Hot Rods Roadster vs Coupe. which is faster?

so ive been mulling this over for a while for a little bit and im curious as to what you guys think.

lets say you had a real steel ford coupe, (3 or 5 window, it doesnt matter) with a 350/350 combo (just hear me out) slicks, all the good stuff and you ran it down the drag strip under ideal weather conditions and engine temps yada yada yada. you got your time.

now what if it turns out you are actually a douchebag and you decide to take a sawzall and cut the roof off your coupe ( you leave the windshield). you then go on down the drag strip (being a douchebag) and make as best a run as you can, under the same ideal conditions and engine temps yada yada yada. we shall assume the being a known douchebag on the roofless run has no effect on how the car will run.

which car ran faster?

For anyone who has hacked the roof off a coupe, i mean no offense.

 

Coupe.

 

The one with the mouse motor!

 

Roadster will weigh less so it will be quicker. Neither has any aerodynamics to speak of so that is moot. It's just weight and muscle and in a situation where all other things are equal the lighter car ALWAYS wins.

 

The one with the douchebag?

 

That said, you'd still be douche in a roughly sawed up coupster

 

I have to think the difference between the two is going to be so small it's not worth worrying about. A roadster with the windshield off might be faster just because it has a smaller hole to punch in the air, and doesn't have a big flat panel on the top of it, but otherwise there's not a lot of difference. The top tin and wood doesn't weigh that much.

 

I would be willing to bet my top weighs at least 100 lbs and it has lexan windows. Glass is pretty heavy too. Old drag racing pearl is that you if you can remove a 100 lbs from your car then you will shave a 0.10 off of your 1/4 mile ET. In drag racing that's a big deal.

 

I would think the point of this thread is "not worth worrying about!

 

Takes more zot to go the same speed or ET if you will in a roadster. That is part of the reason that make them run in different classes.

 

Empty or full douche bag?

 

Everything that moves through air is subject to the laws of aerodynamics. It is not something that one or another thing "has". One car can have a better aerodynamic drag coefficient that another. In this case, it would be the coupe.

 

You think my coupe has aerodynamics do ya? Hahaha! It's like pushing a barndoor! I understand drag coefficients and such but something you may never have experienced is making that barn door fly like a rocket sled from hell with just good old fashioned horsepower. Haha! If I can make it weigh less with the same power then I'm going to go faster.

 

Without some sort of help like a wing and or a tonnue a roadster of the same body style will never have the aerodynamics of a coupe.

If you coupe is like pushing a barn door the same body as a roadster will be more like a billboard.

 

A Bartender called me a "Douchebag", maybe I shouldn't have ordered a Vinegar & water

 

Well I know this. I sure don't like to look over and see a roadster in the opposing lane. Good to hear though because I was just about to fire up the sawzall!!!! Whew!!!...wadda relief!!!

 

yawn

 

awesome thread.

 

Buy one of each,....and save commiting the crime of hacking up a coupe.

4TTRUK

 

Now we are both relieved.

So which is faster a roadster or a pickup?

I guess from a land speed standpoint I suppose it is a valid question, but even at that they are different classes so if a record is what you crave it really doesn't matter.

 

Like folks have said, less weight is usually quicker on the dragstrip.

If you were looking at top speed ie LSR stuff, it appears as tho the roadsters are quicker than the coupes of similar engine types. Of course nothing is ever similar when doing comparisons.

Engine type Gas Roadster Vintage Gas Coupe
v4 152 109
v4f 110 82
xf 153 132
xo 165 143
xxf 184 156
xxo 180 153

Data taken from my 2009 SCTA rule book.

 

Only if you can make it hook.

 

Funny you should mention rockets. I did build a retro-rocket rig, to stop an Airstream trailer and a Suburban, for a television show. I did also make a 18lb. frozen turkey fly, aslo via rocketry. I know my rockets. As for old-fashioned horsepower, 1200 is about the most I have been in control of. Aerodynamics, me, into the wind, at 240, on the bike.

 

I have stashed away some place that I can't find right now a list of CD (drag factors) for a variety of vehicles. Believe it or not, a Lotus Super 7 - a tiny little thing with open suspension and lots of stuff dragging in the wind like a hot rod - has a higher CD than a Greyhound bus. So, for the most part any hot rod is nothing more than a brick in the wind. Aero styling on a hot rod is just that, only for looks. Gary

 

I think that is why if you cover the suspension etc with sheet metal it is considered stream linning on the salt.

Stuff that is open and out in the breeze catches wind, open cockpits do the same, a pickup truck with an open bed is like dragging a parachute. None of that has much effect until you really get going.

 

Roadster, no questions. Check this one out? Chick on this link: http://www.motorntv.com/modules.php?name=ZClassifieds&file=detail&cat=21&de=2114

 

Jerry Kugel's first roadster was a topless 5 window, but I'll let someone else tell him he's a douchebag.











And everyone knows a roadster pick up is faster than a roadster!!!!!

 

Frank
All I saw was an ad for a roadster for sale. Not even a traditional roadster.

I do like the color of it.

dean I would tell him that for sure but I am not sure I want to be beat that bad. From what I understand he's been building and racing a long time, that pretty much mean that he was around when rodders and racers were not nice.

I admire that roadster a ton. I wa not aware that it was buolt from a coupe until I read it in a magazine recently.

 

Aerodynamic drag depends on frontal area as much as Cd. While the roadster is aerodynamically quite dirty the coupe isn't exactly a perfect theoretical teardrop, so I'd expect that any advantage the coupe has in Cd would be more than offset by its greater frontal area.

My sources indicate that a stock base '32 Ford coupe weighs 159lbs (7.7%) more than a stock base '32 Ford roadster. In all I'd give the nod to the roadster.

 

I agree