QuestionI've searched all over and haven't found an answer, much to my surprise.
I have a 1979 MGB, US model. Engine compression is 8:1 if I have looked in the right place.
What is the best fuel for this car? Should I use the 87 octane, or use a higher octane?
Thank you.
AnswerHi Bobby. The short answer is - use the higher octane.
The MGB engine was designed to use leaded 97-octane gasoline, and most of them had a compression ratio of about 9:1.
In the late 1970s some states like California had stricter emissions regulations, so a low compression single carb version was produced with all sorts of extra equipment (eg an air pump) and I guess you have one of these. If you care to give me your complete engine number (it should start with 18V) then I may be able to tell you more about its specification.
With a compression ratio of 8:1 the low compression version will run quite happily on unleaded gasoline so long as it has an octane rating of 92 or more. I would not recommend the use of 87-octane gasoline in such an engine.
These engines are low on power, so performance will not be very exciting. Personally, (if the law allows) I would fit the earlier twin-SU setup along with a stage 2 cylinder head so that I could enjoy the performance that these cars were designed for.
