I just got my Z last weekend and I filled it up with plus, 89/90 octane (middle grade) I will probably fill it with premium every other tank.

My mom has a 2004 Maxima with the same engine and uses the PLUS (middle grade) and her car runs great! Not sure if it is the same exact specs.

 

what i mean is...within 4-6years of ownin your car. Youll have no warranty and the major mechanical problems will start comin up. Trust me I know. I own 3 mechanic shops 2 body shops and 2 junkyards. Like i said cars are the worse investments you can make anyway. I just feel a lot better if i change up my cars every few years. With technology and hp race these days our cars will become obselete in time.

 

I tested out the 87 last week to see if this is true...I got less MPG and my car was running like shyt! stick to 91!! The money u save comes out even..but on the other hand u are fukin up ur car and ur car is running like a turtle!

 

JUST GIVE YOUR Z THE BEST (read highest octane) available!! Take care of your baby and your baby will take care of you!!

 

If you are worried about saving $5-$10 on a tank of gas you shouldn't be driving a Z................................ IMO

 

You might want to check on that. Your Mom's 3.5 is tuned differently and whatever you do never tell Nissan you are putting anything but premium in your Z.

 

Premium...hell i would even put premium in my VW GTI. Peace of mind is worth the 5-10 bucks to me...just my 2 pesos

 

2nd that.

 

its not that i wanna save 5-10dollars a tank but I just dont think its worth the extra 5-10. Its only a nissan. Then again its different for everyone. Some people plan to keep their cars for a long period of time. If I planned on keepin my car for more then 3 years then yes I would probably care. At this rate tho I can careless what I put. that 5-10 a tank adds up in the long run. Theres jsut more important things in life then a car.

 

Why is that? I can't have a nice car but still try to save a little money at the same time?

Right now I'm of the opinion that as long as gas prices are so high, gas stations should get as little of my money as possible.

Here is the other thing- the Z WILL operate on regular gas. It will not operate to its peak performance on regular, but it WILL operate, and that's all I need. I like driving the car, no doubt, but I'm not worried about losing 10HP due to putting cheap gas in it. If I was worried about optimal performance I would've kept my faster Trans Am.

Besides, I usually don't keep cars for more than a couple of years, so if the engine ultimately takes a dump in ten years because I haven't been using premium, fuel, it'll be someone else's problem.

 

okay, somebody get a gun and shoot this thread dead.

i think it can be officially said that no one will agree and we all have different opinions and different values.

you can only beat a dead horse so much, it ain't gonna get going!!!!!

 

This is very simple..

Knock sensors detect knock, and retard timing to accomodate.

Running 87 octane fuel will simply cause your car to have more knock and thus, the timing will be automatically retarded to accomodate.

you will loose some HP, and some throttle response.

YOU WILL NOT BLOW YOUR ENGINE.

However.. I would not go bouncing the engine off the redline with the lower octane fuel. Your ECU's timing retard will only do so much. At higher RPM's you are more likely to cause engine damaging detonation.

A good reason to use at least 89 octane is that 89+ octane fuels tend to have more cleansing additives that will keep valves, cylinders, exhaust, etc free from carbon build up. To combat this.. every so often run tank to empty and fill will premium fuel. Run the car hard for a few miles (WOT high rpm driving). The higher temps in the engine combined with the cleansers will help burn off some of the carbon build up. It's not uncommon to see some gray smoke when you are in higher rpms. It's just the carbon burning off.

fyi - I know this because I used to own a CITGO gas station, and was forced to attend multiple fuel training sessions were they explained the differences between the grades. Octane is important, but the additives are also very useful.

 

[QUOTE=mc350z]bottom line own a nice sports car that requires premium. put premium in it, end of discussion. gas prices are a ***** but its not your Z fault dont take it out on the Z

dont wanna put high end gas in the car? there are other options

just saw a cute commercial on TV last night for it. it gets 40 MPG!
QUOTE]

 

Do you **** in the washer fluid tank to save a buck or two? Buck up and put premium in it!

 

I'm converting mine to run on potato oil ! That'll be cheap ! :P

 

 

WOW, there are a lot of hard headed people here... running 87 will in no way hurt the motor, you will just loose a little performance... All these cars running around that require premium means that they were most likely tunned by the factory on 89octane.

We have 93 around here and I always just put premium in, but I wouldn't think twice about using 87 everyday.

BTW you people saying that you shouldn't be driving a Z if your worried about a few $. Since I've had my Z, gas prices have gone up by about $1.25 . I usually fill up about 6 times a month so thats $150 extra a month in gas So you need to back off, its hard on a lot of people these days, i for one haven't been getting paid any more, and I bust my *** to have some nice things. ---> Junior carrying 15hrs and working 40hrs a week, the Z is my baby, no matter how bad of a day I'm having, driving the Z makes me happy so its not going any where...

 

Look in your manual, premium is needed due to 10.3 to 1 compression. None of the LS1's never were that high and a dino Ferrari if I remember correctly is listed at 10.25 to 1, still lower than our babies we talk of here.

Also, running leaded fuel will only clog the cats is your still running them!!!
Leaded fuels are the 100 low leads we call AV-Gas. Race gas varies by company, check before using if running your stock cats. They are expensive to replace....but do use premium....

 

Always get premium, but I prefer Chevron, Shell and unocal 76. I also get costco gas if the line isn't that long.

 

For the knock sensor to correct timing with lower octane rating, knocking has to occur. It will keep occuring again and again, as the engine tries to maximize fuel economy.

Thinking that running regular saves money on a car designed to run premium is silly. You're car has to detune itself to run and THAT kill mpg...

Run whatever you want...

On my little Impreza (2.5 liter NA) I would get 60-70 km more out of one tnak on the highway. More than compensating for the price difference at the pump.

Plus, the engine runs smoother/cleaner.