Welcome to ZRoadster.org - BMW Z1 Z4 Z8 Z3 Forum and Technical Database

If you want to join in with the discussion, and see the areas which are available only to members then sign up now!

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

ASC Disconnection & Avoiding ASC applying the Brakes on Traction Loss

Discussion in 'Z3 Roadster & Coupé' started by PeterJ, Aug 11, 2014.

  1. PeterJ

    PeterJ Zorg Legend
    Hong Kong Zeds

    Joined:
    Jan 7, 2012
    Messages:
    147
    Likes Received:
    185
    Trophy Points:
    72
    Location:
    Hong Kong
    Model of Z:
    Z3 2.8 Roadster M52B28
    In preparation for installing RaceLogic Traction Control on my 1998 M52B28 fitted with ASC (not DSC), I have removed the whole ASC butterfly valve assembly & fitted a smooth intake boot for better airflow and of coarse the 'ASC' light is on as expected.
    My understanding is the the ASC operates by cutting the air take & apply the brakes.

    My objective is for the ASC to do absolutely nothing & I have already achieved the first part of that by removing the valve assembly so it no longer effects the air intake. This is clear. No problem.

    However, I was thinking about how to be sure that the ASC software is not applying the brakes (as I am told that it does) when the wheel sensors detect loss of traction? I am told the engine power can overcome the brakes, but obviously it is something I do not want to happen.

    I now have the option of:

    1. Removing the ASC bulb as it no longer functions (the ASC light is 'on' irrespective of pressing the ASC button since removing the ASC valve)

    Question: Will the ASC system still apply the brakes when loss of traction even though the ASC light is always on? I think/hope it will not so I might as well just remove the ASC bulb?

    or
    2. Fitting a 20 ohm resistor to 'fool' the system that the ASC valve is still in place and operating normally

    Question: presumably this will make the ASC light go out so the ASC will still apply the brakes on loss of traction (unless I press the ASC button so ASC light comes on to indicate the ASC system is off) ? I really do not want to have to remember to switch the ASC button every time I use the car

    I think the bottom line is that when the ASC light is on for any reason (fault of any type or switched off by ASC button) the whole ASC system is disabled and no brakes are applied even when loss of traction?

    Therefore, it seems the best solution is option 1 & just remove the ASC bulb ...& then connect the RaceLogic TC

    Any comments/advice views most appreciated on what is the best way to achieve my objective of not having the brakes applied by ASC on loss of traction

    Thanks all :)
     

    Attached Files:

  2. Aceman

    Aceman Moderator
    British Zeds 3rd Party Trader

    Joined:
    Dec 5, 2011
    Messages:
    2,221
    Likes Received:
    713
    Trophy Points:
    156
    Location:
    Wakefield
    Model of Z:
    ///M Roadster
    Hi Peter,

    I would tend to agrre with you in that if the ASC light is no permanantly lit it is detecting a fault and telling you that the ASC is not functional. I suppose one way to check this would be to go and do some drifting :ymdevil: and see if you can feel the brakes cutting in as it should be able to sense through your buttometer.

    Hoe does the racelogic control the power when it senses loss of traction.?
     
  3. PeterJ

    PeterJ Zorg Legend
    Hong Kong Zeds

    Joined:
    Jan 7, 2012
    Messages:
    147
    Likes Received:
    185
    Trophy Points:
    72
    Location:
    Hong Kong
    Model of Z:
    Z3 2.8 Roadster M52B28
  4. Brian H

    Brian H Zorg Guru (V)
    British Zeds Scottish Zeds

    Joined:
    Dec 5, 2011
    Messages:
    3,512
    Likes Received:
    2,564
    Trophy Points:
    195
    Location:
    Killin
    Model of Z:
    E36/7 3.0i - E85 Z4///M
    This is a difficult one to call @PeterJ , I have only ever seen RL fitted to cars that have no ASC or DSC. Which ever route you take remember that the ABS system is closely linked to the ASC system, disabling one may also effect the other?

    I wonder if there is a coding option to permanently disable the ASC whilst leaving the ABS in tact?

    Where does the RL system pick up the wheel sensor inputs? Is this from the cars in built module or do you splice into the loom at a specific point?

    Edit: Peter have a look at the simple mod in the link provided below, it fools the system into thinking you have switched off the ASC system.

    HTH

    http://www.bmwtips.com/tipsntricks/tips_pages/DSCoff.htm
     
    #4 Brian H, Aug 11, 2014
    Last edited: Aug 11, 2014
  5. zedonist

    zedonist Guest

    I like Brian, think the ASC is connected to the ABS, that said some one should be able to access the module amd map it out, i believe @deano1712 has fitted Race Logic or similar to his V8 conversion?
     
  6. Brian4

    Brian4 Zorg Guru (IV)
    British Zeds East Anglian Crew

    Joined:
    Dec 23, 2011
    Messages:
    2,558
    Likes Received:
    2,035
    Trophy Points:
    173
    Location:
    Hinckley/Burbage
    Model of Z:
    Z3 3.0i Auto
    Have you asked RaceLogic what their thoughts are? the traction control on our old Mondeo mk2 applied the brakes so this sort of system has been around for ages and loads of other BMWs use the ASC system so they must have come across the problem.
     
