[TR] 1980 Spit: vacuum retard

[Randall]

> It gives you 
> marginally better fuel mileage at part throttle.  Does that 
> matter in a Spitfire?  Well, of course, but not so much as 
> for a heavier car with a bigger engine.

Even if you start at 30 mpg, a 10% saving can be significant if you drive
very much.  At 10k miles per year and $2.50/gallon; going from an average of
30 mpg to 33 mpg would save you about $75/year.  Pretty good return for
something that also reduces CO2 emission.

It also seems to me that having a working vacuum advance makes the engine
more responsive at part throttle.  It's a subtle effect to be sure; but
several times now (on different cars), I've thought the engine seemed
sluggish only to find that the vacuum advance was not working.

But I agree with Jim, I wouldn't bother with vacuum retard.

Randall