If the DCT GTS tune is so good, why don't we have it from the factory?

[drwankel]

Just curious of some others thoughts here.

If the GTS DCT tune is so good, why didn't BMW ever start using it from the factory for all of the DCT cars?

Is there some risk that I am unaware of?

[cenix]

Because it is reserved for the more pricier GTS. They need a way to differentiate their top of the line offering from the standard run of the mill M3.

[narkotic]

The GTS comes with a DCT Oil cooler.

I run the firmware on the street but haven't tracked it. I'm guessing it can cause higher temps...

[Shredicus]

Originally Posted by narkotic

The GTS comes with a DCT Oil cooler.

I run the firmware on the street but haven't tracked it. I'm guessing it can cause higher temps...

All DCTs use 2 stage cooling:

http://www.m3post.com/forums/showpos...1&postcount=26

Also faster shift speeds should mean less friction and therefore less heat if I understand the wet clutch setup correctly

[duvinclunk]

Originally Posted by Shredicus

Also faster shift speeds should mean less friction and therefore less heat if I understand the wet clutch setup correctly

Is this true?

[Sneaky Pete]

Makes sense...the benefit is somewhat offset though by increasing the stress on the drivetrain by shifting "harder".

[redpriest]

I can say for sure that under stressful track conditions, eventually you'll get heat soak and you'll start to feel sluggish upshifts/downshifts. This is with a DCT tune. Never have any problems on the street.

[duvinclunk]

Originally Posted by redpriest

I can say for sure that under stressful track conditions, eventually you'll get heat soak and you'll start to feel sluggish upshifts/downshifts. This is with a DCT tune. Never have any problems on the street.

Is this from experience?

[dparm]

Originally Posted by redpriest

I can say for sure that under stressful track conditions, eventually you'll get heat soak and you'll start to feel sluggish upshifts/downshifts. This is with a DCT tune. Never have any problems on the street.

I have never experienced DCT sluggishness on the track, even during 30 minute sessions. My car is bone stock. Why would the tuned software cause that sort of problem? Are you suggesting it generates additional heat because of the faster shifts? Your car is modified so it's apples-to-oranges.

[dparm]

Originally Posted by drwankel

Just curious of some others thoughts here.

If the GTS DCT tune is so good, why didn't BMW ever start using it from the factory for all of the DCT cars?

Is there some risk that I am unaware of?

It's a balance between reliability, drivability, and performance.

The GTS software is more aggressive. That equates to better performance, but at the expense of drivability and reliability. GTS owners may be using their cars on the track more often than a standard M3 owner, so they're willing to sacrifice drivability and reliability to get that extra bit of performance.

I think it also comes down to BMW wanting the GTS to be just a little bit better than a regular M3, so they dial everything up to 11. If I paid all of that extra money, I'd want it to be noticeably different.

[redpriest]

Originally Posted by duvinclunk

Is this from experience?

Yes, it doesn't happen often, and only on certain tracks where there are a lot of turns which require frequent gear changes. I'm not blaming the tune, necessarily. This has happened to me at Buttonwillow and Thunderhill a couple times. I am talking about > 1-5 seconds between pressing the lever and getting a reaction. I will definitely be investing in a DCT cooler upgrade.

[redpriest]

Originally Posted by dparm

I have never experienced DCT sluggishness on the track, even during 30 minute sessions. My car is bone stock. Why would the tuned software cause that sort of problem? Are you suggesting it generates additional heat because of the faster shifts? Your car is modified so it's apples-to-oranges.

I think it depends on the conditions. I've been out on the track for sometimes up to an hour straight and it doesn't happen.

Not sure why my mods would make a difference other than raising the engine temp a little more meaning the coolant is hotter etc, and the heat exchanger isn't working as effectively. My engine temps are < 250 and my water coolant temps ~ 185 (when the sensor works, lol).

[dparm]

Originally Posted by redpriest

I think it depends on the conditions. I've been out on the track for sometimes up to an hour straight and it doesn't happen.

Not sure why my mods would make a difference other than raising the engine temp a little more meaning the coolant is hotter etc, and the heat exchanger isn't working as effectively. My engine temps are < 250 and my water coolant temps ~ 185 (when the sensor works, lol).

What DCT fluid do you have, and how old is it? Is the filter still original?

[e90///M3]

my understanding, not only DCT but with other Dual clutch autos, firmer shifts causing less friction = equal less heat and wear
Isn't the GTS tune only making the shifts a bit faster? I'm actually thinking getting the alpine GTS tune

[BrewRifle]

Originally Posted by e90///M3

my understanding, not only DCT but with other Dual clutch autos, firmer shifts causing less friction = equal less heat and wear
Isn't the GTS tune only making the shifts a bit faster? I'm actually thinking getting the alpine GTS tune

Faster and less jerky both upshifting and downshifting. Also, going into reverse is instant as opposed to having a bit of lag time in between.

[e90///M3]

Originally Posted by BrewRifle

Faster and less jerky both upshifting and downshifting. Also, going into reverse is instant as opposed to having a bit of lag time in between.

is still snappy at WOT? I don't want to necessarily be smoother , i like that nice kick when i shift. I'm on the euro DCT tune... is it noticeable upgrade?

[dparm]

Originally Posted by e90///M3

is still snappy at WOT? I don't want to necessarily be smoother , i like that nice kick when i shift. I'm on the euro DCT tune... is it noticeable upgrade?

The best metaphor I have heard is that it basically moves everything up one DriveLogic notch. So the new "5" now feels like the factory "6" (the mode that's available when DSC is disengaged). It's not an insane difference, but it should be noticeable.

[Leonardo629]

GTS also holds about a liter more fluid...which is why our GTS DCT flash is modified to compensate for that, or so I was told.

DCT in our car actually prefers to be driven hard, it's the stop and go driving that cause everything to heat up and you get problems, like when I lost all odd gears.

[BrewRifle]

Originally Posted by e90///M3

is still snappy at WOT? I don't want to necessarily be smoother , i like that nice kick when i shift. I'm on the euro DCT tune... is it noticeable upgrade?

It still lunges you forward when up-shifting at high RPMs, which I'm a big fan of .

[e90///M3]

Originally Posted by dparm

The best metaphor I have heard is that it basically moves everything up one DriveLogic notch. So the new "5" now feels like the factory "6" (the mode that's available when DSC is disengaged). It's not an insane difference, but it should be noticeable.

does the apply to the euro DCT tune?
the one where it starts in D1 with 2 bars.

[redpriest]

Originally Posted by dparm

What DCT fluid do you have, and how old is it? Is the filter still original?

It's the correct fluid. Fluid is relatively brand new - they had to change it out a year and a half ago because I had the infamous DCT oil pan and side gasket leak at 50k miles.

No idea about the filter.

[dparm]

Originally Posted by e90///M3

does the apply to the euro DCT tune?
the one where it starts in D1 with 2 bars.

As I understand it, the Euro DCT software doesn't shift any faster, it just has some usability tweaks like starting in D versus M.