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 > Suspension | Brakes | Chassis
 
ESS Tuning
Post Reply
 
Thread Tools Search this Thread
      03-18-2013, 02:43 PM   #1
Raucky2000
Lieutenant
 
Raucky2000's Avatar
 
Drives: SGM E90 M3 dct
Join Date: Nov 2012
Location: Ohio

Posts: 483
iTrader: (3)

High Frt Spring Rates

Is there anyone out there running a high spring rate on the front of the car?
Like 14kg or 16kg?
Raucky2000 is offline  
0
Reply With Quote
      03-18-2013, 02:54 PM   #2
Richard@M-World
 
Richard@M-World's Avatar
 
Drives: NASA TTA #92 M3
Join Date: May 2011
Location: TX/IL

Posts: 683
iTrader: (0)

I currently run 12 kg on the front for DOT-R tires. KW recommended 14 kg for full slicks.

Are you thinking about going that direction?
__________________
Authorized AiM Dealer - Solo/Solo DL | SmartyCam HD | www.m-world.us
Richard@M-World is offline   United_States
0
Reply With Quote
      03-18-2013, 03:22 PM   #3
Raucky2000
Lieutenant
 
Raucky2000's Avatar
 
Drives: SGM E90 M3 dct
Join Date: Nov 2012
Location: Ohio

Posts: 483
iTrader: (3)

Well I'm running 285/30-18 DZII tires but ill be on concrete at the larger events (auto-x). I have to much dive on the frt with my current setup of 450/700 IMHO.

I ordered a set of swift 14kg spring for the front as a guess to test out.
Raucky2000 is offline  
0
Reply With Quote
      03-18-2013, 03:47 PM   #4
RickyBobby
Lieutenant
 
RickyBobby's Avatar
 
Drives: M3
Join Date: Mar 2008
Location: NorCal

Posts: 462
iTrader: (1)

Are you sure it's front dive and not rear lift? They can feel the same since the ultimate affect is forward pitch. Shocks should be able to slow that down as well. Speaking of which, what kind of shocks are you running to handle that #785lb spring? I would also be on the lookout for loss of mechanical grip in the corners even if you fix the fore/aft weight transfer you are working on.
Keep us posted on the experiment. I've also accumulated a garage full of springs over the years.
RickyBobby is offline  
0
Reply With Quote
      03-18-2013, 04:06 PM   #5
Raucky2000
Lieutenant
 
Raucky2000's Avatar
 
Drives: SGM E90 M3 dct
Join Date: Nov 2012
Location: Ohio

Posts: 483
iTrader: (3)

Yeah it is forward dive from the rear springs/shocks lifting. I'm running TCK DA shocks and an H&R front bar but no rear bar.

My rebound setting on the rear shocks is just right IMO and its over powering the front.
Raucky2000 is offline  
0
Reply With Quote
      03-18-2013, 05:25 PM   #6
sensi09
Lieutenant Colonel
 
Drives: .
Join Date: Dec 2010
Location: socal

Posts: 1,764
iTrader: (1)

Where would you source the springs?

I'd check with TC kline if those konis can handle a 800-900lb spring.
sensi09 is offline  
0
Reply With Quote
      03-18-2013, 06:05 PM   #7
Raucky2000
Lieutenant
 
Raucky2000's Avatar
 
Drives: SGM E90 M3 dct
Join Date: Nov 2012
Location: Ohio

Posts: 483
iTrader: (3)

Swift and a few other brands out there make springs that stiff. I have a set of Swift springs coming my way.
Raucky2000 is offline  
0
Reply With Quote
      03-18-2013, 06:11 PM   #8
1MOREMOD
2014 Track Days - 9|Ridge 1:52:25|Pacific 1:35:72
 
1MOREMOD's Avatar
 
Drives: Race car->
Join Date: Mar 2009
Location: check your mirrors

Posts: 11,946
iTrader: (5)

I'm not sure I follow. Haven't done set up on suspension but it seems you think the problem is rear lift. If that is the case the front isn't overcompressing and higher rate spring isn't going to help as much as rear rebound to slow that transfer or a different braking technique to balance the car slightly better.
1MOREMOD is offline   United_States
0
Reply With Quote
      03-18-2013, 06:26 PM   #9
Raucky2000
Lieutenant
 
Raucky2000's Avatar
 
Drives: SGM E90 M3 dct
Join Date: Nov 2012
Location: Ohio

Posts: 483
iTrader: (3)

I need that much rear spring rate and compression/rebound to handle tossing the car and hard first/second gear accelerations. Auto-X racing is the American version of football, where everything is hard, fast, and not pretty all the time.

