BMW M3 Forum (E90 E92)

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


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Track / Autocross / Dragstrip / Driving Techniques
 
European Auto Source
Post Reply
 
Thread Tools Search this Thread
      08-29-2008, 11:15 PM   #67
lucid
Major General
 
lucid's Avatar
 
Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

Posts: 8,034
iTrader: (0)

Quote:
Originally Posted by sayemthree View Post
so is the M3!!!!
Not at all. They will make more than 10000 of M3s per year. How many Viper ACRs do you think they will sell at $100k? And the Viper ACR is clearly meant for the track; adjustable suspension and wings and all. I read 1000 lbs potential downforce at 150mph!
__________________
lucid is offline   United_States
0
Reply With Quote
      08-30-2008, 12:09 AM   #68
sayemthree
Brigadier General
 
sayemthree's Avatar
 
Drives: bmw
Join Date: Aug 2007
Location: usa

Posts: 4,845
iTrader: (0)

Quote:
Originally Posted by lucid View Post
Not at all. They will make more than 10000 of M3s per year. How many Viper ACRs do you think they will sell at $100k? And the Viper ACR is clearly meant for the track; adjustable suspension and wings and all. I read 1000 lbs potential downforce at 150mph!

in a world of 250,000 camrys and accords each imported to the USA , 10k sounds pretty limitedd pruduction to me.

agree tho the ACR is in another league - but its also clearly not a DD.
sayemthree is offline  
0
Reply With Quote
      08-30-2008, 12:17 AM   #69
sayemthree
Brigadier General
 
sayemthree's Avatar
 
Drives: bmw
Join Date: Aug 2007
Location: usa

Posts: 4,845
iTrader: (0)

the top times , ACR and GT3 are on PSC rubber. I think even the GTR tires are aan almost R-comp tire. I am thinking the M3 could break into the 1.39's on R rubber?


Viper ACR 1:35.117
GT3 1:39.517
GTR 1:40.4
Z06 1:40.919
R8 1:40.9
911T 1:42.5
M3 1:42.9
Exige S 1:45.818
Cayman S 1:47.577
EVO 1:47.7
Cobalt 1:47.7
335i 1:49.038
Mazdaspeed3 1:50.375
Rx8 1:50.4
S2000 1:50.738
Mini S JCW 1:51.733
MINI 1:51.9
Civic Si 1:54.990
sayemthree is offline  
0
Reply With Quote
      08-30-2008, 01:20 AM   #70
e36jakeo
Captain
 
Drives: 2008 M3 6 Speed MT!
Join Date: Oct 2006
Location: Northern CA

Posts: 624
iTrader: (0)

[quote=sayemthree;3247979]the top times , ACR and GT3 are on PSC rubber. I think even the GTR tires are aan almost R-comp tire. I am thinking the M3 could break into the 1.39's on R rubber? ]

I think PS2s are probably close to as sticky as PSCs (which are not that sticky for an R-compound). I'd guess that a switch from PS2s to PSCs would be worth 2 seconds at the most. And if you went to something stickier (R6 or similar) then you would be seriously taxing the suspension (not a high enough spring rate/dampening or enough camber) so just bolting them on may not be worth as much as you might think. Still, 1:39.9 is only 3 seconds away . . .

Anyone want to volunteer to try for the '39s?!
__________________
Driving sideways: It's not faster, but damn it's more fun!
e36jakeo is offline   United_States
0
Reply With Quote
      08-30-2008, 02:12 AM   #71
sayemthree
Brigadier General
 
sayemthree's Avatar
 
Drives: bmw
Join Date: Aug 2007
Location: usa

Posts: 4,845
iTrader: (0)

[quote=e36jakeo;3248128][quote=sayemthree;3247979]the top times , ACR and GT3 are on PSC rubber. I think even the GTR tires are aan almost R-comp tire. I am thinking the M3 could break into the 1.39's on R rubber? ]

Quote:
I think

a PSC will beat the PS by 1.36 sec. over a 30 sec autocross. translate that to a 1.40 time and thats over 4 seconds!!!! (tire rack tests)


http://www.tirerack.com/tires/tests/...ay.jsp?ttid=36
sayemthree is offline  
0
Reply With Quote
      08-30-2008, 03:19 AM   #72
footie
Major General
 
footie's Avatar
 
Drives: ????????????
Join Date: Oct 2007
Location: BMW M3 will get a V6TT

Posts: 7,507
iTrader: (0)

Garage List
2008 E92 M3  [0.00]
Quote:
Originally Posted by e36jakeo View Post
I think PS2s are probably close to as sticky as PSCs (which are not that sticky for an R-compound). I'd guess that a switch from PS2s to PSCs would be worth 2 seconds at the most. And if you went to something stickier (R6 or similar) then you would be seriously taxing the suspension (not a high enough spring rate/dampening or enough camber) so just bolting them on may not be worth as much as you might think. Still, 1:39.9 is only 3 seconds away . . .

