i live in ny and these are my gas options. Which would be the best one to pick? or is there any difference?

 

yea big difference .......93 is the best in ny, 91 only if 93 not available. you car will run like crap with 87 or 89

 

91 only if thats the best you can get. Here in NC we get 93 as well and I have heard that places like NJ have upwards of 94. Just don't settle for less than premium in your area.

rx7/350z: what kind of rx7 you got? I recently sold my single turbo 93 for my 350z.

 

yeah my bad it is 93 as well, I was using 89 but i guess im going to start using 93 now

 

I use 93 since I bought the car, never run on any lower in the Z.

 

The owner's manual also suggests using minimum of 91. Here in Cali, we only have 91 to run off. It's not bad, but I sure wish it's not 93 or 94. I remember reading that there is closer to 100 in Arizona or Nevada or something. Now that would be sweet!

 

whats the difference between the grades?

 

The higher the octane the less ping/knock in the engine. Also, I think there is better combustion (power) with higher grades. With a performance engine in the Z, you don't want to skimp with cheap gas. Economy cars call for 87 octane (my sentra does).

 

On the OEM setup all that happens if you run <91 octane is that a few degrees of timng gets pulled due to detection of slight knock. So the ed result is small $ reduction in power. Now if you run an ECU re-flash (ie TS) or FI, you really must run 91 or better or you run the risk of detonation damage.

 

002-M-P
i have a 93 fd touring model
intake/cat back/ic/dp/pfs pmc

 

91. always go with premium

 

Yup. Nissan says 91 MINIMUM. Don't run less than that. Car won't run well and you risk warranty problems if Nissan finds out. For that reason alone, you should always run whatever your owners manual recommends. It's usually printed like on the gas cap or somewhere thereabout. I've never actually looked though...

 

The octane rating describes what % of octane is in the gas i.e. 93 Octane is made up of 93% Octane and 7% n-heptane. The higher the Octane rating, the more resistance to compression it has. A 87 octane gas has a lower resistance to compression and is more likely to ignite from compression rather than from the spark. This would cause "knocking". To off-set this, you would use a higher octane gas that can handle the compression and ignite from the spark rather than spontaneously igniting. The only benefit from running higher octane is if your compression is higher or you're running FI.

 

Yes and the OEM CR is 10.3:1 , hence the recommnedation to run 91. If you get a tank of 87 by accident in the OEM setup I don't want anyone to freak out, cuas ethe ECU will protect the engine by pulling timing. From the factory it is pretty grunt proof.