BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i)
 





 

Post Reply
 
Thread Tools Search this Thread
      10-10-2014, 07:51 AM   #45
fe1rx
Captain
1390
Rep
776
Posts

Drives: 135i, 328i, Cayman S
Join Date: Jan 2008
Location: Canada

iTrader: (3)

Quote:
Originally Posted by Ganicki View Post
Well, the weekend was a blast, learned a lot, NCM Motorsports Park is awesome and long-- 23 turns-- got consistently faster and faster--Instructors were great at guiding and even got confused on the course-- I have a long way to go before I'd do any other mods to the 135i. Have a lot of other elements of HPDE to pick up and perfect before I start spending money.

fe1rx thats everything I heard from my instructors after 8 sessions it was all starting to sink in-- Thanks

The image below is from turn 19 into the sinkhole and yes, that is the angle of descent-- map is upside down because the Pit out is at turn 1B
I am glad you went and got hooked. The track looks very interesting and challenging. Spend lots of money on track fees and tires before you worry too much about modifying your car. I am sure you now have an appreciation about how much there is to learn at the track. Have fun doing that!
Appreciate 0
      10-10-2014, 09:55 PM   #46
Diver
Brigadier General
Diver's Avatar
United_States
504
Rep
3,446
Posts

Drives: Black '12 135i - Sold
Join Date: Nov 2010
Location: Texas

iTrader: (0)

Some things...

Many around here go from the 215-40/245-35 setup to 225-40/255-35. That does nothing to either increase front grip or decrease rear grip. It is possible on the later model 135i cars to get 1.5 degree negative camber up front via alignment adjustment.

All sorts of mods get discussed around here, but I can't ever remember seeing before and after lap times. At least with engine mods there are dyno runs and time slips. Lacking good data, it is hard to believe just about anything.

The guys who say learn how to drive fast, are the smartest guys in the room.
__________________
Appreciate 0
      10-11-2014, 10:33 AM   #47
Ginger_Extract
California-bound
Ginger_Extract's Avatar
United_States
383
Rep
1,480
Posts

Drives: BMW 135i
Join Date: Jan 2013
Location: Los Angeles, CA

iTrader: (3)

Quote:
Originally Posted by Diver View Post
All sorts of mods get discussed around here, but I can't ever remember seeing before and after lap times. At least with engine mods there are dyno runs and time slips. Lacking good data, it is hard to believe just about anything.

The guys who say learn how to drive fast, are the smartest guys in the room.
See my signature, stock 135i with 225/255 compared to Vorshlag camber plates on stock springs/dampers w/ 255 squared. With no other changes netted me about 2 seconds a lap at most of the track I frequent.

With AutoX, it's harder to put a concrete number on it since the course changes every event. However, comparing deltas between myself and the hot shoes in my class, the difference from tire grip alone was substantial. However, the car needs a lot more tire to really turn the way I want it to.
__________________
Streets of Willow: 1:27.7 CW 11/15/15; 1:29.5 CCW 8/15/15 |||| Autoclub Speedway ROVAL (CCW): 1.52.6 - 12/2/17
Willow Springs - Big Willow (CW): 1:35.8 - 3/31/18 |||| Buttonwillow #13 (CW): 1:59.3 1/27/18
https://www.facebook.com/JakeStumphRacing |||| http://www.youtube.com/user/RaceMeMZ3
Appreciate 0
      10-13-2014, 09:32 AM   #48
fcman
Captain
654
Rep
976
Posts

Drives: 2023 G87
Join Date: Mar 2014
Location: Atlanta, GA

iTrader: (0)

Quote:
Originally Posted by Diver View Post
It is possible on the later model 135i cars to get 1.5 degree negative camber up front via alignment adjustment.
Source on this?
Appreciate 0
      10-13-2014, 01:25 PM   #49
Diver
Brigadier General
Diver's Avatar
United_States
504
Rep
3,446
Posts

Drives: Black '12 135i - Sold
Join Date: Nov 2010
Location: Texas

iTrader: (0)

Quote:
Originally Posted by fcman View Post
Source on this?
I don't have an instrument for an accurate measurement, but I would say -1.5 is what I have on a stock 2012 that was aligned at the dealer. I did not ask them to max it out, but that is what they did.
__________________
Appreciate 0
      10-13-2014, 02:18 PM   #50
02rsxpilot
First Lieutenant
02rsxpilot's Avatar
United_States
47
Rep
327
Posts

