2,046 Miles of Gasoline Research

[hallzee]

A few weeks ago, there were some threads about regular vs. premium gas, and the merits of each. Both 'R' and 'K' engines were discussed, and as usual, there were varying opinions.

I have always used premium, because that's what is called for in an LT, and didn't feel saving .80 cents on a tank was worth switching. However, I was intrigued by some reports of increased gas mileage on regular. If mileage is indeed increased by regular gas, it would stand to reason that there has been an increase in performance.

My wife and I took a trip from the Lake Tahoe area to Whidbey Island in WA. I decided to take this opportunity to test the theory of "better mileage on regular". I was a little apprehensive about using regular, so I remained extra observant to detect any signs of decreased performance on regular, such as acceleration lag, ping, etc.

I ended up going slightly over half of the trip on regular, because at sea level, I heard some serious ping at low end of the power curve with hard accelerating. It took half the trip to notice this because I was finally in a situation where I had to pour on the coals more aggresively than usual. I switched back to premium on the next tank; the "regular gas" experiment was over for me.

This actually worked out well to provide some additional data (and also prove that I have way to much free time).

Regular Gas (Chevron): 1,118.7 miles, on 25.21 gallons = 44.37 MPG
Premium Gas (Chevron): 927.3 miles, on 20.02 gallons = 46.31 MPG

BTW, BMW Computer had slightly different numbers.

[surfran]

I too tried the regular gas experiment this last week on my trip to Americade. I didn't track as rigorous as you, but did notice that the mileage was about the same, but what really switched me back was the low end hesitation especially in 2nd gear. It first thought maybe my rear drive was going as it felt like it was dragging bad, then all of the sudden it would take off and act normal. I ran 3 tanks through of regular then switched back.

Once back to 93 octane the problem went away. No more 87 for me either.

Next experiment is to put my old stock shield back on and see if I get the mileage back that I believe I lost with the V-Stream.

[skaboots]

5 tanks premium, 40.3mpg
3rd tank 85-87 octane, 39.1mpg so far

Conditions; Brown wire cut, to and from work and local, 5000-5500ft altitude, driving habits same, speeds fast-slow daily 30-100mph, about 50mi/day. Temperature variance; typically 40 degrees morning to afternoon in the high desert.

The premium is looking better and better, we'll see in 2 more tanks.

[pkpr1998]

Great info, but you guys have way too much time on your hands!

[skaboots]

what else you gonna do while riding ??

[c00k1e]

Once back to 93 octane the problem went away. No more 87 for me either.


No wonder fuel is so cheap in the US! 87 and 93 octane!!
I use 95 in the UK and was tempted by the new 100 in Europe, but was going to check with other members before trying it.

[jeffklt]

Great info, but you guys have way too much time on your hands!
Some of us just enjoy watching the numbers. For the first 47,611 miles I used 1,071 gallons of premium for 44.45 mile pers gallon. For the last 69,800 miles I used 1,516 gallons for 46.03 miles per gallon. I have never used regular. I have had six different windshields, mostly solo, mostly at sea level, sometimes with Ft Worth rack and sometimes with Corbin Smuggler. I have never heard it ping with mid grade.

YMM(will)V

[hallzee]

Some of us just enjoy watching the numbers. For the first 47,611 miles I used 1,071 gallons of premium for 44.45 mile pers gallon. For the last 69,800 miles I used 1,516 gallons for 46.03 miles per gallon. I have never used regular. I have had six different windshields, mostly solo, mostly at sea level, sometimes with Ft Worth rack and sometimes with Corbin Smuggler. I have never heard it ping with mid grade.

YMM(will)V
Jeff, you forgot to include average tire PSI information.... he he :D

[jeffklt]

Jeff, you forgot to include average tire PSI information.... he he :D

The file is too big :histerica

[pkpr1998]

Some of us just enjoy watching the numbers. For the first 47,611 miles I used 1,071 gallons of premium for 44.45 mile pers gallon. For the last 69,800 miles I used 1,516 gallons for 46.03 miles per gallon. I have never used regular. I have had six different windshields, mostly solo, mostly at sea level, sometimes with Ft Worth rack and sometimes with Corbin Smuggler. I have never heard it ping with mid grade.

YMM(will)V

For someone who stores their Unigo in the room at Chateau Elan...........


It was really a good idea!

[BallsCasten]

One point I was taught is that there are more BTU’s (energy) in the lower octane rated fuel.
Higher-octane fuels do not burn hotter or have more energy. They are merely formulated to work under more sever environments of higher compressions, higher temps and quicker timing.

[strsout]

No wonder fuel is so cheap in the US! 87 and 93 octane!!
I use 95 in the UK and was tempted by the new 100 in Europe, but was going to check with other members before trying it.


I'm too lazy today to find it for sure, but I'm sure someone will point if I'm wrong :)
The European octanes measurement is different from American measurement (what are not?? ) :)

[robasay]

Between May and June from AZ to FL to MA to Canada and back to AZ 7928 miles. I tried the lower octane fuels on the first part of the trip and notice lower MPG. In the east the octane used was at least 93, which is not available in AZ, only 91 octane. The difference between lower (87) and higher (93 or 91) was about 3-4 miles per gallon. Between 93 octane and 91 octane 1-2 miles per gallon different. I usually drove 5-7 miles an hour over the speed limit. My milage computed manually average was over 49 miles per gallon for the whole trip. My lowest tank to tank mileage was 39 mpg with lower octane and the best was 54.7 mpg!

I'll burn high octane as it has been said before $0.50 to $1.00 per tank is worth the performance and mileage.

[skaboots]

ive burned my last voluntary tank of low octane...mileage, performance; both down on 85/87 octane... :p