  7. zedonist

    zedonist Guest

  8. PeterJ

    PeterJ Zorg Legend
    Hong Kong Zeds

    Joined:
    Jan 7, 2012
    Messages:
    147
    Likes Received:
    185
    Trophy Points:
    72
    Location:
    Hong Kong
    Model of Z:
    Z3 2.8 Roadster M52B28
    Thanks all for the tips. Leaving the ASC alone is not an option as it is already in the trash can and the new boot installed. I think my Z3 is OBD I?? (Asia market Car 1998 Pre-facelift M52B28). I am a self confessed non-engineer and am not doing the installation myself (that would be a total disaster! :p ) but I have a good guy doing it for me. I 'think' (dangerous coming from me!) the RL is spliced in the loom at some point and feeds it's own control box. My original intention was to have the ASC completely removed from the ECU (or wherever it is) & the guy at http://rumatuning.co.uk/ would did my custom ECU remap said he could do this, but getting him out to Hong Kong again is a bit pricy & am reluctant to let another person do it (= blame each other if anything goes wrong :p ) ...but if I can can catch him next time he is passing through HK, I will ask him. With the ASC Valve removed and the ASC light on, I think I will have to assume that the ASC is totally off (including wheel breaking) so it's looking like 'ASC light bulb out' until I can get the ASC deleted from the software & in the meantime I will contact RL for their advice
     
  9. zedonist

    zedonist Guest

    I think the problem you will have is that you will not have ABS,,as the ECU thinks you have a fault with the system. Can you not get the ECU sent to your guy, would be cheaper?
     
  10. Brian H

    Brian H Zorg Guru (V)
    British Zeds Scottish Zeds

    Joined:
    Dec 5, 2011
    Messages:
    3,512
    Likes Received:
    2,564
    Trophy Points:
    195
    Location:
    Killin
    Model of Z:
    E36/7 3.0i - E85 Z4///M
    @PeterJ, if you fit a 20ohm resistor to fool the system to thinking that the ASC valve is still there and then apply the mod as I posted above this will give you a car with ABS and an ASC system that is switched off when you start the car. Your RL system can then be fitted and used as desired.
     
    • Like Like x 1
  11. PeterJ

    PeterJ Zorg Legend
    Hong Kong Zeds

    Joined:
    Jan 7, 2012
    Messages:
    147
    Likes Received:
    185
    Trophy Points:
    72
    Location:
    Hong Kong
    Model of Z:
    Z3 2.8 Roadster M52B28
    Thanks Brian & all.

    Here are my questions to RaceLogic and their answers. I have been told that as my Z3 is an Asia market car it is neither OBD I or OBD II and has different Plugs and software to OBD's. I want to avoid having to remember to switch the ASC button every time I start the car as it is just an annoying nuisance (!) & am concerned if we fitted the 20 ohm resister, the brakes may try to operate on wheel spin if the ASC button has not been pressed.
    RaceLogic TC's have been fitted very successfully to many BMW's similar to mine (mainly E36's rather than E36/7) and the problems with the RPM limiter only seem to occur with more recent OBD II cars so should be OK as my Z3 is not even OBD I

    I once had a coil fail causing a misfire on one of the cylinders and I do not recall the RPM limiter cutting in at limp home mode although I drove it gently so perhaps it did??? Anyway, we will find out within 3 to 3 weeks and if all is well as is, I will just remove the ASC light bulb and throw it in the trash as it will serve no useful purpose.

    I will let you know how we get on....

    The ABS currently works OK (with ASC light on and ASC Valve removed) so hopefully that will mean I will still have ABS with the RL.

    My Engineer said he disconnected that ASC braking system by removing a fuse or something (did not really understand!)

    Cheers!

    Peter J

    (from RaceLogic)
    1.Racelogic Traction Control does not interface with a vehicle’s throttle. RLTC interfaces directly with the injectors.


    2.This is something you will have contact BMW for an answer. Please note, when using RLTC you must turn off any factory traction control systems in order for it to operate correctly.


    3.If you vehicle’s ECU has a misfire detection feature, the check engine light may turn on and your vehicle may go in to ‘limp’ mode following an RLTC traction event. This is because we cut the injectors to reduce torque when wheel spin is detected.


    Best Regards,

    John.


    John Holman
    [​IMG][​IMG]



    Dear RaceLogic,


    I purchased a Traction Control system from you about two years ago via CA Technologies International (UK) and had it sent out to me here in Hong Kong and it is finally about to be installed on my (Asia Market) 1998 BMW Z3 2.8 with M52B28 engine. The car had ASC fitted and not DSC.


    I have completely removed the ASC butterfly valve assembly and fitted a smooth air intake boot instead and consequentially the ASC light is always on (as expected) and I intend to just remove the ASC light in the instrument display.


    Please could you advise the following:


    1. Is there any issues regarding this ASC valve removal and the fitting of the RaceLogic TC?


    2. Do you know if the ASC system will still apply the brakes when loss off traction if the ASC light is on as a result of the ASC valve removal? (Ie, when using the RL TC after fitting)


    3. Will there be any circumstances that the engine RPM Limiter may be switch to 'safety mode' (reduced rpm limit) as a result of the RL TC (I have heard this has happened with OBD II). I think my car is OBD I
     
  12. PeterJ

    PeterJ Zorg Legend
    Hong Kong Zeds

    Joined:
    Jan 7, 2012
    Messages:
    147
    Likes Received:
    185
    Trophy Points:
    72
    Location:
    Hong Kong
    Model of Z:
    Z3 2.8 Roadster M52B28
  13. Stormy_be

    Stormy_be Zorg Guru (I)
    Belgian Zeds

    Joined:
    Oct 29, 2013
    Messages:
    745
    Likes Received:
    470
    Trophy Points:
    97
    Location:
    Belgium, ieper
    Model of Z:
    Z3 2.8 Roadster
    any update on this?
    Did it work without issues?

    For info:
    I will be changing the ecu completely to a kms system.
    This will remove all asc dsc whatever from the ecu.
    The guy helping me with the installation has told me it is also very easy to have a button in the car to be able to switch on or off the abs.
    I would like to keep the abs as optional, while completely removing asc, etc

    Regards, Koen