possibly building my car for top speed
 

I don't know if anyone on here is really interested in top speed racing, but i've pretty well decided that's what i'm primarily building my car for. i need some opinions on aerodynamics and gearing options.

i really want a lot of downforce on this thing. i've had a few different aftermarket bumpers, but i'm going to go back to '99oem or stock, with a jdm lip, as well as add a couple dive planes to the nose. for side skirts i just want something low and flat. i'm considering constructing my own out of heavy rubber ( i believe this is how the can-am guys used to do it) so that they'll also be forgiving, not to mention they won't add much to the lines of the car. as for the rear of the car, it looks like i'm going to have to use the RE-style diffuser or construct my own. i also need to decide on a wing. i need something with a good amount of downforce. i really dont want to go with the rice-tastic park bench approach, but i will if it's the best option. i also would like to construct a full undertray, probably out of 1/16th" aluminum sheet, so that it will withstand road debris and whatnot. any techniques or anything to keep in mind when building this? or should it just be flat and cover as much as possible?

as for my gearing issue, my initial goal will be to top 200mph. i can obviously do this with a different ring and pinion, but i would much rather do it with a 6spd tranny, and not sacrifice my acceleration. what are the common 6spd swaps (if any)? every time i search for six-speed options for the FD i come up with little or nothing. maybe i'm just looking in the wrong place.

anyway, sorry for writing this novel, i appreciate any help you all can offer.

contact RX-Heven- I believe you can put a Renesis (RX-8) 6 speed behind a 13B-REW. He can provide you info on a company in Austrailia that can turn them into dogboxes and/or provide the info to adapt one.

Another option I'm sure is a T56 from a Viper/Camaro with an adapter plate. .75 5th and .50 6th......

Whichever you chose it ain't going to be cheap.

Do you plan to take this to Bonneville Salt Flats or what? Weight for top speed is a bonus for stability.... it really doesn't affect top speed much at all. Aerodynamics are the key. Maybe even 225/16's mounted on your stock FD rims.

-GNX7

bonneville isnt totally out of the question, but im more looking into the smaller runway-based competitions, and maybe a few early morning deserted-highway runs. basically, i still want to be able to drive my car and have fun with it, as well as do the top speed stuff., as for tire size i'm currently running a 225/285 combo, which will be revised. i guess i'm more talking about "wangan" racing than hardcore top speed competition, which is why i want to keep the acceleration. i dont look to see any moon discs on my wheels in the near future. lol

you want minimal downforce as downforce produces drag. You want the lowest possible coeffcient of drag. I'm sure youve seen the video of the racing beat rx7 flipping. That car didn't have a lot of downforce because downforce adds drag. They added ballasts to the car, i believe 300lbs, and went from there. Top speed is not a joke. Research the topic outside these forums is the best advice i have for you. good luck.

Duttweiller built a few top speed Firebirds/Camaros with small block chevies and they are very aerodynamic. he even blocked off the front and had a 50 gallon water unit inside the car for the cooling system and ballast. In addition he had tons of lead in the car. I think it weighed well over 4000lbs. Nonetheless it had a small wing out back and spun/flipped going about 230mph.

Similar thing happened to the Racing Beat FD and the FC I think too....?

Stock FD gearing with enuf power is supposed to do 180mph or something. You could always put taller tires out back...... 6speed would be a good choice as long as the gearing is there and you have enuf torque/HP to make such a high gear still pull.

The FD is very aerodynamic as I'm sure you know (.29-31). I'd try to have some form of lip up front and definately a '99 RZ or larger wing out back to keep the rear firmly planted. The R1 '93-95 rear spoiler does nothing to aid downforce. A roll bar/cage would be a good idea and quality belts (helmet?) as well. Crash at 150mph+ and one rarely walks away from it.

I crashed at about 70mph on a crappy road and clipped an immovable object with about 4-6" of the passenger side of my FC.... took the front fender clean off and the suspension, nailed my A pillar and bent the roof up, door out into a "V", and ripped my wheel clean off. 100mph more on top of that you better make sure you have plenty of room and are on quality roads with nothing to crash into.

-Mark

A cage, racing seat, belts, and full driver safety equipment should be the VERY first things on your list. Maybe your wording is just awkward, but it seems like that's something you're thinking about doing after the fact.... not the right thought process IMNSHO. An extremely stout cage with the primary goal being safety would be #1. Completely encapsulate the driving compartment, including building in bracketry for the seat. DO NOT bolt the seat to the floor of the car -- make a bucket out of smaller diameter tubing and bolt the seat to that. Triangulate the hell out of the cage and make damn sure you don't have any "dead load paths", where a tube intersects another tube in a T without something on the other side of it. There are a lot of cage builders that inadvertantly do that because they don't look closely at the cage. A dead-load path aimed properly can kill you instantly via a tube through the head or chest. Not a pretty sight for anybody that responds to the crash, let me assure you.

Seeing as how you'll be doing in excess of 100MPH, a HANS device would be a good thing to have, as well. You may not be running near any walls, but if you do catch air (as obviously many cars do) the ground is now your immovable object... and it's even less likely to move than a tree or concrete barrier.

Good advice Chris. Going at high speeds any spin is likely to turn into a major accident. I would look at a fire system and a fuel cell as well.

Sounds like I need to get you to look at my "modified" cage on the e-prod car. I also need to look at the seat set up. I'm afraid it's as you describe above. I'd like to build an adjustable bracket.

If you're truly intending on attempting to achieve high-3-digit speeds with any regularity, it's going to take a lot more than some backyard aerodynamic engineering to get there, and with any semblance of safety. A lot of research will be necessary, the vast majority of it beyond this forum, or even the internet. Do your homework, otherwise there's a pretty good chance you and your car will end up being an out-of-control 2750-plus-pound projectile. If you really think you're going to do this, I'd start with the advice from christaylor and cpa7man before you do anything to the car itself.

What the hell is "wangan" racing?

I wish I could heed my own advice. Unfortunately, I have to settle for adding metal strap to the floor to stiffen things up.

Sometimes I wish people wouldn't take advantage of rules intended for safety... this is one of those times where those guys screw all of us sissy-men. :D

wangan is street racing at high speeds. Something kids got from reading option etc.

As i said before go do some real research. this topic is beyond what this forum has to offer.

Good grief... :rolleyes:. Nevermind...