still too long, feels like the car loses 50hp relative to what it should be in 4th gear, but there's nothing the rear end could do about 4th alone. If you go 4.56 4th is way better but then 1-3 are too short IMO.
 

 
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