Home Forums Road Racing Rear Diffuser

This topic contains 6 replies, has 5 voices, and was last updated by  Chris Reinhardt 5 years, 1 month ago.

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  • #13050

    George Sunderland
    Participant

    With talk of Daytona, does anybody make a rear diffuser to put into a full floor?  I’ve made them myself in the past but its a lot of work and they crack easily when I do them.  I know road racing is in decline but seems like there would be a market for the handfull of  laydowns and superkarts running.

  • #13051

    Brian Wilhelm
    Participant

    I experimented with a couple of different designs, but I couldn’t get any gains.

  • #13120

    bo rougeou
    Participant

    Isn’t there a formula to use for the relief that is built into the rear?  What do you call that thingie?

  • #13162

    Brian Wilhelm
    Participant

    <div class=”d4p-bbp-quote-title”>Chris Reinhardt wrote:</div>

    Brian Wilhelm wrote:
    I experimented with a couple of different designs, but I couldn’t get any gains.

    They don’t work very well without a rear wing :)

    That certainly explains that!

  • #13305

    Peter Zambos
    Participant

    2 questions.

    Why would a diffuser not work well without a wing?  My grasp of aero suggests that if you were considering a rear wing, you wouldn’t have to any longer after putting in a diffuser.

    Question two is: if you want a cheap, easy and perhaps more durable solution in place of a homemade diffuser, couldn’t you put in a row of small naca ducts into the belly pan at the rear?

  • #13327

    Chris Reinhardt
    Participant

    I really wish the quote button worked……..

    First off, air passes above and below, as well as each side, so a wing is affective above the car, and a diffuser below, so one will work without the other somewhat, but neither replaces each other.

    A diffuser in order to work as designed needs to do several things.  One to slow down the speed of the air, and two speed it back up again.

    You can’t use a NACA duct to vent the air into the body work, that would be like a parachute under the car.  It’s designed, or should be designed to work like an airfoil, faster moving on top, slower moving air under equals downforce.  If you drilled a bunch of holes in the wing, besides the turbulence, you wouldn’t have a good separation between the faster and slower moving air.

    Not having a wing means there’s lots of turbulence behind the car messing up how the air comes out of the diffuser, making less effective and giving it more drag….

    Hope that helps….

    CR

     

    Chris Reinhardt

    CR2 Motorsports

    http://www.cr2motorsports.webs.com/

    XV Racing Products

    http://www.xvengineering.com/

    ­­

  • #13119

    Chris Reinhardt
    Participant

    Brian Wilhelm wrote:
    I experimented with a couple of different designs, but I couldn’t get any gains.

    They don’t work very well without a rear wing :)

    Chris Reinhardt

    CR2 Motorsports

    http://www.cr2motorsports.webs.com/

    XV Racing Products

    http://www.xvengineering.com/

    ­­

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