Gas type and emissions testing?

[mark pruett]

Anyone have any idea if using a higher grade of octane gas will have any effect on emissions testing?

Also, does using reformulated gas in a modern fuel-injected engine do better or worse than regular gas?

I'm curious, because I could drive out into the country and fill up if it made any difference vs. the reformulated gunk they sell around here.

 

[uconn1150]

The reformulated stuff will help emissions, but it's not nearly as potent as "regular" gasoline...

 

[DEWFPO]

I've seen data to indicate that new cars, with all the electronics and emissions controls are helped the LEAST by reformulated gasoline. The reformulated gasoline helps older cars with less sophisticated emmisions controls the most.

DEWFPO

 

[eljefino]

Use the grade of gas rated for your car for the emissions test. It'll be "hot" at the right time in the combustion process. But, do use something fresh from a high-volume station. RFG probably will still do you some good; 90+% of cars on the road are closed loop FI systems and the EPA still forces this cheezy gas on smoggy areas. I myself would schedule it so I'd always be on "E" when I happen to be in the country (& ready to fill up) just because of the MPG improvement from that regular unleaded.

 

[mark pruett]

So in a nutshell, running higher octane won't help me any. Also, reformulated gas while less efficient than regular gas, still helps a little in a modern engine, but helps even more in an older carbureted/non-computerized engine.

Is this right?

 

[DEWFPO]

Yes.

DEWFPO