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      09-04-2014, 07:59 PM   #1
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Best way to launch DCT at Drag Strip

I have an FBO Z4 35i running E50 with DCT and I am planning on hitting the drag strip in 2 weeks. This car is so much easier to get our of first gear without spinning everywhere than my previous 135i 6MT but I want to get some ideas on how to run the fastest time. I have heard that it is best to launch in 2nd gear and I have also heard to launch from 1st in sport plus mode and manually shift into 2nd and so on. I could also use launch control but it seems like this will cause significant spinning to get out of 1st.

This is the first time to the drag strip with this car and I want to run the fastest launch rather than experimenting all night. What are you thoughts.
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      09-04-2014, 08:16 PM   #2
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Ever try the launch control?
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      09-04-2014, 09:04 PM   #3
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My DCT 35i was on stock tires when I took it to the drag strip and the launch control caused too much wheel spin and gave a worse 60 ft time.

My best run was with DSC OFF, gearbox in manual mode. I feathered the throttle off the line and let the gearbox upshift for me.

When I used sport+ the 2nd gear shift would be so abrupt it would chirp the tires and activate the traction control, but with DSC OFF this wasn't an issue

Good luck and please post up some slips!
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      09-04-2014, 09:19 PM   #4
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Quote:
Originally Posted by nicknaz View Post
My DCT 35i was on stock tires when I took it to the drag strip and the launch control caused too much wheel spin and gave a worse 60 ft time.

My best run was with DSC OFF, gearbox in manual mode. I feathered the throttle off the line and let the gearbox upshift for me.

When I used sport+ the 2nd gear shift would be so abrupt it would chirp the tires and activate the traction control, but with DSC OFF this wasn't an issue

Good luck and please post up some slips!

Thanks. Off subject but we are considering flying into San Fran and taking hwy 1 to San Diego over 8 or 9 days. This is probably not a fair question because there are probably 1,000 places to see but what should we not miss.
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      09-04-2014, 09:45 PM   #5
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Quote:
Originally Posted by Lambobimmer View Post
Thanks. Off subject but we are considering flying into San Fran and taking hwy 1 to San Diego over 8 or 9 days. This is probably not a fair question because there are probably 1,000 places to see but what should we not miss.
17 mile drive in pebble beach area and Laguna Seca are the top 2 things that come to mind. Try to time it so you can do an HPDE. Great track.

Other highlights are driving over the Bixby Bridge in Big Sur, entire Santa Barbara Area is nice as well.

In my opinion, once you get past LA you've seen the highlights and you might consider just getting on the 5 and pounding through the rest of the trip.

If you have some spare time in San Diego, shoot me a PM. I have some ideas for restaurants as well (both SD and SF (lived there for 06-09)), in case you are interested
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      09-04-2014, 11:26 PM   #6
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I agree on DSC=off + manual DCT mode. Sport+ is too jerky for any type of serious driving. Also you may want to shift before red-line at speeds above 100kmh to stay within the max power band of a tuned N54.

It is not recommendable to go WOT until the clutches are fully engaged btw... If you want to go WOT from a stand-still you better use Launch Control to avoid excessive clutch wear. Also remember to let the box cool down between runs (but do not let it get too cold though). Our cars do not feature a dedicated DCT oil cooler in the same way M-cars do. Normally high rpms are what causes the box to heat up.

Also make sure you re-program the DCT to lower the probability of clutch slip due to running "higher-than-OEM" torque. It is all about increasing the safety limits in the software. More info here:

http://www.e90post.com/forums/showthread.php?t=745616
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      09-05-2014, 06:59 AM   #7
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Quote:
Originally Posted by Asbjorn
I agree on DSC=off + manual DCT mode. Sport+ is too jerky for any type of serious driving. Also you may want to shift before red-line at speeds above 100kmh to stay within the max power band of a tuned N54.

It is not recommendable to go WOT until the clutches are fully engaged btw... If you want to go WOT from a stand-still you better use Launch Control to avoid excessive clutch wear. Also remember to let the box cool down between runs (but do not let it get too cold though). Our cars do not feature a dedicated DCT oil cooler in the same way M-cars do. Normally high rpms are what causes the box to heat up.

