2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

guess my top speed!

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Old Dec 20, 2001 | 11:58 PM
  #1  
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From: Duncan, BC, Canada
guess my top speed!

1st gear 60 km/h or 37mp/h
2nd gear 110 km/h or 68mp/h
3rd gear 150km/h or 93mp/h
4th gear 210km/h or 130mp/h
5 gear ??? i had just over 2 grand left in fifth until redline.
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Old Dec 21, 2001 | 12:02 AM
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what rpm in 4th? my redline is like 190 or so. do you have 3.9 rear end?
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Old Dec 21, 2001 | 12:12 AM
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those speeds were all redline
couldnt redline 5th cause i ran out of road.
no clue its a 87 gxl with lsd
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Old Dec 21, 2001 | 12:14 AM
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u serious?? 190 in 4th at redline?? weird i had 2 friends in the car with me too

o yea also another question how fast can u get these cars gonig before u start to feel the shaking?? man these cars r stable
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Old Dec 21, 2001 | 12:22 AM
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I'm not 100% sure. I have better things to be watching at those speeds and I know the tranny gearing changes between N/A and turbo aswell as 86-88 and 89-91. so both are probably right. but I think mine is 190 or so. I haven't redlined 4th but I hit 180 and was pretty close I think.
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Old Dec 21, 2001 | 12:28 AM
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haha yea i never usually look at the speedo but my friends were leaning over looking at it so i did too

yea i think the n/a's 5th gear is more like a over drive gear so forth is big and 5th gear is bigger on the turbo's then the n/a's
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Old Dec 21, 2001 | 12:55 AM
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I had my '89T2 up to 163 before I backed down. I still had plenty of gear left in 5th. Of course, this was on a dyno run.

jerk_racer@hotmail.com
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Old Dec 21, 2001 | 01:30 AM
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It's late, and I'm not at all tired. What the heck, let's see if my military intelligence still works...

Your gears are:
1) 3.475
2) 2.002
3) 1.366
4) 1.00
5) 0.697
LSD 4.10

Your tires are:
205/60VR15

Your top speed in 5th gear is:
291 kph / 181 mph

You like driving in 3rd gear best, you prefer sausage over bacon for breakfast, you prefer basketball to hockey (strange for a Canadian), you like that girl in your science class, your politics tend toward oligarchy, you are the youngest of the family, and your favorite thing about your RX-7 is that it really pisses off the dominant male in your family.

OK, how did I do?
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Old Dec 21, 2001 | 01:38 AM
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Originally posted by Evil Aviator
It's late, and I'm not at all tired. What the heck, let's see if my military intelligence still works...

Your gears are:
1) 3.475
2) 2.002
3) 1.366
4) 1.00
5) 0.697
LSD 4.10

Your tires are:
205/60VR15

Your top speed in 5th gear is:
291 kph / 181 mph

You like driving in 3rd gear best, you prefer sausage over bacon for breakfast, you prefer basketball to hockey (strange for a Canadian), you like that girl in your science class, your politics tend toward oligarchy, you are the youngest of the family, and your favorite thing about your RX-7 is that it really pisses off the dominant male in your family.

OK, how did I do?
My turn next!
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Old Dec 21, 2001 | 04:17 AM
  #10  
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http://home.rmci.net/panther/rx7specs.htm
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Old Dec 21, 2001 | 04:39 AM
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Originally posted by Evil Aviator
Your gears are:
1) 3.475
2) 2.002
3) 1.366
4) 1.00
5) 0.697
LSD 4.10

Your tires are:
205/60VR15

Your top speed in 5th gear is:
291 kph / 181 mph
Well, not REALLY 291/181. Ideally, of course, running in a vacuum. Even that's flawed, though, as the engine wouldn't be running if there wer no air for combusion...

Anyway, aerodynamic drag will keep the top speed well below the above theoretical top speed. In stock from for your car, the top speed is drag-limited to about 218/135. This is because the engine doesn't produce enough power to propel the car through the air at higher speeds.

