Home Forums Gear Hunting Trucks and Four-Wheel Drives 89 octane

Ok, so there is a station near where I live that sells mid grade (89 Octane) at the same price a reg(87)
All my vehicles don't require high(91) and call for 87.

06 F350 with 5.4 litre
02 honda civic with 1.7 litre
04 honda odessy with a 3.5(I think?)(wife's BTW! )

Is there any benefit to buying the 89 Octane for these vehicles/ Better mileage? Or, are they meant for 87 octane and thats what I should buy?

I run 89 in my Tacoma as it does run better.

But if the price is the same I'd be filling up with the 89 since it's 5-10 cents more per gallon else where just to get my sh!7s and giggles from depriving the oil co.s from their profit.

You probably won't notice a difference but fill up and tell me!

The 89 octane usually has ethanol in it (10%). Here it's also 5-10 cents cheaper than the 87.

Thats what I've seen, if it is 89 and the same price, its ethanol. Saw on another post some students did a study, cars running on E85 got something like 30% less fuel economy. I didn't verify that, just read it on another post.

E85 is a whole different animal than the 10% ethanol 89 octane.

If it's 89 octane with no ethanol added there is a benefit as the computer will control the timing to match the fuel. e.g. better fuel, more timing, more timing, better economy & more power. up to a point of course.

All the local Valero station sale 89 Octane for the price of 87 on Mondays. I feel up then, but can't telll a difference in gas mileage. We don't have ethanol around here, so that wouldn't matter. Now when they had 92 Octane for the price of 89, I filled up with it and did notice a little better gas mileage.

Thanks guys. This station does not sell gasoline with ethanol so it looks like I might as well get the 89?

I had read a couple of studies on fuel economy that E10, the 89 octane stuff would give approx. 2% less mpg than pure gas. However, around here, the ethanol blend is 5-7 cents cheaper making it the best choice. If they were the same price, I would go with the 87 octane gas. Just my 2 cents

Ethenol is just a bunch of political BS to get the farmers vote. Vehicles get horsesh** mileage with it and the engines are haveing trouble with it(especially in E-85). I buy the 89 stuff here just because its here. I'd like to buy more home grown stuff but lets face it, it has to work first.

Colorado has ran 10% ethanol "winter blend" for 20+ years now, fuel milage drops off in my Chevy pickups about .5 to 1 mpg during the winter.

I kept very close track of a brand new 91 Chevy for about 20,000 miles. Here at 6000+ ft in altitude, one loses a fair amount of hp with altitude--especially when climbing on the highway at 9-10,000 ft.

I alternated 87 vs 89 on a number of occasions running the same route. Mid grade got better fuel milage--usually 1 mpg, sometimes a it appeared a tad better. The truck went up the hill easier to, and I didn't have to down shift with my manual as soon.

But back then the difference in price in reg vs mid was only 4-5 cents, and after a lot of calculating I figured midgrade was a tiny bit cheaper to run.

Now that there is 10 cents diff between reg and mid, that's no longer true. When I go over the hill in my gas pickups, I still put midgrade in, otherwise I run regular.


Casey

i can't afford new vehicles so all mine are 90's or older and if you drive longer distances you can notice sometimes 3 or 4 more miles to gallon so i aways buy mid grade my s 10 piece of junk 2.2 gets 5 miles more a gallon over cheap grade but no more in high test which i buy when in areas feul is cheaper like the south that is my experience

I have seen several articles that seem to confirm that you might get 1-2% less fuel economy with the 10% ethanol blend, but I agree that when it is 7-10 cents cheaper it is still the better buy. I do go with the pure 87 octane gas if the prices are the same.

Don't know about the ethanol thing but 87, 89, etc., octane gas all have the same power on tap/available so you do not gain power from higher octane gas. The only thing it does is allow higher compression without pinging. Wether some on board computers monitor octane rating and adjust timing to hit differing peaks in the compression stroke I don't know.....but have my doubts.

To give you guys an idea.................You can make more power with a drag race car runs on alcohol than with gas. IIRC, alcohol has higher octane. However, it takes a lot more fuel to get the extra power when you run alcohol. You had run MUCH bigger jets in the carb to make alcohol work.