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Aerodynamics of the Gremlin |
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WesternRed
AMC Addicted Joined: Aug/03/2010 Location: Australia Status: Offline Points: 5799 |
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Just for fun one of my work buddies had a crack at some Computational Fluid Dynamics (CFD) using the Autodesk Fusion 360 software, it's a pretty crude model at this stage, but still looks cool:
Red is high pressure, blue is low pressure. If anybody has an accurate 3D cad drawing of a Gremlin, let me know.
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I've finally given up drinking for good...........now I only drink for evil.
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6881 |
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You would think the factory rear spoiler curved down like they did with the TransAm cars would reduce drag some by sending some high pressure air into the vacuum at the rear.
My cousin used to run stock cars and although they had many class rules, they all took advantages in hopes of not getting caught and getting an edge. He would rake back the windshield 3/4" to 1" and pull side panels/fenders in were it was hard to accurately measure. Radiuses of some curves were increased and others near the bottom sharpened. Never had the software as you show, but getting an extra lap out of the tank of fuel and winning races was all the proof of concept he went by. You see new cars like my son's Honda with the full aluminum underbelly engine pan and almost smooth bottom under the car. The 1-1/2" air dam added to the front bottom of the motorhome added a measurable 0.4 to 0.5 MPG.
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BBO UK
AMC Nut Joined: Feb/17/2020 Location: UK Status: Offline Points: 288 |
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I also thought that a Breedlove type spoiler which splits the air flow and sends some down into the vacuum at the back of the car might help? Similar spoilers are fitted to modern hatch backs and a front air dam to stop air going under the car will help.
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WesternRed
AMC Addicted Joined: Aug/03/2010 Location: Australia Status: Offline Points: 5799 |
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This popped up on my facebook feed this morning, Wally Booth's Gremlin running a front spolier:
It's the only picture I can find anywhere of a Gremlin running any sort of front aero device, so I'm thinking either it didn't work, or was not allowed under the rules. Do notice that they tended to run the cars very low at the front, which might reduce the amount of air going under the car or maybe they just ran a lot of rake on the cars to try to help with downforce at higher speeds. I suspect the front spoiler would be against the rules, they were pretty strict on maintaining stock appearance by the looks of it.?
Edited by WesternRed - Jun/03/2023 at 6:18pm |
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I've finally given up drinking for good...........now I only drink for evil.
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PROSTOCKTOM
Supporter of TheAMCForum Joined: Jun/20/2010 Location: Indiana Status: Offline Points: 2450 |
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I don't think NHRA would have ever allowed that spoiler. However a lot of Pro Stock guys match raced during the week or the off weekend when an NHRA event was not scheduled. My guess it was used during a match race where the rules weren't enforced or required.
Tom
Edited by PROSTOCKTOM - Jun/12/2023 at 9:52am |
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Molnar Technologies Full Service Dealer - Crankshafts & Connecting Rods
1969 AMC Rambler Rouge Race Car 1974 AMC Hornet Hatchback, Wally Booth Outlaw Nostalgic Pro Stock Race Car Project |
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Hurst390
AMC Addicted Joined: Apr/20/2008 Location: secret Status: Offline Points: 5818 |
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I do not have or have never claimed to have an original Pro Stock Car.
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SC/Hurst Rambler
11.62 120 100% Street Legal |
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WesternRed
AMC Addicted Joined: Aug/03/2010 Location: Australia Status: Offline Points: 5799 |
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Just revisiting this post, under car view without the belly pan doesn't look very aerodynamic: this is my revised belly pan: Will hold less oil now, but is re-engineered as an aerodynamic device. I ran this at the track last time out with some interesting results, average of best 3 runs (different events): Without belly pan: 60' 1.602, 330' 4.587, 660' 7.109, 1000' 9.309, 1/4 mile 11.176 @ 120.61 D/A 222' With aero belly pan: 60' 1.616, 330' 4.603, 660' 7.123, 1000' 9.317, 1/4 mile 11.175 @ 121.56 D/A 113' I also made some tuning changes, but mostly aimed at improving the launch, obviously that didn't work because the car was slower every except for the 1/4 mile ET, which is basically the same, but it has picked up nearly 1 mph across the finish line. Not sure if I can put that down to the revised belly pan, but an interesting result. |
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I've finally given up drinking for good...........now I only drink for evil.
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PAGAENT
AMC Apprentice Joined: Jan/16/2020 Location: 93446 Status: Offline Points: 140 |
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It's always good when your "improvements" don't slow you down.
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Pat Gary
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Class Guy
AMC Addicted Joined: Jul/02/2007 Location: Arkansas Status: Offline Points: 969 |
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Aerodynamics: Gremilin = Brick
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Addicted to acceleration.
Owner and Admin for www.classracerinfo.com |
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