With the price of gas here in Canada skyrocketing I was wondering what performance problems I may notice if I switched to 89 octane? The price of gas here by the litre can be 1.08 in the morning then at night the price drops down into the high 90's. I have to think we are getting burned and 91 octane is usually 20 cents a litre more. Maybe better would even be to fill up alternatly with 91 then 89 and so on?

 

I use 89 all the time........I don't think it is too bad, but atleast it isn't 87

I haven't noticed any performance reduction from when I used 91 at the begining. MPG is also the same as before.

 

any engine knock issues when you push the car?

 

91 Octane...the truth about octane...

Read what I wrote...

A-Train

 

Not once have I experienced anything other than smooth shifting and low engine noise. Unless it is drowned out by the intake.......

 

Is there any truth to the rumor that gas stations only have 2 tanks for 87 and 91, and if you purchase 89 they just combine the two fuels?

 

I use 89 all the time with no adverse effects.

 

Wow, it's tough to be Canadian. 20 cents more a liter? Thats roughly 80 cents a gallon (for the metrically challenged). That is a hefty difference.

 

besides 91vs94 debate (which mountain area doesn't even have), local gas stations are out of everything other than regular. I stopped at 3 stations this week and regular was all I could find.

Anyway, car is running like crap and I'm being grandma on gas pedal. 89 works wonder in my area since it's higher elevation and not as hot as texas. I wish I can find some soon.


I say in Canada especially in the west, 89 runs like using 91 in California.
Now, 87 runs like crap so I can't imagine myself using it in California.

 

I've only had my car 2 months and for each fill up except the last I used 93. My last fill up I put in 89 octane and just hit 300 miles on the tank of gas. No performance difference that I could tell and my gas mileage did not suffer. I will be using 89 from now on. They don't sell 91 here in VA so why pay for 93 which is higher than required.

 

This is one of the most frequently asked questions on this forum the last few months. It's already been asked a couple of times in the last month. A quick search would yield THIS ARTICLE addressing the issue more than adequately. That should answer your question.

Search is your friend.

 

At 0.05 or less a gallon (around here) to go to premium I pay the extra. Everything I've seen justifies eliminating the knock and better gas mileage.

 

I know that gas stations do use this method to produce fuels of varying octanes, but I'm not sure exactly how it works, i.e., if 93 is mixed with 87 to make 89 and 91, or if 93 is from a separate tank and only 91 and 87 are mixed, etc.

 

today I was still able to chrip tires with 87 octane. I think weather wasn't hot enough to cause timing delay. Anyway, power loss is there but mileage loss is not.

 

If they do mix then even better because all the sell where I live is 93 and 87 and they advertise midgrade at 89. If they mix the 2 it would net out to 90. Drove by Sheetz tonight and the difference between 87 and 93 was 30 cents/gallon and 89 was 15 cents more than 87.

 

I just saw a new high for premium here in town. $3.47.

 

Interesting to me—I normally use 93 octane, but Sunoco started carrying a 91 octane so I decided to give it a try to see how it was. The price makes no difference as it's only 2¢ a gallon cheaper (last weekend, $3.15 a gallon for 91 versus $3.17 for 93). My mileage seems to be slightly worse with the 91—18 to 19 mpg in the city versus 21 to 22, and 27 mpg on a recent all-highway tank versus 30 mpg with the 93 octane.

I think I may just stick with the 93, including from the Sunoco station.

Trying to do some rough calculations to figure out the effect of this on annual spending. Assume you put in precisely 15 gallons per fill-up (unrealistic, but easier for the math). Assume the price per gallon cited above. If you were to fill up three times per month, you'd spend $1,701 per year for the 91 octane versus $1,711.80 a year for 93. So you're not really saving any money. BUT it's unrealistic to assume that your fillup schedule would be the same if you're getting crummier mileage with the 91. So assume the same 15-gallon figure and use the 18 mpg and 22 mpg averages. Using 91 octane, you'd get 270 miles per tank, whereas using 93 octane, you'd get 330 miles per tank. Figure that with a 60-mile difference per tank, or 180 miles over three fill-ups, you might fill up four times a month with the 91 octane instead of three times per month with the 93. Suddenly your annual gas bill has climbed to $2,268 for the 91 versus the same $1,711.80 with the 93. $500 is a bit more relevant than $10 is!

Interesting stuff. Of course this model is oversimplified because it can't account for things such as road trips, traffic fluctuations due to different times of year, the traffic jam you hit that screwed up your commute, etc. I also have no good way of determining whether the difference between the 91 and 93 is as real as it seems or whether other factors influenced it. For example, on the way up to New Jersey last Sunday I averaged 27 mpg, but it included a detour on US-40 and US-13 when I-95 ground to a standstill 10 miles short of the Delaware state line, so that might have hurt the mileage. Drove back to Virginia yesterday without filling up first, so I was on the same tank of gas, and the tank average stayed 27 mpg despite being on the expressways the whole way (but I also hit three traffic jams that cost me 10-15 minutes each time). It's impossible to try to account for all of this stuff on every tank, so you have to assume, as I do, that over the course of the year all this crap averages out.

 

It's my understanding that where 93 octane is sold, the mix is 65% 89 and 35% 93 which works out to 89.1 octane.

I've seen a station with 5 grades of gas from 87 to 93. Saving 5 cents a gallon by running 91 instead of 93 would make sense if it isn't out of your way.