Hi Paul All vehicles will lose power through their transmission, Most rolling road charts calculate aprox 26-27% loss in fourth gear on manuals as in most cases this gear has a ratio of 1 : 1. In the Deloreans case 1.057 : 1 and with the final Diff ratio of 3.44 : 1. Working your math's out you have aprox 144 bhp at the flywheel. If this is correct you have nothing to worry about. Regards Mark hi all, just wondering what oil do you guys use in the stick shift model.because im loosing over 39 bhp trough the gear box so i feel a oil change has to help. beat regards paul o malley.