I was wondering if anyone has a SE S/C and If they have used regular or plus gasoline instead of Premium? Did you notice a difference?

two words pre detination, its only a problem if you really dont like your pistons.

87 octane will yeild more power However with any boosted motor higher octane will burn slower and more complete and much less of a chance to detonate (ping) under boost.

Keep the motor safe and run 92 octane if your boosted. if you are still pinging with 92 octane have the knock sensor checked out, if that is fine, retard the timing a few degrees.

REALLY REQUIRED? No. safe? Yes. If all you can get is 87 octane in an emergency situation you can run it without problems, just keep the boost way down.

This thread was going on when I bought my SC this past summer. Based on this info, I've run nothing but premium in my baby.

Premium Fuel Thread

It is necesary to use premium. Otherwise the comp. will hear ping, retard timing, put the super on bypass, and for the most part run like chit.

When I bought my X 2 years ago I ran 87 in it cause that is what the dealer told me I can use. We didn't notice the poor mileage until we decide to drive from Sacramento to Washington. We went through a tank in about 150 miles.

I've said it before, and I'll say it again. The people that design, test, and build your engine usually know what they are talking about. If Nissan says Premium is required, then it is.

i agree with the above posts, and also you should find that you get slightly better mileage with the better fuels, which would offset the original cost

I put Distilled Spring Water in mine and it runs fine.

Definitely required. When the manual says "use premium" why even ask? It's not like Nissan sells gas - but they do build engines that use premium.

Mine pings unless I use Shell or 76 premium - I suspect that the others are chaeating on their octane ratings. Once in Death Valley I had to run on premium to get out; it was the only thing available. 1/4 tank of premium and 2 bottles of STP octane booster, to get me to the next Shell station.

I wouldn't bother using anything other than premium. Why take the chance?

Can we get a sticky flashing banner on the top of this webpage indicating that premium gasoline must be used in the supercharged Xterra?

My friend just sold his 2002 Sc and NEVER used high octane..he sighed when I told him that's all I persoanly use...
well he used his truck to work with-so a lot fo driivng-nevr had a problem...

And just to make a note- it states 'recommend' it doesn't say 'obligatory' towards using high octane-

but despite that,..I myself care too much for the X to put anything but super...oh well...

Sorry as I may be thread jacking here! I have a non SC '02 2WD V6 and I used 89 Octane until about a year ago when it started pinging rather severely. I have checked the timing and its dead on. If I run 91 Octane I have no problems so I have been sticking with it.

The knock sensor seems to be working as I have checked the codes after any pinging and it has been set so I assume this means its working. The question would be what should happen when the engine detects knocking? I checked my manual and it says it will retard the timing in “emergency situations” when knocking is detected but exactly what do they consider an emergency???

I'm not really sure what to do as I'm thinking any fix the dealer can come up with will be more costly than the added cost of the fuel!

Any ideas???

Shitty gas probably. You can also ping if the mixture is too lean, When the engine is in a lean state the exhaust temps will rise as will chamber temperatures. carbon buildup on the pistons will glow like coals also causing pre-detonation.

Check the plugs recently?

Last ditch effort, Retard the timing a few degrees and throw some 87 octane in it then give it a shot.

Edit: The manual is correct when it detects a ping it will keep pulling timing off to negate the ping.

I use Chevron which I thought was pretty good gas but now you got me thinking about them plugs! I was gunna change 'em with the timing belt but I have been reading some posts about how bad some peoples plugs have looked at 60/70k. Maybe my problem!

I've had my '02 SE-SC for awhile now and have had the chance to try 89, 91, and 94 octane. I've had no problems with pigning in any of the octane levels. I have noticed that I do get the best performance with the 91 octane, and that's what I stick with. It's what the engine is tuned to use.

You can't hear all pings. But the knock sensor does, retards the timing and thus the shitty performance.

Your wise to just stick with 91.....

I WENT THRU 2 KNOCK SENSORS USING PLUS....THE DEALER TOLD ME THEY WILL NO LONGER REPLACE THE KNOCK SENSOR UNDER WARRANTY IF I CONTINUE TO USE PLUS. 92 OR BETTER IS REQUIRED!!!! NO IF'S ANDS OR BUTS ABOUT IT!!

Well don't tell them that you are using plus..

I just got a bad batch of gas today, I ping under WOT in the upper RPM range.

I CAN HELP ALL OF YOU RIGHT NOW,I WORK AT NISSAN AND I ONLY USE 93 IN MY NON-SC. EVER LOOK AT A MOTOR THAT ONLY USED 87 OR 89. BLACK EVRYTHING INSIDE FROM ALL THE CARBON. BESIDES HAVE YOU EVER SAT DOWN AND FIGURED OUT THE COST SAVINGS OF RUNNING REGULAR , I WOULD SAVE ABOUT $4 A TANK. IS IT WORTH KILLING YOUR MOTOR FOR 4 BUCKS.

What you are saying makes no sense, and is in conflict with my experience in engine tear downs, and thermodynamics in this regard.

It is possible that you are referring to engines with other incomplete combustion, or coking issues?

For example, all the premium does is burn slower (Which is all an octane rating refers to...)

...if the timing is set to burn faster gas (Run on Regular), then you are MORE likely to have incomplete combustion,

....as the gas would not have enough time to complete the burn/and/or the piston has already left the station by the time the flame propagation is ready to push it....and scavenging has commenced.

So, running the wrong timing (By running too slow a gas) will not save gas, or keep the engine cleaner.

The carbon deposits are more likely due to coking of the oil, than due to the suspected gas issues you mentioned.

Oil coking is the primary source of carbon deposits in most engines.

Check your records, and you will find that the pattern you had assumed existed, in fact, does not, and is attributable to other factors.

So - Always good to have another industry insider on board.



What do you do at Nissan?

wow, you know more than me . all i am is a ASE certified master tech, but you forgot one thing 93 has detergents to clean motors, that would keep the carbon build up from being excessive. by the way what engines do you tear down, anything new or just old technology.

Either someone is going to learn something new or this is going to be another long winded useless thread from here on. :rolleyes:

EricX03- I don't see how running lower octane gasolene will cause the engine to be black inside. I was not aware that 93 octane fuel has special detergents that lower octane fuels don't have. However, if this is the case, then the reason for the black deposits would be due to the quality of the gasoline and lack of detergents as opposed to the octane rating.