Can you use regular gas in a 1994 j30?

Answer 1

The J30 engine has a very high compression ratio. If you use lower octane gas, it will cause inefficient combustion in the cylinders. I've used 89 octane a couple of times. It worked okay, but I wouldn't do it very often. Too low an octane can cause tapping sounds in the engine. Long term use will cause engine damage.

As far as a money saver, one has to realize that if you use lower octane the mpg will drop too, as the engine has lost efficiency.

High octane requirements is a common thing with Nissans.

AnswerNo, you must use 91 octane or higher in the J30, it pretty much shares the same engine as the legendary Z cars. If you were to look at a picture of a Nissan Z tt (twin turbo) from '93-'96 you will see that the J30's engine looks almost exactly alike. Which means with a little fabrication you could also hook up twin turbos to the J30, others have done it. But anyway that's why you need premium gas in your car.