Octane vs. Performance

[Lockout888]

So if the manual says to use 87 or higher octane gas, are there any performance benefits to using 89 or 91 on a stock Yukon?

 

[andrew383]

There are 2 timing tables that the computer goes off of (high/low)..The stock settings for the high table are not really much more than the low table..
You might tell a slight difference but if its bone stock id just use 87..

 

[MOBmentality]

There are about to be a bunch of answers to this.. and a million schools of thought on why one is correct...

But without going into all that.. im gonna say this..

If i get 300 miles on a tank on regular.. with an 18 gallon tank... which is 16.6mpg

and premium is 30 cent more per gallon.. it will cost me.. $5.40 more per fillup on a zero to full fillup...

So if gas is $3.00 a gallon for regular..

then i would have to gain enough performance to get me 30 extra miles per tank to break even on the cost of gas.. which is a 1.6 mpg increase.

So there are going to be people saying premium will get you 0 miles per gallon increase and those who will say 3 or 4 ... but reality is.. in this scenario.. you will NEED 1.6 miles per gallon extra... to break even and run premium for free.


So lets just PRETEND like getting the extra 1.6 mpg is a FACT (for the sake of argument) so then if it is.. then its really Free at 30 cents extra per gallon.


But if its free.. and BP isnt lying.. and premium has less gunk in it and has additives the will decrease the chances of engine buildup and lousy plug fire.. then you will actually be MAKING money off of running it since you WONT be replacing parts that the gas companies claim you will have to replace sooner on regular gas.

Also.. crappy plug fire and crap around valves ect is power robbing.. therefor decreasing miles per gallon... So.. again.. in theory.. the amount of money you save by running premium would INCREASE over time on an engine thats not regularly maintained.


PLUS you can feel premium a lil in the pedal... so the lil bit more pep is a bonus in itself.



All this is just hubbub according to some folks.. and if you google it there will be a billion hits telling you premium isnt worth it.... but IN MY PERSONAL OPINION.. for an extra $5 a tank... and knowing if i ONLY GET a mile and a half extra per gallon.. then its free anyway.. its worth it to follow the hype.. and run my shit on only the best!


BTW gas stations have their own blends of shit they add to gas.. their own secret recipe of octanes , methanols and additives.. so BP might get you more MPG then EXXON and Sunoco medium might get you more MPG than Chevrons Premium... so the best way to REALLY test it.. would be to map it out and figure out mpg of a specific brand.....

IM talking more about mpg because free performance with no fuel increase is easiest to measure in real world applications in mpg.. if the car has more performance on the same amount of gas then MPG will increase.. know what i mean?

In the end.. i run premium!

 

[chip]

All you need to do is match your octane to your compression ration. Nothing more. Just move the decimal point.

Example: If your truck has an 8.9:1 compression ratio, move the decimal (8.9 = 89.0 octane). Likewise, if it has 10:1 compression, then you should ideally be using 100 octane. This rule of thumb will always tell you the optimal fuel for your vehilcle. This formula works for any vehicle, any compression ratio, any gas.

 

[ThwopKing]

Unless your behicle requires premium fuel...using it you are just throwing away money. If your vehicle isnt tuned for it it can burn quicker causing lower mpg's. And since its more expensive it totally useless and a waste of money.

 

[chip]

FYI: The higher the octane, the slower the burn (that's the whole point of Octane Ratings).

 

[ThwopKing]

Burn to slow and you dont get an efficient enough burn...hence wasting gas. if your vehicle isnt tuned for it..ie correct spark trim...you are wasting gas.

 

[chip]

Too low = Detonation

Too High = wasted money/gas

 

[dwmmatt23]

I run 91 in my 2001 z71 because I can definately feel and hear the difference compared to 87, it doesnt run nearly as smooth and i get detonation. Thats my reasoning and to each his own. Plus when i get my efans im gettin BB tune for 91 octane so that will be my reasoning then

 

[blueflamed03]

Burn to slow and you dont get an efficient enough burn...hence wasting gas. if your vehicle isnt tuned for it..ie correct spark trim...you are wasting gas.

yep.

If its stock, go off book.