Drives: 2012 BMW 135i
Join Date: Apr 2013
Location: NorCal

iTrader: (2)

Garage List
2012 BMW 135i  [10.00]
2013 Mini Cooper S  [0.00]
2002 Acura RSX  [0.00]
Quote:
Originally Posted by Diver View Post
I don't have an instrument for an accurate measurement, but I would say -1.5 is what I have on a stock 2012 that was aligned at the dealer. I did not ask them to max it out, but that is what they did.
It's well documented that stock 1ers of all years can only achieve a max camber of around -0.5 per side. That's all multiple shops in my area could get out of my stock 2012. You need camber plates and M3 LCAs to get anywhere near -1.5. No way a dealer could or would get you there, particularly if you didn't ask for max camber. Even if they could get you that much, the alignment machine would flag that as being out of the accepted range and the tech would adjust it back down.
__________________
2012 BMW 135i DCT - M3 Front Control Arms, Whiteline RSFB, Dinan camber plates.
Appreciate 0
      10-13-2014, 04:23 PM   #51
Diver
Brigadier General
Diver's Avatar
United_States
504
Rep
3,446
Posts

Drives: Black '12 135i - Sold
Join Date: Nov 2010
Location: Texas

iTrader: (0)

Quote:
Originally Posted by 02rsxpilot View Post
It's well documented that stock 1ers of all years can only achieve a max camber of around -0.5 per side. That's all multiple shops in my area could get out of my stock 2012. You need camber plates and M3 LCAs to get anywhere near -1.5. No way a dealer could or would get you there, particularly if you didn't ask for max camber. Even if they could get you that much, the alignment machine would flag that as being out of the accepted range and the tech would adjust it back down.
If I take a carpenter's level and get it vertical against the tire, just far enough from the contact patch so that the tire is not squishing out at the bottom then then near the top of the tire it will be .5" leaning in towards the car's center over a 21 inch space. That slope is .0238. The tangent of 1.35 degrees happens to be about the same, so I think the camber is 1.35 degrees negative.

Now perhaps I am doing that completely wrong, so enlighten me. What I don't understand around here is a lot of forum members keep the three size differential between front and rear when the first thing I always thought was a cure for under steer was larger front tires. Some of the AC guys go square which should help things a lot. I get the impression that over steer might help a lot more on and AC course than a road course.

Meanwhile, even if I see one report of a track time comparison, which is nice, I rarely see them, and driver skills play a greater role at the track or AC than at the drag strip. It may be the same driver before and after, but an occasional track user is not going to be as consistent as a pro, and will probably improve more noticeably between sessions.

Unfortunately we don't have the kind of twisty mountain roads where I live that will reveal a car's flaws at reasonable speeds. I am set up now with 225/40 front and 245/35 rear Michelin PSS. The car seems well planted.

I am not saying that all of this is BS, but solid data is hard to come by.
__________________
Appreciate 0
      10-14-2014, 08:35 AM   #52
fcman
Captain
654
Rep
976
Posts

Drives: 2023 G87
Join Date: Mar 2014
Location: Atlanta, GA

iTrader: (0)

Quote:
Originally Posted by Diver View Post
If I take a carpenter's level and get it vertical against the tire, just far enough from the contact patch so that the tire is not squishing out at the bottom then then near the top of the tire it will be .5" leaning in towards the car's center over a 21 inch space. That slope is .0238. The tangent of 1.35 degrees happens to be about the same, so I think the camber is 1.35 degrees negative.

Now perhaps I am doing that completely wrong, so enlighten me. What I don't understand around here is a lot of forum members keep the three size differential between front and rear when the first thing I always thought was a cure for under steer was larger front tires. Some of the AC guys go square which should help things a lot. I get the impression that over steer might help a lot more on and AC course than a road course.
You need to measure at the rim rather than the tire. As for why we dont run square set-ups, some do, however in autox I cant fit larger than 225s up front due to wheel width restrictions in my class. I could lower the rear tire width but in a tight autox course I need all the traction I can get. The car can still be coerced into oversteer when it's needed but I actually haven't had many problems with understeer.
Appreciate 0
      10-14-2014, 02:28 PM   #53
02rsxpilot
First Lieutenant
02rsxpilot's Avatar
United_States
47
Rep
327
Posts

Drives: 2012 BMW 135i
Join Date: Apr 2013
Location: NorCal

iTrader: (2)

Garage List
2012 BMW 135i  [10.00]
2013 Mini Cooper S  [0.00]
2002 Acura RSX  [0.00]
Diver, you are spot on that the best way to alleviate understeer on this car would be increasing front tire size and leaving the rear alone. The main reason you don't see that often here is in the extreme performance category there are little to no options with a 245 rear. Going square is an option, but at that point you are choosing handling balance over total grip, which in theory should make you slower, not faster (all things being equal).

