vie2233hil

Sup,

Can I put regular gas in? Did anybody try that? Will the engine knock? If the engine knocks for a long time what part of engine gets damaged?

Thanks

Poison123

iTrader: (2)

Well with the way modern engines are and how the ecu's are programmed, it would simply retard the engine and you'd lose a wee bit of power.

Your only gonna save roughly 1 dollar over 5 gallons if you use regular over premium though.

zzz350

Come on you bought a Z, put the right fuel in it. If you don't care about performance buy a Corolla, sheesh!

Dave Buswell

I believe the manual calls for a minimum of 91 octance fuel.

I further believe (although a petroleum engineer or chemist might confirm or deny) that if you mix half a tank of 89 octane with half a tank of 93 octane you will be on the money,

Dave

oscarmayer00

Go ahead and use regular, if you race your Z I'd use premium.

The main advantage of premium-grade gas is that it allows automakers to advertise a few more horsepower by designing and tuning engines to take advantage of premium's anti-knock properties. But auto engineers generally agree that if you use regular in a premium engine, the power loss is so slight, most drivers can't tell.

Today's engines use highly evolved versions of a device called a knock sensor to adjust settings automatically for low-octane gas. And more engine control computers have adequate memory to allow separate sets of instructions for various octanes. The engine control computers keep pushing to maximize performance on whatever grade of fuel is used.

The only modern engines that should really need premium are those with superchargers, which force-feed fuel into the cylinders. "You're driving along and just tramp the gas and the knock sensor cannot sense the knock fast enough in some cases," because the supercharger boosts pressure so fast, says Bob Furey, chemist and fuels specialist at General Motors.

Burning regular when the owner's manual specifies premium won't void the warranty, nor damage the engine, even the most finicky automakers say. "You're giving up perhaps just a little bit of performance that a customer wouldn't really even notice, it's so slight," says Furey.

All Porsche engines are designed for premium, too, but it's not available everywhere. "Our cars must be able to drive all over the world, and so we are able to run on regular," says Jakob Neusser, director of powertrain development at Porsche's research and development center in Weissach, Germany. "You don't have to feel that a mechanical problem or anything else will happen" using regular gas, even in the highest-performance, regular-production Porsches.

Premium, in fact, sometimes is worse fuel than regular. It resists knock because it's harder to ignite than lower-octane fuels. As a result, some engines won't start as quickly or run as smoothly on premium, notes Gibbs, the SAE fuel expert.

http://www.usatoday.com/money/autos/...emiumgas_x.htm

Zquicksilver

iTrader: (5)

i thought it was a minimum of 90 according to the manual, so i've been putting in 89 which i feel is close enough. no knocking or anything... i do mix it up though. i'll put in 93 and 89 every other tank or 93 every third.

that's the only octane offered here in chicago. 87,89 or 93!

marhot

Yea, just use regular unleaded. Nissan engineers are morons, what do they know? I NEVER follow the instructions found in the owner’s manual. {/sarcasm}

I agree with zzz350 . You’ve bought a $30,000+ car, why be cheap just trying to save .20 a gallon?

VeeTec

Are you guys serious, just a wee bit?

I notice a difference from one type of gas to the next, even though they are supposed to have the same 93 rating.

My car hates QT 93, but runs great on BP 93. I also go to a station that has individual pumps, so I don't get any 87 thats in the line, if thats what was used last.

The dealer put in 87 when I first got it, and it ran pretty crappy on it. My gas mileage was about 1.5 mpg lower as well.

Stick to premium, imo, after all, it was designed for premium.

oscarmayer00

Premium lovers are passionate, they would simply stop driving rather than switch grades.

The difference between 87 and 93 octane is so insignificant that you will realize neither better mileage nor fewer maintenance bills by buying supreme. It makes no difference unless the car is supercharged.

"Buy the cheapest -- unless you're in Mexico, where the cheapest is closer to kerosene."

Car and Driver magazine conducted a test in 2001 that determined that even most high-performance vehicles will run normally on regular with only a marginal loss of performance.

"If the car is sufficiently new and sophisticated, it will not suffer any ill effects," the magazine concluded. "But be ready to switch back to premium at the first sign of knock."

luvmyG35

This is an arguement throughout the car world that will never be solved. If you are so worried about regular giving you engine knock, then just use the MEDIUM grade. Should be good enough for everyday driving.

ezee

I've been using medium grade 89 octane in my Z for months and it runs just fine. Haven't tried 87 octane yet.

