ZPOST
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   ZPOST > BMW Z4 Technical Talk > Track / Autocross / Dragstrip / Driving Techniques
  TireRack

SUPPORT ZPOST BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER, THANKS!
Post Reply
 
Thread Tools Search this Thread
      05-05-2009, 10:04 PM   #23
Z4Kevo
Private First Class
Z4Kevo's Avatar
85
Rep
168
Posts

Drives: 2007 M Coupe
Join Date: Sep 2008
Location: Republic of Texas

iTrader: (0)

i find that the throttle response is not 100% consistent. the electronics must sense some subtle not-so-obvious difference and not allow the throttle to come up the same every single time. other instructors/drivers have made this comment when driving my car for a session or two.

Also, if you try to rev it once and you don't get enough throttle blip...good luck trying to get it to blip right away again without having to mash it down more than you want to (assuming you even have enough time to attempt another blip). it most often refuses to sufficiently respond to the additional blip.

I have found that waiting until the last possible moment to press the clutch pedal and initiating the blip/shift helps keep the tranny and engine at similar enough speeds to make the blip/shift smoother. when i get early to the clutch it can cause problems.
__________________

2007 BMW Z4M Coupe | Sapphire Black | 19" ZCP Wheels | Michelin PSS - 245/285 | Carbon Leather
Black Corners | UUC Short Shifter | ///M Racing Pedals | OE Strut Brace | LED Accents | PEMP Android
Appreciate 0
      05-06-2009, 12:44 PM   #24
The HACK
Midlife Crises Racing Silent but Deadly Class
The HACK's Avatar
1820
Rep
5,337
Posts

Drives: 2006 MZ4C, 2021 Tesla Model 3
Join Date: Oct 2007
Location: Welcome to Jamaica have a nice day

iTrader: (1)

Quote:
Originally Posted by Z4Kevo View Post
i find that the throttle response is not 100% consistent.
Typical of ALL newer BMWs with electronic drive-by-wire. Actually the MZ4 Coupe has the most consistent throttle response of all the drive-by-wire BMWs built to date.

You should drive an E9X and see what "inconsistent" throttle feels like. MASSIVE throttle delay.
Appreciate 0
      02-21-2010, 10:34 PM   #25
<<M>>
New Member
2
Rep
18
Posts

Drives: z4
Join Date: Oct 2008
Location: NC

iTrader: (0)

FWIW, I too roll my foot over. I use one half on the brake and the other half on the gas, similar to the method JRagan has come to adopt.
Appreciate 0
      02-22-2010, 02:28 AM   #26
ryanchua
Z4MC Sapphire Black
Singapore
45
Rep
177
Posts

Drives: 570-4SL
Join Date: Feb 2008
Location: Singapore

iTrader: (2)

This is me driving below. Just view the first ten seconds. Unless you want to see us monkeying around on the track.

Found that using the ball of my heel works very well. All in all, practice, practice, practice. I never got it right and always blamed the car, until one of my friends who's a better driver could nail 4-3-2 on my car very very smoothly. Only THEN i started to get it right.

Throttle is always very precise.

[u2b]<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/au_1HFpUJRo&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/au_1HFpUJRo&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>[/u2b]

Quote:
Originally Posted by jragan View Post
I, personally, am having a hard time blip-ing on downshift with the stock pedals. I can't see there's any way for me to heel-toe and it looks like the only thing I could do is along the lines of a side-step. What "maneuver" have you guys found that works best for you?
__________________
Sorely missed:
Zeta le Z4M Coupe (2008-2012)

BMW.SG - Singapore's Ultimate BMW Enthusiast Community
Appreciate 0
      02-22-2010, 07:50 AM   #27
zeroselect
New Member
0
Rep
25
Posts

Drives: Z4 M Coupe
Join Date: Jul 2009
Location: Fairfax, VA

iTrader: (0)

Quote:
Originally Posted by Z4Kevo View Post
I have found that waiting until the last possible moment to press the clutch pedal and initiating the blip/shift helps keep the tranny and engine at similar enough speeds to make the blip/shift smoother. when i get early to the clutch it can cause problems.
You should have your clutch depressed at the moment of braking. If you don't release the engine from the drivetrain you not only be braking to reduce the motion of the car but also your engine as well. Some might think that "engine braking" would help the car decclerate faster but it does the exact opposite.
__________________
Daily/Autox: 06 BMW Z4M Interlagos Blue
Track: 95 Nissan 240sx SR20DET powered
Beater: 87 Toyota Cressida
Spare Track: 93 Nissan 240sx
Appreciate 0
      02-22-2010, 08:46 AM   #28
onelove
Track Head
onelove's Avatar
United_States
24
Rep
503
Posts

