[moldcad]

With ACS only announcing power gain for their tuned 225d (or M235i), I'm even more curious about the torque increase. Just look here:

http://www.racechip.com/chiptuning/b...60kw/index.php

This piggy-back is supposed to transform the 450 Nm 225d into a 581 Nm rocket! Now, is the zf 8hp45 SAT converter going to withstand that?

[DMM235i]

Does not look like we get beyond 450 nm

[dave235]

100% continuous torque, 101 to 110 6 seconds

[moldcad]

Originally Posted by dave235

100% continuous torque, 101 to 110 6 seconds

Could you elaborate? A take it a ZF 8HPxy is rated 10*xy Nm with continuously maximum torque of 10*xy Nm for 6 seconds, but what is the "101 to 110" part?

Also if you don't mind - may I ask for the source?

Thanks

[Steven1077]

Is the M235i fited with a 8HP45? Even at stock power the numbers are at the limit of that box, I'm pretty sure the 335d has a 8HP70 so I wouldn't take too much notice of that chart as far as models go

[moldcad]

That's my point - even mild tunes are going to exceed it.

[235newbie]

I doubt a major car manufacturer is putting a gear box into a car that is right on the limit of handling torque. There will be at least 50-100 nm to play with.

[hyperzulu]

There is a thread discussing this topic. General consensus is that ZF over-engineers their transmissions (based on employee testimony) but rates them for resale and liability purposes lower than what they can handle. Also anecdotal evidence of F30 guys tuning much longer than F22 guys with same engine and tranny and no issues. May the transmission eventually develop problems if you are generating 450tq and pushing it every day for five years? Sure... it is possible.

[dave235]

Originally Posted by moldcad

Could you elaborate? A take it a ZF 8HPxy is rated 10*xy Nm with continuously maximum torque of 10*xy Nm for 6 seconds, but what is the "101 to 110" part?

Also if you don't mind - may I ask for the source?

Thanks

Haha it was a joke, I was hoping maybe a few ppl would get it. But in more serious more transmissions can exceed there limits for a short period of time without damage

[Cyberdemon]

As an engineer, you design things to spec, and test beyond spec to accommodate for all kinds of tolerances and variables.

On paper, it's going to stay at the 450 ft lb rating. Just like your engine is rated at "320" crank HP.

There is most likely considerable overhead, but when they come to that rating you have to expect there are dozens of tests, conditions, etc that go into that rating. For example, they most likely approve that rating based on all worst case scenarios - super low temperatures, super hot temperatures, etc.

You'll never get a precise number at what point it will crap out since it's going to vary from car to car. Given the level of a normal tune you will most likely be fine, but under extreme use (lots of power mods + track abuse) you'd have to forgive it if it eventually craps out.

[BRM6]

Originally Posted by DMM235i

Does not look like we get beyond 450 nm

That does not include the F22 M235i ... curious if it uses the same as the M135i?

[hyperzulu]

Originally Posted by BRN55

That does not include the F22 M235i ... curious if it uses the same as the M135i?

The Wikipedia article for the 2 series shows ZF 8HP45, as expected.