andrew7 Posted November 19, 2009 Share Posted November 19, 2009 I know a Seven is not aerodynamic compared to new cars. My high top conversion van will top out around 65mph down a steep hill. My last drive a couple days ago, I went down some of those Pa. hills in the Seven. The top of the hill I was at 52mph, pushed in the clutch and wondered how fast over the national limit I would be at the bottom. My van felt like a runaway freight train at the bottom, the Seven manage an astounding ..........51mph. One back county hill the van hit 60 before having to jump on the brakes while the Seven sat at 46/47mph for most of the hill. Has anybody done a neutral downhill coast to see how fast the air will let you go? Link to comment Share on other sites More sharing options...
scannon Posted November 19, 2009 Share Posted November 19, 2009 Not an official coast down test but I have noticed that on down hill grades in my Se7en the engine requires some throttle to maintain speed, however my Silverado picks up speed, even when the transmission is in Drive and my foot is off the throttle. I know that a Caterham has a substantially higher Cd than a brick and a lot more frontal area. Link to comment Share on other sites More sharing options...
Kitcat Posted November 19, 2009 Share Posted November 19, 2009 A7: In the "interest of science", try it next time without the windshield and see if that makes a difference. I will try the downhill coast test next time I am out to see what the result is. I have Brookland screens wh/shd help. Mike Link to comment Share on other sites More sharing options...
andrew7 Posted November 20, 2009 Author Share Posted November 20, 2009 Mike, only motorcycles are allowed to be windshield less. I'm 99% sure even Dean's series 1 needs a full 12" windshield or it can't be registered with PennDOT ,pre'48 registered street rods are the exception. I don't want to be explaining my scientific experiments to any LEOs. Please inform us of your findings from Ohio when you get a chance. Link to comment Share on other sites More sharing options...
slngsht Posted November 20, 2009 Share Posted November 20, 2009 it's not just a matter of drag... weight also is a factor. your van releases alot more potential energy from the top of the hill to the bottom. So, even if they both had the same aero force acting on them, the seven will slow down alot more (or fail to speed up) than the van. Sort of like dropping a feather and a bowling ball. Link to comment Share on other sites More sharing options...
Hank Posted November 20, 2009 Share Posted November 20, 2009 So a fat kid in a sled going down hill will have a higher terminal velocity than a tiny kid? PE = m*g*h Link to comment Share on other sites More sharing options...
slngsht Posted November 20, 2009 Share Posted November 20, 2009 So a fat kid in a sled going down hill will have a higher terminal velocity than a tiny kid? PE = m*g*h as long as his frontal area is not bigger :leaving: Link to comment Share on other sites More sharing options...
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