Accidentally put Premium for First Fill-up...

[Ryude]

If the car is tuned for 87 and you put 93, you might see a small difference in drivability at low RPM (where knock is most prevalent). So for example, the car may be smoother on take off since it doesn't have to make as many adjustments. I wouldn't expect extra power though.

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[NorthernEX-T]

"...

The Vibe? Just a base model. Switching to 89 from 87 (91's our highest)... It ran fine for years, but the pinging started about a year or so back. My wife insists she can't hear anything and that nothing's wrong. Maybe it'll go away with new plugs. The original Iridiums are getting closer to the end of their lives since they have 100k miles...

Its definitely your plugs.. I had a 04 GT get before I got my new civic. 11.5:1 compression. Got 370kms out of it before I blew the syncros in the 6 speed. Still ran like a top. And it loved a daily diet of rev limiter bashing. It actually called for 92 octane. But where I live the best is 91, which it ran fine on. There's no reason why your regular vibe shouldn't run fine on 87.

This thread, and any gas thread on here pisses me off. I really would like to put a civic on a dyno when the 6 speed comes out with regular gas and premium to shut up all of you high octane believers. Have fun throwing 5-8$ away every time you fill up with the placebo effect superdooper premium gas.

I'll keep running Shell 87 in the time being because that is what Honda calls for,, nooooo wait, 87 or higher so let's throw all our money away and run 91, 93, 94, blah blah, blah,

 

[lamichlein]

I think you all missed the fact that the original question came from a person who needed a simple answer for everyday driver and most of us don't have a clue what all the gibberish is you high performance ' I built it' and tore it down myself, graphs included people are saying!

The manual says what to use. The engineers said what to use. I will do that because that's what the warrantee is based on. Simple. Answer to the original question...you didn't wreck anything putting high octane in once by accident and the suggested fuel is mid grade no more than 15% ethanol. Just put that in from now on.

 

[Troy Jollimore]

What the engineers tell you is a minimum required specification. They're not saying you can't do better, just that you shouldn't do worse.

Personally, opinions are opinions. Google a Fifth Gear test on YouTube where they take a car, and run different grades of gas through it under controlled conditions. My word, they DO see a power increase with higher octane fuel, and, as expected, it's not really enough to notice in daily driving. Again, today's cars adapt. A 'tune' pushes the limits and reduces/eliminates the safety barriers.

So, running a different grade of gas in a car recommended for a certain grade is fine within certain limits. YMMV, of course. Running a lower grade in a car 'tuned' for a certain grade is better. Running higher is fine, and usually advantageous. The only car ever to buck this trend was the '98-'02 Honda Accord V6, and I don't think anyone ever figured out why...

 

[mechatune]

That's the predicament I'm in. I put 91 octane just to see if I can feel a difference in my 2.0 all motor.

And I do. Acceleration is smoother and "faster" across the board. The problem is, it's about a $6.80cad difference per tank, and about $340cad extra a year.

Currently debating if I want to spend that.

 

[xjoshuax89]

What the engineers tell you is a minimum required specification. They're not saying you can't do better, just that you shouldn't do worse.

Personally, opinions are opinions. Google a Fifth Gear test on YouTube where they take a car, and run different grades of gas through it under controlled conditions. My word, they DO see a power increase with higher octane fuel, and, as expected, it's not really enough to notice in daily driving. Again, today's cars adapt. A 'tune' pushes the limits and reduces/eliminates the safety barriers.

So, running a different grade of gas in a car recommended for a certain grade is fine within certain limits. YMMV, of course. Running a lower grade in a car 'tuned' for a certain grade is better. Running higher is fine, and usually advantageous. The only car ever to buck this trend was the '98-'02 Honda Accord V6, and I don't think anyone ever figured out why...

To quote another person

"High performance engines operate at higher compression ratios, than your standard economy engines. Performance engines compresses the Fuel / Air ratio many times higher than your standard engine. As a result, it requires fuel that will not detonate early under extreme pressure. Fuel sellers accomplish this by adding a chemical that delays how quickly the fuel will burn. 97 Octane fuel starts out as 87 Octane. The fuel distributor adds chemicals to retard the ignition, thus making it 97 octane. You might say that high octane fuel burns slower than 87. In fact, if you regularly put 97 Octane in an engine designed for 87, the slow burning high octane fuel will create carbon build-up inside the engine. Soooo, higher octane does not increase your horsepower. It's specially designed for high compression engines that benefit from it's slower burning characteristics."

