335d Guys, Anyone ever swap LSD gear ratios?

Rotorocious · 03-08-2012, 09:45 PM

I have a buddy with a 335d I'm trying to help.

So I read the 335d has a 2.81 gear ratio.
Has anyone ever swapped it out when upgrading to an LSD to a 3.08 or 3.46?
Just curious how that may effect rpms and driveability etc on a diesel.

minus13 · 03-09-2012, 07:53 AM

Considered it - not touching it. There's already significant torque down low to be sacrificing top end speed and cruising ratio. These cars launch in second gear for crying out loud. If you want a tighter ratio, put her into first gear (I know I am oversimplifying, but you get my point).

My humble opinion - not necessary.

mosx · 03-09-2012, 08:59 AM

I don't own a diesel but I'm guessing if you put a 3.08 or a 3.46 in there you'd just spin the tires on every launch. Gobs o' torque.

Thud · 03-09-2012, 02:09 PM

1st gear is already useless as it is, what good would a shorter rear end ratio do?

Concentric190 · 03-09-2012, 02:13 PM

if anything I'd want a taller gear so I could make use of 1st gear and have a lower rpm cruising on the highway. 2.50 LSD would be nice. It would probably be faster and get better MPG's.

minus13 · 03-09-2012, 03:40 PM

Quote:

Originally Posted by Concentric190

if anything I'd want a taller gear so I could make use of 1st gear and have a lower rpm cruising on the highway. 2.50 LSD would be nice. It would probably be faster and get better MPG's.

I like the way you think. I wonder how this would affect shift points when in drive and DS? I shift my own gears with the 335d, but I'm curious nonetheless. I still have some time to make this change. VAC is building me a final drive unit right now. You think 2.50 would be the way to go?

minus13 · 03-09-2012, 03:51 PM

Looking into it. VAC is building me a final drive unit. I'll let you guys know.

minus13 · 03-09-2012, 05:54 PM

Looking into 2.53:1 ratio... Still curious as to how this will affect shift points when in drive or DS. I guess we'll see. In drive, second gear launch may be a dog.

Rotorocious · 03-09-2012, 07:33 PM

Interesting points guys.
Thanks for the input

Concentric190 · 03-12-2012, 01:25 PM

Quote:

Originally Posted by minus13

Looking into 2.53:1 ratio... Still curious as to how this will affect shift points when in drive or DS. I guess we'll see. In drive, second gear launch may be a dog.

there are some calculators out there that will tell you what your rpms will be at different speeds in different gears. I had it on my home computer but its been a while since I used it.

That would be the best to determine what gear you want.

03-08-2012, 09:45 PM	#1
Rotorocious Lieutenant Colonel 103 Rep 1,520 Posts Drives: 335xi Join Date: May 2010 Location: Colorado iTrader: (3)	335d Guys, Anyone ever swap LSD gear ratios? I have a buddy with a 335d I'm trying to help. So I read the 335d has a 2.81 gear ratio. Has anyone ever swapped it out when upgrading to an LSD to a 3.08 or 3.46? Just curious how that may effect rpms and driveability etc on a diesel.
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03-09-2012, 07:53 AM	#2
minus13 Private 2 Rep 93 Posts Drives: 2009 335D Join Date: Feb 2012 Location: South Carolina iTrader: (1)	Considered it - not touching it. There's already significant torque down low to be sacrificing top end speed and cruising ratio. These cars launch in second gear for crying out loud. If you want a tighter ratio, put her into first gear (I know I am oversimplifying, but you get my point). My humble opinion - not necessary.
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03-09-2012, 08:59 AM	#3
mosx The mod bug has bitten. 22 Rep 565 Posts Drives: 2008 M3 Sedan Join Date: Jun 2010 Location: North Texas iTrader: (1) Garage List 2008 BMW M3 [0.00]	I don't own a diesel but I'm guessing if you put a 3.08 or a 3.46 in there you'd just spin the tires on every launch. Gobs o' torque.
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03-09-2012, 02:09 PM	#4
Thud Throbbing Member 43 Rep 1,433 Posts Drives: Join Date: Jan 2008 iTrader: (0)	1st gear is already useless as it is, what good would a shorter rear end ratio do? __________________ 2014 Tesla Model S 85kwh Previous cars: 2011 335d / Deep Sea Blue / Saddle brown / sport / premium 2008 BMW 135i / 6MT 2002 Z06 Corvette
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03-09-2012, 02:13 PM	#5
Concentric190 Second Lieutenant 7 Rep 264 Posts Drives: 335d Join Date: Mar 2011 Location: Willowbrook, IL iTrader: (0) Garage List 1997 BMW M3 [0.00] 2009 BMW 335d [0.00] 1995 BMW M3 [0.00]	if anything I'd want a taller gear so I could make use of 1st gear and have a lower rpm cruising on the highway. 2.50 LSD would be nice. It would probably be faster and get better MPG's. __________________ ///Andres 09 335d evolve tuned - 327whp / 490wtq -- 13.0@105 95 M3 Turbo - Built 3.0l s52, PTE74GTQ, AEM EMS & CDI 97 M3 NASA TTB build for 2014!
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03-09-2012, 03:51 PM	#7
minus13 Private 2 Rep 93 Posts Drives: 2009 335D Join Date: Feb 2012 Location: South Carolina iTrader: (1)	Looking into it. VAC is building me a final drive unit. I'll let you guys know.
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03-09-2012, 05:54 PM	#8
minus13 Private 2 Rep 93 Posts Drives: 2009 335D Join Date: Feb 2012 Location: South Carolina iTrader: (1)	Looking into 2.53:1 ratio... Still curious as to how this will affect shift points when in drive or DS. I guess we'll see. In drive, second gear launch may be a dog.
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03-09-2012, 07:33 PM	#9
Rotorocious Lieutenant Colonel 103 Rep 1,520 Posts Drives: 335xi Join Date: May 2010 Location: Colorado iTrader: (3)	Interesting points guys. Thanks for the input
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