Actually the owners manual says 91 is recommended not required

At least that's what the Canadian owners manual says.

That said I use premium from Chevron which I think is 92. They don't have 91.

 

I guess you're right...the heading in the manual does say fuel recommendation not requirement.

The exact wording is, "Your vehicle is designed to operate on premium unleaded gasoline with a pump octane number of 91 or higher." and that's enough to get me to pump nothing less than that.

 

I've been going with the "recommended" train of thought. In reality I try to use 93 probably 99% of the time, but on rare occasion I feel cheap, so I put in 87. As that article someone posted said, it really didn't change my gas bill much when I first went to a premium required car. I did the cost analysis then and figured in the end it'd only be a couple hundred dollars extra per year. If I could afford to buy the more expensive car (at the time) and higher insurance, I could certainly afford the slightly higher gas bill. The good mpgs this car gets is a fair tradeoff anyhow. My other car is a V6 that claims it requires premium also. Once again I CAN put 87 in it just fine. I fill it up all the same.

 

the recommended octane (91)

 

I have tried, tested and kepts logs of gas mileage and performance using 87, 89, 91 and 93 gas on my 2009 TSX. There is basically no difference whatsoever. 0-60 and gas mileage is identical.

That is a good article posted above and people should read it. Most people who are using premium will swear they get better performance / gas mileage to justify they fact that they have been wasting their money for so long

Like the article says - its almost a guilt / emotional attachment and people think they are abusing their car if the go with a lower octane

87 octane - will never pay for premium.

Tony

 

that makes 2 of us-no problems with my 06 tsx with almost 88,000 problem free miles-

 

This will ultimately be as charged of a conversation as engine oil, politics & religion.

The car has to be engineered to function on the lowest common denominator for ron/mon rating on account of the different grades available across the country.

However, I can tell a difference when I use crap gas & contrarian comments that I'm foolish and wasting my money on premium are unfounded in my experience. There's not exactly an abundance of power in this car to begin with, so I'll take the best I can get (within reason).

There is a difference in fuel grades and between manufacturers. To express how much difference between, say 93 & 92, in performance applications, check out the example below.

In a 99-00 Civic Si B16A, when supercharged with say, a Jackson Racing base kit 6 psi (with no Boost Timing Master) the initial advance timing on the factory equipped non-boosted engine is 16 deg BTDC using 93 octane. With only 6psi of boost and 93 octane, the stated settings for reducing your timing is 10 degrees.

If you can only get 92 octane in your area, the stated timing settings are 8 degrees BTDC. This could be confirmed with Keith Taber @ Moss Motors tech line. (Jackson Racing's distributor, so to speak.)

That's a huge loss of initial power for only one point of octane decrease & it only gets worse as the numbers fall to, say, 91. I do plan on boosting this car and continuing to run 93.

I know these cars aren't boosted stock, don't take that as the premise of my argument, but rather to demonstrate that there *is* a difference. One can run whatever crap gas they want, it's their car.

Edit: I typed this in a hurry at work, please excuse any typos.

 

You know I can't honestly say premium doesn't help with performance. I used to have (long ago) a saturn SL2. It used regular, and of course putting premium in it when new did nothing. I was told that at the dealer, and after putting it in, of course nothing happened. Later on however when the car had a lot of miles (~180k) it did actually make a very noticeable difference. The car accelerated just a tad faster and the engine ran a bit smoother. Same brand gas. Just ran the tank of regular empty, put in premium, and voila. Very soon after driving away I could feel the difference for sure. Now whether it was the gas or the computer I have no idea. I just know it did help. It also worked the other way around. Going from premium to regular was noticeable as well. In my new TSX however, I notice nothing. lol

 

we owned a 1991 Mazda MX-6 GT and a 1998 Eagle Talon TSI-AWD, both bought new. When we sold the cars, the Mazda had 250,000+ miles and the talon had 125,000+ miles. They both had their original engines, turbos, clutches, transmission and ran excellent. We used regular gas even tho premium was recommended. If fact numerous drivers wanted to race the mazda-they lost.

 

Dealer told me 87 is fine and that is what I use.