Hey guys

anyone got calculator for actual speed in TII based on gearing and tire size?

For example, whats real speed at 7000 rpm in 5th gear on 245/40/17 tire with stock TII (4.1) gearing?

thanks

 

Depends on if it's a s4 or s5 tranny.

Somewhere just under 200 mph iirc.

 

ive got a calculator that does those measurements, is that what you wanna find the speed of?

:edit:

the theoretical speed of that is @ 164 mph give or take for different factors 4.1 gear ratio and .762 5th gear

 

S4 tranny

 

^^^^

 

thanks, will confirm it with GPS

 

I have. It's called MS Excel with added FSM.

S4 and S5 have different 5th gear ratios. For S4 (0.762:1) it would be 157mph, for S5 it would be (0.719:1) it would be 167mph.

 

are you sure you took the tire size? because when i plugged it into my MS excel i got 164

 

A 205/60x15 tire has a calculated radius of 313.5mm, but the measured rolling radius (i.e from the ground up to hub centerline, with deflection due to weight into account) is 300mm. A 245/40x17 has a calculated radius of 313.9mm (+0.4mm), so I just used the same 300mm rolling radius for my calcs.

The only variable not known for certain is tire size. Unless you have the actual measured rolling radius for a specific tire, you can't expect to get an accurate figure.

 

^ damn im lost now

 

Yea, I think I understand what they are doing... *scratches head*... this seems just like one of those problems I had to do in geometry where they give you the radius of a bicycle tire and ask you if a person rides for a certain amount of time at a certain amount of rpm, how much distance will he cover... anyway, how do you get one of those calculators...

 

It's in MS Excel. All it is is a spreadsheet you plug numbers into and it gives you the answer. He can prolly send it to you if you ask him nicely

 

kewl... can you please please please send it to me....

 

search google, they have a ton of those calculators, everything from hp, to 1/4mile times, to top speed, etc.