I usually put 87 octane gas in my car but it was running really badly. Sometimes i would hit the gas and actually slow down before i sped up but even then i barely accelerated. I've recently started using 92 octane gas and my car has become an animal. It never hesitates anymore. Now, i floor it and it moves like a beast. Here's my question though. I used to get better gas mileage on the 87 octane. What's the difference? Is it just the amount of oxygen in the gas? Can using a higher or lower octane have any permanent positive/negative effects?

 

Well I don't know of any long term effects (if any) of running a higher octane fuel.. except race gas.. But basically what the higher octane does is slow down the combustion .. thus yeilding a little more power.. on my car I never really noticed a difference.. but I run midgrade on mine.. which it seems to prefer over the regualr and the premium..

 

Storms: "I used to get better gas mileage on the 87 octane."

That's probably because you weren't "trying to feel a power difference" when you used the 87 octane. Those numbers on the pumps to strange things to people's minds. Depending on your compression ratio you might not have any use for the higher octane ratings at all. Any change in gas mileage shouldn't get worse with the higher ocatane either, in my opinion/experience. If your engine needs higher octane than what you're running, you'll definetly know it- i.e. knocking.

 

man, you guys are in the darkages for octane.....

About the lowest I can get over here is 95! I think what we can get is 95 as standard, 98 as super, and 100 as the premium!

Sounds like your engine is setup to expect 92 or more. You'd probably need to retune the engine for anything above or below what it was setup to run on.

Si.

 

si it's not the same thing. your 95 is like our 87, differant scale to rate the octane.

 

Yikes!

Even having worked in an oil refinery I never realised there was so much to it. Also scarily enough, me brother just sent me an email (completely unprompted by this thread) with this www page all about octane etc.

http://www.faqs.org/faqs/autos/gasoline-faq/part3/

A lot of reading but interesting enough.

Si.

 

There are two different methods used to determine the octane rating of a fuel. There's "R," which stands for "research." The research octane number (RON) is determined in a lab with a test engine running at 600 rpm, which represents a low-compression, low-knock situation. Then there's "M," for "motor." The motor octane number (MON) uses a test engine, also in a lab, at a higher rpm. That's supposed to represent higher-speed, higher-temperature operation, where knock is more likely.

The way we get the number on the pump is by averaging "R" and "M." Or, put another way, "(R+M)/2." So, if the RON of a fuel is 93 and the MON is 87, the octane rating you see on the pump is 90.

atleast, thats how it is in the states...
gas is also alot cheaper here... :lala:



Storms Of War :
most likely whats happening is your engine would see a knock with the lower octane gas, and pull timing.... hence the lil bog.



you should be able to run 87 in your car without a problem



(i'll space that out so everyone can see it)
the reason you're having a problem right now, is your engine is more likely to detonate then it should..... id suspect carbon deposits inside....

 

I thought you didn't have a car.
https://www.thirdgen.org/techbb2/sho...hreadid=220549

 

I have a car. I have a white 1986 Monte Carlo. It's got a 4.3 liter v6. I just saw that ad and nearly crapped my pants when i saw a third gen selling for $500. I've been saving my freakin *** off so i can hopefully get a Trans Am. It's not that i don't like my car, just that i think it's time for me to move up to something better. Now i'm just debating on what type of car to buy after this. The other thing is that i'll only buy GM after having this car. Everyone said to get a foreign car because they're reliable but my car has never given me a problem. I must say that GM kicks ***.