As for the camber measure, put it on a Hunter alignment and see what it spits out if you want to be sure. DIYing it typically has a margin of error of +/- 0.5 degrees, which is probably not the level of confidence you want when measuring something that should fall within a 1 degree range.

And yes, as much as I wish people would be more diligent about posting lap times, etc... the reality is there are way too many variables in play to make any of that statistically reliable. Bottom line: come to forums for ideas and lots of anecdotal evidence, but only rely on your own testing for the truth.
__________________
2012 BMW 135i DCT - M3 Front Control Arms, Whiteline RSFB, Dinan camber plates.
Appreciate 0
      10-14-2014, 05:10 PM   #54
Diver
Brigadier General
Diver's Avatar
United_States
504
Rep
3,446
Posts

Drives: Black '12 135i - Sold
Join Date: Nov 2010
Location: Texas

iTrader: (0)

Quote:
Originally Posted by 02rsxpilot View Post
Diver, you are spot on that the best way to alleviate understeer on this car would be increasing front tire size and leaving the rear alone. The main reason you don't see that often here is in the extreme performance category there are little to no options with a 245 rear. Going square is an option, but at that point you are choosing handling balance over total grip, which in theory should make you slower, not faster (all things being equal).
Fortunately the Michelin PSS is available in 245/35-18. That may not be the ultimate, and as you say choices are sparse, but it is a good one and that is what I have with a 225/40 front. The swap improved the ride and reduced noise. The scary thing is if I trash one of those rear tires away from a big city it will take at least two days to get a new one.
__________________
Appreciate 0
      10-14-2014, 05:13 PM   #55
Dackelone
European Editor
Dackelone's Avatar
Germany
10511
Rep
22,992
Posts

Drives: N54 e82
Join Date: Feb 2010
Location: Bayern, Germany

iTrader: (1)

Quote:
Originally Posted by Diver View Post
Fortunately the Michelin PSS is available in 245/35-18. That may not be the ultimate, and as you say choices are sparse, but it is a good one and that is what I have with a 225/40 front. The swap improved the ride and reduced noise. The scary thing is if I trash one of those rear tires away from a big city it will take at least two days to get a new one.
That's why I carry a spare tire. Or in the very least you should have one at home.


This thread has been very good in pinpointing how to reduce our car's understeering nature.
Appreciate 0
      10-14-2014, 07:43 PM   #56
z3papa
Captain
United_States
190
Rep
969
Posts

Drives: 11 E92 M3 ZCP, 07 335i
Join Date: Oct 2009
Location: Bloomington IL

iTrader: (2)

Quote:
Originally Posted by Kgolf31 View Post
Can I ask what your suspension settings are?

My best guess is that you don't have the car setup right. And the fact you ignored my post kind of shows it.
OK Kevin -- I'll bite -- what are your autocross settings on concrete with RS3's?
Don't tell me you are running anything short of -2.8 of camber. EDIT -- looks like it is somewhere between -3 and -3.5 so IMHO while bushings, sway bars and spring rates may help, adding some negative camber will have a profound impact on reducing BMW engineered understeer.
__________________
Sold 2011.5 E92 M3 ZCP.

Last edited by z3papa; 10-14-2014 at 08:12 PM..
Appreciate 0
      10-14-2014, 11:11 PM   #57
Diver
Brigadier General
Diver's Avatar
United_States
504
Rep
3,446
Posts

Drives: Black '12 135i - Sold
Join Date: Nov 2010
Location: Texas

iTrader: (0)

Quote:
Originally Posted by Dackelone View Post
That's why I carry a spare tire. Or in the very least you should have one at home.


