Owning a Lotus 7 S2

We have been a little unhappy with the shallow linkage mechanism which we have used until now. The operation was OK but very much either on or off. We have now reinstalled the original throttle linkage which produces a much smoother action.

Our Lotus has the basic configuration of a single Weber 40DCOE 2 on a Lotus alloy manifold. The performance of the basic engine is moderate, 66 HP at 4600 rev/min. The ports of our engine have been enlarged and the combustion chamber has been flowed moderately. Also, humps and edges in the inlet manifold have been smoothed out and the exhaust is 4-2-1. But most importantly, the engine is equipped with a fast road A2 cam. With the 0.06″ overbore our data show a power output of some 80 HP at 5200 rpm. Not a high reving engine but an engine with good midrange torque.  This power figure has been used for jetting of the Weber extrapolating from the unmodified engine. 

                                Basic 66 HP              Modified 80 HP

Camshaft                      Ford                                   A2

Choke                              26                                   28

Aux. venturi                     4.5                                  4.5

Main jet                          115                                 125

Air jet                             165                                 160

Emulsion tube                 F16                                 F16

Idle                                 45F9                              45F9

Pump jet                          65                                   65

With this setup up the car is lively and has no hesitation during acceleration.