How Fast Have You Gone

[2c5s]

Or put 4k into a well used sport bike.

Lol, my Whipple GT ate liter bikes for breakfast.

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[michformulas]

Or put 4k into a well used sport bike.

I had an RF900R that I bought in 2001 for $2500 that would show >170mph on the speedo. The mirrors would fold themselves in at 150mph. They are definitely the cheapest way to get speed.

 

[kn7671]

From what I've heard, getting up to 142 is fairly quick because you can use 5th. However, when you want 145+ and have to go into 6th on the GT with performance pack, it takes forever to add a few MPH.

154.71 MPH is possible in 5th gear at 7,000 RPM with stock height rear tire on the Performance Pack car.

This is calculated out using a 1:1 5th gear ratio, 3.73 rear gear ratio, 7k rpm with a 27.7 tall rear tire.

 

[BoomBoy]

154.71 MPH is possible in 5th gear at 7,000 RPM with stock height rear tire on the Performance Pack car.

This is calculated out using a 1:1 5th gear ratio, 3.73 rear gear ratio, 7k rpm with a 27.7 tall rear tire.

What is the top speed in the 6th gear at 7,000 RPM? Using the same 3.73 rear gear ratio.

 

[Sasuketr]

154.71 MPH is possible in 5th gear at 7,000 RPM with stock height rear tire on the Performance Pack car.

This is calculated out using a 1:1 5th gear ratio, 3.73 rear gear ratio, 7k rpm with a 27.7 tall rear tire.

Well thats the problem theoretical and actual is not matching! The car should hit 62 mph on second gear too according to calcs but it only does 59 mph. So either the stock rear tire height is wrong or the speedometer needs calibration. Something doesn't add up. Henessey tried top speed with their GT PP and they had to shift to 6th gear around 140 to avoid redline :doh:

 

[kn7671]

What is the top speed in the 6th gear at 7,000 RPM? Using the same 3.73 rear gear ratio.

6th gear is an overdrive gear, but 238mph for the sake of math.

Well thats the problem theoretical and actual is not matching! The car should hit 62 mph on second gear too according to calcs but it only does 59 mph. So either the stock rear tire height is wrong or the speedometer needs calibration. Something doesn't add up. Henessey tried top speed with their GT PP and they had to shift to 6th gear around 140 to avoid redline :doh:

Not sure about the speedometer accuracy, but the math does not lie here, it's factual, as I know my car has no problem hitting 7000 rpm in 5th gear. Theoretical would be like saying, "if you hit 7000 rpm in 6th gear, your car would be doing 238mph", but since we know this isn't possible for several reasons, it's theoretical.

 

[JimmyTwoTimes]

Am I missing something? Redline on my tach is 6500. Is it different for automatic transmissions? I know it was a lower redline on automatic RX-8's...

 

[BoomBoy]

6th gear is an overdrive gear, but 238mph for the sake of math.



Not sure about the speedometer accuracy, but the math does not lie here, it's factual, as I know my car has no problem hitting 7000 rpm in 5th gear. Theoretical would be like saying, "if you hit 7000 rpm in 6th gear, your car would be doing 238mph", but since we know this isn't possible for several reasons, it's theoretical.

Well if you have enough horsepower, it's theoretically possible.

 

[fionic]

Am I missing something? Redline on my tach is 6500. Is it different for automatic transmissions? I know it was a lower redline on automatic RX-8's...

No it's not. Check your tach again

You'll see 2 lines. 2nd one is redline.

 

[Toofarfromjune]

I've gone 150 as a stupid young adult on the highway at 3am.

I'll probably never see those speeds again in the mustang or any other car, although it will be quite tempting in the middle of the Mojave on my way to flagstaff this spring, too much to lose these days...

 

[Katastrophe]

Lol, my Whipple GT ate liter bikes for breakfast.

All depends on what speed you're starting at, right? ;)

 

[Gibbo205]

Do they get to 155mph pretty quick and easily or does acceleration drop off?

I'd imagine once you shift into 6th the car accelerates very slowly being an overdrive?

5th good for about 150mph?

 

[cbrookre]

Do they get to 155mph pretty quick and easily or does acceleration drop off?

I'd imagine once you shift into 6th the car accelerates very slowly being an overdrive?

5th good for about 150mph?

Having trouble copying the youtube url from my phone, but Hennessey did a 0 to 150 run, gets into 6th at about 140. See the video here :

[ame]

 

[pinero61]

I hit 145 easily, but it becomes a dog as soon as you shift into sixth. Even with the PP 3.73's

 

[Mustang_Owner]

Like I said above, up to 142 is ok in 5th. 145+ needs you to be in 6th with 3.73 gears and you have no acceleration in 6th (without a SC). See speed vs. RPM here (use the front tire chart as it seems to be more accurate than the rear tire one for some reason):

http://www.mustang6g.com/forums/showthread.php?t=14552&page=4

For $5300, you can get a basic supercharger and install it (or remove it) yourself. I'm emailing the SC vendor tonight for detailed instructions so I can determine if the self-install option is really possible.

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