S13 Coupe vs. Fastback for track use

[Def]

I don't have an S13 240SX yet, but as soon as things settle down in my life I plan on picking one up and turning it into a dedicated track ******.

Now, aesthetically I like the fastback. Yet I keep hearing that the Coupe is a good 50-60lbs lighter and more rigid due to the bracing behind the rear seat.

Yet the fastback with a properly design airfoil on the rear(extending out a few inches and up maybe 6") will most likely have a clear aerodynamic advantage. While it may seem small, when the wick gets turned up on the engine and your average speeds around a track might be 60-70mph, with bursts up to 100mph+ on a few sections - a small difference in your coefficient of drag adds up. Of course one can always make more power to overcome that - but this discussion is about efficiency. Choosing the right tool for the right job.

So from everybody's opinion, does it seem that the extra chassis rigidity and lighter weight of the Coupe clearly outweighs the small aerodynamic advantage of the Fastback?

Will things like a cheap front and rear strut bar and a rollbar(think half a full cage behind the driver) easily bridge the rigidity gap on the Fastback. Yet you're dealing with even MORE weigh there. Easily 100lbs over a Coupe, and that's substantial when you're talking about stopping and turning all that mass as fast as possible.

[GroundZero]

yes the coupe is lighter and more rigid, but there is a limit to how rigid a car can be. aerodynamics is another story either a car has it or it doesn't, aerodynamic improvements can be made to the coupe but thats money that didn't need to be spent or could have been spent improving the already superior aerodynamics of the FB.

The same rigidity level can be reached in either car with strut tower bars, sway bars, ladder bars, maybe some subframe connectors, roll cage, control arms, tension rods, springs, shocks, pillow ball mounts... the list goes on. seeing as you'll be putting most of these parts on which ever one you get it doesn't really effect the differance in weight. if you really want you weld a couple bars in behind the back seat of the FB.

The weight issue of the FB is nothing to be concerned about, weight is easily dropped by stripping out the interior, stripping the car down, changing out metal body parts for fiber glass or carbon fiber, switching out the glass for lexan, removing unessential components such as the ac system or audio system. me and my friend dropped about 50 pounds off his mr2 by removing unused bolts, brackets, and other useless hardware.

my overall pick would be a 1991 240sx Fastback SE like the one i have, i have the super hicas model which you might not want because of the extra weight. but ultimately the choice is up to you, just throwing my opinion out there like you wanted. good luck picking and building your car.

[TBreu007]

I used to say buy coupe, but I don't know any more. Just replacing the rear window with Lexan in the FB (if your race class will allow it) will probably drop 30lbs, and a good cage will stiffen up the car A LOT. I haven't driven a FB with a cage, so I can't say for sure which is stiffer with a cage. I thought the difference in weight from the coupe and FB was 80lbs, but I could be wrong. I do know that my coupe has no problem making minimum weight of 2650lbs with driver, but the FB comes in a bit heavier no matter what is removed (within the rules).It's really a tossup which will probably come down to what one you think looks better

[float_6969]

I've owned both models and autocrossed both models and I prefere the feel of the coupe. I don't know that there is much real merit to it, but I think the coupe 'feels' stiffer. It was one of the first things I noticed actually. Ultimatly it's up to you, but I'm driving a coupe now.