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87 vs 91 (or 92) Octane? - READ ONLY

74 messages,  Last post on Jun 19, 2012 at 4:11 PM

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What is this discussion about? Gasoline

Messages Page 7 of 8

#55 of 74 Re: 87 vs Higher Octane [steve_] by oldbearcat

Dec 16, 2011 (10:13 pm)

Replying to: steve_ (Dec 14, 2011 9:27 pm)
One of them is not too far from me - the one in St. Albans. If I'm over that way, I'll stop and tank the car up. Be interesting to see how MPG responds.
 
Regards:
Oldbearcat

#56 of 74 Re: 87 vs Higher Octane [oldbearcat] by andysd

Dec 17, 2011 (3:07 am)

Replying to: oldbearcat (Dec 16, 2011 10:07 pm)
Thanks, Oldbearcat - (Do you prefer that to Oldengineer?)
 
The following quotes from you beg the question whether they are directly comparable!
 
I filled her up with premium outside of Atlantic City, NJ, and got 34.5 MPG running her 70 - 73 MPH on cruise - headed for home in WV.
 
When I use 87 octane gas on my Pittsburgh runs, the CRV typically gets 24.5 MPG.
 
Regards,
AndySD

#57 of 74 Re: 87 vs Higher Octane [andysd] by oldbearcat

Dec 18, 2011 (1:31 am)

Replying to: andysd (Dec 17, 2011 3:07 am)
Oldengineer was my original handle - couldn't use it to log in here anymore because Verizon sold out to Frontier here, and, our email and internet changed over. Half the time I forget, have a senior moment, and use the old name. To answer your question - No, they're not comparable. When I was putting gas in the car that time in New Jersey, I noticed that there were no ethanol labels on the pumps. Curious, I went into the station and asked the attendant about it. He indicated that the premium gas didn't have any in it. Given this tank full delivered the best MPG the CRV has gotten to date, I think he was accurate. I've never found 93 w/o ethanol since to try to duplicate these results. All the 87 I find in my multi- state travels is laced with ethanol as well. My apples to apples comparison results in a typical 3 MPG differential between the two. That brings up one of my pet peeves with my CRV. I've made the same round trip to Pittsburgh in a 2006 Jaguar S-Type VDP with a 4.2 Liter V8 under the hood. The Jaguar easily got 30 - 31 MPG running this trip.
 
Regards:
Oldbearcat

#58 of 74 Re: 87 vs Higher Octane [oldbearcat] by andysd

Dec 18, 2011 (7:58 am)

Replying to: oldbearcat (Dec 18, 2011 1:31 am)
Oldengineer, that's great info.
 
First, the reason I asked about comparability is it's almost unbelievable that your mpg jumped so much just from a gasoline change, using higher octane than mfr-required (not like your engine required premium and you used regular). Whether or not ethanol is involved, do you believe your CR-V's mpg went up so much - was it 24.5 to 34.5? Just seems over the top.
 
Re a different car's mpg for the same trip, in this case, the Jag, I'm not surprised. I think gearing has a lot to do with it. In my '99 Camaro Z28 I've driven three times round trip to The Formula One race in Indianapolis, and gotten just over 30 mpg door-to-door with regular gas. I attribute that to the fact that in sixth gear the engine turns 1,500 rpm at 65 mph, just idling along. Not that I didn't exceed 65. And I went via the Colorado mountains.
 
Regards,
AndySD

#59 of 74 Re: 87 vs Higher Octane [andysd] by oldbearcat

Dec 18, 2011 (10:34 pm)

Replying to: andysd (Dec 18, 2011 7:58 am)
Andy:
 
I couldn't believe it either. The car's computer kept telling me I was getting this fantastic gas mileage on this trip. Then when I filled it up again in Flatwoods, WV, I checked it with a manual calculation, and, it agreed with the car's computer. A few months ago, my CRV was recalled, and, the dealer reflashed the computer. Today, Wife and I took a run up I 79 to Morgantown and back - about a 350 mile trip. The CRV, running 93 octane for the trip, got 25.1 MPG. That's basically a neglible difference over running 87, and, not worth the extra expense - other than the car feels a bit more athletic.
 
Re: The Jaguar - its more than just the gearing (6 speed). The Jag's VVT setup and induction system are more sophisticated than Honda's. Because of this the torque curve for their V8s and V6s is very flat - peak torque is available over a very wide RPM range starting at about 1500 RPM.
 
Regards:
Oldbearcat

#60 of 74 Re: 87 vs Higher Octane [oldbearcat] by andysd

Dec 19, 2011 (2:11 pm)

Replying to: oldbearcat (Dec 18, 2011 10:34 pm)
Happy Holidays and Merry Christmas to you, Oldbearcat and all who read these golden words:
 
Well, talk about dashing cold water! I know you give dependable data, so with your last CR-V trip you have singlehandedly sunk this big ship.
 
Regards,
AndySD

#61 of 74 Re: 87 vs Higher Octane [andysd] by steve_ HOST

Dec 19, 2011 (3:18 pm)

Replying to: andysd (Dec 19, 2011 2:11 pm)
All the more reason to keep a gas log. I'm sure I've transposed plenty of numbers in mine, but the log goes back for years and years so the errors get marginalized. If that one tank of Oldengineeringbearcat's was an anomaly for some reason (maybe a bit of a tailwind in both directions, lol), it'll get "fixed" over time.
 
(by the way, this is a paying gig Andy. So no tipping, even if it is the holiday season. )

#62 of 74 Re: 87 vs Higher Octane [steve_] by andysd

Dec 19, 2011 (9:18 pm)

Replying to: steve_ (Dec 19, 2011 3:18 pm)
Okay, Steve, if you insist. Let us know when you and your wife come to San Diego, and we'll try Hob Nob, or take you to Phil's BBQ and fix up your cholesterol.
 
I have got to get my act together and write C&D. Oldbearcat's last contribution negates the mpg improvement part of the fun, but horsepower increase was actually the starting premise. Also, I'm just about convinced that smoother engine performance is a side benefit.
 
In addition to trying higher octane, I plan something else with my Fit. Since I thrash it at the red line in the mountains, I figured out a way to effectively gain about 5 horsepower - and improve cornering: am going to remove the rear seats, which I've read weigh over 100 pounds. That will improve the power to weight ratio by about 2,550 / 2,450 = 1.04, as if the horsepower were increased by 1.04 x 117 = 121.8.

#63 of 74 Re: 87 vs Higher Octane [andysd] by steve_ HOST

Dec 19, 2011 (9:25 pm)

Replying to: andysd (Dec 19, 2011 9:18 pm)
Now you're talking. Forget if the Fit has a spare. Even if it's a compact one, stash it in the closest and replace it with a can of Fix-a-Flat.
 
That said, I lost 30 pounds in the last year and my mpg nor performance haven't improved (hasn't helped my car's mpg or hp either ).

#64 of 74 Re: 87 vs Higher Octane [steve_] by andysd

Dec 19, 2011 (10:03 pm)

Replying to: steve_ (Dec 19, 2011 9:25 pm)
But you're on the right track, Steve. Lose another 70-plus pounds and then see!

Messages Page 7 of 8

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