Drives: 07 Z4M
Join Date: Jan 2008
Location: Orlando,FL

iTrader: (0)

I used the alternative method as well, practice every day on my commute to work, trips to the grocery store, etc. It's quite funny how many people will try to race you thinking you're "reving" at them but I just ignore it. I've also found it a lot easier to learn with sport mode off, but have things figured out where I can also manage with it on now as well.
Appreciate 0
      02-24-2010, 02:55 PM   #29
R32
Second Lieutenant
7
Rep
222
Posts

Drives:
Join Date: Jul 2007

iTrader: (0)

Quote:
Originally Posted by zeroselect View Post
You should have your clutch depressed at the moment of braking. If you don't release the engine from the drivetrain you not only be braking to reduce the motion of the car but also your engine as well. Some might think that "engine braking" would help the car decclerate faster but it does the exact opposite.
i've never heard this bit of advice before-- just the opposite, really, which is to keep the car engaged in gear as much as possible.

what you say is true, of course, since the engine just adds to the momentum (and inertia) of the moving car while in gear.

i'd guess it would be harder (for me) to properly rev-match if the rpms are allowed to fall all the way to idle by disengaging the clutch as soon as the brakes are applied.
Appreciate 0
      02-24-2010, 03:33 PM   #30
O-cha
Brigadier General
O-cha's Avatar
218
Rep
4,726
Posts

Drives: Mcoupe
Join Date: Oct 2007
Location: In front of you

iTrader: (2)

Quote:
Originally Posted by zeroselect View Post
You should have your clutch depressed at the moment of braking. If you don't release the engine from the drivetrain you not only be braking to reduce the motion of the car but also your engine as well. Some might think that "engine braking" would help the car decclerate faster but it does the exact opposite.
About 1 million racers data acquisition and physics disagrees with you.

Quote:
Originally Posted by R32 View Post
i've never heard this bit of advice before-- just the opposite, really, which is to keep the car engaged in gear as much as possible.
Go to 7k and kick in the clutch, then go to 7k and just take your foot off the gas, pretty clear what the difference is.

Friction and pumping > inertia in this case, especially in an 11.5:1 engine.
__________________
Appreciate 0
      02-25-2010, 12:21 AM   #31
RussRamz
M Slut
RussRamz's Avatar
United_States
18
Rep
564
Posts

Drives: 2011 M3 Coupe Mineral White
Join Date: Sep 2007
Location: Adenau, GE via 3 years in dreadful El Paso, TX

iTrader: (0)

Quote:
Originally Posted by zeroselect View Post
You should have your clutch depressed at the moment of braking. If you don't release the engine from the drivetrain you not only be braking to reduce the motion of the car but also your engine as well. Some might think that "engine braking" would help the car decclerate faster but it does the exact opposite.
I agree you should not engine-brake since that is what brakes are for, but depressing the clutch while braking is only necessary if you are changing into a different gear.
__________________
You have to be 100% behind someone before you can stab them in the back.

David Brent
Appreciate 0
      02-25-2010, 09:40 AM   #32
O-cha
Brigadier General
O-cha's Avatar
218
Rep
4,726
Posts

Drives: Mcoupe
Join Date: Oct 2007
Location: In front of you

iTrader: (2)

Quote:
Originally Posted by RussRamz View Post
I agree you should not engine-brake since that is what brakes are for, but depressing the clutch while braking is only necessary if you are changing into a different gear.
I've always felt that the car wants to rotate more when I end up braking at really low revs or with the clutch in.
__________________
Appreciate 0
      02-25-2010, 03:10 PM   #33
onelove
Track Head
onelove's Avatar
United_States
24
Rep
503
Posts

Drives: 07 Z4M
Join Date: Jan 2008
Location: Orlando,FL

iTrader: (0)

Quote:
Originally Posted by O-cha View Post
I've always felt that the car wants to rotate more when I end up braking at really low revs or with the clutch in.
I've found similar as well.
Appreciate 0
      02-25-2010, 04:01 PM   #34
F360C
Major
United_States
366
Rep
1,373
Posts

Drives: E86 S54
Join Date: Apr 2006
Location: Hoboken, NJ

iTrader: (2)

Quote:
Originally Posted by zeroselect View Post
You should have your clutch depressed at the moment of braking. If you don't release the engine from the drivetrain you not only be braking to reduce the motion of the car but also your engine as well. Some might think that "engine braking" would help the car decclerate faster but it does the exact opposite.
Please tell me you are not serious?
__________________

