We have a couple of Cosworth YBs which run in competition and on trackdays. 34mm inlet restrictors are fitted to conform with stage rally regs. Engines have earlier 205 blocks and current turbo is hybrid T3/T35.

Just like to call on the experience of other YB owners. What level on boost, power and torque do you achieve reliably with a standard engine under fast track conditions? What relatively cheap mods have you made to make YB reliable at higher boost and power? I know there are £30k YB engines available but that's way outside my budget.

For starters we run up to 1.5 bar boost and get between 270 and 300hp (34mm restrictor). Peak torque remains a mystery.