Regular Gas in a 300ZX?


Can anyone tell me if I can burn regular gas in a 300ZX; say a 1993 model?


idk if you are supposed to, but the reason for 91, 93 ect octane gas, is because when your piston moves up, the compression can explode the gas itself, without spark. this is a pre detonation, also known as knocking. you can hear it if it is happening, if it is, you need to drain your gas and move up to a higher octane, knocking is horribly bad on your engine, “most” factory engines dont build enough compression to worry about this, however, when i threw in my weisco high comp piston in my dirt bike, i had to move up to 93 octane. so, i would just try a gallon or so of 89, and if your car starts to knock, drain it, and go get some 91 or whatever.


If you can’t afford the $3-4 per tank for premium you can not afford the car. Buy a Sentra…


Yes, but do not allow the engine to ping or knock. If you must blend the gas to a higher octane than reg in your area. Mix a half of high with the low octane. Your car will not die if it knocks but you will burn gas poorly and you will shorten somewhat the remaining life of the engine. The compression ratio determines the knock performance and octane for the engine for optimum performance. At this cars age there is not a big problem since everything is so worn that it is a question of when not if the engine will need a rebuild. You should not spend the bucks for high octane if the engine does not knock.


Sure, but the knock sensor will retard the timing to prevent knocking, gas will not burn efficiently, covering internal parts with carbon, and the gas mileage will be less than if you used the right gas. Plus, the car will drive like it is towing a boat anchor. But it will run.


Is a 93 new enough to even HAVE a knock sensor?

If the 300ZX is the non turbo version, then you might get away with it, but check the owner’s manual to be sure. If you just bought this car and it doesn’t have one, check some place like ebay or and get one.

I was nice enough to find it for you:


And, if it does have a knock sensor, it would be very important to verify that it is still working after 15 years.


put the highest octane in it!! why risk causing engine damage for an extra few dollars per tankfull? you should live in england where i live,and i pay the equivalent of $11 dollars a gallon for shell v power!!! you guys are so lucky in the usa in having cheap petrol,(sorry,i mean gasoline!)


Every FI car has a knock sensor, except for some pre-80’s mechanical systems. My '88 Toyota has one, and the turbo version has 2.


At $40 per tank, what’s an extra dollar or two? Use the recommended octane and get your best performance.


Thanks to all that have responded to my question. You have been most helpful.


We have an '87 300Z, and when it was running, we found it got much better gas mileage with premium gas - and ran smoother too.