[ghostedtamil]

I did a launch from a stop after many years, and with the Continental summer tires, the RPMs just dropped back to under 1k RPM since the tires did not spin at all. I could probably break traction on them if I wanted to with higher RPMs, but the question is, how bad is it for the RPMs to drop like that and the stress on the diff?

Car is a e90 330i 6sp manual

[tlow98]

Mostly just wearing your clutch. The diff is the last thing in the drivetrain I would worry about.

[ghostedtamil]

well that does not worry me too much - the sudden drop in RPMs due to sticky tires not breaking was a bit disconcerting. Not like the 350z I had which would spin both wheels nicely and shoot out of the hole. 2 totally different cars -and the BMW is the one I would keep if I had to pick

[Efthreeoh]

Did you have the DTC turned off?

[Efthreeoh]

And second, if you want a car to do burnouts, buy a Mustang.

[ghostedtamil]

I did have the DTC activated fully (held down the button and it went into 2nd OFF mode).

I do not desire burnouts as much as hard launches. In fact, burnouts do not appeal to me - i just do not see the point. But tire spin that helps in acceleration and jump starts off the line! That appeals to me a lot! My e90 m3 would do them easier than the e90 330i - both were 6MT

[ghostedtamil]

edit - the DTC was turned off as you said Efthreeoh. Not "activated" into 2nd off mode as I said

I thought DTC stood for disabled traction control, but now I recall that in the cluster, when deactivated, it will read as DTC off.

[Tambohamilton]

DTC stands for dynamic traction control. So the normal mode is full nannies. Press and release the DTC button and you get 'dynamic' mode (allows more slip before cutting in), press and hold and you get minimal nannies (traction control is off, but the e-diff still runs etc).

[ghostedtamil]

Nice but we are still looking for a mesmerizing, convincing, and epistemologically transformative response to my original question. So far, tlow98 thinks the damage was only clutch related, and perhaps that is all that needs to be said about it. I have no symptoms since the event but nonetheless - I do wonder if anyone has indeed fried a diff or caused serious damage with one or more of these types of launches where the the clutch is released and the tires have too much traction to break - causing the RPMs to die off rapidly.

Perhaps an easier and more simpler question is: Are the e90 6mt 330i differentials particularly stout and/or overbuilt?

[JonOhh]

This isn't the exact answer to the question you're asking, but:

The first case of diff issues I've heard on this platform at all was just the other day on a 335, which has a stronger diff anyway. I'd say that failure is extremely, extremely rare. On Indy 500s my 330 could light up the rear end with an aggressive launch, as could it with burnt out Pilot Super Sports. On 265 wide V12evo2s, it can't, and I'd feel bad launching it hard since I know the tires just won't give, but it's not the diff I'm worried about- I think typically the axles go first.

Regardless, I seriously do not think you've done any damage by one hard launch if everything seems fine. You've likely worn your clutch a tiny bit, but nothing out of the ordinary. I am on the factory clutch at 125k, with multiple track days, hard launches, and even in a very rare occasion, clutch kicks in corners to kick the back end out during a few drift events, and much more, and it still bites just as hard as I'd expect it to with a stock CDV. I wouldn't worry about doing any harm at stock power levels- these cars are very, very stout, and damn near impossible to kill at stock power. 7 redlines a day keeps FCP euro away as well

[ghostedtamil]

7 redlines a day - well then I should be fine.

Your post is quite the data based feedback I was looking for. On another note your post about the ability of the car to take hard driving is yet one more reason that the e90 330i is such a GEM of a car - a reliable, fun, well designed and built daily driver. I made a post a while back - HERE IS THAT LINK -"Ode to the 330i e90 manual"

[JonOhh]

Originally Posted by ghostedtamil

7 redlines a day - well then I should be fine.

