Jimellow

I bought my car a few years ago, and I recall the dealer recommending I use 87 (low grade) fuel in the car..

Lately, my parents have been using the car, as theirs is having work done, and they have been putting 89 octane (regular) fuel in it, insisting that it will give more power and that it's recommended over 87.

I was under the impression that 87 octane was ideal for my car, and I'm curious if other Accord owners could comment on this.. I understand my parents' argument that higher octane = better, however, I also remember what the dealer told me, and I tend to put his informed opinion over that of my parents in this case.

I'd apprecaite some feedback/guidance here, as I don't want to damage my engine as a result of using the wrong type of fuel. Even though damage is unlikely, I'm still curious about this and would appreciate feedback from those familiar with Honda Accords.

Thanks!

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cyrnel

Higher than recommended octane won't damage anything but your wallet. It might hurt performance, or help, but that depends on engine design and condition. If you've ever noticed knocking with 87 then real 89 or higher would help. If your engine has knock sensors and retards timing automatically then higher might help performance. It depends. I only have anecdotes with my old '90 GS. Check the manual for factory recommendation. Check out Acura forums for trends on stock engines.

For the disturbing part, mid-grade has often been tested as a profit item placebo, with similar or identical actual octane values to regular.

BTW, do a google for "gasoline faq". It's a long read but has great information.

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There are a vast number of people who are uninformed and heavily propagandized, but fundamentally decent. The propaganda that inundates them is effective when unchallenged, but much of it goes only skin deep. If they can be brought to raise questions and apply their decent instincts and basic intelligence, many people quickly escape the confines of the doctrinal system and are willing to do something to help others who are really suffering and oppressed." -Manufacturing Consent: Noam Chomsky and the Media, p. 195

Jimellow

Thanks for the reply.

My concern was that using a higher grade might cause knocking, but I haven't experienced any yet.. Generally I've been content using the low grade, and am relieved to read that there shouldn't be any negative consequences, price aside, from using a higher grade.

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Desperation is no excuse for lowering one's standards.

cyrnel

Not sure I misunderstood, but to be clear, a higher octane number indicates more resistance to knocking. 87 would be more likely to allow knocking than 89. (assuming the 89 is really 89) If yours never knocks with 87 it will almost surely lose power with anything higher, unless it's detuning itself for regular.

A fair test of long term performance and efficiency is mileage. If you have a steady foot and consistent driving patterns your mileage will tell you which works better. Good luck telling the difference between 87 and 89 though without instrumentation.

Last thought would be that _very_ few cars today are built to require anything above 87. A minority automatically tune themselves depending on octane. A smaller number still require premium due to performance design characteristics (compression, timing, a braindead computer, etc.) I could be wrong but I don't think any street Hondas are in that category. Maybe NSX??

__________________
There are a vast number of people who are uninformed and heavily propagandized, but fundamentally decent. The propaganda that inundates them is effective when unchallenged, but much of it goes only skin deep. If they can be brought to raise questions and apply their decent instincts and basic intelligence, many people quickly escape the confines of the doctrinal system and are willing to do something to help others who are really suffering and oppressed." -Manufacturing Consent: Noam Chomsky and the Media, p. 195

hemiram57

As others have stated, unless your car is knocking, using anything higher than 87 will not only waste your money, but could result in lower gas milage and performance. For your car, stick with the 87.

catback

I'm gonna go against the majority just because I can and say that your parents should put in 91 or higher octane...reasoning behind this is premium grade gas has better detergents to clean and keep clean the fuel system and engine and since they're paying for the time being might as well cash in on it. As for the affect it'll have on mpg and performance, it may lead to a little loss in both but really doesn't matter how many mpg your getting if your not buying the gas and performance wise you or your parents aren't racing your '96 accord are you?

shakran

That's a myth catback. 91 doesn't clean any better than 87. And in fact, it can foul things up if the car's not designed to run on it.