If you had the factory Sport aero package (front air dam spoiler, rocker extansions, short rear spoiler), you could probably go about 234/145. This is because the coefficient of drag (Cd) drops from the stock 0.31 (your car as it is now) to 0.29 (same as a C5 hatchback, btw). If you lower the car about an inch, you can probably get close to 242/150. Either of these increases will be slow, and will require A LOT of straight, open road to achieve.

Conversely, anything you do to increase drag will reduce top speed. If you open your sunroff, you can probably count on 210/130 being your top speed. Open the windows as well, and you probably won't make it past 202/125.

89-91 NA's will have a higher top speed in stock form. Although they weigh more, the added power is what gives them a higher top end. Once you get past about 161/100, it doesn't matter much how heavy your car is. The main limiting factor in top speed is aerodynamic drag, with some influence from lift (less is better = more downforce)

Series 5 cars have a higher Cd than the Sport series 4's, because the rear wing on the former creates more drag than the rear spoiler on the latter. However, the rear wing on the series 5's does create more downforce. I don't have any figures for the Cd of series 5's, but I would guess it's about 0.31 (FD's with R1/R2 have 0.31 vs 0.29 for base/touring models). I don't have any clue what the downforce figures are for any of the cars.

Before someone pipes in, saying, "Well, my car does better than that!" remember, I'm using STOCK configurations. Your results may vary...

Ren
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Old Dec 21, 2001 | 12:12 PM
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Damn what mods do you have to push you up that fast????

I cant see a stock T2 pushing 180mph even as slick as our cars are. Ive seent he drag racers "chart" for wieght vs gearing vs HP for speeds granted its generic and its based on a 3000lbs car. It basicly said at 150 there is a dramatic incress in HP required for pushing the car from 150 to 200 then you can add 100 hp for every couple of miles per hour after that.
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Old Dec 21, 2001 | 02:25 PM
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A stock NA won't be able to accelerate in 5th after you've redlined in 4th gear.



-Ted
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Old Dec 21, 2001 | 04:42 PM
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From: Duncan, BC, Canada
well i like basketball more then hockey u got that right
and 3rd gear and 2nd r my fav,the rest r wrong
good try though

yea 5th gear is worthless in my car its only good for saving gas
i could max out the speedo on a nice strech
i did that speed in 20 seconds r so from 100km/h up to 210km/h
im pretty sure 5th gear would pull me up to the end of my speedo though.
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Old Dec 21, 2001 | 04:45 PM
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From: Duncan, BC, Canada
o yea and the tire size was right too
and to hailers that site isnt very good. look at all the 1/4 mile times
they r wrong wrong wrong for stock.
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Old Dec 21, 2001 | 04:54 PM
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Originally posted by HAILERS
http://home.rmci.net/panther/rx7specs.htm
is that site accurate?

seems kinda farfetched that my 90 NA can do the 1/4 in 15.3!

but if so, rad!
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Old Dec 21, 2001 | 05:23 PM
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If you could pull 7K rpm in 5th you'd be looking at around 180. I've had my TII up to 150 at about 5.5k rpm. Hey thats plenty fast. If you wanna go 180 get a bike. I had a 94 Kawasaki ZX-9 with a few bolt on mods and it would hit 196 on the speedo, reality was more like 185 mph. Talk about bang for your buck. I payed 4.5k for it used.
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Old Dec 21, 2001 | 05:28 PM
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Originally posted by CanadianRX7
well i like basketball more then hockey u got that right
and 3rd gear and 2nd r my fav,the rest r wrong
good try though
Hehehe, just having some fun - shows you what "military intelligence" is worth.

Hey, you asked about top speed, but didn't specify the conditions. I'm fully aware of all the speed-limiting factors, but your car should be able to do 180-181 under it's own power, downhill with a tail wind. If you really want to get **** retentive, then you need to also take into conderation tire friction, road friction, Cd, tire pressure, rake, ambient temperature, ambient pressure, ambient humidity, etc.

