demarco5

First I would like to say I completely understand putting 91 over a lower octane fuel will save me money throughout the tank, due to engine efficiency with the fuel.

Now I always put in 91, or 93 if choosing between 89 and 93. I am almost positive the price is about 10cents more for every octane rating you go up.

Example 87=4.00, 89=4.10, 91=4.20, 93=4.30
Give or take a few cents.

Now I went to go fill up and noticed right before choosing 91 (the highest octane at this specific station) that the price difference was significant.

89=3.95, 91=4.20 Now this is 25 cents per gallon difference. Running the normal math for the situation I initially gave it makes more sense to use the recommended octane. I have been averaging 26-27 mpg in 6spd base. I thought I would try 89 and save 14gal x $0.25 = $3.50.

So far I have 60 miles on my tank and my average is 26 already. I understand down to the thermodynamic level what is happening with the fuel (engineer lol) but I am wondering will it HURT my car in any way. I do not drive hard at all, maybe 1 or 2 5-6k accelerations per tank but other than that 2.5-3k shifts just commuting.

Any opinions? I thought I would try it and find out only because 25 cents is such a huge difference. Noco gas by the way.

ggesq

iTrader: (1)

just keep running 89 and save the $3.50. you'll be fine.

that should have been in red text

justnspace

iTrader: (1)

^red text.

erdoc48

Very simple- use 91 octane or above as the TL has a high compression motor and a lower octane fuel used will result in pre-ignition/detonation and over time harm the engine. It's tempting to use the 89 octane fuel because it's cheaper, but not smart. Even if the fuel is more expensive, it's worth using that which will preserve engine life in the long run. If the TL was designed to run on 87, that's what I would use- since it's designed for 91, use it.

Mafyoso

iTrader: (1)

Just Run 91 instead of 93. 91 is always a lil cheaper than 93

AirForceFX

If you fill up twice a month, your saving $7. Are you really that strapped for cash?

RaviNJCLs

iTrader: (4)

I fill up twice a week and will not put in anything less than 93 in my car. We don't really have a lot of 91 Octane available in PA.

My take is that a lot of people have claimed to get about 8-10% better mileage out of 93 vs. 87. Aside from being bad for the engine, If you do the math it is just not worth saving on individual fillups if you have to do it more often.

Jcaron9gt4

What I want to know is how you have a 6spd and only hit 5-6k once a gas tank. Maybe this is why I'm getting 19/20 mpg

ez12a

+1 on 91. No need to put 93 in, since 91 is all what us californians get at a typical gas station.

MandoTL

I usually put in 91 at chevron, costco or shell, but there have been a few times i have put 89. No noticeable difference in gas mileage, but yes it may cause harm to the engine in the future.

Their was only 1 time I put 89 from Arco only because I was a bit low on cash, empty tank, was the closest gas station to my place, and avoid using my debt card. Arco is horrible my car burned through the gas very quickly in less than a week
Compared to my 3 common gas stations with 91 would last me a week and a half.

swoosh

iTrader: (5)

WHAT HE SAID...

now read again what he said....then search the forums on the same issue and then read all the threads about what everyone else said

ggesq

iTrader: (1)

We are done here. Read swoosh's post above.