Lifting at high speed

Discussion in 'Mustang Chit Chat' started by davidjurss1, May 9, 2019.

  1. davidjurss1

    davidjurss1 Junior Member

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    So, admittedly, I know little to nothing about aerodynamics. I've noticed lately that my 08 GT/CS start to feel like its lifting at speeds above 100. It starts to feel like it's almost floating. So far, its lowered, with Koni shocks and struts, with a GT500 rear spoiler. What else can be done to help it stay lower to the ground? I've been looking at the GT500 front splitter, but wasn't sure if that will make a real difference.
     
  2. Macman45

    Macman45 Resident Geriatric

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    Need a better rear spoiler that provides some downforce but I doubt you're really experiencing float at 100MPH in a 3700+lbs car. But I do know the GT500 spoiler was more bling than downforce. Thats why the KR is flatter.
     
    redsnake likes this.
  3. davidjurss1

    davidjurss1 Junior Member

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    Above 100 is where I feel it. Closer to 120 or 130 is more accurate. It doesn't feel as responsive at that point, and it just feels like it got lighter.
     
  4. Dino Dino Bambino

    Dino Dino Bambino I have a red car

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    A front splitter will definitely help to provide more downforce and reduce lift.
     
    redsnake likes this.
  5. fdjizm

    fdjizm Drag Queen

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    The front of our cars are like bricks in the wind so they do feel a bit lifty at high speeds.
    A front splitter would help, also heard of people using the front under-tray bits from the 2010 mustang to help.

    AR3Z17626A DEFLECTOR
    AR3Z6C038A HEAT SHIELD
    W710564S439 Retainers x4

    2010 Mustang GT

    "Ford says the new Mustang body yields 23 percent less aerodynamic lift at the front with a new slotted panel installed under the radiator to direct air, 50 percent better in front/rear lift balance, and has seven percent less aerodynamic drag. They tell us it is 12 percent quieter in wind noise than the outgoing car, 15 percent quieter in the case of the convertible. Ford also points to a 33 percent reduction in squeak and rattle performance, and a 10 percent improvement in speech intelligibility due to interior noise reductions, especially in the convertible"

    [​IMG]
     
    Last edited: May 9, 2019
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  6. Shotokan1509

    Shotokan1509 forum member

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    I've wondered if that will help with hoodshake at speed by helping to evacuate more air from engine bay. Also any tried it with bmr k-member?
     
  7. fdjizm

    fdjizm Drag Queen

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    I was going to do it last year but forgot, I have a UPR k-member and still might pick the stuff up.
    I don't have any undertrays at all lol
     
  8. Sactown

    Sactown Sactown

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    I have had my car over 150mph more times than I can count never once did it feel like it was floating, do get some hood vibrations on the front corners.
     
  9. Macman45

    Macman45 Resident Geriatric

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    Let me know if you decide to do this with your CS. I was wondering if that deflector would fit our CS front fascia
     
  10. Dino Dino Bambino

    Dino Dino Bambino I have a red car

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    I did similar aero improvements on my car. Gained ~1mpg in highway cruising and reduced the hood shake.

    http://www.angelfire.com/my/fan/Mustang2006GT/Aero.html
     
  11. 06JET

    06JET forum member

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    This is interesting. I have been worried about my carbon hood not having hood pins. I do not want hood pins. I love the sleek look of my hood. I even bought the Aero Catch pins but have refused to install them as of yet. My car doesn't have an undertray piece. I guess the PO didn't put it back on when he installed the Procharger. My hood shakes above 70 so I wonder if I fabbed one up and installed it, would it reduce the pressure on my hood and make me worry less about the hood letting go?
    012.JPG
     
  12. davidjurss1

    davidjurss1 Junior Member

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    Glad to hear others arent feeling lift. Really happy for you.

    Doesnt really solve my issue though.

    I get vibration and shaking in my hood as well, but it's fiberglass and I kinda expected it. I installed some Shelby hood pins and havent had an issue with it since. I'm just not a fan of the lifting.
     
  13. 759-OR

    759-OR Junior Member

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    Yeah, this is pretty well played out. As the dudes already nailed it.

