Cheapest way to upgrade DCT gearing?

[Shredicus]

Hey all,

Got hit a while back and my right rear wheel took the brunt of the impact. Looking into upgrading my DCT diff to a more aggressive ratio like 3.45 to increase mechanical torque and was just wondering what the cheapest route to upgrading would be?

The sets I've found seem ludicrously expensive so I'm just wondering if anyone has found a more cost effective ring and pinion set that would interchange for a similar effect.

While on the topic, LSDs as well?

TIA

[dparm]

Originally Posted by Shredicus

Hey all,

Got hit a while back and my right rear wheel took the brunt of the impact. Looking into upgrading my DCT diff to a more aggressive ratio like 3.45 to increase mechanical torque and was just wondering what the cheapest route to upgrading would be?

The sets I've found seem ludicrously expensive so I'm just wondering if anyone has found a more cost effective ring and pinion set that would interchange for a similar effect.

While on the topic, LSDs as well?

TIA

I've not seen anything in the way of "cost effective" DCT gearing upgrades. There just isn't much demand. However, our basic gearbox is built by Getrag and used by other manufacturers, so maybe you could use some of those internal parts instead?

BMW brands our box generically as the "M-DCT" but it's really a Getrag 7DCL600. The Ferrari 458 uses the 7DCL750; the final 3 digits denote the power rating.


As for the LSD, there have been a few big threads on that. One guy has tried a whole shitload of different models:
http://www.m3post.com/forums/showthread.php?t=788992

[JJH]

You don't say who you have contacted but have you tried diffsonline? > http://diffsonline.com/. I have sourced pinion and ring sets from them for previous BMWs and have been happy with their products.

[gan1hck]

Turner Motorsports rear differential...comes from diffsonline, I think.

Very happy with mine.

[Shredicus]

Originally Posted by JJH

You don't say who you have contacted but have you tried diffsonline? > http://diffsonline.com/. I have sourced pinion and ring sets from them for previous BMWs and have been happy with their products.

Originally Posted by gan1hck

Turner Motorsports rear differential...comes from diffsonline, I think.

Very happy with mine.

Good call. I'll give them a ring. Didn't know they sold ring&pinion sets separately just preassembled diffs. Could you give me an idea what a set runs?

[Dave07997S]

The reason you don't see people just changing the R&P vs. buying the whole diffy is the fact if you don't get the backlash right you will destroy the R&P. They are finicky and are a pain to get the backlash right. I talked to a few shops and they didn't want to touch the R&P. They all suggested just changing out the whole diffy.

Dave

[Dave07997S]

Originally Posted by dparm

I've not seen anything in the way of "cost effective" DCT gearing upgrades. There just isn't much demand. However, our basic gearbox is built by Getrag and used by other manufacturers, so maybe you could use some of those internal parts instead?

BMW brands our box generically as the "M-DCT" but it's really a Getrag 7DCL600. The Ferrari 458 uses the 7DCL750; the final 3 digits denote the power rating.


As for the LSD, there have been a few big threads on that. One guy has tried a whole shitload of different models:
http://www.m3post.com/forums/showthread.php?t=788992

I think he was just talking about the diffy, not the internal gearing of the DCT.

[Patrón]

E9xm 6sp mt diff swap.

[Shredicus]

Originally Posted by Patrón

E9xm 6sp mt diff swap.

3.85 is a liiiitle steep. I don't know that the DCT would jive with that aggressive of a ratio

[Shredicus]

Originally Posted by Dave07997S

The reason you don't see people just changing the R&P vs. buying the whole diffy is the fact if you don't get the backlash right you will destroy the R&P. They are finicky and are a pain to get the backlash right. I talked to a few shops and they didn't want to touch the R&P. They all suggested just changing out the whole diffy.

Dave

Good feedback. I'll see if I get the same pushback from local diff shops

[Patrón]

Originally Posted by Shredicus

3.85 is a liiiitle steep. I don't know that the DCT would jive with that aggressive of a ratio

it's not a huge difference but I think it's 3.65 or 3.67:1

if i was n/a i'd go 4.10s.

[JJH]

Originally Posted by Shredicus

Good call. I'll give them a ring. Didn't know they sold ring&pinion sets separately just preassembled diffs. Could you give me an idea what a set runs?

I believe our cars have a 210 mm housing so these are your options > http://diffsonline.com/differential-...nd-pinion-set/

[jcolley]

If you change the final drive ratio significantly, you'll most likely need a modification to your DME tune for the ratio. E6x SMG guys went through this. 3.91 was fine, but 4.01 changed ratios enough that gears dropped out due to speed limiting calculations between the DME and SMG. mss60 / DCT uses the same code functions for this as mss65 / SMG.

[Shredicus]

Originally Posted by jcolley

If you change the final drive ratio significantly, you'll most likely need a modification to your DME tune for the ratio. E6x SMG guys went through this. 3.91 was fine, but 4.01 changed ratios enough that gears dropped out due to speed limiting calculations between the DME and SMG. mss60 / DCT uses the same code functions for this as mss65 / SMG.

I've heard of the 3.15 to 3.45 swap in the e92 is probably the most common/popular as its not too over the top. Think the 3.45 would have this issue?

[Redd]

I've done some research and there are issues with rev matching in DCT with a shorter ratio. Lots of info if you Google for it.