genieman17

I'm not gonna pretend to know the answer to this question, but I will tell you this. A buddy of mine is a mechanic and works for BMW. Most BMWs have the same minimum octane suggestion of 91. He warned me against using anything less. He said that even though the engine will retard the timing, which will avoid knock and predetonation, the lower octane fuel doesnt burn as well and causes residue within the motor which can lead to clogging, which then leads to BAD SITUATION. He said that just by looking he can tell who uses regular gas (not by looking at the car, but by looking at the engine when its disassembled). He said there have been several cars in for serious engine work because the owners used regular gas...Now that may just be an issue for Beemers...but I wouldn't take the risk for only 20 cents per gallon.

sausage5000

this subject has been beaten to death, resurrected, and qaushed over and over on other forums. much more insight was provided, with not just some obviously pure genious GM people quoted.

the manual says using regs can damage the engine. i'm not going into that proven fact.

when using regular octane, the knock sensor will retard the timing long before any audible sound. then the ECU does not automatically reset when you put 91/93 in, it takes a while. your performance is thereby degraded considerably.

go get a cavalier. i heard they burn regular no problem.

overlord tom

$0.20 extra per gallon x 20 gallons = $4 per TANK . What...4-5 tanks per month? I'm so sick of everyone bitching about gas prices. We have one of the lowest gas prices in the whole world.
If $20-$25 extra in gas per month is going to squeeze the budget, then you totally bought the wrong car. Buy a Metro or a hybrid. You'll save $100's per month in car payments, and cops will never look at you twice.

87 or 89 octane will ruin the engine in the long run..period. The knock sensor might compensate for the knock itself at low altitude, but just because you can't hear it knock doesn't mean you aren't trashing your valves.

RTFM! lol

phoenixZ33

The Maxima, Quest, Murano, FX45, Altima 3.5L, SE-R Spec V and every Infiniti are all "designed" for premium fuel as well.. do you honestly think Nissan expects ALL of those customers to run Premium all the time? The knock sensor does a good job of sensing regular vs. premium fuel and adjusting engine timing accordingly. I'd be willing to bet a car will knock less on regular as a restult of timing retard, than it will on premium trying to run higher timing advance. You'll lose performance, but that's it. Dyno a car with regular vs. premium and see what happens..

sausage5000

no. a car will "knock" the least running the designated fuel. in reality though... no actual knocking usually occurs, just degraded performance and eventually ECU/engine damage.

but how does a knock sensor really work? that is what you need to understand.

the engine usually will never knock. the knock sensor detects harmonic distortions that happen long before any detonation, which what you call "knocking". ...the timing is then retarded to avoid detonation and possible real engine damage. ...your performance is considerably degraded at that point, but the engine is not actually ever "knocking"

buildup and valve/seal damage over time is a real thing... but ECU damage can happen much quicker running the incorrect octane.

OP Z

iTrader: (1)

ECU damage? I doubt it!!!

cwerdna

sausage5000: I think your info is off. Engines w/knock sensors still can knock. My 02 Maxima (same negine as the Z) was knocking and pinging on light throttle in hot weather on level ground and quite a bit going up hills w/91 and 92 octane. I had them apply a TSB that was for "lack of power" (I was trying to get this one throttle hestiation prob resolved) which involved reflashing the ECU and replacing the MAF sensor. I recall the service dept. mentioning that when they ping like that this usually fixes it or that they have sometimes have to replace the ignition coils. Problem went away. It hardly pings on 91/92 now.

A number of 00-01 Maxima (3.0L V6) and some 02-03 owners had bad ignition coils which resulted in pinging.

phoenixZ33: The Z's manual is MUCH more explicit about running on premium than the 02 Maxima's probably due to different engine tuning and ECU firmware. In the 04 Z's manual on page 9-3, the part where it says "If premium gasoline is not available, unleaded regular gasoline with an octane rating of 87 AKI number (Research octane number 91) may be temporarily used, but only under the following precautions:

- Have the fuel tank filled only partially with unleaded regular gasoline, and fill up with unleaded premium gasoline as soon as possible.

- Avoid full throttle driving and abrupt acceleration.

However, for maximum vehicle performance, the use of unleaded premium gasoline is recommended." is different on the Max.

On the Max manual, it says just says "If unleaded premium gasoline is not available, unleaded regular gasoline with anoctane rating of at least 87 AKI (Research octane number 91) can be used.

However, for maximum vehicle performance,the use of unleaded premium gasoline is recommended."

nitrousoxidex

iTrader: (4)

I used 87 before and today I put premium in it 91. You actually feel a little bit of difference. I think from now on I'm gonna stick with 91. I've only used 87 the first two times of fill up so I don't think I did too much harm on my engine. I wonder what 98 octane feels like(they have this stuff in other countries).

steig

you can get unleaded 98 octane at drag racing tracks or gas stations near one. Also Ohio has an emissions check required for registration, I would think that using less than 91 octane would lead to some gas not combusting and failing an e-check if you had regular in your tank.