Question about the drivetrain and Dynos

Discussion in 'Modifications & DIY how-to' started by StarquestAndyR, Apr 25, 2014.

  1. So I was watching the video I took of my wagon being dyno'd at TopSpeed and I have a concern.
    Some background: I've got a 2002 wagon with a 6-speed swap and no DCCD control. With no DCCD control the center diff is locked at open, with a 51/49 split (It's an 06 transmission).
    I remember that after the dyno was done, the brakes were applied to the dyno and the rear wheels stopped almost immediately. The front wheels spun down from 120mph for a good 15-30 seconds before coming to a stop on their own. I asked the guy about the front not braking and he said it was normal for any cars with a 6-speed and no DCCD.
    My question here is:
    Could this cause any damage to the center diff to run that fast and long of a speed differential between the front and the rear?
    Is this typical of AWD dynos to not have any braking on the front drums and let all the braking be applied to the front via the cars drivetrain? Would stopping the rear wheels and not the front at 120mph cause excessive drivetrain stress in my center differential?
    Doing a quick search on dyno drum weight yields a minimum drum weight of 2500lbs. This is 2500 lbs of rolling mass applied to only the front wheels of the car.
    Should I be concerned about my center diff at this point? I was about to hook up the DCCD controller, but I've got some drivetrain noise going on, so I was wondering...

    Any thoughts on this would be good.
     
  2. So... no one has any knowledge on this at all?
    Should I take this to mean that everyone believes that stopping a 2500lb front dyno roller solely with your drivetrain is OK?
     
  3. Matt

    Matt Think before you post Staff Member Supporting Member

    If anyone would have the correct information, it would be TopSpeed. Who did you talk to about it up there?
     
  4. superhawk28

    superhawk28 Member

    Topspeed has been doing this for years. Doug knows what he is doing. I'm sure you are fine.
     
  5. superhawk28

    superhawk28 Member

    Speaking of which what Dyno does TS have now? I think they upgraded didn't they?
     
  6. Matt

    Matt Think before you post Staff Member Supporting Member

    No. They've never upgraded
     
  7. rsutton1223

    rsutton1223 Obsessed Supporting Member

    Your car is fine. They would never do something that would hurt it like that on the dyno. Doug is a Subaru wizard. Arguably the best turner for them in the country for over a decade.

    Next week I believe. They have a Mustang ready to go in but needed to wait for OLOA so they don't interrupt tuning schedules.
     
  8. superhawk28

    superhawk28 Member

    Incorrect (well technically you are right)....they were/are trying to sell the Dynojet. They may still be using the Dynojet but last I am aware of it's very close to being pulled out for a Mustang.
     
    Last edited: Apr 28, 2014
  9. Thanks for the info and reassuring words everyone.
    sorry it took so long to respond, work and home life have been holding my attentions.
    I just wanted a third opinion and I now have it.
     
  10. integroid

    integroid Supporting Member

    Some cars work ok on a dyno without dccd and some do not. Mine did not and I had to get a DCCD controller so Doug could lock down the center diff. Doug knew immediately after putting my car on the dyno and pulled it off and told me I needed the dccd controller before he could dyno/tune my car.
     
  11. Justin V

    Justin V Member

    a simple relay works too.

    run a switch to trip the relay and just run 12v across the green and black wires to the dccd and it will lock up.

    Pretty much only functional for drag racing, snow driving and dynos.
     

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