Say you wanted to achieve 91 octane by blending 87 and 93, how much of each would you want in an 18.5 gal tank? 6.1? 12.4?

 

You are a piece of work, aren't you, FF! I guess high school algebra was not your strong suit, but you are very close.

A 50/50 blend would give you 90 octane. To get to 91 octane you require 66.667% 93 octane and 33.333% 87 octane or a 2 to 1 ratio, got it? So it equates to 12.334 gallons of 93 and 6.116 gallons of 87. The trouble is you will never be able to put 18.5 gallons in your tank. I ran out once and filled the gas tank up until it was spilling out and I could only put in 17.75 gallons, IIRC.

I don't know what you are trying to achieve other than perhaps saving 50 cents.

 

^^ his aglebra was on, not as precise as yours(i dont think i could squeeze out 6.116 gal exactly if i wanted to), but frank i dont see what you would be saving remember time is money and your just talking more time, also you are assuming the two are going to equally disperse.

 

I started my diatribe before I did the calculation and decide to give my good buddy, Frank Fontaine, the raspberry just the same. I believe Frank is an 87 octane user, so he is probably pinching nickels and dimes in this scenario.

As an **** retentive accountant, my cheapness may well have been eclipsed and I didn't think it was possible, lol!

 

So could you just fill up with a tank of 93 for every two tanks of 87?

 

No!

 

No, but it would be roughly 2 parts 93 octane to 1 part 87. If you're pumping it yourself it's very doable, because using straight 93 is burning some of that super right out the tailpipe with no benefit. Nissan states it needs 91. But in NJ, it would be a pain in the a** since every place is full serve. Sure, maybe custom blending is better left to the drifter race teams but it's food for thought.

That RMurdoch obviously isn't a chef, because there is a recipe that we do where it calls for 2 parts water and 1 part olive oil. No, they don't mix but it must be the other ingredients that makes the recipe work. Next time he tells me to go buy a b*w I can't wait to respond! Nah, I'll just keep my comments on roadfly....

 

You guys know that the different octane ratings don't actually "blend" right?

 

I have no idea what you are talking about and could care less. Stick to your 87 octane gas.

What does this thread have to do with BMWs?.

I also changed my moniker and suggest you not refer to me by my old one as I changed it for a reason.

I thought you lived in Philadelphia, what's that got to do with New Jersey?

And by the way, I am an excellent cook!

 

The octanes are 'blended' coming out of the tanks anyways. Only 87 and 93 are delivered to gas stations. The rest of the combinations are derived by the pumps themselves.

 

thank you!

 

proof/source?

 

rofl why not just buy 91 octane..... thats midgrade here

 

 

Well I thought it was pretty common knowledge, but...

http://www.cartalk.com/content/colum...4/June/07.html

 

uuuuh... just a question on doing this... Why?

 

werd how would it be cheaper? i mean instead of doing all of that, your better off just buying the dam 91

 

I saw this on 20/20 10 years ago. Damn Mickey Rooney.

 

Here in Mass we only have 87, 89, and 93 (a few places have 91). US octane ratings are an average of 2 other octane ratings (hence the R + M / 2 you see), and so as other people have stated, the blending calculations aren't as straighforward as one might think.

 

just put 93 in if you cant find 91
(which unfortunately is the case for me) Be nice to your max and it will do the same for you.

for the umpteenth billionth time..............

 

Motorweek just did that thing last episode (the one with the Z06 Vette). They stated you can use regular even if your owners manual says premium (WOW, what blasphemy!). I'm not kidding, they said if your car doesn't seem to run as well, then use premium. So we have the web, Motorweek, Mercedes Benz all saying that regular can be used with no damage whatsoever to the vehicles.

here's another puzzler--does the 2k6 Toyota Avalon require premium? My buddy asked me this am since he wants to buy one. Nowhere in the Toyota literature or on the web does it say. But in tiny print, it claims the HP results were obtained with premium fuel. That to me says it was designed for premium, but doesn't require it. If it weren't designed for premium, it cannot obtain any benefit whatsoever from 93 over 87. My buddy who got the 2k5 330i performance package runs his car on regular. Yes, his power should be diminished, but he's doing no harm to the vehicle (that cheap b******!)

 

I just put 93 in mine. I'll pop for the extra $2 a tank. Anything is better than the $90 a tank I was spending on my truck (for 87).

 

Although isooctane and heptane do blend linearly, that is assuming all other factors are the same, which they are not. I can understand why they dummied down the answer severly, almost to the point of being misleading, because it is published in a wide variety of newspapers where space and ink do count, not to mention most people just wouldn't understand anyway.

Instead of trying to crack some retarded joke, they could have used that space and ink to atleast throw out words like research octane number, motor octane number, how federal regulations require a 3rd octane rating system to be posted on all commercial gas pumps (R + M / 2). Maybe talk about the differences and what they mean. The misleading part comes in because technically with the lack of detail they provide, they are wrong. Octane ratings are affected by level of saturates, aromatics, and olefins in the gasoline. Because of that you cannot simply say if I mix 10 gallons of 87 and 10 gallons of 93 I will have a 90 octane gasoline.

wait, what? a 3rd party publication knows better than the manufacture? Not only that, but one which has put in as much R&D as GM has with the Z06 Corvette?

Just because it can be used and not cause any damage the vechicle doesn't mean you should. Always use what the manufacture suggests. Yes, most cars that are suggested to run on premium can run on 87 octane, this is thanks to a wonderful instrument called a knock sensor. While yes, your engine is running and most likely running somewhat safely (generally because your ignition timing/maps are being retarded as a safegaurd), it is not operating at it's peak efficiency.

not always the case. The Avalon could very well be designed to run on 87 octane gasoline, however running premium may allow it to run a more agressive ignition curve resulting in slightly more power. It doesn't mean the car was designed for it, it's just something that happens. Advances in engine management allow for cars to adjust on the fly versus a locked in curve like the past.