Setting rev limit lower than tcu shift point? 6AT

[Giberish33]

This is a theoretical. Since steptronic will automatically shift up at redline despite being in manual mode would it be possible to set a lower rev limit, let say 6000rpm, to prevent the gm tcu from requesting a shift? You can hold a gear till close to redline in manual shift mode but ultimately it will shift for you.

I know the usual "get a manual" line, but for reasons I have 128i auto and it works well for my needs minus the auto shifting. Has anyone tried something like n2mb wot box to set a rev limiter (not 2 step just a general limiter) and held the gear until the driver pulls the shifter / paddles?

[golfer23rm]

also interested. i am fine with the steptronnic shifting at redline as that sound is so good. but i would like the car to shift up at 1500rpm in auto. if possible.

[blackberryq10android]

You think it would increase 0-60 times with a lower rev limit to automatically upshift in manual mode?

To slightly change subject but still discussing the steptronic. What are your thoughts on the kickback always downshifting? Does it slow down acceleration if you are at a good rev in a higher gear instead of 100% acceleration in that gear? I certainly think so.

Also, why is the manual faster than the automatic when we can just put it in manual mode ourselves? Isn't it due to the gearing set by bmw for the auto to shift and hold revs, compared to the manual?

[Giberish33]

I don't really care about 0-60 times in my case I'm aiming to be able to hold a gear indefinitely for snow drifting. The auto looses some power through the torque converter as well as being slightly heavier than the manual cars.

For your other question about kickdown, yes I'd agree it is quicker to stay in gear than letting it kick down to another gear. It will take time to shift down then again take time to shift up a half second later.

[rjahl]

Originally Posted by Giberish33

I don't really care about 0-60 times in my case I'm aiming to be able to hold a gear indefinitely for snow drifting. The auto looses some power through the torque converter as well as being slightly heavier than the manual cars.

For your other question about kickdown, yes I'd agree it is quicker to stay in gear than letting it kick down to another gear. It will take time to shift down then again take time to shift up a half second later.

Transmission shift points are based on throttle and tail shaft output. I think by setting the engine RPM limit below the shift set point for that throttle load you could ride the limiter indefinitely. Keep in mind that the DME has soft and hard limits you would need to set them up to match.

Also the transmission peak rpm shift logic is based on a predicted RPM rather than actual. It takes so long to shift , the TCU needs to predict the RPM rise.

Bouncing off an RPM limiter could be problematic.

[Giberish33]

Originally Posted by rjahl

Transmission shift points are based on throttle and tail shaft output. I think by setting the engine RPM limit below the shift set point for that throttle load you could ride the limiter indefinitely. Keep in mind that the DME has soft and hard limits you would need to set them up to match.

Also the transmission peak rpm shift logic is based on a predicted RPM rather than actual. It takes so long to shift , the TCU needs to predict the RPM rise.

Bouncing off an RPM limiter could be problematic.

Thanks for your input, it doesn't seem to be a popular thread. What is the soft limiter? My understanding is that there isn't one, only a hard limit just before 7k rpm. I can rev to redline in neutral and every gear when in steptronic / manual mode. I've seen a soft limiter in newer Audi's that only allows ~4k rpm in neutral, this doesn't seem to be the case with the N52 + GM 6L45 combo. Please correct me if I'm wrong.