07 Z4 M Coupe AW/IR
Appreciate 0
      02-26-2010, 12:59 AM   #35
RussRamz
M Slut
RussRamz's Avatar
United_States
18
Rep
564
Posts

Drives: 2011 M3 Coupe Mineral White
Join Date: Sep 2007
Location: Adenau, GE via 3 years in dreadful El Paso, TX

iTrader: (0)

Quote:
Originally Posted by O-cha View Post
I've always felt that the car wants to rotate more when I end up braking at really low revs or with the clutch in.
Do I understand you are depressing the clutch in the corner in order to rotate the car? I use trailing-throttle-oversteer to rotate through corners and have tuned the suspension in order to accomplish this. The only time I am on the clutch is changing gears. Balancing the car through the corner modulating the throttle is my driving style. One of many fundamentals I was taught by a pro race driver was to put the car into the proper gear BEFORE entering a corner--this includes clutch depression. I'm not saying what you are doing is necessarily wrong, just not what I learned and not my style. I would think using trailing-throttle oversteer would rotate the car more than simply depressing the clutch.
__________________
You have to be 100% behind someone before you can stab them in the back.

David Brent
Appreciate 0
      02-26-2010, 01:26 AM   #36
O-cha
Brigadier General
O-cha's Avatar
218
Rep
4,726
Posts

Drives: Mcoupe
Join Date: Oct 2007
Location: In front of you

iTrader: (2)

Quote:
Originally Posted by RussRamz View Post
Do I understand you are depressing the clutch in the corner in order to rotate the car? I use trailing-throttle-oversteer to rotate through corners and have tuned the suspension in order to accomplish this. The only time I am on the clutch is changing gears. Balancing the car through the corner modulating the throttle is my driving style. One of many fundamentals I was taught by a pro race driver was to put the car into the proper gear BEFORE entering a corner--this includes clutch depression. I'm not saying what you are doing is necessarily wrong, just not what I learned and not my style. I would think using trailing-throttle oversteer would rotate the car more than simply depressing the clutch.
No, you're way off base. I am simply saying hat if you brake really hard out of gear, the car wants to rotate more, like in a straight line. Loss of engine braking does that since the brake bias effectively changes as a result.


Same idea as if you go through a corner that you could be in 2nd gear for in 3rd, you will push like crazy because the weight isn't being put on the front wheels from the engine braking.
__________________
Appreciate 0
      02-26-2010, 01:31 AM   #37
Diokaef
Engineer
Diokaef's Avatar
United_States
212
Rep
2,122
Posts

Drives: M235I 2015, 335i 2011
Join Date: Dec 2009
Location: TAMPA FL

iTrader: (17)

Garage List
2008 Z4M Coupe  [6.33]
Quote:
Originally Posted by RussRamz View Post
I use trailing-throttle-oversteer to rotate through corners and have tuned the suspension in order to accomplish this. The only time I am on the clutch is changing gears. Balancing the car through the corner modulating the throttle is my driving style. One of many fundamentals I was taught by a pro race driver was to put the car into the proper gear BEFORE entering a corner--this includes clutch depression. I would think using trailing-throttle oversteer would rotate the car more than simply depressing the clutch.

I agree

That is how I do as well, and work's perfectly for me. I start using that after driving a oldsmobile for sometime, and that car was horrible, so using this method I always had way more control.

please don't ask me what I was doing driving a oldsmobile
Appreciate 0
      02-26-2010, 01:35 AM   #38
Diokaef
Engineer
Diokaef's Avatar
United_States
212
Rep
2,122
Posts

Drives: M235I 2015, 335i 2011
Join Date: Dec 2009
Location: TAMPA FL

iTrader: (17)

Garage List
2008 Z4M Coupe  [6.33]
Quote:
Originally Posted by O-cha View Post
No, you're way off base. I am simply saying hat if you brake really hard out of gear, the car wants to rotate more, like in a straight line. Loss of engine braking does that since the brake bias effectively changes as a result.


Same idea as if you go through a corner that you could be in 2nd gear for in 3rd, you will push like crazy because the weight isn't being put on the front wheels from the engine braking.
I agree with that as well, but really depends on your suspension setup. I always had my suspension done for my way of driving.

(off topic: Illinois sucks about people to work on race or sport cars)
Appreciate 0
      02-26-2010, 01:41 AM   #39
Diokaef
Engineer
Diokaef's Avatar
United_States
212
Rep
2,122
Posts

Drives: M235I 2015, 335i 2011
Join Date: Dec 2009
Location: TAMPA FL

iTrader: (17)

Garage List
2008 Z4M Coupe  [6.33]
Quote:
Originally Posted by O-cha View Post
No, you're way off base. I am simply saying hat if you brake really hard out of gear, the car wants to rotate more, like in a straight line. Loss of engine braking does that since the brake bias effectively changes as a result.


