TheSauceBoss

So naturally I'm getting crappy gas mileage.

I was just wondering if its possible to "balance it out" (I'm at half a tank of 93) by adding a half tank of 89 octane.....resulting in an average of 91?

Or is this the worst idea of all time?

Thanks either way,

justnspace

iTrader: (1)

What!?!?!?!
93 octane is great for the car!!!!!!!!!!!!
P.s. in some states only 93 is offered.

TheSauceBoss

Are you serious? Lol I thought that 91 was manufacturers spec....and the engine's compression ratio is optimized for 91. I definitely get better gas mileage with 91...I guess I never really thought about it past that

MyGuti

acura recommends anything 91 and above...

nfnsquared

I've run 87 octane for over 167K miles, no issues

truonghthe

put water in the tank, its will balance thing out automatically.

peter6

Yes, it's well known DIY method for water injection.

BROlando

Higher octane fuels just resist knock/pre detonation better. 91...93, close enough.

Some states/areas have 91 as the highest available standard pump gas octane. Other places get 93.

I'm sure the car runs fine on anything 87 to 100ish+ octane.

GreenSpades

Wow. Just wow. I mean ignorance is bliss my friend and I am jealous honestly of the blissful life you must lead. You will be fine. Dont even sweat it, these cars will take any gas from what ive seen.

WheelMcCoy

That's how gas stations make 89 octane... that is, by mixing various grades to get an average. You should be fine without doing anything, but it won't hurt if you want to mix it yourself. Your engine knows how to use the higher octane.

Engines rated for 87, however, don't know how to use higher octane and it would be a waste of money putting in a higher octane (unless your engine is knocking).

TheSauceBoss

It's crazy to me how l paid no attention to gas octane until today....I wouldn't go so far as to say blissful - I did a trans drain/refill yesterday evening, as well as a trans fluid filter replacement (that housing was a bitch...not to mention pouring tranny fluid all over the bottom of my bay- 3 hours of my life I wish i had back.....but then today I turn around and realize I don't know how gas affects the engine.

strange indeed lol

Slpr04UA6

LoFl!




I've only used 93 octane, as that is Supreme gas here in Florida. (Recommended)

horseshoez

iTrader: (2)

If you're getting crappy gas mileage it has nothing to do with the 93 AKI (do not confuse the U.S. AKI rating with "octane) fuel you put in your car. FWIW, the fuel where I live is 87 AKI, 89 AKI, and 93 AKI; I only use 93 and today after a few days of driving my nephew around to see some sights here in New Hamster, I filled up; my average speed was 50 mph (probably 70% highway, 30% urban), I drove 428.4 miles on 14.263 gallons which works out to just over 30 mpg. Not exactly what I would call crappy gas mileage.

grandlaker

Only ever used 87 in both my TL's, the '01 now has 293K miles and never one ping. Be interesting to calculate the amount of money I've saved:-)

horseshoez

iTrader: (2)

Probably none.

nfnsquared

about $5K, assuming the difference in price between 87 and 91 is $0.45/gal and 25 mpg avg....

horseshoez

iTrader: (2)

A forty-five cent delta between regular and premium? Yikes, don't know where y'all live but around here the delta between 87 and 93 is only twenty cents.

That plus a likely reduction in fuel economy and I highly doubt running regular will result in any savings at all.

thoiboi

WheelMcCoy

My experience as well. When I use a lower octane, I get slightly lower fuel economy. And V-TEC works better with the recommended fuel. But sadly, in the Northeast, the delta between regular and premium can be between 35 cents and 50 cents.

WheelMcCoy

LOL. I know, I know. Yet another fuel thread.

horseshoez

iTrader: (2)

Interesting, I'm in New Hampshire and typically see twenty to twenty-five cents as the delta.

Agreed on the "yet another octane thread". I'm thinking it might make sense to lock this one as the OP has already had his answer covered several times.

nfnsquared

I've run 87 octane for over 167K miles and it hasn't affected MPG at all. And any thought that VTEC works better is just that, a thought. I recorded multiple WOT runs to near redline on Torque Pro and didn't register any timing pull whatsoever on 87 vs 91 octane.

