Top speed

[THX 138]

I'm on 30-series Hoosier R7s, and I'm at 137 MPH in 4th gear at ~8,100 RPM at the end of the front straight on my local track. On the original, 35-series MPSS, the top speed in 4th gear is a little higher, but the effective gearing is higher (numerically lower), so not as preferable for track work in my opinion.

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[72&18]

I have hit low 130's in 4th at Heartland Park Topeka. There is more there, but not quite ready to push that hard.

 

[oldbmwfan]

Upfront disclaimer *semi high jacking the thread
So what is the top speed in each gear?

Just repeat the equation above for each gear ratio (1.24:1 is 4th gear; sub the appropriate gear ratios for the other gears and you have your answer). And sub the GT350 tire diameter for the GT350R tire diameter shown, if appropriate. Teach a man to fish ...

 

[pilotgore]

Just repeat the equation above for each gear ratio (1.24:1 is 4th gear; sub the appropriate gear ratios for the other gears and you have your answer). And sub the GT350 tire diameter for the GT350R tire diameter shown, if appropriate. Teach a man to fish ...

For the GT350:
1'st gear = 55mph
2'nd gear = 80mph
3'rd gear = 111mph
4'th gear = 144mph
5'th gear = 178mph
6'th gear = 283mph (theoretically)
reverse = 60mph

For my GT350R brethren:
1'st gear = 54mph
2'nd gear = 78mph
3'rd gear = 108mph
4'th gear = 141mph
5'th gear = 174mph
6'th gear = 277mph (theoretically)
reverse = 59mph

Thanks for teaching me how to fish

Edit: I want it to count, so here's the math for the Non-R ;)

1: 680.55 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 54.9 mi/hr

2: 991.84 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 79.97 mi/hr

3: 1373.79 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 110.76 mi/hr

4: 1783.71 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 143.8 mi/hr

5: 2211.8 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 178.32 mi/hr

6: 3510.79 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 283 mi/hr

R: 749.76 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 54.9 mi/hr

 

[Captian_Eddie]

Does not count unless you show your work. Just Sayen

 

[pilotgore]

Does not count unless you show your work. Just Sayen

Fine, fine. . . you win. Updated, along with numbers for the R size tires.

 

[Tomster]

For the GT350:
1'st gear = 55mph
2'nd gear = 80mph
3'rd gear = 111mph
4'th gear = 144mph
5'th gear = 178mph
6'th gear = 283mph (theoretically)
reverse = 60mph

For my GT350R brethren:
1'st gear = 54mph
2'nd gear = 78mph
3'rd gear = 108mph
4'th gear = 141mph
5'th gear = 174mph
6'th gear = 277mph (theoretically)
reverse = 59mph

Thanks for teaching me how to fish

Edit: I want it to count, so here's the math for the Non-R ;)

1: 680.55 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 54.9 mi/hr

2: 991.84 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 79.97 mi/hr

3: 1373.79 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 110.76 mi/hr

4: 1783.71 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 143.8 mi/hr

5: 2211.8 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 178.32 mi/hr

6: 3510.79 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 283 mi/hr

R: 749.76 wheel rev/min*85.14 in/rev*60 min/hr / 63360 in/mi = 54.9 mi/hr

That seems about right. I can verify the top speed in 5th gear. I was trying to find the top verified speed in 4th via the track addict app last night, but it didn't let me break it down to speeds at a known shift point.

Edit:
4th seems a little off for the R. I was able to find the MPH in the track addict. A 5 MPH or so difference???

 

[460Fred]

No theory here, I’ve had my GT350 to 284mph on our local back roads ;-)
Seriously though, if the numbers are correct that’s some serious drag limitations. Isn’t our top speed 100mph less?

 

[aggarcia70]

6th Gear is an economy gear, so the car cannot get back into the power band to reach max torque or HP depending on over coming the aero drag. If 6th gear was something different, the top speed should increase.

 

[pilotgore]

Bit off topic but has anyone ever redlined in reverse?

Asking the question that really matters!

 

[WD Pro]

Bit off topic but has anyone ever redlined in reverse?

And if so, does the shift light work ?

WD

 

[Tomster]

6th Gear is an economy gear, so the car cannot get back into the power band to reach max torque or HP depending on over coming the aero drag. If 6th gear was something different, the top speed should increase.

I found it was able to slightly accelerate at top 5th gear speed. Not much though.... it certainly was enough to maintain speed. I thought this might have been useful on the track where you dont want to keep the RPMs up for a cool down lap or even a parade lap or two if thats your thing, lol

What I dont like is that the exhaust valves close in 6th gear. Some have used this to their advantage at laguna seca to get past the sound mic. There is a company that makes a override for the pipes (i think the company is AWE). I have a controller I never installed. Maybe one day I'll get off my ass and do it.

 

[oldbmwfan]

No theory here, I’ve had my GT350 to 284mph on our local back roads ;-)
Seriously though, if the numbers are correct that’s some serious drag limitations. Isn’t our top speed 100mph less?

That's why the top speed is redline in 5th. It's gear-limited in 5th gear, then drag-limited in 6th, but actually slows down in 6th because the lower wheel torque can't overcome the drag at 170mph+

 

[Tony_the_Brit]

I hit 137 on the straight at Gingerman in 4th which was about 7,800 (I was watching my braking point not the tach so that is very about - going off the shift lights).

 

[JZTRK]

I backed out at 180mph in 5th at an approved event in my 2016 tech pack car

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