RS2 speed in different gears

[A80Avant]

Anyone has this info?

i need the speed of an rs2 with ADU cams on 5000rpm on each gear. If any of this info is available please let me know!
thanks
vasilis

[Error404]

Engine components make no difference.

From workshop manual the calculation is this:

V = (n / iov) x (ua x 0.06)

v = speed
n = engine speed
iov = overall drive ratio (gear ratio x final drive ratio)
ua = rolling circumferance of tyre

[A80Avant]

well what are the proper values then?

i have : ua=629mm
gear ratios already known
engine speed: 5000rpm

example: 1st gear:

V= (5000/3.5x0.71) x 629x0.06=38494

obviously the circumference needs to be in m? cm?

gear ratio x final drive ? final drive being the 6th gear?

[A80Avant]

im not doing something right, cause if i use m for circomference, it seems ok for 1st gear but it brings me to 140km for 2nd gear and 201km for 3d gear at 5000rpm, which is not correct

[A80Avant]

oops!
wrong calculation for final drive!

[A80Avant]

using the correct final drive, values are too small again, so im either doing it wrong(likely) or there something else..

here are the gear ratios

http://www.s-cars.org/postnuke/modul...rder=0&thold=0

[Error404]

circumferance needs to be in Meters
Looks like you are using diamter in mm @ 629 which is 1.98m circumference.

so you have:
1st 5000/14.8 x 1.98 x 0.06 = 40km/h
2nd 5000/7.77 x 1.98 x 0.06 = 76km/h
3rd 5000/5.43 x 1.98 x 0.06 = 109km/h
4th 5000/4.23 x 1.98 x 0.06 = 140km/h
5th 5000/3.53 x 1.98 x 0.06 = 168km/h
6th 5000/2.92 x 1.98 x 0.06 = 203km/h
R 5000/14.2 x 1.98 x 0.06 = 42km/h

[A80Avant]

aaaah yes.

629mm is my tyre-wheel diameter.

hmm it seems a bit low to be 203 only in 6th gear 5000rpm... can i go from 5000rpm to 6500rpm on my car from 203 to 280km?

[Error404]

6500rpm in 6th is 264 km/h - 280km/h is 6880rpm

7200rpm in 6th is 293km/h

so it is all about right. Speedos in cars tend to over-read by 5-10%

[driftin jo]

judging by the diameter of tire you have given (629mm) I take it you are using a 215/40/18 ?

The reason I say is this is slightly less than the stock tire diameter of (632mm) for a 205/55/16.

The thing is that with the stock tire the speedo reads too fast by about 5mph / 8 kph .
The tire you are using will increase this error even more .
I have a satellite speed device that is guaranteed to .5 mph and my S2 speedo over reads by 2.5 mph and I run 225/40/18 (637.2mm) diameter.


So unfortunately this means your not going as fast as you think .

[Error404]

AFAIK he's running 245/35 18s

[driftin jo]

AFAIK he's running 245/35 18s

Even worse then as 245/35/18 is (628.7 mm)

just a little

[Error404]

so a 235/40 18 would read just about spot on then I guess

[driftin jo]

so a 235/40 18 would read just about spot on then I guess

yes , speedo would be good with this size . probably read about 1 mph over , Close enough

[A80Avant]

yes, that is what i use, 245/35/18 so its very close to 629. i think a couple of tyre calculators bring it up at around 628+ so no big difference.

Good info Error, all vems users with a speed sensor can now use this calculation!