Bad gas...

[1974dodgecharger]

I had my first taste of bad gas with blower.  Wow it was weird....knocking on anything over 2k rpm even when I dialed back the timing 15 degrees still knock.  I also satisfied my curiosity a car can knock when temps r low.  Did not get above 180 at all and knocked. 

Had to add 110 octane and knock was gone.  Won't be filling up at circle K gas again. 

Bad gas is not a myth as Google would say it is...us hot rodders especially the classics know what it is vs modern where computer knocks back timing without driver knowing to avoid knock.



Man though the knocking was scary.....

[68pplcharger]

Yeah I learned twenty seven years ago to sick with either Shell or Sonoco stations with motors on the edge of detonation. Anything else tends to be lower octane than the rating claims. Not always but I never had an issue with these two stations from California all the way across to Kentucky where I live now. I had an 11:1 motor with cast iron heads that was very picky. I made it work and drove across the country, lived for a while in Cali, then drove back and never had knocking issues.

[BSB67]

It is hard to believe that there is "bad" gas delivered by the refiners.  Fuel station tanks are all pretty good today too.  That said, not all gasoline is created equal, and octane ratings is only a small part of of the picture.  Then factor in the 20 or so different blends that are formulated based on regional environmental requirements, along with seasonal requirements, and you can reasonably conclude that gas will be different from station to station, region to region, and season to season.  You will need to see what works best for your car.

[68pplcharger]

I'm sure the gas from the refinery isn't to blame in a majority, if not all of cases, but I know that certain companies i.e. circle K etc. I've consistently had issue when using their gas even today. I've recently owned a 2004 GTO and had the engine light come on until the fuel was out of the car. This happened twice at the same Circle K and two months apart. I wanted to check to see if the same still held true. I know only two data points ,but still suggest the station generally is an issue and back up what I've witnessed for nearly thirty years. My wife's twin turbo BMW will have issue if she strays to this type of station. That's not to say that they don't have a crack in the tank or whatever. I know stations like these regardless tend to have more issues. In the 30 plus years I've been building and driving race/street cars and muscle cars I've never once had an issue at shell or Sonoco. When I worked at Paul's Automotive Engineering several years ago. Paul would only use Shell for the same reason. He has never encountered an issue with the 93 octane gas on the street Blower motors that were built and/or dynode at his shop. His shop has been around for thirty years now.

[1974dodgecharger]

They all get it from 1 or 2 refineries its what each gas station does after that we dont know.  Also I read gas picks up water and each grade has an acceptable water gain from sitting.   That day I got my gas their could of been too much water gained and they didnt care or didnt know.....

[68X426]

There is certainly bad gas.  In Northern California we have a chain named USA Gasoline.  I don't go there anymore, not that I was a frequent user, but I finally diagnosed the problem as their gas, no one else's.  A tankful from them would set off the sensors in my Mini and Challenger.  No other brand or independent's gas does it. 

[1974dodgecharger]

I'm sure the gas from the refinery isn't to blame in a majority, if not all of cases, but I know that certain companies i.e. circle K etc. I've consistently had issue when using their gas even today. I've recently owned a 2004 GTO and had the engine light come on until the fuel was out of the car. This happened twice at the same Circle K and two months apart. I wanted to check to see if the same still held true. I know only two data points ,but still suggest the station generally is an issue and back up what I've witnessed for nearly thirty years. My wife's twin turbo BMW will have issue if she strays to this type of station. That's not to say that they don't have a crack in the tank or whatever. I know stations like these regardless tend to have more issues. In the 30 plus years I've been building and driving race/street cars and muscle cars I've never once had an issue at shell or Sonoco. When I worked at Paul's Automotive Engineering several years ago. Paul would only use Shell for the same reason. He has never encountered an issue with the 93 octane gas on the street Blower motors that were built and/or dynode at his shop. His shop has been around for thirty years now.

I use she'll from now with my blower I read where she'll is more diligent on gas quality than others.

[Kern Dog]

Octane matters. My 2007 Ram 1500 is a 5.7L truck, just a basic package but octane matters even with new stuff. I run 89 octane mid grade and have since crossing 125,000 miles. When I have ran 87 octane, the fuel mileage is worse and the power drop is noticeable. The computer pulls timing, reducing engine efficiency. The new HEMIs run less timing than old style wedge engines, often having total timing around 22-24 degrees as compared to 32-36 degrees in our old engines. I have ran the 91 supreme and have not noticed an improvement over the 89 octane.
The OPs blower/supercharger artificially boosts compression so the octane requirements are certainly much higher than regular pump gas!

[rt green]

could be the gas from the refineries are good going into the service station tanks. what comes out?

[myk]

Only Chevron and Shell for me.  Had the CEL light go off in my '97 Z28.  Took it into the dealer and after a few minutes they asked me what gas I used; I had been desperate and bought gas from 7/11.  Dealer said to never use anything but big brand gasoline.  I told they were full of it, but I haven't used anything since then and haven't had any trouble either...

[69rtse4spd]

Where my wife works their fill ports in the parking lot were not high enough. Rains had, water puddles get big enough & water would leak into the tanks. She was told not to say anything if someone had trouble with their car, corvete guy did. Took it to the dealer, got fixed, after enough car fixes the company redid the fill ports, raised up with new concrete around them. What comes out of the ground is ify sometimes, next time you pull in & rainning, see where puddles form. .

[Stegs]

my local station has 90 octane ethanol free gas. I run it in my lawn mower, atv, power washer etc.....stuff i fill up with a 5 gallon can

I started using it in my charger....never looked back. Car runs fantastic on it! no knocking or pinging at all....idles very smooth

ethanol has a big play in todays gas, more than "octane ratings" imo.

older cars, by which i mean early 2000s or older just run better on pure gas....

anything newer than that seems to handle this ethanol stuff

But yes i never run anything but shell/mobil in my other vehicles

[c00nhunterjoe]

Octane matters. My 2007 Ram 1500 is a 5.7L truck, just a basic package but octane matters even with new stuff. I run 89 octane mid grade and have since crossing 125,000 miles. When I have ran 87 octane, the fuel mileage is worse and the power drop is noticeable. The computer pulls timing, reducing engine efficiency. The new HEMIs run less timing than old style wedge engines, often having total timing around 22-24 degrees as compared to 32-36 degrees in our old engines. I have ran the 91 supreme and have not noticed an improvement over the 89 octane.
The OPs blower/supercharger artificially boosts compression so the octane requirements are certainly much higher than regular pump gas!

Have you verified that timing? My 07 5.7 would regularly peak 40 degrees as will my 06 6.0 ls motor. Fwiw, my 6.0 idles in the 20s.