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200mph road car???

Old 02-23-09, 08:00 PM
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200mph road car???

I was just wondering what would it take to make a 200 mph road car. im just wondering pretty much if it can be done.
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Old 02-23-09, 08:43 PM
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Lots of modern supercars can do it. So yes it is possible. What do you need? Power, proper gearing, appropriate tires and decent aero.
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Old 02-23-09, 09:36 PM
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Old 02-26-09, 11:01 AM
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"I was just wondering what would it take to make a 200 mph road car"

It would take Massive dollars, even if you could do ALL the work yourself.

Power required to overcome aero drag is a function of velocity squared.
To go from 150 mph to 200 mph takes 1.8 times more power.
to go 33% faster takes 80% more power
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Old 02-28-09, 01:18 AM
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lol hmmm i wonder how close you can get with about 500hp? lol i should ask racing beat lol they have those salt lake cars
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Old 02-28-09, 01:34 AM
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theres a difference in a salt lake race car, and a street car.

theres no such thing as a 200mph street car that can do it safely and repeatedly.
MotorTrend did a test with the 599 GTB, and the ZR1 and the GTR. The 599 had a tire blowout, and took a good distance to get to 200. Nothing you could ever achieve on anything but a circuit. There was no way to do repeated runs like that without replacing the tires.

HP aside, its all about the aero. getting to 150 is easy. Its having the car slippery enough to get it past that mark in a short enough distance. Its easy to make horsepower, its much harder to mod a cars aero for those kinds of speeds.

The salt lake cars do it because they have unlimited room. Any car with enough power, right gearing, and proper tires can get to 200 on the salt flat.
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Old 02-28-09, 02:09 AM
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Originally Posted by NCZ13 View Post
HP aside, its all about the aero. getting to 150 is easy. Its having the car slippery enough to get it past that mark in a short enough distance. Its easy to make horsepower, its much harder to mod a cars aero for those kinds of speeds.
Didn't the S4 with aero package have a Cd of .29? Isn't that really low?
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Old 02-28-09, 10:33 AM
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an FD with 400hp should be able to do it.
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Old 02-28-09, 11:11 AM
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What about gearing though? If you're at redline in top gear at 150mph, you're NEVER going to get to 200mph, no matter how much power you have, how little drag you have and so on. If I'm not mistaken, NO RX-7 has ever had gearing that'd even let it get all that close.
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Old 02-28-09, 11:28 AM
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The auto select Fd3s was able to with 3 rotor,twin gt40 turbo and greddy six speed tranny. The tranny is like 20,000 so I don't want to know what the cost to make the engine was. Supposedly you can get three different gear set with the tranny depending on your purpose. it was on an option video I saw so looked into the cars specs. you can you tube the video....rx7 cannonball
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Old 02-28-09, 11:36 AM
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Originally Posted by HotRodMex View Post
Didn't the S4 with aero package have a Cd of .29? Isn't that really low?
Cd isn't the only factor; it's just as it's defined, a coefficient. You have to take that with the frontal area to get the total affect. i.e. most BMW's have really low Cd (as compared to most cars), however they have a much larger frontal area.
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Old 02-28-09, 12:13 PM
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There's A LOT more to aero than just drag. A car might have really low drag, but if you could propel it to 200mph, the lift might be picking it up off the ground (almost ALL road cars produce lift). That's not good.
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Old 02-28-09, 12:41 PM
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In a dream I had I got up to 175Mph this was with 465whp but the car did begin to feel very light in the front. I think with a T56 gear box and about 550-600 rwhp with the right aerodynamics it would easily be done.

I also had a dream about me as a passenger in a friends Toyota supra doing well over 185MPH! but then he had 540rwhp.

Last edited by Erdin; 02-28-09 at 12:42 PM. Reason: needed to add
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Old 02-28-09, 12:56 PM
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It wasn't a dream...
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Old 03-01-09, 08:27 AM
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Mazda claims 158 mph top speed for the FD.

here's the formula:

drag coefficient (.3 non R1) (.31 R1) times frontal area (19.26 sq feet) times mph CUBED divided by 146,600

.3 X 19.26 X158 cubed/146,600= 155 hp.

to that (155) you add 5% transmission loss, 6% total rotating inertia and 60 hp for tire rolling resistance.

155+ 8 + 9 + 60 = 232 flywheel hp.


using the same formula and solving for 200 mph...

410 flywheel hp........ 349 RWHP

note that to go 26% faster (158----200) it took
76% more horsepower!

getting back to 200 MPH.

using the stock tires 835 revs per mile the stock rear end 4.1, and the stock 5th gear...

9000 times * .719 (fifth gear) / 4.1 rear ratio * .95 (slippage) = 2900

so 9000 is 2900 net revs per minute on stock tires.