Anyone want to volunteer to try for the '39s?!


Finally, someone else saying basically the same as I have done on multiple thread when the subject of R-compound rubber is mentioned and by how much it will improve a car on stock suspension.
footie is offline   No_Country
0
Reply With Quote
      08-30-2008, 07:26 AM   #73
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,705
iTrader: (0)

The main reason that I run an "R" compound tire on the track is to reduce costs.Most R compounds cost about 50% of the the stock PS2's and will last much longer than a street tire with a little bit of care.I think the stock PS2's do a darn good job and my Toyo r888's are an OK trackday tire but far from being the quickest available and to take full advantage of the grip available there are things that should be done(alignment),but I will not do as this would ruin the everyday livibility of this car.If I get real serious about track days in the future,I will stop doing bike days and my Ducati track bike will be replaced by a proper dedicated track day car with full safety gear.
Gearhead999s is offline  
0
Reply With Quote
      08-30-2008, 10:22 AM   #74
sayemthree
Brigadier General
 
sayemthree's Avatar
 
Drives: bmw
Join Date: Aug 2007
Location: usa

Posts: 4,845
iTrader: (0)

Quote:
Originally Posted by footie View Post


Finally, someone else saying basically the same as I have done on multiple thread when the subject of R-compound rubber is mentioned and by how much it will improve a car on stock suspension.

I have run stock BMW's for years with R-comp tires. they rock, they do last much longer on the track too. also street tires overheat quickly and lose grip on the track.

also how can you argue with the Tire Rack test.
sayemthree is offline  
0
Reply With Quote
      08-30-2008, 11:06 AM   #75
Dascamel
Lieutenant Colonel
 
Dascamel's Avatar
 
Drives: 2008 e92 M3, 2010 e91 328i
Join Date: Jul 2007
Location: Bakersfield, CA

Posts: 1,662
iTrader: (0)

2-3 seconds b/c of improved traction isn't far fetched...
__________________
2008 E92 M3 Jerez Black,DCT,Fox Red ext,Prem,Tech,19", ipod/usb, CF roof and trim
2010 E91 328i Space Gray,Black int, M sport, most options
2007 Montego Blue 335i (retired)
Dascamel is offline  
0
Reply With Quote
      08-30-2008, 01:26 PM   #76
footie
Major General
 
footie's Avatar
 
Drives: ????????????
Join Date: Oct 2007
Location: BMW M3 will get a V6TT

Posts: 7,507
iTrader: (0)

Garage List
2008 E92 M3  [0.00]
Quote:
Originally Posted by sayemthree View Post
I have run stock BMW's for years with R-comp tires. they rock, they do last much longer on the track too. also street tires overheat quickly and lose grip on the track.

also how can you argue with the Tire Rack test.
Sayemthree,

You and I have never crossed words or disagreed on very much and I don't want this to happen here either, so please let me explain why I say what I do and why I know I am correct.

Firstly, yes I totally agree, R-compound will last much longer than stock rubber, they were never meant to get the kind of abuse that trackdays give, they were design for comfort, noise, dry handling & braking plus wet handling, braking and aquaplaning. Basically a road tyre is a jack of all trades, something a race breed compound doesn't have to contend with.

Secondly, I am not saying that fitting R-compound tyres won't improve the time of a stock car, I have never said different, all I am saying is that the tyres aren't working at their optimum and to do that the suspension has to be tuned to work the tyres harder. Manufacturers work very closely with tyre manufacturers to develop a tyre for a certain model, if anything it proves that you can't just throw on anything and hope for the best.

What Tire Track tests are proving is there is a difference but then I never said there wasn't, just that it's not as great as it could be.
footie is offline   No_Country
0
Reply With Quote
      08-30-2008, 07:41 PM   #77
sayemthree
Brigadier General
 
sayemthree's Avatar
 
Drives: bmw
Join Date: Aug 2007
Location: usa

Posts: 4,845
iTrader: (0)

Quote:
Originally Posted by footie View Post
Sayemthree,

You and I have never crossed words or disagreed on very much and I don't want this to happen here either, so please let me explain why I say what I do and why I know I am correct.

