35iS - a dagger-proof rat?

Busterboo · Post by **Busterboo** » Mon Apr 10, 2017 11:03 am

Have had a 35iS for 6 months now. Very pleased. No significant complaints or problems. Except one.

At a busy roundabout, for example, in 'Normal' - not 'Sport' or 'Sport+' - a stabbed accelerator produces ... nothing. (So, I drive round town in 'Sport', which gives instant response.)

From the outset, I assumed that 'Normal' was 'Strassenkreuzer' mode and this accelerator lag didn't bother me. Recently, though, I've been caught out a couple of times.

So, the question. Other than using 'Sport+' all the time, is there a solution?

lordgrover · Post by **lordgrover** » Mon Apr 10, 2017 11:22 am

Doesn't sound right to me; I don't experience the issue anyway (35i not S).

R.E92 · Post by **R.E92** » Mon Apr 10, 2017 1:45 pm

It's not throttle lag, it's the gearbox disengaging both clutch packs while coasting below a certain speed threshold in "Normal" mode. In Sport mode it keeps the clutch engaged until you get to a stop. It depends on the firmware in your gearbox, some revisions are worse than others.

If the car is under warranty then you can start a complaint about the gearbox behaviour and the first part of rectification at their end will be a software update. If no warranty then you could ask BMW to update all the software on your car when it next goes for a service.
You can also update the gearbox yourself with WinKFP but it will be a huge headache to get setup if you haven't done any previous coding.

Busterboo · Post by **Busterboo** » Mon Apr 10, 2017 1:51 pm

R.E92, thank you very much, indeed.

I'll do what you say and ask BMW for a software upgrade at the next service.

R.E92 · Post by **R.E92** » Mon Apr 10, 2017 2:20 pm

No problem

You can alleviate the symptoms by keeping on the accelerator slightly when coasting or by applying a tiny amount of pedal for a couple of seconds when approaching a place where you may need to make a quick getaway. Over time you will be able to feel when the car engages and disengages the clutch.

Be careful when asking for a software update. In my experience they will do it for free, but I've heard some places wanting money for doing it. If you ask to speak to a tech when you drop the car off you can mention the gearbox feels a bit indecisive and enquire about an update and just hint that they can do it while carrying out the paid service.

Kingfisher · Post by **Kingfisher** » Mon Apr 10, 2017 4:07 pm

Maybe you could try a smoother approach than "stabbing"! ...

David-H · Post by **David-H** » Mon Apr 10, 2017 4:53 pm

Busterboo wrote: ↑Mon Apr 10, 2017 1:51 pm R.E92, thank you very much, indeed.

I'll do what you say and ask BMW for a software upgrade at the next service.

In the meantime, you could push the gearstick to the left when approaching the places that your problem happens and return it to normal once in the clear?

jimbo1958 · Post by **jimbo1958** » Mon Apr 10, 2017 7:08 pm

R.E92 wrote: ↑Mon Apr 10, 2017 1:45 pm It's not throttle lag, it's the gearbox disengaging both clutch packs while coasting below a certain speed threshold in "Normal" mode. In Sport mode it keeps the clutch engaged until you get to a stop. It depends on the firmware in your gearbox, some revisions are worse than others.

Very interesting....didn't know that. Cheers.

Busterboo · Post by **Busterboo** » Mon Apr 10, 2017 10:24 pm

Kingfisher wrote: ↑Mon Apr 10, 2017 4:07 pm Maybe you could try a smoother approach than "stabbing"! ...

An old Porsche habit.

Busterboo · Post by **Busterboo** » Mon Apr 10, 2017 10:29 pm

David-H wrote: ↑Mon Apr 10, 2017 4:53 pm
Busterboo wrote: ↑Mon Apr 10, 2017 1:51 pm R.E92, thank you very much, indeed.

I'll do what you say and ask BMW for a software upgrade at the next service.
In the meantime, you could push the gearstick to the left when approaching the places that your problem happens and return it to normal once in the clear?

Thanks. I'll try that (as an alternative to 'Sport+').

Busterboo · Post by **Busterboo** » Mon Apr 10, 2017 10:53 pm

R.E92 wrote: ↑Mon Apr 10, 2017 2:20 pm No problem

You can alleviate the symptoms by keeping on the accelerator slightly when coasting or by applying a tiny amount of pedal for a couple of seconds when approaching a place where you may need to make a quick getaway. Over time you will be able to feel when the car engages and disengages the clutch.

Be careful when asking for a software update. In my experience they will do it for free, but I've heard some places wanting money for doing it. If you ask to speak to a tech when you drop the car off you can mention the gearbox feels a bit indecisive and enquire about an update and just hint that they can do it while carrying out the paid service.

Will do both, thank you.

Having spent 5 years with a non-turbo'd 911 with a (Mercedes) Tiptronic 2 box, I'm used to a different power delivery through a different box than the 35iS, of course.

Whilst the Tip 2 box is maligned by some as a 'slush box' - although it's faster than most people can change gear manually - I always found it an intelligent and efficient box to use, particularly in hybrid mode. So, for example, I liked the way I could let it change down and engine brake of its own accord while I was braking hard down steep (and fast) hills.

The DCT is better, no doubt, but it's taking me a while to learn it.

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