anyone care to comment about my post above (#27) regarding the fuel additives?

 

Ok, on the way home, I noticed a BIG DIFFERENCE! It didn't have the power I'm used to. I feel like I'm driving grandma's car. Can't wait to use up the gas to get my premium fill back! (note to self: Put sticky note on gas cap that says "PREMIUM" for my wife.) But mpg seems to be normal.

 

Yes, there is that much difference between 89 and 87.

I have owned nothing but Maximas since Oct 1984, and have always dropped to midgrade after around 18 months. I have never been able to detect any change in performance, and the carefully measured MPG never dropped.

The 7th gen Maxima fuel system is set up for 91 octane, which means it probably makes little or no adjustment for octanes between 90 and 92, and only a very slight adjustment for octanes 89 and 93.

But 87 is an entirely different ball game, and this baby will not run well at all with 87 octane. In fact, I would expect that continued use of 87 could damage the fuel system. If brisk acelleration was done with 87 over an extended period, I would not be surprised to see engine damage.

If someone accidentally put regular in my Maxima, I would drive extremely carefully, and as soon as I had used even one or two gallons, I would top off with premium. I would continue topping off with premium every time I had used one or two gallons. Just a few such topoffs would raise the octane to a level the Maxima could handle. UNDER NO CIRCUMSTANCES would I EVEN DREAM of using even half a tank of regular before adding premium.

 

I never knew light that there was such a difference between 2 octane ratings like that. Good to know. Personally, since here in NJ there is only a 10 cent difference between 89 and 93, I'm going to stick with the 93 Octane since I don't mind spending the extra 1-2 bucks a week the premium is going to cost over the mid-grade.

I can certainly understand you wanting to do the mid-grade since 1) in your area there is a much bigger difference then 10 cents between 89 and 93 octane and 2) you have been using it for years and have seen no decrease in performance/fuel economy then all power to you!!

If you or anyone else for that matter ever find some idiot puts regular in instead of premium or mid-grade, all you have to do is baby the car for that tank of gas. That is what I did and I got through it with no problems!

 

My wife and I drive mostly city, stop and go, with spurts on the highway bout 3 -5 miles a time. Typically we use 91 BP Gas. Have been averaging 25.8 MPG for the last 3 fillups. That is from the computer reset every time. And when figuring it by hand we got 25.67. So Very close!!!

 

I think there is a difference between certain gas companies. For instance, I will never put Arco gas in my car. I have heard from a person who had researched this that refineries are allowed to put a certain amount of water processed into the gas. Arco has one of the highest ratio's on the market. I have had cars years past that used Arco and the would stall at idle. Just doesn't run good. But when using say Chevron, I never had that problem again. Point is, stay with the premium stations and you will be fine. As for additives, I think the Chevron gas has the best there is. Never had a problem with injectors or anything else for that matter.

 

We could look at this another way, which might help grasp this:

87 octane is the ABSOLUTE LOWEST OCTANE for which ANY widely-produced gasoline-powered vehicles are set up by manufacturers to use.

91 octane is the ABSOLUTE HIGHEST OCTANE for which ANY widely-produced gasoline-powered vehicles are set up by manufacturers to use.

Sure, there are those who have warm fuzzy feelings about 93 octane, but cars set up for premium such as the 7th gen Maxima have a fuel system set up for 91 octane, because that is the highest octane available in many parts of the country.

SO: the difference between 87 octane and 89 octane represents one full half of the entire scale of octanes for which widely-produced cars are set up to use. That is why changing from 89 to 87 octane has such a pronounced effect on our 7th gen Maxima.

 

Your wording is a bit off. It's not PUT, it's ALLOW. Gas/water doesn't mix very well at all....

Most gas has some water in it, but the alcohol additives usually help it evap out. If you're in a high humidity area or someplace it rains more than 250 days a year or like what most boat owners so, they add StaBil or some other water evaporator product into any gas they purchase to help alleviate the issue. I use Stabil on all my lawn stuff and my gas pressure washer for that reason, but not my car since a full tank of gas doesn't sit idle in it all the time.

 

Actually it is allow as the wAter is mixexc with the gas by I think hydrolizing it. Not sure if that is the correct term or not but the water is added in a stabilized form which allows it to mix.