ive been running my max off 93 since the day i got it. My bank account is gettin a lil low and im in college=no job. i travel A LOT. i was wondering how bad 87 is to put in our tanks.. we have a pathfinder in our family with about 80,xxx miles on it, all of which were 87 octane. No problems have come up with it and it recommends 91+. I know i am probably going to get scolded, but i am shy on money and looking for ways to save, give me honest input please, thanks.

87 isn't bad at all.

You just wont get optimum performance.

^ +1 ... however, some folks say that the high grade fuel will give you more mpg ? and that you actually come off better using the high grade stuff. i dont know if this is true or not, maybe some gas companies got the word around, lol ! but yeah certainly wouldnt hurt anything.

Running 87 won't hurt anything. It just won't performe as well. If you do get some engine knock the knock sensor and ECU will put the timing in a safe mode to compensate for the lower octane.

just do be easy on the car with the 87 in the tank,
no WOT or blasts up to redline or anything like that

87 is perfectly fine for the maxima....nowhere in the manual it states that 91+ must be used...it only says 91+ is recommended if you want maximum performance...

Why not?...

87 works fine (used it when my MPG was around 15-17 before I got new O2s) - if you're an auto, you'll have this annoying lag for a second or two when you start accelerating (went away with premium gas)

I guess we won't be see you in the Max Kill forums. But anyways,87 will work .Just means you have to act like a CamryCord driver till you get the good stuff.

If your engine is knocking constantly at 87 gas, it WILL damage your engine over time. No ifs ands or buts. Using the lower octane gas will also result in lower fuel economy ~ it might negate any benefits of using the cheaper gas to begin with.

For example, during a road trip up in northern Alberta this summer, I had to fill up, but the station only had 87 octane. At 70mph, I got 325 miles on 13 US gallons or 25 mpg. On the return trip, I refilled with 91 octane however I got 30mpg, or almost 400 miles, ~ 15% better milage. The cost difference between 91 and 87 octane was negated by the fact I got better fuel economy on the higher.

If your stuck, running on lower octane gas once in a while won't kill your engine, however there are lots of studies out there that prove engine knock will damage your engine. Most supporters who say it's ok to use regular gas, are not being entirely true or correct. Standford university has a great article here about engine knock and what it can do to your engine here.

Then again, it's your car - put what you want it. But don't whine when your car blows blue smoke when you start it up next year.

The gas mileage of your trip was probably largely affected by wind.

It was a hot week with no winds. Since I was driving east to west, then west to east on flat level prarie land, can't say it was the route, or any weather induced effects.

Maybe it was the gas?

us who have knock sensors dont have to worry about knock

320 Miles/16.5 Gallons x $2.80 = 6.9 miles per dollar
380 Miles/16.5 Gallons x $3.00 = 7.7 miles per dollar

I ran 5 or 6 tanks of 87 octane and filled up within .1 or .2 of 16.5 gallons everytime and got between 310 and 330 Miles per tank every time.

I switched to 93 Octane and got between 370 and 400 Miles per tank since (until my Knock sensor went out at least)

Some people say this is not conclusive evidence but I think it is....
I also had noticably more power once I switched to 93 octane (until my KS went out >.<)

Yes I know I didn't specify that $2.80 and $3.00 was the price of regular and premium...at the time I did this regular was still $1.80 or so but the difference was still 20 cents between the two. so when premium is 20 cents more than regular it's worth it... in my opinion

Some good advice here so far. The question of improved gasoline mileage with premium is the only one where there is some disupute. I did a small test this past summer that showed the increase cost for premium was about equal to the inproved mileage (so the cost per mile was the same for both grades of gasoline.) I will do a better test this Dec-Jan. Around town, I suspect that it would be hard to tell if premuim gets better mileage.

My manual says that occasional light engine knock is OK -- but you don't want it to continue or you will expericence engine damage. If you are young enough, you should be able to hear light engine knock. My hearing is shot -- too many loud Rock songs -- so my wife has to tell me when there is knock. When that happens, I simply downshift to a lower gear.

My 04 has a knock sensor and I still experience light engine knock when the temp is over about 72 degrees F and I am climbing the hill to my house (burning 85 octane regular). Above 4K feet in elevation this lower octane regular is OK per my manual.

WOT (wide open throttle) is probably not too smart with regular. You may not be able to hear the engine knock with all of the noise and excitement. If you want to race or get max preformance from your Max -- burn premium.

I have almost 40 K miles on my 04 and have largely burned regular for all of those miles. I do not get any "blue smoke" from the exhaust (which means you are burning oil that can not be handled by the cat converter). I do not drive like a Camray or Accord driver, I just don't race anyone -- ever. I do like to accelerate, which my Max does just fine on regular. With a 6-speed manual, I do not experience any lag burning regular that some with auto trannies report. Don't know what that could be??

