fuel mileage

[blackhandbeagles]

I suppose this is the correct place to post this.

When running a stock engine, what octane fuel get's the best mileage?

[Pu241]

89 works best for me and my driving style, I can reliably get 3+ MPG better out of 89 vs 87
But test it yourself run 5-10 tanks of 87 then switch to 89 and see what you get.
It's alway a good idea to keep a fuel log, so this is a good time to start.
I use a 3x5" spiral bound booket for the log, about $1.50.
Cheap to keep track of fuel, oil changes, and repairs.

[georgeb]

If it doesn't ping on 87, use it. Reg is also the most widely used, therefore the freshist.

[geezerstiva]

Pu241, did you advance timing or something when you switched to 89? I've never gotten better mileage running anything other than 87...

[Movin]

87 4000 ft and above
blend of premium to go
down to 1500 ft.
premium to go to coast.
I run a little extra for timing.

[Pu241]

Pu241, did you advance timing or something when you switched to 89? I've never gotten better mileage running anything other than 87...

Years ago I adjusted timing for maximum MPG on 87, then switched to 89 and adjusted it again to get as much out of it as possible.
Seat of the pants, none quantifiable, its seems to runs smoother and start faster on on the 89.
Running anything higher, octane wise, didn't show an improvement.
But a lot depends on your driving habits, so a longer average (5-10 tanks), helps define a significant change.

[bhazard]

It's alway a good idea to keep a fuel log, so this is a good time to start.
I use a 3x5" spiral bound booket for the log, about $1.50.
Cheap to keep track of fuel, oil changes, and repairs.

How about fuelly.com's mobile site?

[Pu241]

How about fuelly.com's mobile site?

I use that too, but it isn't always convenient to log in at the pump, especially on a phone!

[nitrofarm]

87 4000 ft and above
blend of premium to go
down to 1500 ft.
premium to go to coast.
I run a little extra for timing.

Movin- I dont understand...... Are you saying too use 87 octane in between 1500 & 4000 ft elevation? I'm @ 700 ft above sea level most of the time. (Lol I still remember checking those Altimeters for preflight inspection.)
I use 87 octane & I'm running 12 deg initial advance.This sound @ right to you? The motor seems to be making good power?

[Movin]

A lot of stations out here have dropped the three grades. When I go down
I fill at half tank and alternate 92 and 87 to make my own 89..it works
pretty good.

I am at 14 so you should be pretty good at your elevation.
The best mileage is right before detonation and engine damage.
The best throttle feel is about there too.
It can be a dangerous game for your engine of how close to
the fire can you get without getting burned!!

I am still a student pilot but yes we are very aware of fuel mix
and elevation! I keep wanting to pull back on my festiva
steering wheel....