Hehehe, Ted, I argued the same 5th gear acceleration theory against Scott, and darn it if he didn't prove me wrong. That was over 10 years ago, and he still rags on me for it! I can assure you that a stock NA will accelerate in 5th, but it takes a loooooooong time. No, it won't get anywhere near the gear-limited speed without some help from mother nature, but it will go faster than you think if you have enough road and patience.

BTW, the reason that I mentioned 3rd gear was because mathematically you should have gotten a little bit more speed in 2nd, so I assume you shifted slightly early. I also noticed that in 4th, but figured that you ran out of road. I could be wrong, though, as I did the calculations pretty quickly with my Windows calculator.

Since I'm obviously not Miss Cleo, maybe Felix should try to figure out the speeds of his cars with this formula:

Speed in mph = (Rear Tire Circumference in inches * Tachometer RPM) / (Transmission Gear Ratio * Rear End Gear Ratio * 1056)
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Old Dec 21, 2001 | 05:42 PM
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I'd say about 140mph as you won't have enough power to overcome the drag at that point.
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Old Dec 21, 2001 | 11:38 PM
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Originally posted by Evil Aviator

Since I'm obviously not Miss Cleo, maybe Felix should try to figure out the speeds of his cars with this formula:

Speed in mph = (Rear Tire Circumference in inches * Tachometer RPM) / (Transmission Gear Ratio * Rear End Gear Ratio * 1056)
Nah, I don't like to speculate. I just hit the Interstate and find out for real
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Old Dec 21, 2001 | 11:40 PM
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bikes are hype,
but you can't drift in them nor can you take alot of stuff either.
and if you crash, you die.

Originally posted by West TX RX-7
If you could pull 7K rpm in 5th you'd be looking at around 180. I've had my TII up to 150 at about 5.5k rpm. Hey thats plenty fast. If you wanna go 180 get a bike. I had a 94 Kawasaki ZX-9 with a few bolt on mods and it would hit 196 on the speedo, reality was more like 185 mph. Talk about bang for your buck. I payed 4.5k for it used.
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Old Dec 21, 2001 | 11:45 PM
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A stock NA won't be able to accelerate in 5th after you've redlined in 4th gear.
I agree, every RX-7 I've had has not been able to accelerate in 5th after redline in 4th. Evn in my current car- (ported 90 gxl) I can go to 220+ KM/hr in 4th, thats well past the 8000rpm redline. If I shift into 5th at that speed, with the amount of aerodynamic drag, It actually starts slowing down. For me, I think 5th tops out at about 190-200 km/hr, engine torque being the limiting factor. I have much more power at 8000 rpms than I do at 5500, plus gear torque multiplation.

I'm really wondering whats going on here....
Happy Hollidays
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Old Dec 22, 2001 | 12:02 AM
  #23  
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Originally posted by CosmicButtHairs
bikes are hype,
but you can't drift in them nor can you take alot of stuff either.
and if you crash, you die.

I have a video of a Busa, R1, CBR1100, and (I think) a GSXR1000 doing crazy ****. Among the crazy **** is drifting Not as far as a car drifting, but still...
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Old Dec 22, 2001 | 02:12 AM
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Check our Super TT bikes. The better riders pull off two wheel drifts quite often during these races.

jerk_racer@hotmail.com
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Old Dec 22, 2001 | 12:04 PM
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Originally posted by Bambam7


I agree, every RX-7 I've had has not been able to accelerate in 5th after redline in 4th. Evn in my current car- (ported 90 gxl) I can go to 220+ KM/hr in 4th, thats well past the 8000rpm redline. If I shift into 5th at that speed, with the amount of aerodynamic drag, It actually starts slowing down. For me, I think 5th tops out at about 190-200 km/hr, engine torque being the limiting factor. I have much more power at 8000 rpms than I do at 5500, plus gear torque multiplation.

I'm really wondering whats going on here....
Happy Hollidays
The trick in the S4 is to not be at WOT. The car will initially slow down when you shift to 5th, but will then slowly accelerate again if you hold slightly less than WOT. I'm not sure if this will work in the S5.
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