[W126 Coupe] Brake Pads

[Divov]

I am amazed that you say your car doesn't understeer because these are understeering cars by design which is what makes them so safe and docile as street cars. 
Next time you race, as you pit, jump out and feel your tyre temperatures. My front tyres were very considerably hotter than the rears which clearly shows they are working a hell of a lot harder. I felt in some corners I was 4 wheel drifting - tyres screaming like hell - but just kept the power full on as there was still enough road left and the car was stable. In the tight stuff I was definitely having understeer. Only a total of 30 - 40 miles race distance and previously 50% worn front tyres were totally trashed. Its a right hand corner circuit so left outer smooth and right side inner smooth.
I only have 170KW compared to a Euro 560 which has 220KW so you can use your extra power to break rear traction and hang the back out.
A difference of 50KW is massive. Where does a 560 get all this extra grunt? Surely not just from an extra 600cc?
I had my car on a Dyno and got 150hp on the wheels which the guys said was exactly par for a 500 on their dyno. 
Note that we are at 6000ft altitude and as a rule of thumb we are 17% down on coastal power output & no 2 dyno's read the same so it is comparing apples to bananas.

I have considered using double stock anti-roll bars because the design of the merc anti roll bar is not as simple to fabricate as on many other cars and also I happen to have a spare AR bar. Just have to figure out a mounting arrangement which I don't think will be too difficult.
Re: tyres used. See my previous post - Bridgestone RE 71.
Pressures were cold. (tyres filled with Nitrogen - not air.)
Re: Shocks - I am using the Bilstein AMG adjustable shocks. Front were set full soft and rear set full hard.
Springs: Front are cut down stock springs and rears are H & R's replacing the self levelling suspension.
Lowered front by a whopping 85mm (previously my car always stood particularly high in the front) & rear by about 70mm
  ----- Original Message ----- 
  From: Jonathan Hodgman 
  To: Mercedes Coupes Mailing Lists 
  Sent: Monday, April 02, 2007 6:55 PM
  Subject: Re: [W126 Coupe] Brake Pads


  Hello Alex,
  Yes, very different conditions as well! Road Atlanta is fairly long, 4.088k. My brakes were OK aside from the one hard stop from from 230 kph down to 80 or less kph.  Right before this run is the 2nd hardest braking point on the track.  Brake fluid was about 20 hours old when I went out;-)  

  To be honest, the car doesn't really understeer..  I have switched all my springs for fresh H&R's, running 2 nib in the front, 3 nib spacers in the rear.  I'm using Bilstein HD shocks all around.  The next time I go out I'm going to add spring rubbers to the shims as I'm getting a bit too much compression on the drivers side.  What tyres are you running?  I was using Pirelli P-Zero Corsa's 255/40/17's. 

  Are those tyre pressures hot or cold? I was running 2.75 bar in the front, 2.85 bar in the rear.  I found in raising the rear above that caused it to get a little loose..  

  I've have heard differing opinion on running a thicker rear anti roll bar..  Some say it will upset the handling, others say it handles much better. 

  Jonathan
  I know one fellow down in AU actually managed to double up on the rear bars, and he was thrilled w/ how the car handled.

  On 4/2/07, Divov <divov at tiscali.co.za> wrote:
    Hi Jonathan,
    Bridgestone RE 71  205 55 VR 16 front
                                         225 50 VR 16 rear
    tyre pressures 2.8 bar front
                              3.2 bar rear

    Track is very short & very tight. Lap times 58 sec!
    Max speed down main straight is only 150kph then braking into a hairpin bend.
    Back straight maybe 130/135 kph braking into hairpin.
    Two other braking points.
    Brakes never have a long time to recover.....
    Very different conditions to your track.
    Lichtenburg circuit has a reputation for being hell on the brakes.

    How fresh is your brake fluid?
    I had boiling fluid until I flushed it out & put in fresh fluid.

    What have you done to counter the under steer?
    Are you still on stock rear anti roll bar?

    I think I need to make up a new one 16mm diam in place of the stock 14mm item.
    Is that going to be enough? - time will tell.

    I also melted the sensors long ago. Don't bother will them on the track.

    Alec

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