[SirHoward]

http://www.cbc.ca/marketplace/episod...mpfiction.html

[The Low Key OG]

You can't just put 93+ in a car that takes 87 and expect a gain in hp. You have to have an accompanying tune.

[VTECaddict]

Public misconception about octane ratings has been going on for years. People think higher octane makes your car perform better, or its cleaner, or higher quality, or cleans your engine better....which is all wrong.

But of course, oil companies and gas stations won't correct you or inform you of what octane ratings mean because they want you to pay more for premium whether you need it or not.

Basically, just use whatever rating your manufacturer recommends. That's what they engineered the engine to run on so that's what you should use to make it run optimally.

Using higher than recommended does nothing for most cars because the computer won't take advantage of it. Using lower than recommended can cause problems with performance, mileage, pinging, pre-detonation, etc.

[ragingpanda]

My car requires E85 and 93 for it to run peppy.

[Dark_Knight_335]

Right about now ill take any kind of gas I can get, so long as it's enough to get me back home...

[E90_boostjunky]

Originally Posted by Dark_Knight_335

Right about now ill take any kind of gas I can get, so long as it's enough to get me back home...

for a second i was like are you serious, but then i remembered the east coast.. GL buddy hope ur doin well.

[335BBS]

Originally Posted by OSHEIT

http://www.cbc.ca/marketplace/episod...mpfiction.html

I saw that show too. I loved the Yoga lady that ran 91+ because someone told her it burned cleaner yet the opposite was true after testing. We should just post that episode every time this octane thread comes up .

[328i M-Sport]

Higher octane is more resistant to detonation. It can make more power by not reducing timing to avoid knocking.

If the car does not have a high compression engine or advanced timing, it will not benefit from it. Higher octane gas in theory actually burns slower. And most brand name gas stations put the same cleaners into the fuel for any octane.

[335BBS]

Originally Posted by 328i M-Sport

Higher octane is more resistant to detonation. It can make more power by not reducing timing to avoid knocking.

If the car does not have a high compression engine or advanced timing, it will not benefit from it. Higher octane gas in theory actually burns slower. And most brand name gas stations put the same cleaners into the fuel for any octane.

IF engine was designed to do so. This TV show proved that a car designed to run on 87 got worse gas mileage and polluted more on 91 as it was unable to process the fuel correctly.

[328i M-Sport]

Originally Posted by 335BBS

IF engine was designed to do so. This TV show proved that a car designed to run on 87 got worse gas mileage and polluted more on 91 as it was unable to process the fuel correctly.

The problem with their test was that the car looked pretty new. Of course, a new Chevy Cruize will run the best on regular as designed.

As cars get old, especially if they were driven by grandmas and never taken above 2500 rpms, carbon deposits will get inside combustion chambers. Smaller (effective) combustion chambers will act the same way as the engine with a higher compression. And a car that always ran well on regular can start pinging. Direct injected engines create carbon deposits a lot quicker than regular SFI cars.

There are services like MotorVac that can help with the problem but a higher octane gas will work as well.

[335BBS]

Originally Posted by 328i M-Sport

The problem with their test was that the car looked pretty new. Of course, a new Chevy Cruize will run the best on regular as designed.

As cars get old, especially if they were driven by grandmas and never taken above 2500 rpms, carbon deposits will get inside combustion chambers. Smaller (effective) combustion chambers will act the same way as the engine with a higher compression. And a car that always ran well on regular can start pinging. Direct injected engines create carbon deposits a lot quicker than regular SFI cars.

There are services like MotorVac that can help with the problem but a higher octane gas will work as well.

Back in about 1982 my New Monte Carlo used to ping on occasion so I would fill up with "premium" and the pinging would stop. Like the Cruze, All modern day engines have systems to prevent an engine from ping

[328i M-Sport]

Originally Posted by 335BBS

Back in about 1982 my New Monte Carlo used to ping on occasion so I would fill up with "premium" and the pinging would stop. Like the Cruze, All modern day engines have systems to prevent an engine from ping

Yes, the way they do it is by reading the knock sensor and reducing timing. For safety reasons, the "recovery time" for the timing to get back to normal is set to take a while. While it is happening, it will feel like a small misfire if there are enough carbon deposits.

So you would feel the difference in a newer car with carbon deposits after filling it with premium.

[335BBS]

Originally Posted by 328i M-Sport

Yes, the way they do it is by reading the knock sensor and reducing timing. For safety reasons, the "recovery time" for the timing to get back to normal is set to take a while. While it is happening, it will feel like a small misfire if there are enough carbon deposits.

So you would feel the difference in a newer car with carbon deposits after filling it with premium.

If youre feeling "misfire" is it not time for service? Bad part of that show was the interview with the Lawyer representing the fuel companies. He had no clue.

[Sam335ix]

Give me 103 octane or give me death...

[335BBS]

Originally Posted by Sam335ix

Give me 103 octane or give me death...

2014 M3 will probably be sweet!

[Dark_Knight_335]

Originally Posted by E90_boostjunky

for a second i was like are you serious, but then i remembered the east coast.. GL buddy hope ur doin well.

Thanks brother- still waiting on power...getting cold here. Thank god my bro in law and sis just across town have power. Luckily I got some Sunoco high test after 2 hours wait.

[Braumin]

I guess this was somewhat interesting but of course it really falls on the consumer's shoulders. It wouldn't take much research for the to see that they don't need premium.

As someone who has always known what the Octane rating is actually for, I find it funny when people tell me they use premium and they get better gas mileage. What's even more funny is when you try and explain that, actually, no you don't, so stop wasting your money, and then they get argumentative.

I like Marketplace, but shows like this are always a bit over the top. I mean they are asking people who work at a GAS STATION for a living what to put in their car. Those people have no idea, and they spout the same falsehoods that most people believe. They get NO training from the oil companies about what the different grades are. I mean, with the turnover of staff at a place like that it would be almost impossible to actually educate even the staff.

Even their so called "expert" who was running the dyno thought the premium would be better.

I may switch to regular in my 335 for the winter. I can't drive it hard enough to get it to knock anyway with the icy roads.

[cgy-jim]

Originally Posted by 328i M-Sport

Higher octane is more resistant to detonation. It can make more power by not reducing timing to avoid knocking.

If the car does not have a high compression engine or advanced timing, it will not benefit from it. Higher octane gas in theory actually burns slower. And most brand name gas stations put the same cleaners into the fuel for any octane.

Burns slower? Say what?

It will burn inside the burn parameters in a tighter range but not slower. Just more controlled.

[John 070]

Random octane testing is here, so dishonest stations will get theirs someday...

[328i M-Sport]

Originally Posted by cgy-jim

Burns slower? Say what?

It will burn inside the burn parameters in a tighter range but not slower. Just more controlled.

I tried not to go into details and ended up phrasing things wrong.

Octane has to do with detonation resistance. Flame rate has to do with the gasoline itself. But if you are using fuel that makes more power with advanced timing and all the other variables are the same, it means the fuel burns slower which is USUALLY the case with high octane fuels.

[BMW_Belgier]

Just a small note aside:

Higher temperatures will result in lower octane rates... So cars in need of 91, need 93 to work properly in high summer!

I don't know the ratio octane/temp...

[galahad05]

Originally Posted by John 070

Random octane testing is here, so dishonest stations will get theirs someday...

What? I thought the State inspected stations regularly already...