Does gas quality matter?
- Thread starter berth
- Start date
ilikefood
Well-known member
On my (bike) commute, with gas from the same gas station, my gas mileage (over 180 miles) has ranged from 40 to 45 mpg. Air temperature and riding style plays a larger role in gas mileage than quality of gas.
Though quality issues exist, I don't think they have much to do with mileage. More like weird crap in the gas that clogs carburetors and fuel injectors.
Charles R
Well-known member
Ah, the good old three barrel CVCC carb! That was a tricky one to keep right. Basically a "lean burn" engine. Two barrels ran so lean the mix couldn't be lit off with the spark alone, so the third carb barrel was just to run a rich enough mixture right in front of the spark plug to light the rest of the mix off.
I have no doubt you needed good fuel to keep that one happy!
Last edited:
Chemical Engineer here...
All gas stations within the vicinity of a refinery get their gas from that refinery.
At the baseline, it's all the same. Only difference as someone mentioned is the additives added at the pump.
You can fill up with whatever you want, but may want to fill with Chevron every 4th fill to get the techron cleaning additive.
My two cents.
All gas stations within the vicinity of a refinery get their gas from that refinery.
At the baseline, it's all the same. Only difference as someone mentioned is the additives added at the pump.
You can fill up with whatever you want, but may want to fill with Chevron every 4th fill to get the techron cleaning additive.
My two cents.
Correct; my point was that the gas itself is all the same. Level of contaminants due to maintenance will definitely vary. :thumbup
TheRobSJ
Großer Mechaniker
Ten years ago, that list meant something. Now? Seeing some of the brands that got certified (ARCO, Costco, Valero, Beacon, etc) tells me that TopTier has become nothing more than a shakedown organization that all the companies just have to "play ball" with now.
I see tons of examples of what shit gas does to engines. Arco, Costco, and the other usual suspects are always the cause of premature engine work.
dravnx
Well-known member
The "pump" is at the refinery, not the gas station. The additives are added at the refinery.
The big problem with gasoline and ethanol is phase separation. Ethanol absorbs moisture from the air and over time reaches saturation. The water then separates from the ethanol and goes to the bottom of your tank. It layers out to good gasoline, a mixture of gas and ethanol with a high concentration of ethanol and water at the bottom. If you're using gasoline that suffers from phase separation, it will have preignition because the octane is now very low because the the ethanol is now separated out.
HappyHighwayman
Warning: Do Not Engage
I use 91 because the manual says so but otherwise would put in the cheapest that it called for.I've not had a single issue in my life that I can relate back to fueling.
CDONA
Home of Vortex tuning
Enjoying a beer in Thompson's Corner, got to talking with fuel haulers working from what used to be Exxon in Benicia.
Gas is different in octane ratings, this is a standard.
Different blends of additives are the big difference, and are blended with the gas as tanker is filled.
MBTE and now ethanol are blended as the tanker is filled.
Errors happen as the tanker is filled and blended as to % of anything added.
Gas price is listed on the bill of lading to each stop on the drivers route, same load/blend will change in price at each stop.
Gas is different in octane ratings, this is a standard.
Different blends of additives are the big difference, and are blended with the gas as tanker is filled.
MBTE and now ethanol are blended as the tanker is filled.
Errors happen as the tanker is filled and blended as to % of anything added.
Gas price is listed on the bill of lading to each stop on the drivers route, same load/blend will change in price at each stop.
Maddevill
KNGKAW
Old information but when I was working on bikes we got a bunch whose carbs were all screwed up. The rubber parts were disintegrating. All used Shell gas. My mom's car would ping on Shell. On another note, my wife used to be a transportation manager for a fleet of vans. Arco gas consistantly gave the worst mileage.
GAJ
Well-known member
"Edmunds.com put this question to experts in several fields, including an automotive engineer at a major carmaker, gasoline manufacturers and two engineers with the American Automobile Association (AAA). It boils down to this: You can stop worrying about cheap gas. You're unlikely to hurt your car by using it.
Because of the advances in engine technology, a car's onboard computer is able to adjust for the inevitable variations in fuel, so most drivers won't notice a drop off in performance between different brands of fuel, from the most additive-rich gas sold by the major brands to the bare-bones stuff at your corner quickie mart.
Still, spending a few extra pennies per gallon might provide peace of mind to someone who just purchased a new car and wants to keep it as long as possible. People with older cars might not be as concerned about their engine's longevity. They can buy the less expensive gas and still be OK.
Steve Mazor, chief automotive engineer with the Automobile Club of Southern California, summed it up this way: "Buy the cheapest gas that is closest to you.""
http://www.edmunds.com/car-care/is-cheap-gas-bad-for-your-car.html
Because of the advances in engine technology, a car's onboard computer is able to adjust for the inevitable variations in fuel, so most drivers won't notice a drop off in performance between different brands of fuel, from the most additive-rich gas sold by the major brands to the bare-bones stuff at your corner quickie mart.
Still, spending a few extra pennies per gallon might provide peace of mind to someone who just purchased a new car and wants to keep it as long as possible. People with older cars might not be as concerned about their engine's longevity. They can buy the less expensive gas and still be OK.