I'm in month two of my test of 89oct with 10% ethanol vs 91oct. I get 24 mpg with 89oct, I gas up at the same pump every week, same trips. So I tried 1 month with Phillips 91oct, which came in at 24 mpg, no difference. I'm on my second tank of 91 oct from Quick Trip, so far slightly less 23.5 mpg. I'm giving it two more tanks of the higher octane, until then I've found no difference in mileage between 89 and 91.

Mileage hand calculated, the trip always shows 27mpg

you dont get better gas mileage with premium

you dont get better performance with premium.

????

How would you know stuck in traffic all the time on Long Island?

Even in the "traffic" on Long Island I notice the better gas mileage and performance. With 87 I got an average of 18.5mpg on 3 tanks when I first bought the car with 45k miles on it. Then after reading the forums I tried 93 and my gas mileage jumped to 24.4. I also noticed a hesitation with 87 and more responsiveness with 93.

Nissan says you will get somewhat better performance with premium. I believe them, but burn regular most of the time.

Mileage is so dependent on each specific vehicle, that generalizations are hard to prove or disprove. Then when you are driving in town (in the city) the traffic is so variable that accurate comparisons between tanks of gasoline are also more difficult. In my Max I think I get slightly better mileage on premium, but probably not enough better to justify the extra cost. My highway test this winter will prove (to me) if I can justify the higher cost of burning premium on road trips.

Buying gasoline with 10% ethanol is proven to reduce gasoline mileage by about 6% or so. The ethanol has less energy than the gasoline, so the ethanol content reduces the energy content of the mix.

I have been using Husky 90 octane gasoline with 10% ethanol since May. It is being marketed in British Columbia at 87 octane prices and is as close to 91 octane as d@mn is to swearing for my liking and is Cdn 11 cents/litre cheaper. I have not noticed the vehicle's performance or fuel economy being compromised one iota. I am currently getting 25 -26.5 miles to a US gallon with a mix of 30% city/70% highway driving.

Just be careful with that ethanol, it loves intake valves, a little too much as it often decides to stay on them for more time than most of us would like, nothing a little FP, techron(probally to extreme for this application) or even some MMO every now and then cant fix.

Please note that I did not say that ethanol in gasoline would hurt your car's performance. It only takes more (about 6% more) to travel the same distance. The blend has less energy than gasoline alone. I suggest that the price you pay for ethanol gasoline should be enough less than for non-ethanol (if you can get it) to cover this difference in mileage.

There is no scientific data that shows high octane fuel increases power, or respose time.

You are supposed to use the lowest octane level you can without your car knocking.

High octane is for high compression engines, & engines with turbos or superchargers. So if you max engine hasn't been rebuilt to have higher compression, and is naturally aspirated, you don't need 91 or 93. Save your money.

Also... most of the gas in the USA is shipped via pipeline. All grades & brands, in the same pipeline, including diesel. So there is some mixing & your 91 may be anywhere between 87 & 91.

What I am contending is that I have not experienced a 6% reduction in fuel economy as a result of using 90 ocatnae 10% ethanol gas. It is unchanged from using Chevron 92 octane.

A fuel economy reduction using 10% ethanol gas is a proven fact in modern fuel injected cars. Ethanol produces more oxygen during combustion which is passed out the exhaust. This is detected by the O2 sensor which then tells the ECU your car is running lean so it adds more fuel, hence lower gas mileage.

Ethanol also contains less heat energy than gasline so there is some reduction in power as well. I avoid ethanol blended gas like the plague whenever possible.

BigFly is right on. There may be a few cars that are so out of proper tune that they will not show a loss of mileage when burning an ethanol blended gasoline -- the extra oxygen in the fule corrects the air-fuel ratio to improve combustion. This would be the exception to the rule. I suspect that Bobo is simply seeing the normal variation in mileage from tank to tank and assuming that the ethanol blend is getting the same mileage that he would get burning a non-blended gasoline. A 6% loss is not much given all of the other factors that can affect mileage.

I only buy ethanol blended gasoline when the price is lower by more than 6%. But in may locations you do not have a choice -- an ethanol blend is all that is available. Last week when we were in SD, the mid grade and the regular were both at the same price at many stations. The mid grade was simply regular with 10% ethanol added -- which boosts the octane by about 2 points. I bought the regular. The ethanol belend has to be cheaper to compensate for the loss of energy and mileage -- this wasn't.

What is YOUR definition of high compression? The VQ35 is 10.3:1.