This thread has been very good in pinpointing how to reduce our car's understeering nature.
Dack, I saved one of my run flat front tires for that reason. One thing I have learned, if TPM goes on, stop and diagnose the problem.
__________________
Appreciate 0
      10-16-2014, 04:15 PM   #58
02rsxpilot
First Lieutenant
02rsxpilot's Avatar
United_States
47
Rep
327
Posts

Drives: 2012 BMW 135i
Join Date: Apr 2013
Location: NorCal

iTrader: (2)

Garage List
2012 BMW 135i  [10.00]
2013 Mini Cooper S  [0.00]
2002 Acura RSX  [0.00]
Quote:
Originally Posted by Diver View Post
Fortunately the Michelin PSS is available in 245/35-18. That may not be the ultimate, and as you say choices are sparse, but it is a good one and that is what I have with a 225/40 front. The swap improved the ride and reduced noise. The scary thing is if I trash one of those rear tires away from a big city it will take at least two days to get a new one.
Yeah, the PSSs would be my choice for a dual-duty tire although they have been known to fall apart with track use. My Dunlops are much better on the track, but they are a bit noisy for my taste on the street. The best solution is two sets of tires. You can run whatever cheapies you want on the street, and save the good noisy rubber for the track.
__________________
2012 BMW 135i DCT - M3 Front Control Arms, Whiteline RSFB, Dinan camber plates.
Appreciate 1
      10-16-2014, 05:00 PM   #59
Diver
Brigadier General
Diver's Avatar
United_States
504
Rep
3,446
Posts

Drives: Black '12 135i - Sold
Join Date: Nov 2010
Location: Texas

iTrader: (0)

Quote:
Originally Posted by 02rsxpilot View Post
Yeah, the PSSs would be my choice for a dual-duty tire although they have been known to fall apart with track use. My Dunlops are much better on the track, but they are a bit noisy for my taste on the street. The best solution is two sets of tires. You can run whatever cheapies you want on the street, and save the good noisy rubber for the track.
I am super happy with PSS on the street. As I don't track my car, I will not be needing a second set of wheels and tires. Track use is very hard on all tires. I am glad your Dunlops are working for you.
__________________
Appreciate 0
      10-16-2014, 05:43 PM   #60
dcaron9999
Major
dcaron9999's Avatar
Canada
155
Rep
1,409
Posts

Drives: 2011 135i M package
Join Date: Jan 2010
Location: Mirabel, Quebec

iTrader: (0)

Quote:
Originally Posted by 02rsxpilot View Post
Yeah, the PSSs would be my choice for a dual-duty tire although they have been known to fall apart with track use. My Dunlops are much better on the track, but they are a bit noisy for my taste on the street. The best solution is two sets of tires. You can run whatever cheapies you want on the street, and save the good noisy rubber for the track.
Spot on ...

Been running the ZII's very hard on the track last season (May 2014 to October 2014), and concur. They can take the abuse at the track (pavement or concrete), and do fairly good in the wet. They are noisy (they hum) on the street, more so when cold, or after abuse at the track. They stick like glue when hot. Not sure what to do next season as Im close to the wear bars already. Might give the newer Dunlop ZII's Starspec's a try, or move on to entry level "DOT approved" R-compound tires (Nitto NT01, or Toyo R888) ...

I wish I could afford a dedicated set of Street and Track tires and have the patience of swapping back and forth, but I visit the track as often as every week, so must settle for a dual duty set.
__________________
2011 X3 35i with M pack + 2011 135i w/6SPMT | 255 square tire setup | Quaife 3.46 LSD | Diff lock down bracket | Bilstein B8+Swift SpecR springs+H&R FSB | CDV delete | BMS Oil Tstat bypass | ER FMIC & CP | N54Tuning DP | GC Street Camber Plates | M3 FCA +guide rods+RSFB's+Tranny mounts | Manzo toe arms | Cobb Stg2 agressive tune | Hawk DTC70 brake pads | RB SS brake pistons | Goodridge SS brake lines | Custom brake cooling ducts
Appreciate 0
      10-16-2014, 08:51 PM   #61
John_01
Colonel
John_01's Avatar
Australia
232
Rep
2,643
Posts

Drives: E90 325i, E82 135i
Join Date: Mar 2009
Location: Sydney, Australia

iTrader: (0)

