rotorooter93fd

iTrader: (6)

does anyone know what the top speed for an fd is? taking out coefficent of drag and safety factors aside just focusing on gearing. 9000 rpms with with 4.10 gears factory tranny gearing and the factory wheel and tire diameter. i was told 189mph but couldnt verify it.

Speeder165

iTrader: (7)

Here`s a little thread on your subject. Might could glean some info from it.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/how-fast-have-you-gone-fd-887519/

turbotoaster

if your running 255/40/17s that come on most later fds then that 199mph at 9000rpm

if your running 225/50/16 then thats 198mph at 9000rpm

remember though that this is with new tyres, if they are worn heavy your speed will drop a bit

orange7

iTrader: (23)

Took mY Fd to 174!

RotorMotor

iTrader: (5)

do 4500 rpm in 5th gear, note the speed. double that is your top speed (unlimited hp, aereo, etc). Last i remember it was 203? maybe more

turbotoaster

remember not to go off the speedo but a proper gps unit as you cant assume your speedo is accurate

Montego

iTrader: (1)

Official top speed of an FD is around 155-160 MPH. Thats when a stock FD runs out of HP.

rx7rocks

I DID 178 mph WITH 285- 35- 18, A PETTIT COMPUTER, A SUPRA FUEL PUMP AND FULL EXHAUST. I WILL BE DOING A RUN SOON WITH NEW SET UP ON TWINS.

Julian

iTrader: (14)

Calculation of theoretical top speed based on gearing, tire size and rpms is meaningless in and of itself; you also need the Hp to overcome.
(Tire rolling dia.(inch) x pi x rpm)/(rear GR x 5th GR x 1056) = mph
Stock example: (24.86 x 3.1416 x 9000) / (4.1 x 0.719 x 1056) = 225.7 mph

So what does that tell you, all you need is about 800-1000 Hp.

ptrhahn

iTrader: (9)

And/or a helluva long stretch of flat road.

rotorooter93fd

iTrader: (6)

horsepower is irrelevant in my question . when i stated that coefficent of drag is not considered i basically made a frictionless enviroment other than the tires to the road.

Julian

iTrader: (14)

So as I said: 226 mph in a theorectical frictionless environment.

Now if you add back in engine drag and rolling resistance and delevole some way to keep car on ground without downforce (since no drag their can be no lift (pos or negitive)) its an impossible answer and this is a worthless exercise. I would question wheather a stock engine has enough Hp to overcome 226 mph tire rolling resistance .. probably not.

turbotoaster

that 5th gear ratio your using is wrong, for some reason it was put wrong in the literature

habu2

If horsepower is irrelevant then why state an RPM limit?

IMO your entire question is irrelevant...

Julian

iTrader: (14)

And you think it is what on a US spec car??

I guess my factory service manual is wrong too.

rotorooter93fd

iTrader: (6)

Im trying to figure out what my top speed potential is Im using an 18inch wheels with a 30mm side wall which should create approximately 487mm overall height and a stock wheel and 50mm tire should create an overall width of approximately 457mm so the new wheels and tire should allow my to reach 200 mph in theory provided the information provided is correct. I never stated my motor was stock.
but im hoping my 20b with its 80mm turbo will have enough power to hit a top speed of 205mph

KKMpunkrock2011

iTrader: (5)

recently at the texas top speed run a 500whp lsx FD came very close to breaking 200mph, just an fyi.

rotorooter93fd

iTrader: (6)

i always think its funny when someone posts up something about expanding what our cars could be capable of they are shot down. its almost as if people dont want others to suceed or for that matter for our cars to become any more potent than what they currently are. the fd is an excellent car but things have changed since 1993 the cars that are rolling off of the assembly line are doing some very impressive things. To compete with them we have to up our game or fall behind your choice. personally i want to be some what of a challenge.

Supernaut

iTrader: (83)

We should create a vacuum environment over a huge stretch of land to find out! In these conditions, you would probably have to accelerate lightly to keep traction due to no aero aids if weight is not enough to do so. This whole exercise seems kind of pointless. You can't just focus on gearing even if HP is unlimited. That's kind of like calculating the maximum amount of a good you can buy with alot of money without having a price for the product in qustion.

Montego

iTrader: (1)

I misread the first post


so back to question at hand:


Taking only two factors into account i.e. gearing and 18" wheels: The only true way to find out what is the top speed is to take the car a dyno shop.

Car is standing still= car wont catch air=no aero dynamic deficiencies; Wind speed irrelevant=HP irrevelant; no imaginary stretch of road=not putting self in danger. So if you are truly interested pony up 50 bucks and take it for a test.

RotorMotor

iTrader: (5)

i think the tires would slip on the rollers with the lack of downforce. I guess you could rope it down.... but if you just get on the highway in 5th gear and to 3K rpms... note speed, and multiply by three you have 9K rpm in 5th gear. (plus its free )

turbotoaster

yes since i have a jap spec car and it quotes the same gear ratios

ok easy way to do it, drive at 50mph in 5th, you will find your revs are at roughly 2250rpm

if they are at 1800rpm you are right and your 5th gear is different than mine.

its a mistake that has been in all the literature.

And yes im still running a stock 4.1 diff


Also make sure you use GPS for speed, not your speedo

turbotoaster

well im building mine to do 200mph in 1.5miles so this is very important to me, im going to be running 700flywheel bhp.

running larger rear tyres, is gonna help me so i dont have to change my rear diff ratio for an auto one

Montego

iTrader: (1)

I got a better question: In a fight who would win astronauts or cavemen?

rotorooter93fd

iTrader: (6)

this is a weekend warrior mainly I use the car for street racing but out here in oklahoma since we have a lot of very straight flat highways we do highway runs. normally 150-160mph is acceptable as a top speed but the usual crowd includes one 1000whp viper one viper with a 250 shot an 800hp integra sport bikes a few supras some c6 vettes a 997 turbo porsche and a few amg mercedes. so the crowd is getting tough these days. I also would like to make the 200mph club for the texas mile