Well I still get better fuel economy than virtually every 4th Gen Maxima on the board, even using 10% ethanol blend (90 octane) at 10% lower cost than 91 and 92 octane everywhere else. If I got a 6% improvement in fuel economy by switching back, I would be getting the best gas mileage I've ever received and I have 61K on my OEM plugs. That 6% benchmark may be relevant for US gasoline, but I don't think it is for Canadian gas as we have different additives here (aka better gasoline).

I just read something on the internet put out by the state of Wisconsin that states that studies show that fuel injected vehicles may experience a 2% decline (not 6%) in fuel economy when using 10% ethanol-blended gasoline.

Perhaps that is why I can't tell the difference in fuel economy since I started over-inflating my tires by 2-3 lbs. at about the same time as I started using the ethanol-blended gas, so net-net my fuel economy is probably unchanged as a result.

Here is a Canadian article on the affect of ethanol in your gasoline. It does not say how much it will change your fuel mileage, just that it will be decreased.

http://www.canadiandriver.com/articles/jk/051019.htm

11+ :1

If Nissan considered that high comression, high octane fuel would be listed as required for a VQ35

Ethanol-blended gasoline eliminates the need for winter gas. For many regions of North America that use winter gas, eg. the mid-west, northeast?, you will likely experience better fuel economy running ethanol-blend gasoline as winter gas reduces fuel economy by about 10%.

I still dont get winter gas, or better yet, gas-line anti-freeze that i see all the time at wally world, i believe gas freezes at -185 deg. F, i know some of u guys get colder than us rochester/syracuse folk but geez

Get on the website of your preferred gasoline provider and see where they deliver winter gas to. I wouldn't be surprised if you're buying it in Syracuse.

In British Columbia, only greater Vancouver, Vancouver Island and the Sunshine Coast do not get winter gas from Petro Canada, for example, but the remaining 80% of the province does.

If you don't get winter gas, I would expect places like Minneapolis/St. Paul, Chicago, Detroit, Kansas City and other midwest/prairie cities to get it. In those cases, ethanol gas may be a better winter alternative. It also prevents gas line freezing.

It doesn't have to get very cold to get gasline freeze-up. I have experienced it locally and the coldest it ever gets to is 14 Fahrenheit (minus 10 Celsius), which would be a balmy winter day in many of the cities I've just mentioned.

The purpose of gas line antifreeze is to prevent the water in you tank and gas line from freezing. You say that you don't put water in your gas tank, so don't need to keep it from freezing. Well water gets in your tank two ways: 1) from condensation on the sides of your gas tank when the humidity in the air condenses on the sides of the tank. This is why you want to keep your tank full of gasoline in the winter. 2) Water comes with the gasoline you pump into your car. Most of this comes from condensation on the sides of the gas station tank. If you buy gasoline with ethanol, you don't need to put the gas line antifreeze in too.

Unless things have changed since 1998 when I retired, winter gasoline has to do with the volitility of the gasoline. It is harder to get gasoline to properly vaporize (particularly starting a cold engine) and so oil companies put more volitile compounds (like butane) in the gasoline blend for winter. The government does not allow them to blend these components in gasoline the rest of the year. The presence of these more volitile compounds in winter gasoline will reduce your mileage slightly -- butane has less energy than other gasoline compounds.

Ethanol in gasoline does not have much effect on gasoline volitility, but is reported to increase volitility very slightly. Having ethanol in the gasoline will ensure that any water in your tank will not cause a problem freezing because ethanol "collects" that water in a water-ethanol suspension. The BTU content of ethanol reduces the BTU content of gasoline by about 6% -- so this should be the worse impact on your mileage. You may well not experience this much of a drop, but I suspect that you will at least experience a 2% drop in mileage.

Compression ratios: In the 60s a 10 to 1 ratio was considered high compression and needed premium gasoline. With more modern engine technology, a 10 to 1 ratio is now considered just below high compression. Honda's 6 cylinder engines have this ratio and they recommend regular gasoline. Some earlier VQ engines also had this ratio. The newest VQ engines are at 10.3 to 1 and suggest premium for maximum performance. I suspect that this 10.3 ratio is the limit for being able to safely burn regular gasoline in an engine with modern engine technology (like Honda and Nissan sell). I would not recommend burning regular in a 1965 Corvette engine with a 10 to 1 compression ratio.

hey. hmmm i was just wondering wtf is this knocking sound i hear when i turn off the car. It seem to be knocking or banging like for 5 minutes. I am not sure if it the engine, sound like from the metal. I used 93 octane, so i do not think it the gas. Can someone help me? I have a dumb quesiton and hear different stuffs. When you turn off your car, are you suppose to hold your brake and turn it off or after put you gear at park you just turn off the engine automatically without touching the brake?