Well everyone is telling me to fill up 91..... and on the other hand my dad is saying its all ********... it all comes in the same god damn truck its not worth it... theirs no dif.. just put 87.. what u guys think? 91 is fukin expensive too.. i fill up full onl ike $24.. is it worth it.. or is it all the same bs and wont effect it?

 

Your motor requires premium fuel as stated in the owners manual. If you can afford the 350z, you can afford the extra $3/tank. The 350 motor is setup for premium fuel (high compression ratio, timing...). If you run regular, it might ping and blow up.

 

Yeah, you'll definately need the premium.

I'm still looking forward to seeing pics of your car. Sounds gorgeous to me.

~B

 

If you drive like an old lady you can get away with 87 octane, but like others said this car is made to be run with premium. Actually pump gas (premium or not) isn't best for any car with a high compression rate. But who wants to go through the hassle of adding octane everytime they fill up.

I noticed a gas station the other day with 110 octane fuel. Your Z would be one happy camper if thats all you let her drink. There are no bad side effects of running high octane fuel all the time that i have heard of, have you?

 

So as not to confuse anyone, by "pump gas" i mean the standard octane rates carried by gas stations....

 

Well, other than the significantly lighter wallet .

All cars are designed with certain octanes in mind. The engines on most "normal" cars are designed pretty conservatively, and have a lower compression with retarded timing, and can therefore easily handle the lower octane gasolines. By putting the high octane gas in those cars, all you are doing is wasting money.

Performance cars however, are designed more aggresively. They typically have a higher compression ratio and more advanced timing than their "standard" counterparts. Both of these factors increase the risk of pre-detonation (knock) so a higher octane gas is usually recommended. Because all modern cars have knock sensors, it is possible to run with a reduced octane gas, but the engine will detect a knock (so you will always have some pre-detonation) and then retard timing for some period of time to prevent further knocking. I'm not sure exactly how the VQ engines work, but I'm guessing that after a significant change in throttle position or fuel usase the timing will gradually be advanced back to the default value or until another knock is detected, at which point the process begins again.

So, that is why if you drive conservatively, and don't put large loads on the engine, and don't mind the occasional knock, you can probably get away with 87 octane gas. However, to get the full performance from the engine, you should use 91 octane (or higher). Afterall, what's the point of buying a sportscar if you are then going to drive it real easy. Might as well have purchased a Corolla.

So Vad, if you believe that the gasolines are actually all the same, and that the gas trucks have only one tank (and no separate compartments), then by all means, use whatever gas you want. I personally will just pay the extra few bucks per tank for the added peace of mind.

-D'oh!

 

If your not properly set up, it can kill O2 sensors, and clog injectors and the cat. Higher octane means the fuel burns slower, and also decreases your cylinder presure. If you put too high of an octane fuel in, then the peak of the burn in the combustion stroke will be past TDC and rob you of power. If you put too low of an octane in, your PCM is going to try to compensate by adjusting the timing. Trust me, if you plan on driving your car safely above 3000RPM and having it live for a while AND getting the best performanve out of your car, get the 91-93.

 

Vad, i have always put Sunoco 94, even on my '87 Supra.
A while ago i saw a report done by one of the local news channels (2, 4, or 7). They sent out different grades of gas from different gas stations to an independent lab, to see if there was a difference between the grades. The lab concluded that there was a difference between the grades. However, not exactly what was on the pump. For example; 87 oct. was actually 86; 89 was 88; 91 was i think 89; 93 was 91 and 94 was 92 or 93. MAY not be exactly what the pump says, but, there's was a difference nonetheless.
Now, as far as all the trucks loading up on the same gasoline..well, yes and no. For example 93 oct. is the same whether it comes from sunoco or amoco or whereever, BUT, each refinenery will add their own ADDITIVES, make them different.
I'll give you another example, Merit gasoline staions in my area used to get their gasoline from Hess. The truck read Merit, but, he loaded up in Hess. Other trucking companies may load up in Hess and deliver to different gas stations, and this may be why people think that all gasolines come from the same place, or that they are all the same.

hope this clears things up.


Gerardo