Ford T9 5-Speed Semi-close ratio
This transmission is similar to those used in the Caterham's except it has a short input shaft - about 1" shorter than the version used with the Caterham's. My unit was rebuilt using Ford internals that result in semi-close ratio gears without resorting to straight cut (noisy) gears. Here are the ratios of the stock Ford Sierra/XR4Ti, my semi-close ratio unit and the Quaife close ration transmission. BTW, my transmission is less than 1/2 the price of the Quaife and I get to deal with a Woody at Birkin Sport in Vacaville CA (a big plus with anything on the Birkin):
| Stock | Semi | Quaife | |
| 1st | 3.65 | 2.83 | 2.39 |
| 2nd | 1.97 | 1.81 | 1.54 |
| 3rd | 1.37 | 1.25 | 1.21 |
| 4th | 1.00 | 1.00 | 1.00 |
| 5th | 0.82 | 0.82 | 0.91 |
Final drive ration is 4:10 to 1. I have a Quaife LSD unit, but it has not yet been installed (just lazy I guess).