Long story short, we get FREE 87 octane gas @ my dealership. I have a 6sp Ent. w/ about 7500 miles. However, I cannot get any FACT based answers to the question: Does it make any long-term difference to my engine performance/life to use the free stuff vs. actually buying 93 octane? I don't really seem to notice a difference from the 2 fuels...but I hear both opinions that it makes no real difference, and the other that I'm slowly killing the engine! Ok....help me out...any FACTS on which I NEED to be using?

 

i find the fact that this is even a question in here embarassing to the 350Z community.

please go spend the extra few dollars for premium. otherwise, you got the wrong car. the Honda scene is elsewhere

 

In short, under certain circumstances using 87oct may allow room for pinging.

Thats also depends whether you are running lean as it is anyway.

Up to you if you feel you want to gamble. I mean if you live in a hot area and know your car is lean then stick to high oct fuel.
If you are high altitude and run lean already, put in any **** u want.

Just my opinion on the matter.

 

I would probably stick with 93 octane in hot weather, but I think 87 octane would probably be fine during winter months. I've noticed that on cars that call for premium when you use 87 octane your gas mileage will drop by a good amount, but if the gas is free that doesn't really matter. I don't think that some slight pinging from 87 octane will harm your car, the Z has a pretty sensitive knock sensor so it will turn back timing so it won't harm your engine. I'm sure you will see decreased efficiency, but I doubt you'll see any difference in longevity.

 

"the bluez33"...your sarcastic comments are not appreciated...EVERY Z owner is not a gearhead, or mechanically inclined. I thought that was the purpose of forums like this, so those of us who are "technically & mecahnically" challenged could ASK questions and learn without someone taking cheap shots at them!

To everyone else w/ an informative response....THANK YOU! Keep 'em coming!

 

unfortunatly in cali we have 91octane for premium

 

SCC saw a few HP difference between 91 and 100 (or maybe 91 and 95 or something like that anyway). On their dyno it looked like the Z was hitting the knock sensor on the low octane gas, and that was causing a slight decrease in power.

You can therefore draw a couple conclusions from this:
1. Everyone in CA will be hitting the nock sensor a few times since all we have is 91 octane.

2. 87 Octane will activate the knock sensor more than 91.

So, based on the above you will loose some power and you will hit the knock sensor. How much power you loose and how frequently you hit the sensor will depend on a large number of additional factors, and therefore can not be predicted accurately. You will have to be the one to decide whether it's worth the tradeoff. If you rarely are driving at high engine load or full throttle, then it probably doesn't matter. If you are racing or driving up long hills on hot days then maybe you don't want to scrifice the performance and/or add additional risk.

Personally, I put in high octane (91) since I drive pretty hard every day to work on twisty mountain roads. If I was mainly cruising around the highway or city, then maybe the low octane would be fine.

-D'oh!

 

and then go buy a octane booster for $2-4. Don't they upgrade a tank of gas to some where around 95-98 octane?

He would still be way ahead and giving his baby much higher octane.....

Mark

 

I'm currently using 87 octane now because as you guys know, or may not know, Arizona is in bit of a gas crunch. Yeah, they got the pump working, but gas is still expensive. What I've been doing is using the 87 octane and putting in an octane booster that gives the gas at least 2 more octane numbers, putting it at 89 octane. If you've noticed, the Z's instruction manual (and by the gas cap) does not specify that you HAVE to use premium unleaded, and I have not noticed any knocking or pinging on 87 octane, which is why I had asked the very same question not too long ago. IMO, I think most of the guys here are wasting their money putting in 91 octane, but it also comes down to personal preference. Personally, I'm going to start using 89 octane and use an octane booster.

 

Man its great to be on the east coast and pump 94 octane into it.

 

BRAVO, STL_Z_SELLER!
I couldn't agree more with your response to "the bluez33." Regarding your poll, I voted premium gas, but if gas prices go much higher ($2.00 per gallon for premium in Wisconsin) I may be lookin' at buyin' regular. I don't want to do it; I don't think it's best for the engine. But it's either change to cheaper gas or have the bank repossess! Also, FREE GAS! Wow, that's a great deal!

 

I will stick with the 93, the 87 is proof to be on the edge for the high compression engine (VQ35 10.3:1) you need at least a 91 for ultimate performance for your Z... the oct. booster is not 100% accurate.
Is not that your engine is gonna damage or brake for putting 87 but when the time passes its gonna suffer a little bit... its your choice!

btw... one guy dyno his car w both gas and with the 93 put 3 whp more!

 

I Use 93...lots of 93...It gets hotter than hell in Orlando, and with some of my engine mods, you kinda have to run 93...but then again, my truck runs rich most of the time

 

For those of you that use OCTANE Booster and don't know... When the can (or bottle) says it will raise the octane 3 to 5 POINTS... they mean 0.3 to 0.5 So you'll be at 87.3 or 87.5 1 POINT for Octane is not an entire 1 octane. It's one TENTH of an Octane...

I have to agree with the posters that say...You bought a $30,000 car. A Sports car at that. I knew what to expect and I was prepared for it in my budget. I also know when it comes time to replace my tires, I'll be looking at over a grand for new rubber. I don't plan on getting the 4 for $99.00 special at Pep Boys...

 

Afew years ago one of the car mags did lab testing on the octane boosters. The conclusion was they were all snake oil and did little or nothing to boost octane ratings or performance.
I burn 85 octane in my BR Perf but I rarely go below 6000 ft. Not enough O2 to cause knocking here

 

You sir are a ricer...

If you knew ANYTHING about imports... you'd understand the Z could most likely get away with lower octane than a high revving Honda could. Take the S2000 for example, higher compression, higher revs... FAR more prone to detonation. High octance fuel is a requirement... I'd fear running less.

In my Z however... with the extremely sensitive ECU more so, lower compression and rev limitations... I feel that in an extreme case of high octance NOT being available, we would be just FINE on 87 octance for a short time.

 

I am using 89 and it seems to work fine with me. I feel that the gas milage is poor, but I cant compare it to the 93 coz I havent tried it!! One thing is that when I shift hard at red line, black smoke comes out from the exhaust at the press of the clutch. Other than that, it feels fine.

 

The car is forcing itself to run richer to avoid potential detonation due to lower octane... the black smoke is the added fuel.

Modern day ECU compensation... I love it!

 

You may want to consider a 50/50 mix to get 90 octane.

 

cbsuper- not sure where you found your fuel recommendations in your owner's manual. Mine clearly states, on page 9-3, to use premium fuel with an AKI octane rating of at least 91 and further, if premium is not available, to fill only partially until you can locate premium and during that time to avoid abrupt acceleration and full throttle driving.
I think Nissan has made their point.

Now, the Altima with the 3.5 without variable valve timing only suggests premium. Dragging those extra horses out of the VQ requires many components- premium gas among them.