Hood scoop? Too much air!

Discussion in 'Race 400/430/455' started by dan zepnick, May 8, 2017.

  1. dan zepnick

    dan zepnick Well-Known Member

    After putting a pro stock style hood on my car I have air issues.have the front mounts very secured now,hood doesn't move in front at all,but the rear raises at least a inch or more through the finish line. I have inner fenders on still and thinking about taking them out.what are you guys doing? I'm thinking that all the cars I've seen with this style scoop run without inners?
     
  2. Bens99gtp

    Bens99gtp Well-Known Member

    I have a reverse cowl on my car with inner fenders, does matter if I run a seal plate under the cowl area or not the rear of my glass hood pulls up. Ours just had zesus clips 4 on a side. I drill a hole through the hoods down lip into my fender and put a pin and clip. This is done at the very rear of hood, actually makes a nice hinge pin to open the hood and nit have to lift off. I also stiffened the bottom by roughing up the glass, soaking carpet padding in a liguid glass and hardner resin, then once hard covering with a layer of matting then repainting. These helped alot. I still get lift, but before I lifted so much I aborted the passes for fear of blow off
     
  3. Todd69GS

    Todd69GS Silver Level contributor

    Dan removing the inners does help clear out the air that is trapped and raising the hood. Might even help mph.
     
  4. dan zepnick

    dan zepnick Well-Known Member

    I had a cowl hood on the car before I switched. Trying to get an idea if I would pickup some et,speed.maybe I should try a pass without a hood on.? Right now I am pulling 2 foot wheelies and carrying it out 50 feet.1.35 60 foots.not sure I want to take weight off the front.Lol
     
    Briz likes this.
  5. standup 69

    standup 69 standup69

    try adding some vents at the back to vent it out ? I had a similar prob. with my glass hood wanting to take flight
     
  6. hugger

    hugger Well-Known Member

    Keep the front down, that will improve et

    Stiffen rear shocks a couple clicks and limit front suspension travel, see what happens
     
    Last edited: May 10, 2017
  7. stagetwo65

    stagetwo65 Wheelie King

    What Adam said. Harwood's instructions say to cut at least two 1" vent holes in the rear of the seal plate, so that's what I have.
     
  8. Jim Weise

    Jim Weise EFI/DIS 482

    Pressurized hood scoops are good... defeating that pressurization is counter-productive to your goals.

    We had the same issues on the Regal, once we sealed it up.. and on Sweesy's car.. the cure was to add two hood pins, off of anchor points built off the firewall, and pinned the hood down tight adjacent to the rear of the scoop, on each side. I will see if I can find some pictures.

    JW
     
    Last edited: May 10, 2017
  9. dan zepnick

    dan zepnick Well-Known Member

    Thanks guys,keep the info coming.I may try your idea jim.how did you seal the grill? Don't want to break it .Lol
     
  10. Jim Weise

    Jim Weise EFI/DIS 482

    Dan,
    Cut plexiglass to fit in openings, and drill holes small holes in the plexiglass to secure them to each side of the grill openings with a couple of those electric fan mounting kits. We installed the cover plates on the front side of the grill, used smoked plexiglass. From a distance, it looks perfectly normal, you can't see it's sealed until you get close to it..
     
  11. dan zepnick

    dan zepnick Well-Known Member

    That's sounds like a great idea jim.I think I'll try that first.was also thinking of putting a couple holes it the rear of the scoop.
     
  12. Jim Weise

    Jim Weise EFI/DIS 482

    I would not do that Dan... remember those instructions are from the scoop manufacturer, to make their product not pull the hood off.. this makes it "work" in their eyes.. .they no longer get calls for folks complaining about the hood pulling up in a run. But that is the small picture, from their mindset..

    The whole reason for a forward facing hood scoop, sealed up, is to pressurize nice clean air at speed, and ram in down the carb. The "mailbox" scoop was designed from a lot of R&D to do that by pro stock teams in the 90's.. striking the balance between the ram air effect and wind resistance..

    If you do decide to de-pressurize the scoop, do it at the track between rounds.. I would be curious what it does, if anything to you times and mph.
     
  13. MT BUICKNUT

    MT BUICKNUT Well-Known Member

    Here are a couple of pics on how my cowl is tied down in the rear, it has the the normal four on each side with two in the front center. I don't always use the two rear ones, but if you forget the two front ones it will really bow up. 100_0572.JPG engine.jpg
     
  14. BQUICK

    BQUICK Gold Level Contributor

    [QUOTE

    The whole reason for a forward facing hood scoop, sealed up, is to pressurize nice clean air at speed, and ram in down the carb. The "mailbox" scoop was designed from a lot of R&D to do that by pro stock teams in the 90's.. striking the balance between the ram air effect and wind resistance..

    I.[/QUOTE]

    That's it Jim nice clean pressurized air.....might need one of these:
    http://www.ebay.com/itm/292149551281?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1558.l2649
     
  15. HotRodRivi

    HotRodRivi Tomahawks sighted overseas

    That photobucket and all it's pop ups really are annoying for looking at pics.
     
  16. standup 69

    standup 69 standup69

    Dan can you post a pic of the hood full top view
     
  17. buicksstage1

    buicksstage1 Well-Known Member

    Dan, block the grill off with plexiglass, you will pick up et also.
     
  18. HotRodRivi

    HotRodRivi Tomahawks sighted overseas

    Like the old Saber jet fighter. Or early Russian Mig fighter
     
  19. Bens99gtp

    Bens99gtp Well-Known Member

    We had the same issue with our cowl, we bent some brake line to simulate the the opening in the stk hook, and use the factory latch to hold the front down. Once it was lined up and marked we just laid matting and glassed in right into the hood. Now after all the side clips are locked I just walk to front apoly a little pressure on the nose and it latches down and holds
     

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