2900 times 6.32335 feet * 60/5280 = 208 mph

8653 RPM = 200 mph

i am planning to run 200 in the Texas Mile this year and will be putting a T56 in my FD w a .63 6th gear. 200 will be at a more friendly 7581.

if you just switched to the automatic rear end (3.9) 200 would be 8230. slap on some taller tires and you could run 200 with a more modest investment.

hc
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Old 03-01-09, 11:05 AM
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a friend of mine actually did what howard's math suggests. stock engine, stock turbos, stock body stock gearing. 370ish RWHP

engine popped at 190ish, its not designed to do a pull that long.

this was in 2000-2001, almost preforum!
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Old 03-01-09, 11:47 AM
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howard a bit off topic. but are you ls1? or you do have a t56 on the 13b. if so pm me some insite on cost and how it can be done.

fwiw i have done 176mph calculating tire size and rpm in 5th gear. the speedo was fairly accurate reading at 175mph. but 5th gear is very long. i currently plan on switching over to a jdm 5 speed which i believe tops out at 188mph at 8k rpms. but will get there much quicker. unless i get talked into a t56 by howard...
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Old 03-02-09, 12:49 PM
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howard = rotary

yes, i am going to to switch over to a T56 trans. a fellow boardmember running a 20b has already figured out the right way to do it. i will be copying his setup mostly.

link to one of the threads: https://www.rx7club.com/showthread.p...&highlight=t56

check other threads by him for additional info.

hc
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Old 03-02-09, 01:02 PM
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You need gearing, 600-700 horsepower. Proper footwork is MORE important than just power. Footwork, Aerodynamics, Gearing then a nice responsive engine.

Think of the Scoot Rx7 before it was a 4 rotor. It was a red FD with a 2 rotor with a T51R SPL that made close to 700 horsepower, he did some 200+ mph runs in the New Zealand V-MAX challenge with the HKS Sequential dogbox. But the owner of scoot told me he could do 200 on the wangan even with upgraded gearsets on the stock 5 speed gearbox, and the right suspension and aerodynamics. His car has a full aluminum underbody diffuser all the way from the transmission all the way to the *** end. He had rear wheel covers to help the air channel more efficiently through the diffuser and provide greater downforce. He also had a lower profile GT wing to add downforce and reduce drag. A rear wing can help too depending on how you set it up (either can add downforce or just create drag).

Most importantly his hydraulic suspension (custom 1 off) had the capability to absorb bumps in the road so that the driver does not feel it in the steering wheel.

The autoselect FD was a 2 rotor (i am 90 percent sure) with the Greddy/Quaife 6 speed dog-box.

Aerodynamics is a huge thing. Just to make a point: R32 GTRs vs R34 GTRs. A VW jetta has a better drag co. than an R32, but an R34 has a .3 something drag co. My car would need 700+ horsepower to do 200 mph, but a 34 can do it with 550 whp. My plan is to make this car a 200 mph capable road car.
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Old 03-03-09, 06:55 PM
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Originally Posted by Miata_mx5 View Post
You need gearing, 600-700 horsepower. Proper footwork is MORE important than just power. Footwork, Aerodynamics, Gearing then a nice responsive engine.

Think of the Scoot Rx7 before it was a 4 rotor. It was a red FD with a 2 rotor with a T51R SPL that made close to 700 horsepower, he did some 200+ mph runs in the New Zealand V-MAX challenge with the HKS Sequential dogbox. But the owner of scoot told me he could do 200 on the wangan even with upgraded gearsets on the stock 5 speed gearbox, and the right suspension and aerodynamics. His car has a full aluminum underbody diffuser all the way from the transmission all the way to the *** end. He had rear wheel covers to help the air channel more efficiently through the diffuser and provide greater downforce. He also had a lower profile GT wing to add downforce and reduce drag. A rear wing can help too depending on how you set it up (either can add downforce or just create drag).

Most importantly his hydraulic suspension (custom 1 off) had the capability to absorb bumps in the road so that the driver does not feel it in the steering wheel.

The autoselect FD was a 2 rotor (i am 90 percent sure) with the Greddy/Quaife 6 speed dog-box.

Aerodynamics is a huge thing. Just to make a point: R32 GTRs vs R34 GTRs. A VW jetta has a better drag co. than an R32, but an R34 has a .3 something drag co. My car would need 700+ horsepower to do 200 mph, but a 34 can do it with 550 whp. My plan is to make this car a 200 mph capable road car.
autoselect fd is a 3rotor,it's on an option import video
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Old 03-07-09, 12:02 PM
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Yes 200mph is possible with the stock transmission. I got mine up to 185mph and had a lot more left on the tack. It was one hell of a rush. I would not recommend that you do this with stock suspension, no roll cage, or stock brakes like I did 5 years ago. It scared the crap out of me. This is why I'm now building the car right. see! https://www.rx7club.com/single-turbo-rx-7s-23/4-complete-exhaust-system-build-770041/
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