My front corner weights come in right around 1,000lbs each so having a 800ish lb front springs shouldn't be a problem. The shocks will still work and the chassis will have less movement, which in every other car I've raced has made it better. Time will tell obviously.
Raucky2000 is offline  
0
Reply With Quote
      03-18-2013, 07:36 PM   #10
Richard@M-World
 
Richard@M-World's Avatar
 
Drives: NASA TTA #92 M3
Join Date: May 2011
Location: TX/IL

Posts: 683
iTrader: (0)

Are you keeping rears at 700#?
__________________
Authorized AiM Dealer - Solo/Solo DL | SmartyCam HD | www.m-world.us
Richard@M-World is offline   United_States
0
Reply With Quote
      03-19-2013, 04:19 AM   #11
Raucky2000
Lieutenant
 
Raucky2000's Avatar
 
Drives: SGM E90 M3 dct
Join Date: Nov 2012
Location: Ohio

Posts: 483
iTrader: (3)

I'm going to keep the 700 rear just to see how just changing the front effects the car, but I'm totally open to changing the rears.

^What kind of rear spring rate does KW suggest on Rcomps and full slick?
Raucky2000 is offline  
0
Reply With Quote
      04-15-2013, 09:28 PM   #12
chuxdelux
Captain
 
Drives: 2005 e46 m3, 2013 Jetta TDI
Join Date: Jul 2011
Location: Honolulu,HI

Posts: 636
iTrader: (1)

Did you ever switch to the 14k fronts? How does it feel?
chuxdelux is online now  
0
Reply With Quote
      04-15-2013, 09:42 PM   #13
HP Autosport
BimmerPost Supporting Vendor

 
Drives: E82 1M
Join Date: Mar 2007
Location: Santa Barbara, AP, Brembo, GIAC, Koni, Ohlins, Quaife, Stoptech, Vorshlag

Posts: 11,007
iTrader: (29)

Quote:
Originally Posted by sensi09 View Post
Where would you source the springs?

I'd check with TC kline if those konis can handle a 800-900lb spring.
TCKR DA front struts can not. 500-550 is about max, anything more is off the the service center to upgrade the valving. In our Redline Time Attack days 500 lb springs caused an underdamped issue with Koni DA's on the front. Rears will max out at around 900 lb.

If you get 60mm ID Swift, you will also need to machine your front strut lower perches.
HP Autosport is offline   United_States
0
Reply With Quote
      04-16-2013, 02:56 AM   #14
sensi09
Lieutenant Colonel
 
Drives: .
Join Date: Dec 2010
Location: socal

Posts: 1,764
iTrader: (1)

Quote:
Originally Posted by HP Autowerks View Post
TCKR DA front struts can not. 500-550 is about max, anything more is off the the service center to upgrade the valving. In our Redline Time Attack days 500 lb springs caused an underdamped issue with Koni DA's on the front. Rears will max out at around 900 lb.

If you get 60mm ID Swift, you will also need to machine your front strut lower perches.
Good info, but I'm guessing that tck may have their konis valved differently. They offer up to a 650lb spring for the front on their site.

I'm curious, what rates did you run on your time attack cars?
sensi09 is offline  
0
Reply With Quote
      04-16-2013, 02:57 AM   #15
sensi09
Lieutenant Colonel
 
Drives: .
Join Date: Dec 2010
Location: socal

Posts: 1,764
iTrader: (1)

^Ha didn't realize hpa offers tck. Disregard my last post then...i'm sure you guys know better.
sensi09 is offline  
0
Reply With Quote
      04-16-2013, 11:58 AM   #16
HP Autosport
BimmerPost Supporting Vendor

 
Drives: E82 1M
Join Date: Mar 2007
Location: Santa Barbara, AP, Brembo, GIAC, Koni, Ohlins, Quaife, Stoptech, Vorshlag

Posts: 11,007
iTrader: (29)

Quote:
Originally Posted by sensi09 View Post
Good info, but I'm guessing that tck may have their konis valved differently. They offer up to a 650lb spring for the front on their site.

I'm curious, what rates did you run on your time attack cars?
We have had TCK products on several of our cars, including one competed in Time Attack. Rates end up at 500F and 900R with revalved Koni DA's.
HP Autosport is offline   United_States
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 12:48 AM.




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