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Top speed / gear ratios / calculations



Apoligies if asked before but does anyone know the standard gear ratios for a 172 Cup gearbox, tried searching but not found it?

I'm wanting to confirm max speed in each gear, think there are calculators online from gearing and tyre dimensions to work out theoretical max speed, also any easy way to factor transmission losses?

I work in data / analytics like playing with numbers and wondered whether can model the odd corner / section which is borderline for which gear, appreciate there are a thousand other factors but all other thing being equal there must be an optimum.

If I'm thinking about it in the wrong way happy to be corrected, just an idea (y)
 
  LY 220 Trophy+IB PH1
Something I put together a while ago for my PH1, may be of help.

CarPowerWeightP/Wdrag coeRev limitratio 1ratio 2ratio 3ratio 4ratio 5ratio 6ratio 7FDWheel diam (M)
Clio
165​
1.035​
159.42​
0.358​
7250​
3.09​
1.86​
1.32​
1.02​
0.79​
4.07​
0.576​
MPH
38.90​
64.63​
91.06​
117.85​
152.16​
 

Hollidog

ClioSport Club Member
  182
This is from the PMS website, seems to be accurate to me, ignore the last red line as this relates to installing the 5th gear from a Megane box.

1424611


You can find it here
 

massiveCoRbyn

ClioSport Club Member
  Several
I've got a spreadsheet with them on somewhere (and one for 197/200). Allows you to input tyre sizes, engine speed etc. If you'd like it, send me your email address and can send it over.
 

Nafoff

ClioSport Club Member
I've got a spreadsheet with them on somewhere (and one for 197/200). Allows you to input tyre sizes, engine speed etc. If you'd like it, send me your email address and can send it over.

Morning chap, is it possible to get this file off of you please? would be very useful as I am setting up my RT dash
 

Nafoff

ClioSport Club Member
Something I put together a while ago for my PH1, may be of help.

CarPowerWeightP/Wdrag coeRev limitratio 1ratio 2ratio 3ratio 4ratio 5ratio 6ratio 7FDWheel diam (M)
Clio
165​
1.035​
159.42​
0.358​
7250​
3.09​
1.86​
1.32​
1.02​
0.79​
4.07​
0.576​
MPH
38.90​
64.63​
91.06​
117.85​
152.16​

Was this for a 15" wheel?
 
  LY 220 Trophy+IB PH1
If you add air resistance you can approx actual speed...😉
I calculated that too haha need power (In watt's I think it was) area of the car, drag and air density. Done the below based on sea level if I recall.

Power (BHP*746)
123090​
Width
1.639​
Height
1.417​
Area (Width*Height)
2.322463​
Drag Co
0.358​
Air Den
1.25​
Max speed
132.81

Surprising how much reducing drag buys you in performance, if the 172 had similar slippy-ness to a GTR you'd get:

Power
123090​
Width
1.639​
Height
1.417​
Area
2.322463​
Drag Co
0.27​
Air Den
1.25​
Max speed
145.77
 

bozothenutter

ClioSport Club Member
I calculated that too haha need power (In watt's I think it was) area of the car, drag and air density. Done the below based on sea level if I recall.

Power (BHP*746)
123090​
Width
1.639​
Height
1.417​
Area (Width*Height)
2.322463​
Drag Co
0.358​
Air Den
1.25​
Max speed
132.81
Surprising how much reducing drag buys you in performance, if the 172 had similar slippy-ness to a GTR you'd get:


Power
123090​
Width
1.639​
Height
1.417​
Area
2.322463​
Drag Co
0.27​
Air Den
1.25​
Max speed
145.77

This I like!
 


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