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Any gains from flat underbody panels?

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  • Any gains from flat underbody panels?

    I'm just curious if there are any gains to be had from a flat underbody in the 7? I know that the aero is a ton of bricks on this car but would it benefit from flat underbody panels covering the bottom of the engine? Perhaps if anything, reduce the amount of drag and turbulent air going into the engine bay and reduce lift on the front end even? I wonder if this would cause any overheating issues now that there is less air flowing through. I've skimmed thru the 15+ pages of aero but there isn't much about covering the bottom of the engine... just lots of nasty wings that don't belong on a 7.

    I have modified and added quite a bit of aero on my Exige, completely flat from front to rear (much larger front splitter, side skirts, bigger and longer diffuser, big rear wing, and covering the front and rear wheel bottom openings). I would like to somewhat reduce the drag and lift on the 7... without adding anything that would deter it from it's original look like I love so much. It should be simple enough as I have a few left over aluminum sheets, cut out a few panels, find a way to mount them. If there are overheating issues, add in a few naca ducts...

    What do you guys think, is it even worth doing?
    Last edited by vstryker; December 21, 2014, 12:18 PM.

  • #2
    Generally not worth doing.

    Buy a Radical or something along that line if you want better aerodynamics.

    Just go out and enjoy driving the car. You can get into an upgrade program that takes the car off the road for months, or years.
    Last edited by Doug Liedblad; December 21, 2014, 03:45 PM.


    • #3
      From the archives

      Edit: Be sure to click through on the link at the top for the 'Full Version'. Warning: Donkervoooooort Content.

      Dubble edit: And, the board has been around even longer than that thread! Yikes
      Last edited by moosetestbestanden; December 21, 2014, 05:04 PM.
      A day you don't go a hundred is a day wasted


      • #4
        How about fabbing up some aero body panels like this:

        7 aero body concept.jpg


        • #5
          Originally posted by moosetestbestanden View Post
          Dubble edit: And, the board has been around even longer than that thread! Yikes
          I need to backup the database more often...


          • #6

            The Caterham is somewhat flat on the underside, as is shown in this image that looks like things will get expensive very, very soon.

            /Magnus F.


            • #7
              Realistically, at the tracks in the hood (hereabouts, SoCal) there are only a couple of places where it REALLY matters: Turn 9 at Willow (arguably turn 8, and maybe turn 2 too... wait... did I say tutu?) and Talledega at Buttonwillow. But then, back in the day, I was always HP challenged, so it didn't really matter much in those places even, for my car anyway, although Turn 9 ALWAYS demands respect as it's the last place on Earth you want to drift wide left. Fontana has the banking so ultimately the limiting factor was Cd, not understeer.

              Anecdotes: One weekend at Fontana on Saturday when the weather was on-shore (tail wind down the straight) my oldschool 5 Hz GPS said I managed a buck thirty five on the banking. The following day when the weather turned off-shore and the wind was howling off of the San Gabriels I saw all of one one five, but that was w/ me paddling w/ my left hand as I went along in 4th. I always hugged the bottom as it was the shortest way around. I used to get blistered by Plymouth PT Cruisers (kidding) and Corvettes and such like on the oval until we got to the braking zone before entering the ALMS infield. Then it was GTFOOMW:-D. Oddly, I posted my best time of the weekend on Sunday. I put that down to new(er) tires that I fitted for the last 2 sessions. The infield there is Big Fun!

              To put this in perspective, Stokes w/ his Cosworth Formula Atlantic Spec Truck Motor (aka the 2.3L) never managed to pull top revs in top gear on the banking. But he certainly did manage to complain about it.

              Although it's been a long time, ISTR that Thunderhill presents some challenges for sure (I REALLY want to drive the new long circuit), and maybe Laguna Seca. I've never driven there and I'm too loud now to consider even trying.

              I've had a woody for those CSR wings for a long time. Stokes fitted the CC ones (w/ custom made supports)and said they helped. There are some newer ones out there that are supposed to work w/ the S3, but it's unclear (to me) if they'll fit over - and around - the slicks I run.
              Last edited by moosetestbestanden; December 22, 2014, 09:45 PM. Reason: coz I suck at spelling but my inner german says 'fix it'
              A day you don't go a hundred is a day wasted


              • #8
                I've done some very effective & nearly free areo mods on my Birkin. I've mentioned these before so forgive me if you've seen my comments before.

                The normal 7 windscreen is a flat plank that is the size & shape of the rear "air-brake" on a Bugatti Veyron. The Bugatti's "Lotus 7 Windscreen" pops up to dramatically slow the car when braking. ------------Clearly it has to go! Cutting mine shorter, to 6 inches, made my car noticeably faster in roll-on acceleration. Removing it altogether netted more gains. It's been 4 years since I've used it. Goggles or good shades serve just fine. The car just LEAPS forward.

                The standard Seven headlamps are huge & make people ask if your car is a dune buggy. They are aerodynamically horrible, as well as an annoying obstacle to your line of sight. I replaced mine with small, low-profile polished aluminum oval lights designed for custom Harleys. They look better, do not obstruct view, & the car is faster.

                Lastly, Front fenders. They are your source of front-end lift. They & their brackets are un-sprung weight (bad) and an airfoil that lifts the front end while also acting as a drag-chute. Chuck 'em. In Calif, As long as your reg. says 1971 or earlier & your car weighs under 1500 lbs (it does) you are not required to have them.

                Yes, you get gravel in your hair sometimes. But if comfort is your bag you should not have a Seven anyhow. I've gotten no grief from the fuzz on this. Just the Thumbs-Up as they drive by. I drive it nearly every day.

                When my car is viewed from the front it appears like a squared water heater with fat rear fenders. Not too bad.

                Imagine rolling down the window of your Camry on the freeway & sticking a pair of Lotus 7 headlight into the slipstream. Might break your wrist. Stick an entire windscreen out there & it will yank you right out of the car.

                Those are my cheap/free mods that have netted huge gains.