Lotus Elan and Lotus Elan Plus 2 Forums

Replacing the vacuum tubes for the lights on a UK version 1967 S3. I have found some nice tygon tubing. It is quite flexible. Does anyone know approximately how much vacuum, the engine will pull at max power? IOW, is hard tubing required?

Max vacuum is actually at idle, where you should get 17-21" Mercury. At wide open throttle there is little vacuum.

I've only ever seem the rigid plastic tubing used, Ray (RDEnt) has it at $5 /yard.

Thanks Phil. I stand corrected.

"Max vacuum is actually at idle,"

Think not , Max Vacuum is actually on the over-run , when the engine revs are higher yet the throttle closed ?

John

john.p.clegg wrote:"Max vacuum is actually at idle,"

Think not , Max Vacuum is actually on the over-run , when the engine revs are higher yet the throttle closed ?

John

You are correct, throttle is closed but engine is rotating faster...