Also make sure you re-program the DCT to lower the probability of clutch slip due to running "higher-than-OEM" torque. It is all about increasing the safety limits in the software. More info here:

http://www.e90post.com/forums/showthread.php?t=745616
I didn't think that the DCT could be tuned in our cars. I would be interested if this is something that can be done.
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      09-05-2014, 07:45 AM   #8
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Quote:
Originally Posted by Lambobimmer View Post
I didn't think that the DCT could be tuned in our cars. I would be interested if this is something that can be done.
I think they just increase the DCT safety limits so it doesn't de-clutch/slip because the engine produces higher torque than OEM. I know it is done as part of the ESS tune, and I would be surprised if it isn't done with other Z4 ECU software tunes as well. I haven't seen any dedicated DCT-only tuning products for the Z4 though...
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      09-05-2014, 08:25 AM   #9
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Quote:
Originally Posted by Asbjorn View Post
I think they just increase the DCT safety limits so it doesn't de-clutch/slip because the engine produces higher torque than OEM. I know it is done as part of the ESS tune, and I would be surprised if it isn't done with other Z4 ECU software tunes as well. I haven't seen any dedicated DCT-only tuning products for the Z4 though...

Gotcha. I am running Cobb and I don't think that they tune the DCT. I will check though.
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      09-05-2014, 10:24 AM   #10
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Quote:
Originally Posted by Asbjorn View Post
Sport+ is too jerky for any type of serious driving.
Does ESS have a "linear throttle" map?

The cobb "linear throttle" is very interesting, since it removes that "jerkiness" you were referring to.

Also, for what it is worth, in the stock car, I think sport+ is nice for warm up laps or driving on an unfamiliar road since it still gives a safety net while allowing a small amount of slip angle for fun.

It is too bad the adjustable suspension goes to comfort in the DSC OFF mode. It would have been nice if it stayed in the sport setting.

BTW, I read the first page of the e90 thread and couldn't find any "DCT tuning" references. Folks were just saying not to slip the clutch (i.e. use the kick down switch). Could you please let me know where to read?
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      09-05-2014, 06:58 PM   #11
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Quote:
Originally Posted by nicknaz View Post
Does ESS have a "linear throttle" map?

The cobb "linear throttle" is very interesting, since it removes that "jerkiness" you were referring to.

Also, for what it is worth, in the stock car, I think sport+ is nice for warm up laps or driving on an unfamiliar road since it still gives a safety net while allowing a small amount of slip angle for fun.

It is too bad the adjustable suspension goes to comfort in the DSC OFF mode. It would have been nice if it stayed in the sport setting.

BTW, I read the first page of the e90 thread and couldn't find any "DCT tuning" references. Folks were just saying not to slip the clutch (i.e. use the kick down switch). Could you please let me know where to read?
There is one reference in post #22 at the bottom of the first page, check it out:

http://www.e90post.com/forums/showpo...6&postcount=22

Regarding jerkiness, sorry for being unclear. I was referring to the gearshifts in sport+ which are so brutal that they chirp the tires. It is fun when you want to impress your friends, but isn't something you want during cornering at the limit on a track or on a drag-strip.

It would be fun to try the cobb tune, but probably not easy to do here. Also I am very happy with ESS.

With ESS the throttle response becomes very sensitive no matter the throttle position and drive mode. The drive mode selector essentially works the same, but ESS makes it so that if you move your foot ever so slightly, you are made aware of it. That is the only difference. OEM feels lazy and unresponsive in comparison, but is also much more comfortable to drive. You can relax your leg muscles more, because you do not need to hold your foot nearly as still to maintain constant speed/acceleration.

This has taught me that software can totally transform a car like ours, and that the most responsive "modes" of the N54 are simply not made available with our cars from factory. And I understand why, because someone in high heels wouldn't appreciate it. But I think it is what you get from the M-button in the 1-series M.