Your post is quite the data based feedback I was looking for. On another note your post about the ability of the car to take hard driving is yet one more reason that the e90 330i is such a GEM of a car - a reliable, fun, well designed and built daily driver. I made a post a while back - HERE IS THAT LINK -"Ode to the 330i e90 manual"

The stock drivetrains on most all e90s are very overbuilt. The manual transmission found in the 328 is capable of handling the torque of the N52 in 330i spec (as far as I'm aware, can't find the specs rn) but they upgraded it to the GS6-37BZ to handle the additional torque from the 3IM...for reference, there are people using this transmission on 700HP 2JZ builds. It's stout.

Admittedly this impressive strength comes just as much from ZFs high factor of safety as it does BMWs- the transmission itself is rated for 370nm- the 330i makes nowhere near that- and has been reported to handle over 700NM.

[autoAER]

Originally Posted by ghostedtamil

Nice but we are still looking for a mesmerizing, convincing, and epistemologically transformative response to my original question. So far, tlow98 thinks the damage was only clutch related, and perhaps that is all that needs to be said about it. I have no symptoms since the event but nonetheless - I do wonder if anyone has indeed fried a diff or caused serious damage with one or more of these types of launches where the the clutch is released and the tires have too much traction to break - causing the RPMs to die off rapidly.

Perhaps an easier and more simpler question is: Are the e90 6mt 330i differentials particularly stout and/or overbuilt?

Repeated launches will kill your clutch, but I've never actually seen a differential failure on an E90.

P.S.- I'm on 19's with 255 PSS rear tires and have no problem breaking loose during launches

[ghostedtamil]

Originally Posted by JonOhh

The stock drivetrains on most all e90s are very overbuilt. The manual transmission found in the 328 is capable of handling the torque of the N52 in 330i spec (as far as I'm aware, can't find the specs rn) but they upgraded it to the GS6-37BZ to handle the additional torque from the 3IM...for reference, there are people using this transmission on 700HP 2JZ builds. It's stout.

Admittedly this impressive strength comes just as much from ZFs high factor of safety as it does BMWs- the transmission itself is rated for 370nm- the 330i makes nowhere near that- and has been reported to handle over 700NM.

sweet deal!

Originally Posted by autoAER

Repeated launches will kill your clutch, but I've never actually seen a differential failure on an E90.

P.S.- I'm on 19's with 255 PSS rear tires and have no problem breaking loose during launches

Oh i am sure you have some trouble - as the power is not there like the 350z or others. If I truly wanted to break the traction - I could - but it seems wrong in this car HAHA. On my old run flats, I could do nice launches - just a tiny bit of wheel chirp. On the Conti summer tires - it is different. Need more RPMs to launch.

Good to hear that you too (3rd opinion) who thinks clutch would take the brunt of the force, not the diff.

[autoAER]

Originally Posted by ghostedtamil

sweet deal!



Oh i am sure you have some trouble - as the power is not there like the 350z or others. If I truly wanted to break the traction - I could - but it seems wrong in this car HAHA. On my old run flats, I could do nice launches - just a tiny bit of wheel chirp. On the Conti summer tires - it is different. Need more RPMs to launch.

Good to hear that you too (3rd opinion) who thinks clutch would take the brunt of the force, not the diff.

Launch at 2800 spins the rear fairly easily with traction control completely off but I guess results may vary !

[ghostedtamil]

Many variables - so for sure results will vary. Variables include tire type, brand, model, compound, road temps and level, grip friction between road/tires ambient temps, fuel octane, engine power output, and of course - driver skill!

[gT-BMW]

If your sub frame bushings, diff bushings, motor mounts, shocks worn out you will get wheel hop. you want to avoid that cause that will destroy either your transmission, axles, diff, clutch and flywheel, any weak drive train components will be exposed.

[ghostedtamil]

shocks have been making a bit more noise over undulations - they hiss everytime

[lowrydr310]

Originally Posted by ghostedtamil

shocks have been making a bit more noise over undulations - they hiss everytime

Hissing isn't indicative of a problem though. I have brand new B4 struts that hiss when going too fast over big bumps.

[ghostedtamil]