Steve Mazor, chief automotive engineer with the Automobile Club of Southern California, summed it up this way: "Buy the cheapest gas that is closest to you.""
http://www.edmunds.com/car-care/is-cheap-gas-bad-for-your-car.html
EastBayDave
- Kawasaki Fanatic -
Chevron for me, 76 or what's available in an emergency.
If you only get say 2.5 gallons, & the previous pump user got low octane, there's still couple gallons in the hoses/piping back to the pump. Your going to get what was left + what you actually ordered.
If I'm at a busy station, I may just wait for someone w/a hot rod to fill-up, & grab their pump as they leave...
I miss the old days w/103 Chevron "White-gas"....:x
If you only get say 2.5 gallons, & the previous pump user got low octane, there's still couple gallons in the hoses/piping back to the pump. Your going to get what was left + what you actually ordered.
If I'm at a busy station, I may just wait for someone w/a hot rod to fill-up, & grab their pump as they leave...
I miss the old days w/103 Chevron "White-gas"....:x
dravnx
Well-known member
Couple of gallons?
Gas stations usually have two tanks. One low grade and one high. From those two tanks the pump will blend anything inbetween. From what I understand, the tanks are plumbed to the pump, but what is in the 8ft of hose going to the nozzle is left over from the guy before.
Assume an internal hose diameter of 1/2 inch and a lenth of 96 inches.
3.14x0.25inx0.25in=0.2
0.2square inx 96in=19.2cubic inches which is .08gallons
So .08 gallons of crap in with your good stuff.
EDIT:
Assuming 3/4 inch internal hose diameter and a ten foot hose
3.14x0.375x0.375=0.442
0.442x120=53.04 which is 0.23gallons
0.23gal of 87+3gal of 93=
(20.1 +279)/3.23=92.6 octane assuming the two fuels used the same calculations to achieve their octane rating. (Some race fuels use different methods, but regular vs premium should be the same.
The only real assumption made here is the length of the hose, which I assume would vary depending on the station. Still doesn't seem to make that much of a difference
TheRobSJ
Großer Mechaniker
Performance? No. As long as the engine doesn't ping, there will be little to no performance difference between Arco's 91 versus Chevron's 91 being put in a brand new Lamborghini Aventador.
However, over time, Arco's...shall we say...less than stellar, additive package will lead to more deposits in the engine. More deposits in the combustion chamber will effectively raise the compression ratio, which will make the 91 octane fuel now not enough to fight off the pre ignition from happening. This excessive pinging can damage or stretch valves. This is why so many of the Hondas and Acuras I've seen over my years need valve adjustments sooner when the owner cops to using Arco/Coscto/Valero/etc gas compared to the ones that use Chevron/76/Shell/etc.
And that's all I want to waste my keystrokes on with this matter. Oil, gas, and tires are such an "everyone's an expert" or can quote articles from so called experts to make their case. I've been a professional mechanic for over 20 years and I religiously only will use Chevron or 76 in my own vehicles (even in rental cars sometimes just out of habit). Y'all can take that or leave it, but I won't argue it any more.
However, over time, Arco's...shall we say...less than stellar, additive package will lead to more deposits in the engine. More deposits in the combustion chamber will effectively raise the compression ratio, which will make the 91 octane fuel now not enough to fight off the pre ignition from happening. This excessive pinging can damage or stretch valves. This is why so many of the Hondas and Acuras I've seen over my years need valve adjustments sooner when the owner cops to using Arco/Coscto/Valero/etc gas compared to the ones that use Chevron/76/Shell/etc.
And that's all I want to waste my keystrokes on with this matter. Oil, gas, and tires are such an "everyone's an expert" or can quote articles from so called experts to make their case. I've been a professional mechanic for over 20 years and I religiously only will use Chevron or 76 in my own vehicles (even in rental cars sometimes just out of habit). Y'all can take that or leave it, but I won't argue it any more.
GAJ
Well-known member
On a related note, at around 150k miles my MX5 started pinging on uphills when using high revs when using the recommended regular fuel so I started using premium which eliminated the pinging.
Did that for 30k miles or so until I decided to toss in a can of Seafoam that I use on my bikes.
After that I was able to return to regular gas with no pinging whatsoever.
EDIT: gas brand for first 175k miles was almost exclusively Chevron; Costco or Valero thereafter. I held off trying the SeaFoam because of the Techron marketing hype...I assumed using the SeaFoam would be redundant, which was not the case. I had tried bottles of Techron in the tank prior to using the SeaFoam with no improvement.
Did that for 30k miles or so until I decided to toss in a can of Seafoam that I use on my bikes.
After that I was able to return to regular gas with no pinging whatsoever.
EDIT: gas brand for first 175k miles was almost exclusively Chevron; Costco or Valero thereafter. I held off trying the SeaFoam because of the Techron marketing hype...I assumed using the SeaFoam would be redundant, which was not the case. I had tried bottles of Techron in the tank prior to using the SeaFoam with no improvement.
Last edited: