Premium Fuel

[xantonin]

Originally Posted by hwoalang

it's none of your business if i am deciding to buy the brand new car because of primium gas or not.
do you own this fourm or something?
i clearly don't need your advice so. please dude.

Then why are you posting here? What point are you trying to make? Why don't you email Toyota or Subaru if you don't want anyone else's opinion?

this is public fourm and i am trying to be polite as possible.

once again where did i say i can't afford gas. it will be nice if we can pay less at the pump so that oil company doesn't get so rich.

FYI,

the most profitable company for this year was oil company(Exxon).

Yeah, I don't like it either. Especially since they make more of a profit off of Premium than they do Regular. But what other alternative would you rather see?

I hear a lot of complaints from you, but you're not offering a better suggestion.

talking about depreciation, dude you are funny. this is 3rd brand new sports car i am trying to purchase... talking about depreciation... tell me something i don't know my dude.

Okay, well how about the fact that an engine with a higher compression ratio requires higher octane?

[Longhorn248]

Looks like he's leaving, comments deleted.

[Longhorn248]

Comments deleted.

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[xantonin]

Sounds to me that his parents will buy him the car, but he has to buy the gas himself.

Makes sense now.

[tranzformer]

[Mr.Jay]

wtf happen here lol why does every topic on ft86club turn into flame wars

[Giccin]

Originally Posted by tranzformer

Originally Posted by Mr.Jay

wtf happen here lol why does every topic on ft86club turn into flame wars

Just the Scion part of the forum. :P

And its not flame wars. Its all nit-picking at little things that then turn into flame wars by disagreements and misunderstandings.

[WolfpackS2k]

Originally Posted by Allch Chcar

Uh dude? You're trying to over-simplify and misinform on a highly controversial subject in 100 words or less. It's not going to happen like that.

Besides, you completely misunderstood what he was talking about. He wasn't talking about Ethanol that's for sure.



It's not a universal statement. It really depends on the engine compression ratio, timing, and propensity to knock. Honda engines which are pretty knock resistant are tuned to handle up to 100 octane RON from what I understand. I believe the difference between Premium and regular is around 3% better efficiency. 3% more power is a big deal, never mind 3% more MPG at the same time.

I have heard that BMW did a study on the effect of using Premium vs Regular in engine design. I'm usually to interested in other subjects but I should look for that study someday.

My degree is in mechanical engineering. I've taken classes in automotive engineering and on the internal combustion engine as well as thermodynamics. I also browse several scientific blogs weekly and pay very close attention to engine technology. So while I might not have typed out a novel in my last reply I know what I'm talking about.

And who made a comment about premium fuel potentially improving fuel mileage? How did that even come into the conversation? Anyone that knows anything about fuel octanes knows that nothing about premium fuel will enable an engine (designed for regular 87 octane) to get better mileage. To think so would go against the basic chemistry and physics processes at work inside the engine.

[DRACHENV6]

^I used to be a chemical engineer also (enginerds rule heh heh). Im not sure what happened in this thread earlier but this comment is accurate. The differences in octane come from the chemical bonds between the carbons and hydrogens in the fuel. Higher Octane fuel has a higher number of branch points so it burns slower relative to lower octane which will combust quicker. It also has a higher energy content.

If we were considering energy content per dollar, I am sure the 93 octane would not be much different from 87. If someone searched hard enough they could probably find the calorie or kjoule content of 93 octane vs 87 octane per gallon and divide it by the current price of gasoline to make a value comparison.

Because of the differences in fuel burn times you cannot run low octane fuel in a car with slower timing because you will get knock from combustion not matching engine timings. Similarly we should not run 93 in a car designed for 87 because you'll get carbon buildup from incomplete combustion of slower burning fuel.

[tranzformer]

Originally Posted by DRACHENV6

Because of the differences in fuel burn times you cannot run low octane fuel in a car with slower timing because you will get knock from combustion not matching engine timings. Similarly we should not run 93 in a car designed for 87 because you'll get carbon buildup from incomplete combustion of slower burning fuel.

This right here is well said and straight to the point.