Getting 91 Octane

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Old 02-27-2012 | 09:35 PM
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Getting 91 Octane

As you all know, the TL requires 91 octane. The grades in my area are 89 and 93. Is there any reason I can't fill my tank with 1/2 of each to get to the 91? Thanks for the help!
Old 02-27-2012 | 09:41 PM
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I would probably just use the 93 octane and call it good.
Old 02-27-2012 | 09:42 PM
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it calls for 91 and up.

so, if there's no 91........then use the next highest grade available.
Old 02-27-2012 | 10:59 PM
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Yup - just use the 93. Don't cheap out on gas - you'll get worse gas mileage on regular and end up paying more. Get the premium
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Old 02-28-2012 | 12:21 AM
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The answer is yes you get 91, but why go through the trouble? I always ran my tl on 93 because its the standard high test here.
Old 02-28-2012 | 04:44 AM
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Originally Posted by Alvin1958
As you all know, the TL requires 91 octane. The grades in my area are 89 and 93. Is there any reason I can't fill my tank with 1/2 of each to get to the 91? Thanks for the help!
you can do that, but you should fill a little bit more of 93 then 89. if you do half/half, I think you end up with 90 octane.
Old 02-28-2012 | 07:25 AM
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^why waste your time and effort?

fill up with 93!


Over in the 3rd Gen TL section, we have found that the TL knocks with 93 octane.
A member has observed knock with a knock sensor.
with the compression being HIGH(as high as justin space) 11:1, you'll need the HIGHEST octane available.
through the test, we have found that the TL stops knocking with a mixture of 100 octane with 93 to make 96 octane.


Butt, its just plain silly to mix and match....
Just use the highest available grade.

END THREAD!
Old 02-28-2012 | 07:28 AM
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Probably really not worth the hassle.
Old 02-28-2012 | 07:59 AM
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i think you should do the 1/2 and 1/2 method....i wouldnt, but you should....
Old 02-28-2012 | 08:09 AM
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We have 91 octane here at the Citgo stations (87, 88, 89, 91, 93). However, I only use Shell / Mobil / Chevron and always use 93.

It does seem like quite a pain to mix the two...especially with the minimal amount of savings.
Old 02-28-2012 | 10:53 AM
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I mix & it’s a pain in the butt. Where I get gas they have one pump with 100 & 4 normal pumps with 87, 89, 93. I usually get $50 of 100 then back fill the rest with 93. This will vary my octane from 94.5 up but my computer will adjust to the actual octane level.

I need to shuffle between two pumps the 100 being a pay inside 100 only & the normal 87, 89, 93 pumps are debit card activated. That being said, it’s a maybe once every 10 days thing but it I was doing in once a week or more I would be an unhappy camper.
Old 02-28-2012 | 11:11 AM
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The octane rating refers to the degree of compression that the gasoline/air mixture can be compressed in the piston chamber before it ignites. The higher the octane, the greater the compression, the greater the force upon the piston head over a longer distance.

Mixing two grades of gasoline is a bad idea because they ignite at differing compressions in the chamber. The 89 octane will ignite first (and begin to retard the piston head) before the 93 octane does.

Stick to a single grade, preferably the 93 octane.
Old 02-28-2012 | 12:05 PM
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Most gas stations with 87 - 93 make 89 by mixing it in the pump.
Old 02-28-2012 | 01:18 PM
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My dad used to mix the two grades together in the tank for his Alfa. What a pain in the ass.
I'm sure he got a couple of tankfulls that were simply 89 from my cheap-ass-deadbeat sister.
just buy the super.
Old 02-28-2012 | 01:45 PM
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Originally Posted by xrays
Mixing two grades of gasoline is a bad idea because they ignite at differing compressions in the chamber. The 89 octane will ignite first (and begin to retard the piston head) before the 93 octane does.
FYI : at most (all?) gas stations, the mid-grade is made by mixing the low and high grade... when you pump the mid-grade, you get a little of both.
Old 02-28-2012 | 03:16 PM
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The TL requires PREMIUM fuel and it states 91 or up because in some areas 91 is all thats available. If premium fuel in your area is 93 octane without a doubt use that fuel and do not go mix-matching different grades of fuel. Be happy that 93 is whats available in your area thats good!

James
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Old 02-28-2012 | 04:12 PM
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I used to do that with my old car the last time gas prices went insane. It was a pain, and while the car did not knock or seem to perform worse, it did seem to get slightly worse mileage than on straight 93 premium. You save about .15 per gallon by mixing.
Old 02-28-2012 | 04:36 PM
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Yeah bro, why are you being cheap on your nice car.

Serious man, just get the 93...
Old 02-28-2012 | 04:47 PM
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Thanks all, the verdict is in: Stick to 93!
Old 02-28-2012 | 05:06 PM
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Just 93 it and be done. Don't nickel and dime on something like this.
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Old 02-29-2012 | 09:02 AM
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If 91 is available, get the 91. If all that is available is 93, get straight 93. You WILL notice a difference in performance and mileage that will not be to your advantage. Saving a couple bucks up front isn't worth it to me.
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