Firstly, yes I totally agree, R-compound will last much longer than stock rubber, they were never meant to get the kind of abuse that trackdays give, they were design for comfort, noise, dry handling & braking plus wet handling, braking and aquaplaning. Basically a road tyre is a jack of all trades, something a race breed compound doesn't have to contend with.

Secondly, I am not saying that fitting R-compound tyres won't improve the time of a stock car, I have never said different, all I am saying is that the tyres aren't working at their optimum and to do that the suspension has to be tuned to work the tyres harder. Manufacturers work very closely with tyre manufacturers to develop a tyre for a certain model, if anything it proves that you can't just throw on anything and hope for the best.

What Tire Track tests are proving is there is a difference but then I never said there wasn't, just that it's not as great as it could be.
thats true on a lot of street cars. but the M3 suspension is very well set up. on my e46 for example the tire temps across the tire after a track session indicated need for metter alignment/camber etc. but based on tracking the e92 m3 with AR tires Ifound the tire temps were very even accross the tires.

so we agree a custom alignment would optimize the use of R tires and we agree R tires are faster on the track.
sayemthree is offline  
0
Reply With Quote
      08-30-2008, 08:24 PM   #78
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,705
iTrader: (0)

Quote:
Originally Posted by sayemthree View Post
thats true on a lot of street cars. but the M3 suspension is very well set up. on my e46 for example the tire temps across the tire after a track session indicated need for metter alignment/camber etc. but based on tracking the e92 m3 with AR tires Ifound the tire temps were very even accross the tires.

so we agree a custom alignment would optimize the use of R tires and we agree R tires are faster on the track.
Geez that is not what I found with mine.According to the tire temps that we took on my car with the R888's we were thinking that we needed somewhere around 3-3.5 - negative camber to make the tires work like they should.Toyo & Hoosier and if I remember correctly want to to see 3-5 -camber for the tire to work properly like it is designed.I know that on our old Firehawk car we ran about 3-3.5 -negative front & rear on a very stiff setup(500lbfr/850 lb/in rear) with big bars and tires had very good temps.You must not be pushing that hard if you dont think you need more camber.
Gearhead999s is offline  
0
Reply With Quote
      08-30-2008, 08:49 PM   #79
enigma
Captain
 
Drives: E92 M3 and Elise
Join Date: Oct 2006
Location: Land of the Microchip

Posts: 689
iTrader: (0)

Quote:
Originally Posted by e36jakeo View Post
Anyone want to volunteer to try for the '39s?!
Very tempting......

I already have the race tires and wheels.
__________________
Manual gearboxes, the rotary dial of cars.
enigma is offline  
0
Reply With Quote
      08-30-2008, 08:54 PM   #80
enigma
Captain
 
Drives: E92 M3 and Elise
Join Date: Oct 2006
Location: Land of the Microchip

Posts: 689
iTrader: (0)

Quote:
Originally Posted by Gearhead999s View Post
You must not be pushing that hard if you dont think you need more camber.
Be carefull, he gets upset when you point that out...

The amount of camber you need depends on a lot of things. I don't have enough wear on my nt-01s yet to guage the cars behavior in thise regard. So far it appears to do better than I expected. It also varries a lot from tire to tire.

On one car I had 048s wear even, RA-1s wear very uneven, and the A6s a little uneven but not as bad as the RA-1s. Same track springs and alignment for all.
__________________
Manual gearboxes, the rotary dial of cars.
enigma is offline  
0
Reply With Quote
      08-30-2008, 09:15 PM   #81
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,705
iTrader: (0)

Quote:
Originally Posted by enigma View Post
Be carefull, he gets upset when you point that out...

The amount of camber you need depends on a lot of things. I don't have enough wear on my nt-01s yet to guage the cars behavior in thise regard. So far it appears to do better than I expected. It also varries a lot from tire to tire.

On one car I had 048s wear even, RA-1s wear very uneven, and the A6s a little uneven but not as bad as the RA-1s. Same track springs and alignment for all.
Cars with a lot of castor which promotes lots of camber gain usually do not need a lot of static camber which is a good thing.Threshold braking with a lot of negative can be a very frustrating thing also.Lighter cars like your Lotus usually do not need to be as extreme is alignment settings as a heavier car as they tend to have better geometry from the start.
Gearhead999s is offline  
0
Reply With Quote
      08-30-2008, 09:56 PM   #82
enigma
Captain
 
Drives: E92 M3 and Elise
Join Date: Oct 2006
Location: Land of the Microchip

Posts: 689
iTrader: (0)