 

[Troy Jollimore]

*Sigh* You're so close, Josh... Yes, it burns 'slower', preventing detonation in high-compression engines, which is nearly EVERY engine these days... It burns milliseconds slower, but it still BURNS. Thoroughly, if everything is working correctly. So no, no extra carbon buildup because of that fact. Why on Earth would they sell something you're saying is 'worse' for a premium?

The 'chemical' is a blend of xylene and toluene, which are just different products of oil and petroleum refining. Alone, they don't increase your horsepower. The engine's computer does that when it advances timing as far as it can, and holds it there since it doesn't detect any detonation...

 

[SpartanSi]

It won't 'hurt'. The higher the octane count, the more controlled the 'explosion' of the fuel is, so lower octane gas is potentially more 'dangerous'. That's with E85 and such aside... I'm pretty sure Shell 93 has NO ethanol content.

Troy....well said. Higher octane won't hurt the engine. In fact, the higher octane gases are usually better for your engine as they contain additives that clean your fuel injectors and burn better or more controlled during combustion. Turbo engines typically prefer high octane gases. Although Honda tuned this engine to run on regular, the added benefits of these additives and lubricants should not be lost in the octane discussion. Ethanol....containing fuels like E85 and some Regular fuel blends should be avoided if you plan to drive this car into the ground. Ethanol wreaks havoc on fuel systems, rubber seals/gaskets and attracts moisture. All of these things will shorten the life of any engine. If it were me, I would go for premium fuel simply due to these additives that are not present in regular gas.

 

[Troy Jollimore]

I think pretty much all fuel systems have been changed to cope with 10-15% Ethanol blends without it being too harmful.

 

[VTECYO]

Thank you guys for the help! Y'all are very knowledgeable people!

 

[themzlab]

.....Again, today's cars adapt....

true, they can adapt to some things. However, I've not heard of an engine management system that can sense the octane level or pre-detonation sensitivity of the fuel coming through the system and feed this information into the ECU.

I know there are knock sensors in some engines - at least historically and so the computer could back off the timing when it notices this problem. In order for the Civic to take advantage of high octane..... seems like the ECU would have to experimentally advance the timing until engine knock occurred and then back off from there. That would be extremely crude and possibly harmful. Maybe??? very much wild guess... I wonder if the ECU is sensitive enough to detect the timing of the explosion and notice if it is happening before the spark?

I think it is more likely that the controls expect 87 octane gasoline and do nothing to compensate for higher octane. I use 87 octane but if I see 100% pure gasoline without ethanol I will use the 100% gasoline rather than the 90/10 ethanol blend.

 

[Troy Jollimore]

true, they can adapt to some things. However, I've not heard of an engine management system that can sense the octane level or pre-detonation sensitivity of the fuel coming through the system and feed this information into the ECU.

I know there are knock sensors in some engines - at least historically and so the computer could back off the timing when it notices this problem. In order for the Civic to take advantage of high octane..... seems like the ECU would have to experimentally advance the timing until engine knock occurred and then back off from there. That would be extremely crude and possibly harmful. Maybe??? very much wild guess... I wonder if the ECU is sensitive enough to detect the timing of the explosion and notice if it is happening before the spark?

I think it is more likely that the controls expect 87 octane gasoline and do nothing to compensate for higher octane. I use 87 octane but if I see 100% pure gasoline without ethanol I will use the 100% gasoline rather than the 90/10 ethanol blend.

Yeah, this argument IS moot, because our cars do run fine on 87 and low ethanol blends. And you're precisely correct. The ECU does advance timing in steps until detonation is detected, and then dials things back. Detonation itself isn't harmful, unless it is VERY violent, or persists for extended periods. 'Tuning' the engine entails how far the advance or retard of the timing can go, and at what threshold of knock it takes place at. Run things too much on the edge...Boom.

 

[chessman122]

I was out of gas, happened to be at an advanced auto parts and bought a bottle of 108 octane fuel to get me to a gas station. Felt Peppy, but probably my imagination. I went to fill up with 87 and wasted a few dollars on a few bottles of octane booster as a joke. Still feels peppy on the throttle, but again probably my imagination.

 

[finalnight]

Not gonna lie, based on the topic title's tone, this is what I thought the end result of OP's story was going to be:

 

[sonicBOOMgray]

Thanks for the reasurrance guys! This is my first Honda ever; I've always been a Toyota/Scion guy before then. I'm pretty much babying the car ever since I got it ha

I've had mine on Eco Green Leaf mode since I drove it off my exit on the freeway after purchase! I'm at about 830 miles in so onlt 170 more for 1000 and I'm in the clear. I coddle this whiner cause it gives so much in return.

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