    The S197 has front end lift. Its the front, much more so than the back.

    Those little rear spoilers, BTW, don't do anything. It takes a real wing in clean air to fix the rear lift.

    But back to the issue of the front, which is the real problem. You can look at the progression of the factory cars for answers.

    The undertray is key. Do that. Then perhaps look at a splitter like the new LS cars have.

    Finally, hood venting is key. Real vents and big holes. I went with the ones from TrackSpec, and can recommend. Its a commitment, but worth it.
     
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  14. JJ427R

    JJ427R forum member

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    I've definitely had the front end feel like it's coming off the ground on my 2010 as well, usually starts at about 120mph for my car. At Road America coming up the hill on the main stretch, when I reach the crest of the hill I'm at about 120mph and my car gets very light in the front and defiantly feels like it's lifting, so I try to back it off a little and let my front settle down as I'm coming over that crest.

    At BIR, I bury my needle at 140 on the long track going down the dragstrip, car gets really squirrely then too. I had one of the instructors tell me my front splitter was moving up and down about 6 inches going at that speed and asked if I could feel it in the car, and I really did not???

    Prior to installing MMD hood vents I would also see my hood lift a little in the middle at the high speeds, but since putting those in it's much better.
    On the front I have the Roush Fascia and splitter.
     
  15. davidjurss1

    davidjurss1 Junior Member

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    I appreciate the helpful responses. The hood is going to be changed out soon for something with hood vents, and I it looks like I'll be getting the APR front splitter for the GT/CS.
     
  16. redsnake

    redsnake Junior Member

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    Belly pans cause lower pressure under the car and help w/ downforce, look into a spoiler but they cause drag interrupting the airflow over the car at speed. kev
     
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  17. Pentalab

    Pentalab forum member

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    Per ford, the GT-500 rear spoiler provides for 200 lbs of downforce @ 150 mph. The 2012 version, which includes the tiny gurney flap, provides for 240 lbs of downforce at 150 mph. ( 20% more downforce, 5% more drag). Since pressure increases to the square of the speed of the car, the 2012 GT-500 rear spoiler ( with flap), the downforce drops like a rock with reduced speed. Like just 106 lbs of downforce @ 100 mph.... and just 60 lbs of downforce @ 75 mph. So the benefit of the rear spoiler is minimal.... until you are > 100 mph.

    Look at any large / adjustable rear wing specs...and you will see they too, also have the same 'pressure increases to square of velocity' specs..for any given wing angle. The large rear wing will of course provide for a helluva lot more ultimate downforce...provided it's in clean air, like at least as high as the roof line.

    Regardless of wing angle, you will still notice that at 75 mph, the downforce is only 1/4 of what it is at 150 mph.
     
  18. Wingrider

    Wingrider GT500 track guy

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    I track my 2011 GT500 as a dedicated track car with all the appropriate mods. I have been looking for some sort of downforce helper on the nose. I'm probably looking at a new trucklid and a G-stream for the back as well. I feel lift at tracks like Laguna Seca at speed.
     
  19. Pentalab

    Pentalab forum member

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    Other than a splitter on the front, what other possible options do you have? Splitters are not adjustable in front to back length, and some folks have made em too long. Ideally, you would then need an adjustable wing or similar on the back end, to complete the delicate balancing act. A buddy who tracks his car, added hood vents (heating issue)....and said the front end felt more planted / less lift. But your GT-500 already has hood vents. On the 2012 GT-500, ford changed something in the front end, which supposedly resulted in slightly more down force, and I forget what they did.
     
  20. 759-OR

    759-OR Junior Member

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    Penta. Thanks for the info on the GT500 rear spoiler. I have struggled to find hard numbers on ANY aero add-ons for the S197. I'd appreciate any other info you had.

    My understanding is the lift imbalance front to rear is significant. And that the front is the real problem. Addressing the back without the front only makes things worse.

    Do we have any data on front aero? Which is the problem I am trying to solve. I would prefer to go with something more like the Steeda spoiler rather than a full splitter for practical concerns. But will go there as required.

    150 is pretty quick for most tracks. The best I'll see at any of my regional tracks is more like 130 (maybe a bit more) actual.

    :)