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Audi Quattro and rolling road

Discussion in 'Audi S4/A4/A4 Cab (B8 Chassis)' started by riggssuzuki, Apr 30, 2013.

  1. riggssuzuki
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    riggssuzuki Active Member

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    [Apr 30, 2013]
    Hi. I am planning a rolling road session next week. I have heard on many occassions that there are issues with dynos and the Quattro system. Does anyone know what needs to be done to allow the A4 Quattro to be dyno'd. I believe its something to do with the EDL needing disabled? If its a fuse then which one? I dont want to turn up only then to find there are issues as per the last poor mans attempt!!!
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  3. adamss24
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    adamss24 Well-Known Member

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    [Apr 30, 2013]
    Torsen quattro's can only be diyno'ed on a 4 wheel dynamometer ! Only the Haldex quattro's (a3/s3,golf/octavia,etc.) can be dyno'ed on a 2 wheel dyno by taking the ABS fuse off, turning them into a 2 wheel drive !
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  4. riggssuzuki
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    riggssuzuki Active Member

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    [Apr 30, 2013]
    I don't believe this is the case. Another a4 Quattro owner had issues with a 4 wheel rolling road. I believe that the Edl is the issue and the abs fuse removal fixes it???
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  5. Daggerit
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    Daggerit Active Member

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    [Apr 30, 2013]
    It can be done for sure as there are plenty of A4/6/8 and R8's that have been dyno'd. But it would have to be a four wheel dyno and the mechanical centre diff won't allow for two wheel drive like the haldex with the clutch.

    Whether you have to take the ABS fuse out of not I don't know but I would've thought that would try to break various wheels to keep them all spinning at the same rate so it would make sense.
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  6. s3welshy
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    s3welshy Member

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    [Apr 30, 2013]
    Does that mean I could run my 1999 s3 with haldex in 2 wd?
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  7. adamss24
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    adamss24 Well-Known Member

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    [Apr 30, 2013]
    1 Yes, your car IS front wheel drive until the front wheels slip and the Haldex diff will transfer power to the rear up to 80%...
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  8. adamss24
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    adamss24 Well-Known Member

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    [Apr 30, 2013]
    Torsen will split the power 50-50 in normal conditions but the latest generation as fitted to s4 and rs4 will allow a 60-40 split with bias towards the back to enhance the sporty drive ! Disconnecting the ABS will disable the EDL but with all 4 wheels on the rollers i doubt they will slip ?!
    The centre diff will not allow drive on a 2 wheel dyno but i see no problem on a 4 wheel drive dyno !
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  9. riggssuzuki
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    riggssuzuki Active Member

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    [Apr 30, 2013]
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  10. Audi Dynamik
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    Audi Dynamik Well-Known Member

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    [Apr 30, 2013]
    Thats me !
    I was on a 4wd Rolling Road and there was other Audi Quattro's there which didn't need there fuse taken out which ran successful. all but mine.

    I have asked around tuning companys with 4wd Rolling Road's and this is the solution i came to.

    The Electronic Differential Lock (EDL) permits smooth, comfortable starts on road surfaces that do not have a uniform coefficient of friction. If a wheel starts to spin, EDL brakes it as necessary so that power is transmitted to the wheel with the better traction. EDL reduces tire wear and works up to about 25 mph (quattro®: up to about 50 mph). EDL is part of the Electronic Stabilization Program (ESP®) and the Traction control (ASR).

    What i guess is now that because the Car has edl the abs fuse needs to be taken out for it to work successfully on the Rolling Road or use a VCDS to disable the edl meanwhile it is running on the Rolling Road.

    If this is true or not i don't know ?
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  11. Gavin0478
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    Gavin0478 Active Member

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    [Apr 30, 2013]
    You need a dyno where the rollers front and rear are mechanically linked to fool the car it is on normal road otherwise there is a difference of resistance which the cars computers try to compensate for and basically wont run.

    Copied from a dyno description
    "The key to designing an AWD dynamometer properly is to understand the methods currently being used by manufacturers in the field of AWD drivetrain technology. A dynamometer that can accommodate various types of AWD vehicle transmissions and wheelbases without excessive complication and, more importantly, without risking damage to a client’s AWD system is paramount.Full time AWD vehicles are designed to provide maximum performance regardless of road conditions. In cases where traction is less than ideal, a vehicle may be designed to improve stability and traction at the expense of power. This means adding torque to a spinning wheel or retarding of timing. In order to properly test an AWD vehicle for peak performance, an AWD chassis dynamometer must be able to simulate ideal road-load conditions to the vehicle. This approach allows the vehicle to be evaluated under “optimum” operational conditions; whereby torque is distributed to the vehicle’s tires in the same manner that would normally occur when a vehicle has equal traction at all four drive wheels, and is therefore operating at peak efficiency.
    To achieve this, Mustang’s AWD-500 Series incorporates an internal drive system that synchronizes the front and back rollers to simulate a flat, dry road condition. Synchronization, or linkage, insures that the front and rear rollers are always spinning at precisely the same road speed. This process eliminates the possibility of activating a vehicle’s traction control system and also insures that a vehicle’s torque management system is operating under the assumption that the vehicle is not skidding, turning or slipping."
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  12. Audi Dynamik
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    Audi Dynamik Well-Known Member

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    [Apr 30, 2013]
    Nice find Gav thanks !
    I think i will secure with that answer :)
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  13. Daggerit
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    Daggerit Active Member

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    [Apr 30, 2013]
    Good find! Still doesn't really answer why one A4 was fine on the dyno day but yours didn't?
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  14. Audi Dynamik
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    Audi Dynamik Well-Known Member

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    [Apr 30, 2013]
    Thats true, I don't think there will be anything different because its a Dynamik ?
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