Same idea as if you go through a corner that you could be in 2nd gear for in 3rd, you will push like crazy because the weight isn't being put on the front wheels from the engine braking.

(I believe he does that as well) I do, using the brakes will shift the weight to the front, and that is the moment that shifting to a lower gear and giving gas you gain control of the car, and with some oversteer the turn is complete.

but this need to be a smooth.
Appreciate 0
      03-01-2010, 11:46 AM   #40
zeroselect
New Member
0
Rep
25
Posts

Drives: Z4 M Coupe
Join Date: Jul 2009
Location: Fairfax, VA

iTrader: (0)

Quote:
Originally Posted by R32 View Post
i've never heard this bit of advice before-- just the opposite, really, which is to keep the car engaged in gear as much as possible.

what you say is true, of course, since the engine just adds to the momentum (and inertia) of the moving car while in gear.

i'd guess it would be harder (for me) to properly rev-match if the rpms are allowed to fall all the way to idle by disengaging the clutch as soon as the brakes are applied.
This should be only done if your changing down a gear. If you don't need to change down gear you will not be brake enough anyways to have the engines interia be a problem.
__________________
Daily/Autox: 06 BMW Z4M Interlagos Blue
Track: 95 Nissan 240sx SR20DET powered
Beater: 87 Toyota Cressida
Spare Track: 93 Nissan 240sx
Appreciate 0
      03-01-2010, 11:47 AM   #41
zeroselect
New Member
0
Rep
25
Posts

Drives: Z4 M Coupe
Join Date: Jul 2009
Location: Fairfax, VA

iTrader: (0)

Quote:
Originally Posted by O-cha View Post
About 1 million racers data acquisition and physics disagrees with you.



Go to 7k and kick in the clutch, then go to 7k and just take your foot off the gas, pretty clear what the difference is.

Friction and pumping > inertia in this case, especially in an 11.5:1 engine.
I would like to see the "1 million" of data that racers have.

If someone is still going to school ask your physics teacher.

Also don't forget that "engine braking" will put more stress on your engine.
__________________
Daily/Autox: 06 BMW Z4M Interlagos Blue
Track: 95 Nissan 240sx SR20DET powered
Beater: 87 Toyota Cressida
Spare Track: 93 Nissan 240sx
Appreciate 0
      03-01-2010, 12:18 PM   #42
Crimson92
Smiling Politely
Crimson92's Avatar
United_States
1381
Rep
29,118
Posts

Drives: Like a boss
Join Date: Jun 2007
Location: Whales Vagina

iTrader: (3)

Quote:
Originally Posted by zeroselect View Post
I would like to see the "1 million" of data that racers have.

If someone is still going to school ask your physics teacher.

Also don't forget that "engine braking" will put more stress on your engine.
if thats your theory how would you explain automatics? they engine brake

Watch some races....they dont sit on the clutch when they brake in corners, they use the engine/brakes.
__________________
Quote:
Some people are like slinkies...not really good for much but you can't help but smile when you see one tumble down the stairs"
Appreciate 0
      03-01-2010, 04:10 PM   #43
O-cha
Brigadier General
O-cha's Avatar
218
Rep
4,726
Posts

Drives: Mcoupe
Join Date: Oct 2007
Location: In front of you

iTrader: (2)

Quote:
Originally Posted by zeroselect View Post
I would like to see the "1 million" of data that racers have.

If someone is still going to school ask your physics teacher.

Also don't forget that "engine braking" will put more stress on your engine.
This kids a joke....
__________________
Appreciate 0
      03-01-2010, 04:37 PM   #44
onelove
Track Head
onelove's Avatar
United_States
24
Rep
503
Posts

Drives: 07 Z4M
Join Date: Jan 2008
Location: Orlando,FL

iTrader: (0)

Quote:
Originally Posted by Crimson92 View Post
if thats your theory how would you explain automatics? they engine brake

Watch some races....they dont sit on the clutch when they brake in corners, they use the engine/brakes.
Most current race cars use sequential dog-gear style transmissions which only hammer O-cha's point further. The clutch is used to get the car moving, but between gear shifts up and down only a momentary release of the gas is required to prevent torque transfer from gear to gear. The engine remains loaded except for a brief second for gear changes.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 02:30 AM.




zpost
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST