The great "octane" experiment

I've generally run 89 or better for 6 yrs now. I notice the pinging on hills and low rpms (where best mpg is). .10 diff, worth the extra buck or two, imo.

In summer 08' I ran 87 for first two months (gas was $4.50). Then the usual 89-90 for the next two months. My hilly rural commute is 25 mi r/t with low traffic and only one stop light.

20.2 mpg regular vs 20.5 mpg on higher grade.

Of course there are some variables, but my 'testing' area & driving is pretty consistent. temps were similar being summer, and never use A/C. Now we got 10% ethanol like everyone else. For 4 years never got below 20 all summer... 19.5 is the norm now, tough to even touch 20 anymore.

 

i have also been testing this. I've filled with 89+ siince day one and always get 19-20mgp, last couple fill-ups i tried 87 and was getting 17-18. I'm now testing 93 (plus i added a tonneau this week. I've been keeping track with gas caddy on the iphone

 

I forgot to ask, where you putting Avgas in a Tacoma? It's been a few years since I've dealt with avgas but I thought avgas is leaded. Not as much as the great stuff we had in the 70's but still considered a low-lead fuel (LL), not unleaded. Wouldn't that trash the catalytic converter after a while?

 

Quick update - I've run a few more tanks through, and have been running the a/c for about 70% of the miles.

I'm up to 20.0 overall average mpg since I started tracking, and every tank of the 87 has been above 20.0 mpg independently.

No knock/ping has been identified.

Next tank may be a bit low, as I spent the weekend hooning around while working at the New England Forest Rally ( www.newenglandforestrally.com ). A drop in this tank's efficiency is sure to be observed

 

Ive been using Regular 87 here in houston since i got my truck in February 2008. Ive put about 41,000 Miles on there and havent had any problems lol.

BUT I Do use the lucas fuel cleaner every other fill up. i dont know if that really helps, but i did notice when i use that in combination with the new "nitrogen enriched" gasoline shell has for all grades of fuel, my full tank has lasted a tad bit longer.

 

Most of these 'experiments' listed don't appear to control for variables very well, so I doubt the results will have much value. But what I really get a kick out of are posts that are along the line of '... I did x and my rig ran 'better' than it did on y.'

No operational definition of what 'better' means. If we're honest, many will admit their vehicle seems to run better after a wash and wax. We know that's ridiculous so we discount the subjective 'feeling.' We are even more prone to thinking the truck runs better after an oil change, but I seriously doubt one could tell any real difference just by driving.

 

Phase 2 of this experiment is what the hell happened to the OP? Did he die? I want my 1 month update!

 

My old '88 ran night and day different with a fresh oil change. When the oil was toast, you could here the valve train, but right after an oil change you could put your foot into it and it accelerated smoothly.

I get your point, but just saying... I also agree my bikes run smoother after a bath.

RZ Rob

 

And I agree that you should be able to tell a difference if your oil is 'toast;' that is, if you go long periods between changes, particularly thru a cold winter. What I did not know until I read Bobistheoilguy is that even fresh, unopened oil stored in an unheated garage and subject to temperature fluctuations can permanently thicken due to the cold.

 

I agree. If you want better fuel economy put non-agressive tires on, and use Amsoil 0w-30 engine oil and Amsoil severe gear

$28 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 in the trans. and front and rear diffs. And drive easy. I'm getting 30mpg on the highway at 50 mph.