Sorry I can't agree with using Michelin PSS on the track. They get very slippery when hot and you will see very high wear rates. Save them for the street as they don't work on the track.
Appreciate 0
      10-17-2014, 10:53 AM   #62
02rsxpilot
First Lieutenant
02rsxpilot's Avatar
United_States
47
Rep
327
Posts

Drives: 2012 BMW 135i
Join Date: Apr 2013
Location: NorCal

iTrader: (2)

Garage List
2012 BMW 135i  [10.00]
2013 Mini Cooper S  [0.00]
2002 Acura RSX  [0.00]
Quote:
Originally Posted by Diver View Post
I am super happy with PSS on the street. As I don't track my car, I will not be needing a second set of wheels and tires. Track use is very hard on all tires. I am glad your Dunlops are working for you.
Wait wait wait.... You don't track your car? This is the "Track/Autocross/Dragstrip/Performance Driving" section on the forum, so I guess I assumed you were talking about tracking the car. Where in the world are you experiencing understeer on the street? Handling balance is felt at the limit of grip, not in street conditions, unless you somehow push the car hard enough on the street to get the front tires to give up, in which case, I'm glad we don't live near each other. Almost nothing anyone on here has suggested so far should apply to a street-only car, IMO.

Sorry for the confusion.
__________________
2012 BMW 135i DCT - M3 Front Control Arms, Whiteline RSFB, Dinan camber plates.
Appreciate 0
      10-17-2014, 12:11 PM   #63
Diver
Brigadier General
Diver's Avatar
United_States
504
Rep
3,446
Posts

Drives: Black '12 135i - Sold
Join Date: Nov 2010
Location: Texas

iTrader: (0)

Quote:
Originally Posted by 02rsxpilot View Post
Sorry for the confusion.
I have occasionally driven my 135i fast enough to where under steer just barely becomes noticeable in the form of a bit of noise from the front tires. With the new tires that has gone away and noise is is from the rear tires, at a higher speed. This is not the limit of adhesion, but it is close enough that the change was evident.

Some FWD rental cars I have driven on twisty European roads experienced extreme under steer at relatively low speeds. The worst was a VW mini van. The diesel Golf I had last month was a lot better.

People buy cars because of what they are capable of on the track and never track their cars. 45% of 2014 Stingrays were delivered with Z51, and I doubt that more than a quarter of those will ever see the track. A good many of those Z51 Stingrays had the slow shifting 6-Speed auto.

Cars get lowered and have large diameter wheels installed for looks most of the time. These mods may or may not improve track performance.

One of my motivations for going up a tire size in the front is the 215's just felt too damn small.
__________________
Appreciate 0
      10-17-2014, 02:24 PM   #64
fcman
Captain
654
Rep
976
Posts

Drives: 2023 G87
Join Date: Mar 2014
Location: Atlanta, GA

iTrader: (0)

I use my DD PSSs for AutoX and they work well enough for 4 runs, in terms of heat. Wouldn't want to take them on a track day though
Appreciate 0
      10-17-2014, 02:56 PM   #65
The HACK
Midlife Crises Racing Silent but Deadly Class
The HACK's Avatar
1817
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 Diver View Post
I have occasionally driven my 135i fast enough to where under steer just barely becomes noticeable in the form of a bit of noise from the front tires.
Noise != Understeer. Heck noise != slip. Unless you're on slicks or r-comps, some noise (as in squeal) is common even when tires are at full static grip levels.



Pay attention to the pitch of the tire noise and the sudden change from squeal to "groan".
__________________
Sitting on a beat-up office chair in front of a 5 year old computer in a basement floor, sipping on stale coffee watching a bunch of meaningless numbers scrolling aimlessly on a dimly lit 19” monitor.
Appreciate 0
      10-17-2014, 03:24 PM   #66
Kgolf31
Brigadier General
Kgolf31's Avatar
459
Rep
4,531
Posts

Drives: 2007 Z4MC, 2012 128i
Join Date: Sep 2008
Location: Ohio

iTrader: (4)

Quote:
Originally Posted by The HACK View Post
Noise != Understeer. Heck noise != slip. Unless you're on slicks or r-comps, some noise (as in squeal) is common even when tires are at full static grip levels.



Pay attention to the pitch of the tire noise and the sudden change from squeal to "groan".
Agreed.

Video from when my tires were kind of noisy...but well within their levels of grip

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 10:54 AM.




1addicts
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