And yeah, the delta is $0.45 - $0.55 up here.

horseshoez

iTrader: (2)

Granted I've never put a J32 on a dyno, but when I was with Mercedes we put lots of the (then new) 3.2 liter V6 motors for the (then newish) W210 E-Class on dynos and ran them with different fuels; there was always a noticeable reduction in power in the mid to top RPM ranges and a reduction on BSFC (which has a direct correlation to fuel economy) across the board when lower octane fuel was used.

nfnsquared

I've never put a J32 on a dyno either, but if timing isn't being pulled throughout the entire power band, then no power is being lost. And for 167K+ miles on 87 octane, I still get 30 MPG on the highway.

horseshoez

iTrader: (2)

So what you're saying is you don't really know, you're just guessing.

nfnsquared

If timing isn't being pulled and MPGs are the same, how would any power be lost?

horseshoez

iTrader: (2)

You have absolutely zero way of knowing whether timing is pulled or not; when an engine is running at WOT, there is a very conservative fuel map being run which is very-very rich. Long story short, it doesn't surprise me you saw no difference at WOT.

nfnsquared

Oh, but I do. OBDII data doesn't lie...

So you're admitting that there's no difference in timing whether running 87 or 91 at WOT? Got it, thanks for confirming my results

And like I said, if timing isn't being pulled, then there's no loss in power. And it's backed up by no change in MPG for 167K miles...

RenoTL

I think we are missing the point of the OP's post. He says, "Accidentally put in 93 octane... So naturally I'm getting crappy gas mileage." Running the car on a higher octane gas shouldn't result in "crappy gas mileage". Something else must be going on here.

eastcoastguy

This thread cant be serious, worried about putting in 93 octane. It seems the cheaper gas gets around here the bigger the divide between 87 and 91. 93 is outrageous at the stations that have it, I settle for 91 and I get pinging at that.

thoiboi

Clickbait OP.. same as his "catastrophic cup holder failure"

eastcoastguy

He should get a job as a marketing guy! lol

horseshoez

iTrader: (2)

Negative, when at WOT, all other maps are overridden and the upstream O2 sensor are ignored and a full rich fuel mixture coupled with a very retarded spark timing are the default. Get into partial throttle in the mid ranges and you'll see a very different story. Like I said, you really have no idea what low octane fuel is doing to your engine.

ggesq

iTrader: (1)

You will not convince him horseshoe. This debate has been going on for the last 12 years. Never mind the fact that he lives in N. Dakota where I imagine he doesn't have high temps beyond 80 degrees and does mostly highway driving.

Ive used 87 twice since new and 231k miles later on my 05 and both times driving in this FloriDUH heat I experienced decreased MPG and loss of performance.

musiclevelz5

I wish I could get 93 for 20 cents over 87. Most stations here especially Shell and BP are 70-90 cents higher.

horseshoez

iTrader: (2)

Hmmm, not sure where you got North Dakota from; per my profile I live in New Hampshire. Granted this summer has been wonderfully temperate in that we've only had maybe a dozen or so days over 90°F, that said I've also lived on SoCal, Texas, Georgia, and Virginia, so I know well the effects heat can bring.

TheSauceBoss

Hey, I just wanted people to respond haha...

Either way, thanks to everyone else from getting me up to speed. I ended up just burning the entire tank and it evened out to 25mpg average (on the trip computer, at least) while the previous weekend I hit a 30mpg average on my way to Chicago w/91....though most of my recent driving was highway as well.

Sorry for causing another argument lol

WheelMcCoy

@ggesq was referring to @nfnsquared's location. You can't change @nfnsquared's mind because he is known troll on this board. Don't know his altitude, but high altitude also is a great equalizer of regular and premium -- that is, the advantages of premium start to fade as you go higher.

GreenSpades

Hey, it worked

As for price difference it is pretty standard now in PA that it is X for 87, X+20 for 89, and X+50 for 92-93. Or even more sometimes, especially at top tier stations.

I remember when I was first driving and gas was 1.99 for regular for longest time and it was always 10c more for mid and another 20c more for premium and just about everybody had pricing within a few cents. Nowadays they change pricing all of the freakin time and the pricing is always different lol even within franchises a few miles apart.

04WDPSeDaN

iTrader: (1)

Couldn't agree more.