[v8killah]

Hi all,

First post! I bought an '08 335xi today!

I'm very interested in the tuning market, but I'm trying to determine how significantly the reliability is reduced with bolt-ons (i.e., DCI, piggyback or Cobb, FMIC, DPs) with an occasional romp here and there, and a 1/4 mile run once a year or so. From what I've read, the rated limit of the Steptronic 6HP19TU transmissions is only 332 ft. lbs. of torque (at the wheels or crank?). Even if it is at the wheels, with the amount of cars on this forum greatly exceeding that limit, I'm interested in hearing if there have been any documented failures with around 400 ft. lbs. of torque at the wheels with a decent amount of miles? Thanks

[themyst]

The torque converter is rated to about 300lb/ft torque, which is about the maximum stock output. The thing is, this transmission locks the torque converter at WOT if I'm not mistaken. So the rating of the torque converter isn't that relevant to high-power applications on this platform.

[v8killah]

Thanks for the reply. I didn't think about the torque converter, good point. How about the transmission though?

[themyst]

Originally Posted by v8killah

Thanks for the reply. I didn't think about the torque converter, good point. How about the transmission though?

There are people pushing well over 400whp on the 6AT without issue. Can't comment long-term though.

[vase330]

Seems strong as a bull to be honest. I was worried back in early 2008 and did a ton of research. After a while I stopped worrying. There are guys running insane torque with no issues. In fact its been shown your drive shafts will snap and your rear-end rip out of the subframe before anything happens to the tranny. If you rip your rear-end or snap your axles, you know its time to stop. Unless you want to find the limits for the communities benefits. I'll be willing to donate a penny towards your new tranny.

[v8killah]

Thanks for the good information!

[ultimateendz]

i cant remember what thread i read it in here but most of the tranny components from our steptronics are the exact same ones down to the part number on the alpina b7 and the supercharged rangerover.....so basically u have nothing to worry about....up to probably 7-800wtq

[techlogik]

Search for a post about transmission and power on this section...I thought somebody had posted the spec sheets for the manual/auto.

[enrita]

Pushing 450- 500 ftlb now will see how long it will hold. I recently changed oil at 50k was quite some metal on the magnets.

[v8killah]

Originally Posted by techlogik

Search for a post about transmission and power on this section...I thought somebody had posted the spec sheets for the manual/auto.

Yeah, I found this prior to posting. That was the reason for my worry. The spec sheets state 332 ft. lbs. of torque is the rated limit for the auto.

[v8killah]

Originally Posted by maxnix

I remember reading that both the the B7, and the 335d have different part numbers and heavier duty components. Any ATF coolers on any of these
(and I don't mean in-radiator heat exchanger which serves a different purpose!)?

Not sure about the B7, but I know that the 335d does have a different part number and stronger tranny (something like 700nm/~516 ft. lbs. limit).