whats the best oil weight to use in the car mine doesnt have an owner manual

 

Most people I know run 20-50 I run 10-30

 

Sure you did.

Try the FAQ thread: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/


Here is a cut and paste:

33) What oil should I use?

First, there is the synthetic vs. dino debate. There is no consensus to this issue. Some experts recommend synthetic, others insist on regular oil. Early on, synthetic oil did not burn well in the combustion chamber - but this is not an issue with modern synthetics. What matters is that it gets changed on schedule – every 3000 miles or less. Some owners choose to change at 1500 miles to offset the fact that the oil cooler(s) is not drained during an oil change. The proper weight is 20w-50 in warm climates and 10w-30 in any place that gets cold in winter.

Most FD owners run from 10w-30 to a 20w-50. It depends on whether the car will experience use in cold winter conditions, or extended track conditions. In either case, the thicker 20w-50 is usually ok since fuel dilution will occur and thin the oil. Very thin oils (0w-40) used in some newer cars are not a good choice.