As I understand the cobb "linear throttle" it simply overrides the drive mode switch and gives you "normal", or what should be "normal", response in all drive modes, no? In any case, the type of throttle response I just described is not influenced by the drive mode switch. With ESS, the engine feels more responsive in all modes, but you could say that in sport+, you only have to press the throttle down 50% to get 90% of the power.
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      09-06-2014, 07:28 PM   #12
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Quote:
Originally Posted by Asbjorn View Post
As I understand the cobb "linear throttle" it simply overrides the drive mode switch and gives you "normal", or what should be "normal", response in all drive modes, no? In any case, the type of throttle response I just described is not influenced by the drive mode switch. With ESS, the engine feels more responsive in all modes, but you could say that in sport+, you only have to press the throttle down 50% to get 90% of the power.
Why speculate when Cobb posts the tech https://cobbtuning.zendesk.com/hc/en...rottle-ST-Maps

Quote:
Stock Throttle (ST): The stock throttle maps use the same throttle mapping that the car came with from the factory. For example, the stock throttle provides almost 80% of the requested torque load at 40% pedal input and gives the sensation of speed.

Linear Throttle (LT): LT mapping is closer to a one to one ratio. If you push the accelerator pedal 30%, you should get roughly 30% throttle. The main advantage is the ability to better modulate power and more predictable performance.
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      09-07-2014, 01:53 PM   #13
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Quote:
Originally Posted by Lambobimmer View Post
Thanks. Off subject but we are considering flying into San Fran and taking hwy 1 to San Diego over 8 or 9 days. This is probably not a fair question because there are probably 1,000 places to see but what should we not miss.
Quote:
Originally Posted by nicknaz View Post
17 mile drive in pebble beach area and Laguna Seca are the top 2 things that come to mind. Try to time it so you can do an HPDE. Great track.

Other highlights are driving over the Bixby Bridge in Big Sur, entire Santa Barbara Area is nice as well.

In my opinion, once you get past LA you've seen the highlights and you might consider just getting on the 5 and pounding through the rest of the trip.

If you have some spare time in San Diego, shoot me a PM. I have some ideas for restaurants as well (both SD and SF (lived there for 06-09)), in case you are interested
We should try to get all three Zs together for a pic when you're in SD, Lambo.
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      09-08-2014, 10:51 AM   #14
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Quote:
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We should try to get all three Zs together for a pic when you're in SD, Lambo.
+1

Avis rents the E89 Z428i at SFO in case Lambo is flying in
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      09-08-2014, 05:26 PM   #15
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+1

Avis rents the E89 Z428i at SFO in case Lambo is flying in
My bad. I forgot Lambo was in NC. I thought he was living in NorCal and driving down.
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      09-08-2014, 06:12 PM   #16
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Quote:
Originally Posted by Hujan View Post
My bad. I forgot Lambo was in NC. I thought he was living in NorCal and driving down.
Yep, I will be flying from NC to San Fran and then renting a car and driving down hwy 1 to San Diego. I wish I was able to bring my Z but that won't be an option.
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      09-08-2014, 09:49 PM   #17
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Quote:
Originally Posted by Lambobimmer
Quote:
Originally Posted by Hujan View Post
My bad. I forgot Lambo was in NC. I thought he was living in NorCal and driving down.
Yep, I will be flying from NC to San Fran and then renting a car and driving down hwy 1 to San Diego. I wish I was able to bring my Z but that won't be an option.
You don't happen to have a silver z with m badges on it do you?
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      09-08-2014, 10:26 PM   #18
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You don't happen to have a silver z with m badges on it do you?
Nope
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      09-09-2014, 07:17 AM   #19
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Originally Posted by Crazykoh View Post
You don't happen to have a silver z with m badges on it do you?
Nope
Cool. I saw the silver one down there a couple of weeks ago. I thought the owner might be lurking around here. Your car looks nice. I like the wheels.
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      09-10-2014, 06:49 PM   #20
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Nope
Nice! Wheel brand, sizes, and offsets?
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      09-10-2014, 07:23 PM   #21
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Nice! Wheel brand, sizes, and offsets?
Avant Garde M310 Wheel 19x8.5 5x120 ET35 Hyper Silver
Avant Garde M310 Wheel 19x9.5 5x120 ET33 Hyper Silver

I am running 235 in the front and 275 in the rear. Michelin Pilot Super Sport

If I had to do it over again I would buy the Apex PS-7 if you are interested in this style wheel.
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