5 speed and 6 speed gear ratios
Posted: Thu Nov 24, 2011 10:14 pm
Found some info the other day on Etka that I found quite interesting. Looking in the gearbox section and the ratios for the different gears are shown against the various gearbox codes.
It also lists the diff ratios so armed with this decided to compare a FHN gearbox which is the 5 speed box in my car and the FRK which is a 6 speed box in the 130TDI sport.
The following are the overall gear ratios of each gear.
FHN ......... FRK
1 13.011 .... 13.563
2 7.494 ..... 7.320
3 4.683 ..... 4.766
4 3.110 ..... 3.617
5 2.363 ..... 2.83
6 ............ 2.325
I always thought the 6 speed box had a higher final ratio so better for motorways but it appears not. The difference is marginal. First second and third are much the same the difference comes in 4th and 5th where 4th gear in a 6 speed box is like 3.5 in a 5 speed and 5th is like 4.5.
This shows up better if you look at the speeds achieveable in any gear. Changing up at 4700rpm you get
FHN ......... FRK
1 26.7 ...... 25.65
2 46.4 ...... 47.5
3 74.3 ...... 72.98
4 111.9 ..... 96.2
5 147 ...... 123
6 ............ 149.6
Looking at the quoted performance figures such as 0-60 and top speed there is nothing in them but I always thought that 6th was some kind of overdrive gear and top speed would occur in 5th. I suspect the 0-100 figures would show some difference though.
Karl.
It also lists the diff ratios so armed with this decided to compare a FHN gearbox which is the 5 speed box in my car and the FRK which is a 6 speed box in the 130TDI sport.
The following are the overall gear ratios of each gear.
FHN ......... FRK
1 13.011 .... 13.563
2 7.494 ..... 7.320
3 4.683 ..... 4.766
4 3.110 ..... 3.617
5 2.363 ..... 2.83
6 ............ 2.325
I always thought the 6 speed box had a higher final ratio so better for motorways but it appears not. The difference is marginal. First second and third are much the same the difference comes in 4th and 5th where 4th gear in a 6 speed box is like 3.5 in a 5 speed and 5th is like 4.5.
This shows up better if you look at the speeds achieveable in any gear. Changing up at 4700rpm you get
FHN ......... FRK
1 26.7 ...... 25.65
2 46.4 ...... 47.5
3 74.3 ...... 72.98
4 111.9 ..... 96.2
5 147 ...... 123
6 ............ 149.6
Looking at the quoted performance figures such as 0-60 and top speed there is nothing in them but I always thought that 6th was some kind of overdrive gear and top speed would occur in 5th. I suspect the 0-100 figures would show some difference though.
Karl.