What's the highest Octane Fuel I can run in an internally stock engine? Im not sure if it matters but, I've got a high flow intake, straight pipe replacing cat, exhaust, new ignition, new injectors, and a generally good motor

 

If that's all you have, you're not going to see any gains above 87 or 89 octane.

 

Heat Rave is right, you'll see no benefit. You can safely run a higher octane than you need without causing any damage to car. But you'd be waisting your money. You should only raise your octane to prevent detonation. As you mod out your car, depending on how far you go, you would eventually experience detonation. Higher octanes are just harder to burn, so they don't preignite in a lean invironment(detonation). So, if you make the move to a higher octane without needing it, you're engine will have a harder time burning it, and you could possibly lose power. If high performance cars could run on lower octanes without detonating, they would. It's cheaper and it burns faster.

 

You could warrant higher octane if you can get the ignition far enough advanced to take advantage of it though. That'll give you some more power.

 

But from experience. My Z has always run better on power premium fuel. I noticed a difference when I went from 87 to 91. And I got better fuel mileage. And my Z was and is pretty much stock. But it also says in the original owner's manual. To burn 91 octane or higher. And it does help to make the car run better. And like I said this is from my past experience, and having a Z over 5 years.

 

If that's what the OM says to run, than that's your best bet. I use premium too, but like I said, my ignition is advanved a bit over stock to make a little more power. When I bought it, the timing had been retarded so it was running off 87, I kept it that way for a couple months and got tired of being slow. It wasn't that much cheaper at the time. Gas prices now though, I'm thinking about going back to 87.

 

As with Wildman, my Z also likes premium...especially Chevron premium. Something about that Techron that makes my Z smile and run like a raped ape!!

 

Actually, that's only technically correct. According to the 1982 Owner's Manual, page 112, 91 is the *RON* octane rating they recommend. The Ron+Mon octane (which is the rating most people/gas stations refer to) they recommend is indeed 87.

 

Well I ran on 87 for several months and about a month ago i switched to 89, and i noticed that the idle was smoother, acceleration was improved, as well as gas mileage. A friend of mine with a 1992 Camry XLE V6 switched from 87 to 89 and immediately noticed that the engine ran smoother, and a valve that had been tapping since he had the car stopped tapping, but, back on topic, i wouldn't be harming anything if i were to switch right over to 91 to see the results?

 

I switched from 87 to 89 and I got better gas milage, about 50 more horsepower, my car's bodydamage fixed itself, and it lowered my cholesterol!

 

Smartass!

 

Fla280zxdrifter, you won't cause any damage. Don't worry about that.

 

Well, if shelling out the extra few bucks by moving up to Premium on a pretty stock engine makes it feel like more power, better idle, better gas mileage, etc, etc., then I guess it's worth it. Placebo or not, as long as it feels good that's what matters I guess. ^_~

 

In CA, if you can afford it($$), I'd make the move to 91 anyways, the gas out there is different than most of the other states because of the strict emissions standards. It's formulated to help emissions, and not performance, so make the move if you can afford it. I can run 85 here in SD and not have any problems on stock timing(but I don't). God bless the states with 92+ octane at the pumps.

 

yes, 93 in texas is very good.
I feel sorry for the Californians

 

93 here in texas.. id feel deprived losing those couple of points.. 2.13-2.20 is not fun to pay at the pump

 

Also us Arizonians, 91 is the highest at the gas pumps!

 

That's what you pay for 93 octaine? Our prcies went down this week. In WA we're at about 2.45-2.49 for 91

 

holy cow... we are at 1.99 for 93

 

1.99 87
2.05 89
2.15 91
etc

although those are the cheap cheap gas prices, I tend to stay away from those places and hit up the Gas stations that have been around for more than one season, and as far as the price difference of the octanes, I don't mind paying an extra dollar or two to get better gas. I mean what could I possibly do with a dollar nowadays anyway?. . . that's like half a french fry

 

I think Washington is now as bad with gas prices as California always has been...

 

any "used to run on 87 octane" car with a lil malfunction or in need of a minor tune up will benefit of an octane upgrade


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