If the car's set up to run on 87, higher octane can leave incompletely burned fuel particles in the cylinders, aka carbon buildup. Do this long enough and you can actually cause the engine to start knocking on 87, because the carbon deposits stay hot after the gas ignites, and can preignite the gas in the next cycle. So while 89 won't kill your engine, it can get your engine hooked, so to speak, on 89, to the point where you'd HAVE to use it to prevent pinging.

Scorps

I though above 87 was only for turbo/supercharged engines?

blizzak

hah I think we've had this discussion before on several threads. I won't go and search for them, but shakran is correct in what he says.

Pain Train, it's not necessarily whether the car is supercharged/turbocharged or not, but it's a matter of the compression ratio(which supercharging/turbocharging increases by a lot). The vast majority of cars will take 87, lots of cars non-supercharged definitely say they require 89 or 91 although I still remain a bit skeptical in a few cases. Does anyone have a suggestion for ranges of compression ratios and their respective fuels?

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BadNick

What cyrnel and shakran said about octane is correct I'm sure.


Maybe it's those Honda X cars: for my '04 Acura TSX (Euro Accord in some parts of the world) which is factory stock and not super or turbocharged (yet) the factory recommends premium gas and you can notice increased sluggishness and reduced gas milage (I did not do a cost/benefit on milage) if you use regular octane; like said above, this car's ECU will adjust for it to prevent knock/detonation but power suffers.

stingc

Almost no modern cars will knock under any (reasonable) circumstances. They automatically change the timing before you ever hear anything. You'll only notice decreased performance and fuel economy. Anyway, just stick to whatever the manual recommends.

Also, I'm not sure why several people here are stating that hardly any cars require more than 87 octane. All of the cars I've owned and all of the cars my parents have owned say that they need at least 91 octane. And these cars are/were all normally aspirated. But an Accord will probably be ok with regular.

shakran

Yeah, there's actually quite a few out there that require the higher stuff. But as you mentioned you won't HURT them by putting in 87 - you'll just reduce their performance significantly.

Basically, check your owner's manual - if it says unleaded, you're good to go with 87. If it says premium, get the expensive stuff.

cyrnel

Stingc, I'm guessing all your family vehicles are fairly recent and performance oriented? For comparison, among myself and siblings we have about 15 vehicles registered. Two are Diesels, none of the gassers recommend higher than 87 octane.

The last numbers I read were part of a government study a few years ago. It was dated for 2000 models and put cars requiring premium at ~5%. I assume the number has gone up since with the increasing number of higher performance vehicles, but at the same time knock sensors and engine computers are improving. "Requiring premium" is slowly morphing to "responds well to premium."

I just googled but couldn't find anything recent. Too many garbage hits.

I've never seen a breakdown of vehicles that do and do not tune themselves according to gasoline performance. That's a relatively recent development, say mid/late 90's, so I assume it remains a growing minority. Might be interesting to bring a few dealer techs into the discussion. Make sure we represent the Aveos with the Vettes. I honestly don't know how else to determine what's really rolling off the dealer lots without visiting a few. A dangerous project.

Anyway, we're falling into the usual generalization trap. "Most, many, usually, old, new," etc. In the end we're talking about a poster's specific vehicle, age, condition, etc, and where they're used, no? Makes it tough to give blanket recommendations but that's where we get into trouble.

As shakran said...

__________________
There are a vast number of people who are uninformed and heavily propagandized, but fundamentally decent. The propaganda that inundates them is effective when unchallenged, but much of it goes only skin deep. If they can be brought to raise questions and apply their decent instincts and basic intelligence, many people quickly escape the confines of the doctrinal system and are willing to do something to help others who are really suffering and oppressed." -Manufacturing Consent: Noam Chomsky and the Media, p. 195

stingc

For the most part, they're actually fairly old. But the modern equivalents also require premium AFAIK. Except for a Corvette, they're all BMWs, Mercs, and Jags. Performance was clearly considered more important than economy with these types of cars.

bodypainter

I can confirm that. Premium Unleaded stickers in all the expected places.

I've read reports from other NSX owners using regular gas. They say the car will detune itself and run okay but I won't be trying it.

edit - our SLK requires premium also.