Auto Diff swap 3.46 in MT 135i

500AF · 05-09-2018, 06:55 AM

The MT has 3.08s in it. I am pretty sure you can put the auto trans diff in it which has 3.46 gears . The only difference is the gears.

Is this possible, has anyone done it?

The MT has 3.08s in it. I am pretty sure you can put the auto trans diff in it which has 3.46 gears . The only difference is the gears.

Is this possible, has anyone done it?

wu2x · 05-09-2018, 04:30 PM

Yes it is possible, but make sure to look into the diff housing sizing before doing it. http://www.vacmotorsports.com/news/3...483338466.html

ShocknAwe · 05-09-2018, 06:26 PM

You can, but you'll have to swap the diff and final drive to a large MT pumpkin. Also worth noting most MT 135i diffs are welded, not something you can do in your garage.

As for 3.46 on a MT car, not sure why you would want to do this as it will actually make you slower.

YearOneOne · 05-10-2018, 06:23 AM

Quote:

Originally Posted by ShocknAwe

You can, but you'll have to swap the diff and final drive to a large MT pumpkin. Also worth noting most MT 135i diffs are welded, not something you can do in your garage.

As for 3.46 on a MT car, not sure why you would want to do this as it will actually make you slower.

And the added torque do you really want that when keeping the tires happy is already a problem

lowbudgethero · 05-31-2018, 05:00 PM

I have it, it's fun

500AF · 06-05-2018, 10:23 AM

Quote:

Originally Posted by lowbudgethero

I have it, it's fun

How fast does 1st and 2nd gear wind out?

Big Mexican Women · 06-08-2018, 06:45 PM

BMW does a really good job fitting the appropriate final drive ratio into their cars and tuning all the gear ratios to precisely match the power delivery of the engine. if you're going to change out the diff, I would suggest just getting a LSD.

lowbudgethero · 06-13-2018, 10:52 AM

Quote:

Originally Posted by 500AF

How fast does 1st and 2nd gear wind out?

speed in gear at 7K:
1st- 37.45
2nd - 62.73
3rd - 95.29
4th - 126.52
5th - 150.56
6th - 173.06

Wegz · 06-18-2018, 10:55 AM

I have it on my car as well. No complaints. I'm mostly stock though with just a Dinan flash and MPE.

lowbudgethero · 06-18-2018, 02:31 PM

It works better with lower power outputs for sure, preferably with a tune that is more focused on top end power.

500AF · 06-23-2018, 07:50 AM

Quote:

Originally Posted by lowbudgethero

speed in gear at 7K:
1st- 37.45
2nd - 62.73
3rd - 95.29
4th - 126.52
5th - 150.56
6th - 173.06

wow, thats a raging 1st!

05-09-2018, 06:55 AM	#1
500AF Private 15 Rep 89 Posts Drives: 2013 135 Join Date: Aug 2015 Location: Paris, VA iTrader: (0)	Auto Diff swap 3.46 in MT 135i The MT has 3.08s in it. I am pretty sure you can put the auto trans diff in it which has 3.46 gears . The only difference is the gears. Is this possible, has anyone done it? The MT has 3.08s in it. I am pretty sure you can put the auto trans diff in it which has 3.46 gears . The only difference is the gears. Is this possible, has anyone done it?
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05-09-2018, 04:30 PM	#2
wu2x Captain 36 Rep 717 Posts Drives: 2011 E90 M3 6MT Join Date: May 2008 Location: NorCal iTrader: (0)	Yes it is possible, but make sure to look into the diff housing sizing before doing it. http://www.vacmotorsports.com/news/3...483338466.html
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05-09-2018, 06:26 PM	#3
ShocknAwe 1Addict 3233 Rep 7,893 Posts Drives: E82 Mutt, M57 Truck Join Date: Jul 2012 Location: Charleston iTrader: (22)	You can, but you'll have to swap the diff and final drive to a large MT pumpkin. Also worth noting most MT 135i diffs are welded, not something you can do in your garage. As for 3.46 on a MT car, not sure why you would want to do this as it will actually make you slower. __________________ 2010 135i 6MT Jet Black N54/3 FE82 Mutt \| BUILD THREAD \| GARAGE SALE
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05-31-2018, 05:00 PM	#5
lowbudgethero Captain 125 Rep 750 Posts Drives: '98 Z3M (gone), '09 135i Join Date: Feb 2013 Location: 908 iTrader: (0) Garage List 2009 BMW 135i [8.50]	I have it, it's fun
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06-08-2018, 06:45 PM	#7
Big Mexican Women Banned 102 Rep 343 Posts Drives: 2011 528i Join Date: May 2018 Location: GTA iTrader: (0)	BMW does a really good job fitting the appropriate final drive ratio into their cars and tuning all the gear ratios to precisely match the power delivery of the engine. if you're going to change out the diff, I would suggest just getting a LSD.
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06-18-2018, 10:55 AM	#9
Wegz Enlisted Member 14 Rep 33 Posts Drives: 2013 135i 6MT Msport Join Date: Sep 2015 Location: Milwaukee iTrader: (0)	I have it on my car as well. No complaints. I'm mostly stock though with just a Dinan flash and MPE.
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06-18-2018, 02:31 PM	#10
lowbudgethero Captain 125 Rep 750 Posts Drives: '98 Z3M (gone), '09 135i Join Date: Feb 2013 Location: 908 iTrader: (0) Garage List 2009 BMW 135i [8.50]	It works better with lower power outputs for sure, preferably with a tune that is more focused on top end power.
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