Late Model Downforce....

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  • Cranky
    Senior Member
    • Sep 2014
    • 174

    #1

    Late Model Downforce....

    I do realize that dirt late models are built to be aerodynamic with the body, nose and spoilers. I do know that spoiler angle effects handling but how much effect will cutting "cooling holes" in the nose cause? We run smaller tracks 3/8 mile, 4/10 mile.
  • Matt49
    Senior Member
    • Jun 2007
    • 3123

    #2
    You'll be letting more air under the car and thereby increasing the air pressure under the body. Downforce is as much about low pressure under the body as it is about high pressure on top of it.

    Comment

    • RCJ
      Senior Member
      • Nov 2007
      • 509

      #3
      Most people will cut a 8'' section in the center of the lower valance to let air in.I would add a shroud and larger diameter fan first.

      Comment

      • DEKconsulting
        Senior Member
        • Apr 2015
        • 234

        #4
        Did i see two large holes in the rocket house nose by the left front headlight area of the nose this weekend at shawano

        Comment

        • Kromulous
          Senior Member
          • May 2007
          • 3008

          #5
          I think the aero thing is a bit over sold.

          At Eldora, Florence, Viriginia, places like that where your doing 140 or better, yes, but on small bull rings NO.

          I would get air to the engine, over trying to keep the front end sealed off. Unless your just loaded and like to blow $hit up.

          Just say no...

          Comment

          • fastford
            Senior Member
            • Dec 2008
            • 4059

            #6
            we use to have this problem with our all steel engine on gas, went to a triple pass radiator and never had heating problem again with no holes in 95* temp.

            Comment

            • DEKconsulting
              Senior Member
              • Apr 2015
              • 234

              #7
              I think its important everywhere jmo

              Comment

              • DEKconsulting
                Senior Member
                • Apr 2015
                • 234

                #8
                If it doesnt matter on little bull ring try taking ur spoiler off one night and see how it hurts ya

                Comment

                • Matt49
                  Senior Member
                  • Jun 2007
                  • 3123

                  #9
                  Next time you're running a test day at a 1/4 mile track, take the nose, the spoiler, and the right rear quarter panel off and see how she handles. But take it easy if the track has a wall. The good news is that when you hit it, you'll have less body damage to repair.
                  In the meantime, stick your hand out the window of your pickup going 50 MPH down the road and hold it at a 30 degree angle. Multiply that force times about 200 (to match the surface area of the nose and hood fill) and then tell me that aero does't make a difference on small and slow race tracks.
                  Or better yet do this: Get a 4 foot by 4 foot piece of plywood and get your strongest buddies to see how long they can hold it up at a 30 degree angle in the bed of a pickup truck as you go down some country road at even a slow pace. Just be sure there aren't any cars behind you.
                  Anybody that has carried drywall on a windy day will tell you to not waste your time or insurance deductible with the above experiment.

                  Aero is the cheapest speed you can find in racing yet so many people downplay it because they don't understand how it really works. It's all about air pressure.

                  Comment

                  • Punisher88
                    Senior Member
                    • Nov 2014
                    • 495

                    #10
                    What kills me is when folks started cutting off the left rears and the outlawed it. Why? It was free speed. Heck it was speed that saved you money because you used less material. When they first came out with the rule it said it had to only be 28 inches of "material". So I put about 15 inches of plastic at the bottom of my short quarter and didn't brace it. Shortly after the rules was changed again.. lol

                    Comment

                    • Kromulous
                      Senior Member
                      • May 2007
                      • 3008

                      #11
                      A bit of difference in over sold, and taking the body off.

                      Over sold, as in, by all means keep the engine cool.

                      Although there may be other fixes that work, radiator, shroud and or fan size.

                      Just say no...

                      Comment

                      • powerslide
                        Senior Member
                        • May 2007
                        • 2696

                        #12
                        Originally posted by Kromulous View Post
                        A bit of difference in over sold, and taking the body off.

                        Over sold, as in, by all means keep the engine cool.

                        Although there may be other fixes that work, radiator, shroud and or fan size.
                        Yeah I think he should look to other areas to keep it cool. Holes allow mud/rocks through and cause the radiator to get plugged up or worse.

                        Comment

                        • Matt49
                          Senior Member
                          • Jun 2007
                          • 3123

                          #13
                          One thing that we have done that helps is to build vertical slats under the nose that guide air to the radiator. Sort of like a shroud but in front of the radiator. You can sort of taper them in toward the outside edges of the radiator to catch more air.
                          If you do have to make holes, put some sort of heavy duty screen material behind them to filter out the rocks and larger chunks of dirt. Like the material the shaker screens are made of.

                          Comment

                          • DEKconsulting
                            Senior Member
                            • Apr 2015
                            • 234

                            #14
                            Anyone see the 3 or 4 big 2in or 2.5 in holes yhe 1 car had in is nose at the lf headlight area again this weekend. Anyone have any thoughts on this or just another lets see how many oeople start cutting holes in there noses lol

                            Comment

                            • zeroracing
                              Senior Member
                              • May 2007
                              • 1014

                              #15
                              I noticed that also, not sure what they are after but did notice it.

                              Comment

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