Hi Senoj
Ultimately without knowing the exact dimensions and as a result the lever ratio it could turn out to be a load of old tosh....., but what Nick mentioned seems to make sense to me based on the picture.
As I see it, the shift cables will have a fixed displacement to change gear. My own car which is a 996 GT3 fitted with the 997 GT3 shifter has a gear knob travel of 80-90mm. This will deliver the required displacement of the cables at a given load applied by myself.
Now if I reduce the shift knob displacement to 65mm while maintaining the same displacement at the cables then I need to change the lever ratio. I can do this by shortening the lever above the pivot and as a result the applied load required at the knob to shift gears goes up. Alternatively, the length of the arm below the pivot could be increased. Again, the applied load required at the knob goes up.
In the case of the CAE shifter they have made the arm above the pivot very long yet reduced the shift knob travel. The pivot position and length of the arm below the pivot are key to delivering the same displacement required at the cables. In this case they have raised the pivot to minimise the lever ratio increase, but there is a risk that they couldn't package enough space to match the original car (it looks a very long upper arm compared to anything else I've seen before). Therefore, if the ratio has increase as suspected then the required applied load to make the shift will have reduced.
The problem is that in some cases the driver does not reduce the applied load and therefore the revised lever ratio results in a higher load being seen at the gearbox even though the driver has no idea they are doing anything wrong. This could result in the bent shift forks mentioned by Nick.
As mentioned above, this is just guesswork based on a gut feeling looking at a picture and the feedback from Nick which looked likely at first glance. The measurements would confirm for sure and i'll get ready to eat humble pie. I have a spare GT3 shifter somewhere and may dig it out through curiosity....
I had hoped to introduce myself to my fellow GT owners somehow, but hopefully without pissing anyone off first!
Ultimately without knowing the exact dimensions and as a result the lever ratio it could turn out to be a load of old tosh....., but what Nick mentioned seems to make sense to me based on the picture.
As I see it, the shift cables will have a fixed displacement to change gear. My own car which is a 996 GT3 fitted with the 997 GT3 shifter has a gear knob travel of 80-90mm. This will deliver the required displacement of the cables at a given load applied by myself.
Now if I reduce the shift knob displacement to 65mm while maintaining the same displacement at the cables then I need to change the lever ratio. I can do this by shortening the lever above the pivot and as a result the applied load required at the knob to shift gears goes up. Alternatively, the length of the arm below the pivot could be increased. Again, the applied load required at the knob goes up.
In the case of the CAE shifter they have made the arm above the pivot very long yet reduced the shift knob travel. The pivot position and length of the arm below the pivot are key to delivering the same displacement required at the cables. In this case they have raised the pivot to minimise the lever ratio increase, but there is a risk that they couldn't package enough space to match the original car (it looks a very long upper arm compared to anything else I've seen before). Therefore, if the ratio has increase as suspected then the required applied load to make the shift will have reduced.
The problem is that in some cases the driver does not reduce the applied load and therefore the revised lever ratio results in a higher load being seen at the gearbox even though the driver has no idea they are doing anything wrong. This could result in the bent shift forks mentioned by Nick.
As mentioned above, this is just guesswork based on a gut feeling looking at a picture and the feedback from Nick which looked likely at first glance. The measurements would confirm for sure and i'll get ready to eat humble pie. I have a spare GT3 shifter somewhere and may dig it out through curiosity....
I had hoped to introduce myself to my fellow GT owners somehow, but hopefully without pissing anyone off first!
