Overreving with DCT

[dagolfpro]

Originally Posted by CyrusMccasl

I thought the whole point for dct was for the computer to shift for you

Yes in Auto/D mode. Manual/S mode, you have to shift yourself.

[freeman727]

Originally Posted by m3alabama

THis thread is a fail. Sounds like the OP is legally blind which is more of a concern.

Why are people on forums so quick to criticize. I know what I saw.

[MysticBlue]

Originally Posted by CyrusMccasl

I thought the whole point for dct was for the computer to shift for you

Absolutely not. If all you want is something to shift for you, it might as well be an automatic. Why do you think car companies have gone to all the trouble of designing a DCT when they could have just stuck with an auto. Same reason the technology was developed for racing a decade or two ago. Less torque wasted than an auto, faster shift times than a manual, and the ability to select and hold a gear.
There are many times on the track where you want to hold the gear you're in (even if it's about to redline) for instance, if you're about to enter a corner. That's really the whole point of having different modes in the DCT (S or D).

[CanAutM3]

Originally Posted by freeman727

Why are people on forums so quick to criticize. I know what I saw.

Does your car have an increased rev limit through a tune? If not, as others have said, your thread is hard to believe...

[MysticBlue]

Originally Posted by freeman727

Why are people on forums so quick to criticize. I know what I saw.

Go find an empty highway. After you're engine is all warmed up, put it in S mode and accelerate in 1st gear. Do not shift. When it hits redline, do not lift on the throttle pedal, just leave it there for a few seconds, time enough for you to take a good look at the tachometer. Get back to us and tell us what you saw.

[///Machine]

A more interesting question IMO is: once you rev to the point of fuel cut-off, does it get recorded on the hard drive? Does it impact any warranty coverage? If so, pre-owned M3 buyers should verify that at PPI. It might give clues as to how a perspective car has been driven.

[Parkanzky]

Why should running the car to the rev limit impact your warranty. It shouldn't hurt your car at all. If it does, BMW should have set a lower rev limit...

[MysticBlue]

Originally Posted by freeman727

Launch mode and revs climbed faster than on any of my previous cars. I was in S mode.

If you were really in launch mode, then it should have shifted right before fuel cutoff. If it didn't, it's because you didn't keep the throttle pedal hard on the floor. There is a button under the pedal. It kind of feels like a kick-down on an auto. Try pushing the pedal to the floor while the engine is not running and you will feel it click. This button has to be pushed down by the throttle pedal in order to do a launch in the first place, then it has to be held there in order for the DCT to shift from 1st to 2nd and 2nd to 3rd. If you lift at all after launch, even momentarily, it is no longer in launch mode, it reverts to S mode, which means you have to initiate shifts yourself.

[freeman727]

Originally Posted by ///Machine

A more interesting question IMO is: once you rev to the point of fuel cut-off, does it get recorded on the hard drive? Does it impact any warranty coverage? If so, pre-owned M3 buyers should verify that at PPI. It might give clues as to how a perspective car has been driven.

I did experience fuel cut off. I thought for a split second that the car went into limp mode

[Parkanzky]

Originally Posted by freeman727

I did experience fuel cut off. I thought for a split second that the car went into limp mode

That fuel cutoff happens at red line, not above.

[Ohh_5H1T]

Originally Posted by m3alabama

THis thread is a fail. Sounds like the OP is legally blind which is more of a concern.

[rdollie]

Did it occur to anybody that maybe the OP had a tach failure of some sort and he actually saw what he reported? Maybe a software issue - yes perish the thought we do still have software issues these days.

I could go on and on. For people to say it's impossible for him to have seen what he reported is extremely short-sighted. You don't have to be a scientist to use logical thought patterns. Just because our cars aren't capable of this doesn't mean it didn't happen to the OP - afterall that's why he's here because this isn't normal meaning something could be wrong right?

[MRSSIIM3]

Originally Posted by freeman727

Launch mode and revs climbed faster than on any of my previous cars. I was in S mode.

launch mode? you mean launch control? and launch control shifts automatically for you buddy. no way to overrev if youre flooring it past the click still

[BPMSport]

Originally Posted by m3alabama

This is my point. I am sure you are convinced you saw 9k which is concerning since its impossible. Hence my comment that you may be legally blind but it may actually be worse, you may have problems with illusions as well. Seeing something that doesn't really exist-maybe hallucinations.

In all seriousness, its concerning that you are so convinced in something that is impossible

There is no reason to personally attack him. Stick to the facts.


With regard to the redline, it really depends on what your definition of 'redline' is. There are actually multiple settings in the code pertaining to torque limitation, fuel cut off, etc.. Some to note are specific redline changes for oil temp, gears, warmup, rpm for hot oil temps, rpm for hot coolant temp, and then things like torque limitation fuel cut rpm, and RPM Limit for E2 fuel cut for level 2 torque calculation, maximum relative filling rpm limit, buffer for RPM intervention, etc.. It's not just one change to modify the redline like it used to be years ago. I think it would be impossible for a stock DCT car to exceed 8,600.

OP: I can read the highest RPM you've hit if you are extremely interested in knowing that information. But otherwise, enjoy the car. It's not going to let you over-rev with DCT, so don't worry about it. Manual is a different story and an over-rev would only occur from a misshift. I do see DCT cars consistently have higher freezeframe data for maximum nmax (rpm) achieved over 6MT cars.

My car has hit 8,800 before, still going rock solid.

[MRSSIIM3]

Originally Posted by freeman727

Why are people on forums so quick to criticize. I know what I saw.

because what you saw is impossible. the thousands of ppl on here with M3s can attest to that.

[besiktas]

Originally Posted by Robertyu

This information is absolutely incorrect. It will bounce off the rev limiter until you shift it when in manual mode (unless you're in a launch-control run where it will shift for you until you let off the gas during that run).

+1

[Veloce]

Originally Posted by CanAutM3

Unless you money shift that is

You would be correct. Makes me cringe just thinking about it.

[Mjolnir]

Originally Posted by Robertyu

This information is absolutely incorrect. It will bounce off the rev limiter until you shift it when in manual mode (unless you're in a launch-control run where it will shift for you until you let off the gas during that run).

That's been my experience. Ask me how I know.

[swartzentruber]

Originally Posted by Mjolnir

That's been my experience. Ask me how I know.

Yeah, I've done that a few times myself, typically after driving for a while in D, then switching to S and forgetting about it. Always good for a WTF moment. Sounds to me like the OP didn't use launch control properly, and got a rude surprise, and in the shock of the moment, thought it hit 9K.

[///Machine]

Originally Posted by Parkanzky

Why should running the car to the rev limit impact your warranty. It shouldn't hurt your car at all. If it does, BMW should have set a lower rev limit...

You have a good point. The fuel cut-off in itself is the engine defense mechanism.
Still, I would be skeptical of buying a used M3 with more than a couple fuel cut-offs registered in the hard drive as, to me, it indicates a poor-driving pattern. Say you had a 2009 M3 with 799 fuel cut-offs...

[Parkanzky]

Originally Posted by ///Machine

You have a good point. The fuel cut-off in itself is the engine defense mechanism.
Still, I would be skeptical of buying a used M3 with more than a couple fuel cut-offs registered in the hard drive as, to me, it indicates a poor-driving pattern. Say you had a 2009 M3 with 799 fuel cut-offs...

It could be the guy ran it all the way up in 2nd gear getting onto the freeway every morning on his drive to work (after the car was warmed up). That wouldn't bother me at all.

[Nine]

I must have seen the same thing, it definetly looked like I went over redline, but as others have said, at speeds, maybe it's just our eyes.