Can you mix 89 and 93

[bigcanoe]

To get the required octane, can you use half a tank of 89 and half a tank of 93 to get 91 octane? Does it mix like that? Ya, I am being real cheeeeeep

[SMG]

It's fine until you hit over 8lbs of boost and then the fuel catches fire.

[zeusenergy]

Originally Posted by bigcanoe

To get the required octane, can you use half a tank of 89 and half a tank of 93 to get 91 octane? Does it mix like that? Ya, I am being real cheeeeeep

just buy 93. I've grown to live with it.
You COULD do that though- but why on earth

[vdubbugman53]

Originally Posted by SMG

It's fine until you hit over 8lbs of boost and then the fuel catches fire.

hahahaha

[boogety boogety]

To answer your question, yes. You can mix the two grades with no ill effects, your car will run fine.

Now, unless you're doing it with graduated beakers, you have no chance in hell of getting precisely 91 octane out of mixing approximate quantities of 89 and 93 in your tank, using a very imprecise vehicle gas gauge as your measure. At best, it would be an approximation. Why bother... just go to 93 and happy motoring to you, sir...

[wawalker]

Originally Posted by bigcanoe

To get the required octane, can you use half a tank of 89 and half a tank of 93 to get 91 octane? Does it mix like that? Ya, I am being real cheeeeeep

You can do it--I do it frequently. I filled with premium, then when the gauge reads 1/2 I top off with mid-grade, next time it's at 1/2 I top off with premium.

Now that they have started to widen the prices between grades with the price of gas going up it is starting to make more sense--about $1/tank.

If you are someone who has to go out of your way to a gas station then just wait until you're close to empty and buy premium--at these prices it takes less than 9 miles to burn through the savings. I go right by one a 1/4 mile from my house.

Lately, I have been keeping it below 1/4 tank since I am trying to get rid of it.

[SMG]

Well that whole dollar you save is probably burned up by the ECU re-adjusting itself to the always changing quality of fuel you're putting in it.

I actually got better mileage in my 2.0L with a cam and 91 octane than I did stock running 87, so my fuel bill didn't change.

[wawalker]

Originally Posted by SMG

Well that whole dollar you save is probably burned up by the ECU re-adjusting itself to the always changing quality of fuel you're putting in it.

I actually got better mileage in my 2.0L with a cam and 91 octane than I did stock running 87, so my fuel bill didn't change.

I have been checking my mileage consistently since I bought the car and I haven't noticed any change between running what effectively is a 91 octane mix or straight 93. Afterall, 91 is all that is required.

[bigcanoe]

Originally Posted by wawalker

I have been checking my mileage consistently since I bought the car and I haven't noticed any change between running what effectively is a 91 octane mix or straight 93. Afterall, 91 is all that is required.

Are there any brands/stations that actually sell 91?

[jazzcat]

Originally Posted by bigcanoe

Are there any brands/stations that actually sell 91?

yes

every station that is in my area has 91

[wawalker]

Originally Posted by bigcanoe

Are there any brands/stations that actually sell 91?

Yes, "out west" 91 is premium.

Around here premium is generally 93, some places sell 92 and Sunoco used to sell a 94, but I'm not sure if they still offer that.

As far as mixing: gas stations mix premium and regular at the pump to craete the midgrade--I see no problem making another mix.

[XCman]

I feel your pain. and while I don't think gas mixes like that. I do know that adding octane booster to my car gets me te same mpg with regular fuel (89) that I would get with Premium (91).

Being in the midwest 93 is not available around here.

[wawalker]

Originally Posted by XCman

...I don't think gas mixes like that...

It does. Stations do mix reg and premium to get the midgrade and in some old literature I have from Gene Berg Enterprises (premiere OB tuner) there are instructions and formulas to calculate mixing race gas with pump gas and refiguring the octane rating of the mix. It works. I used to mix race gas with pump gas to get the 98 octane mix I needed in my motocross bikes. On my built OB motor I purposely set the compression at a level where I could run 93 octane pump gas per Berg's recommendations.