Quote:
Originally Posted by Gearhead999s View Post
Cars with a lot of castor which promotes lots of camber gain usually do not need a lot of static camber which is a good thing.
Depends. If you know how fast your turns are, it can be good. Problem is with tons of caster you generally either sacrifice slow or fast turn for the other.
__________________
Manual gearboxes, the rotary dial of cars.
enigma is offline  
0
Reply With Quote
      08-30-2008, 10:09 PM   #83
ace996
NASA/PDA Instructor
 
ace996's Avatar
 
Drives: E92M3
Join Date: Aug 2008
Location: Long Island

Posts: 284
iTrader: (0)

The local rule of thumb has always been that an r-compound DOT-tire, a good one... Hoosier or Kumho slick, will give about 2 seconds for a 1 minute lap on any given suspension. If you have the ability to dial-in the extra grip afforded by the "sticky", then you'll find more time.
__________________

"Arcadian, I've fought countless times, yet I've never met an adversary who could offer me what we Spartans call "A Beautiful Death." I can only hope, with all the world's warriors gathered against us, there might be one down there who's up to the task."Μολὼν λαβέ!!
ace996 is offline   United_States
0
Reply With Quote
      08-30-2008, 11:17 PM   #84
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,705
iTrader: (0)

Quote:
Originally Posted by enigma View Post
Depends. If you know how fast your turns are, it can be good. Problem is with tons of caster you generally either sacrifice slow or fast turn for the other.
I never had a street based car that you could crank in too much castor,but I am sure every case is different.
Gearhead999s is offline  
0
Reply With Quote
      08-31-2008, 12:58 AM   #85
sayemthree
Brigadier General
 
sayemthree's Avatar
 
Drives: bmw
Join Date: Aug 2007
Location: usa

Posts: 4,845
iTrader: (0)

Quote:
Originally Posted by ace996 View Post
The local rule of thumb has always been that an r-compound DOT-tire, a good one... Hoosier or Kumho slick, will give about 2 seconds for a 1 minute lap on any given suspension. If you have the ability to dial-in the extra grip afforded by the "sticky", then you'll find more time.
depends on the street tire. you could have 2-3 sec per lap diff between just between street tires. the tests I have seen show more like 2 to 4 sec per 60 sec lap for a R -comp tire.
heck.... the new BFG tire beat the Hoosier by 1 second alone only on a 45 sec course. thats 1.3 sec per 60 sec lap just between R-comp tires alone!
sayemthree is offline  
0
Reply With Quote
      08-31-2008, 03:41 AM   #86
footie
Major General
 
footie's Avatar
 
Drives: ????????????
Join Date: Oct 2007
Location: BMW M3 will get a V6TT

Posts: 7,507
iTrader: (0)

Garage List
2008 E92 M3  [0.00]
To say as a rule of thumb that R-compound is 1s or more per 60 seconds is not true, each track and conditions are different, the same goes for model that the tyres are placed on. It all depends on the corners involved and the length of the straights.

On a tight course the improvement will be greater but don't think that the same improvement will be there on a track like the ring. Listen to Enigma and Gearhead, they understand that stock suspension settings are not optimum for track tyres, to make maximum gains requires adjustment and a lot more bravery on your part, it is amazing how hard it is to accept that you can go harder.
footie is offline   No_Country
0
Reply With Quote
      08-31-2008, 06:13 AM   #87
Gearhead999s
Major General
 
Gearhead999s's Avatar
 
Drives: E93 335is(wifes)E92 M3
Join Date: Apr 2007
Location: Toronto

Posts: 6,705
iTrader: (0)

Just to clarify a point on knowing that I need a lot more camber in the M3 is that at the 1st trackday that I did with the car,we had a 200 ft skidpad to use and a tire temp gauge.There was over 40 degrees diff inside to outside on the fronts and 15 on the rear in both dirrections.We were not guessing at this.
But that brings me back to the point that the M3 is a wonderful everday car with its standard settings,but like any other car it does need to be optimized for the track to work at its best.I dont think that I am willing to put up with that comprimise,so when I track it I know I am leaving a lot on the table but still having a lot of fun in a fast track day car.
Gearhead999s is offline  
0
Reply With Quote
      08-31-2008, 08:27 AM   #88
footie
Major General
 
footie's Avatar
 
Drives: ????????????
Join Date: Oct 2007
Location: BMW M3 will get a V6TT

Posts: 7,507
iTrader: (0)

Garage List
2008 E92 M3  [0.00]
Gearhead,

Maybe a bit too early but how are the tyres wearing, is it even across the tread?
footie is offline   No_Country
0
Reply With Quote
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
Forum Jump


All times are GMT -5. The time now is 12:36 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
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