Reply
 
Thread Tools Display Modes
  #1  
Old 05-18-2004, 03:02 AM
filmyak filmyak is offline
Member
 
Join Date: Apr 2001
Location: Hollywood, CA
Posts: 998
gasoline questions (nothing to do with current prices)

I've got several q's concerning gasoline.

First, I've heard of a group in SoCal that wants to fight the current price hikes by temporarily getting rid of high octane gas at the pump and replacing it with an additional med octane pump. Now that sounds stupid to me, but here's the question: I have a sports car which, according to the owners manual, requires high octane fuel.

Is this hype? Or will cutting back hurt my engine and/or performance?

Question two: I had a mechanic tell me to use Chevron fuel, claiming that their additive (Techron) actually worked and keeps engines cleaner. Is this a legitimate claim? Or should I assume his brother owns some Chevron stations around town?

Lastly, what's up with every gas station in the U.S. charging $X.XX 9/10. That 9/10 of a cent seems like... an insult. Are they really pretending to save us cash by dropping the price from $2.01/gallon to $2.00 9/10/gallon? How much does the average station earn a year for those extra 9/10 cents?

And pay close attention to the price marquees... the numbers are all changeable. Except for those damned 9/10 cents which are usually permant parts of the price!
  #2  
Old 05-18-2004, 03:23 AM
Nametag Nametag is offline
Charter Member
 
Join Date: Apr 2002
Location: California
Posts: 8,072
Follow the owner's manual. Car manufacturers have no incentive to sell high-octane gasoline; they do have an incentive to make you satisfied with their car. Yes, running a high-performance/high compression engine on low cotane gasoline can cause knocking.

Techron is a detergent. All major gasoline brands contain detergent. In fact, I think that ALL gasoline sold in the U.S. contains detergent.

The $0.009/gal is an ancient marketing gimmick that turned into a tradition so powerful that nothing can kill it.
  #3  
Old 05-18-2004, 03:32 AM
flight flight is offline
Guest
 
Join Date: Mar 2000
Location: Newport News, VA, USA
Posts: 2,704
You see that extra insanity of fractions of a cent in gasoline prices as filmyak said, becasue of marketing. Look at it this way, no one actaully includes it when they speak. People say 2.43 rather than 2.43 9/10, or more logically 2.34. So, when I see two filling stations across the street from one another and one appears to be a cent cheaper, I go to the cheap one. We don't notice there is almost no difference, and people seem to be motivated by very small differences when purchasing gasoline, more than anything else.
  #4  
Old 05-18-2004, 03:39 AM
flight flight is offline
Guest
 
Join Date: Mar 2000
Location: Newport News, VA, USA
Posts: 2,704
First, sorry, I meant to say Nametag, not Filmyak in my last post. Second, you wanted to know how much they make off of that 9/10ths of a cent. Acording to this, we go through 360 million gallons of gasoline a year. That means that by adding on the 9/10ths they are making an extra 3.24 million dollars a year.
  #5  
Old 05-18-2004, 03:49 AM
flight flight is offline
Guest
 
Join Date: Mar 2000
Location: Newport News, VA, USA
Posts: 2,704
Sorry, you asked per gas station. Using the info here (dated 1998), we see that you average gas station pulls in an extra $6,053 a year off of that additional 9/10ths.
  #6  
Old 05-18-2004, 05:50 AM
Airman Doors, USAF Airman Doors, USAF is offline
Member
 
Join Date: Feb 2001
Posts: 13,936
Quote:
Originally Posted by filmyak
First, I've heard of a group in SoCal that wants to fight the current price hikes by temporarily getting rid of high octane gas at the pump and replacing it with an additional med octane pump. Now that sounds stupid to me, but here's the question: I have a sports car which, according to the owners manual, requires high octane fuel.

Is this hype? Or will cutting back hurt my engine and/or performance?
What Octane ratings mean

Quote:
The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.
  #7  
Old 05-18-2004, 06:10 AM
UDS UDS is offline
Guest
 
Join Date: Mar 2002
Location: Australia
Posts: 7,729
Quote:
Originally Posted by flight
Sorry, you asked per gas station. Using the info here (dated 1998), we see that you average gas station pulls in an extra $6,053 a year off of that additional 9/10ths.
Or, alternatively, sacrifices $605 dollars a year by shaving 1/10th of a cent off the price. Isn't that a more realistic view of what is happening?
  #8  
Old 05-18-2004, 09:34 AM
PetW PetW is offline
Guest
 
Join Date: Aug 2002
Posts: 894
no, because an extra 1/10th of a cent would bump it up to where the customer may (as marketing seems to believe) think it's an entire cent more expensive. 1.99 9/10 seems like a whole cent below 2.00.
  #9  
Old 05-18-2004, 09:35 AM
PetW PetW is offline
Guest
 
Join Date: Aug 2002
Posts: 894
Whoops, I see what you're saying now. I guess it all comes down to how the gas station looks at it. Are they sneaking in an extra 9/10 of a cent? Or are they shaving off 1/10 of a cent to make it seem cheaper?
  #10  
Old 05-18-2004, 09:35 AM
Airman Doors, USAF Airman Doors, USAF is offline
Member
 
Join Date: Feb 2001
Posts: 13,936
It's an illusion. Nobody is fooled anymore.
  #11  
Old 05-18-2004, 11:18 AM
Rick Rick is offline
Charter Member
 
Join Date: Aug 1999
Posts: 16,451
Quote:
Originally Posted by filmyak
I've got several q's concerning gasoline.

? First, I've heard of a group in SoCal that wants to fight the current price hikes by temporarily getting rid of high octane gas at the pump and replacing it with an additional med octane pump. Now that sounds stupid to me, but here's the question: I have a sports car which, according to the owners manual, requires high octane fuel.

Is this hype? Or will cutting back hurt my engine and/or performance?
The answer is it may, or it may not depends on the actual requirements of your car, and how you drive. Best to follow the recomondations in your owner's manual.

Quote:
? Question two: I had a mechanic tell me to use Chevron fuel, claiming that their additive (Techron) actually worked and keeps engines cleaner. Is this a legitimate claim? Or should I assume his brother owns some Chevron stations around town?
Chevron has advertised that for years that the big three car makers in Detroit use Chevron for their EPA certification tests. The kicker is that they have to have Chevron trucked in from another state special to use, since Chevron is not sold in Michigan. Also back in the eighties as cleaning additives were the rage, Chevron packaged Techron into bottles for addition to fuel tanks over and above what was in their gas. This is the only time I have ever recalled a carmaker recommending an additive for either fuel or oil. Several carmakers published technical bulletins recommending the use of Techron. Lastly also back from the late 80's I have personally seen cars that had stalling problems cured by the use of Chevron gas.
so is it good gas? Yes. Is it better than everything else out there? I don't know, but it is about the same price as the other fuels, and I do know it works.
Your mileage, of course, may vary.
  #12  
Old 05-18-2004, 11:51 AM
Pork Rind Pork Rind is offline
Charter Member
 
Join Date: Jan 2001
Location: Santa Barbara
Posts: 2,168
Quote:
Originally Posted by filmyak
First, I've heard of a group in SoCal that wants to fight the current price hikes by temporarily getting rid of high octane gas at the pump and replacing it with an additional med octane pump.
They do know that the refineries don't actually make any mid-grade gas, do they? The mid-grade at the pump is just a mix of the regular and premium 'made' in the pump.
  #13  
Old 05-18-2004, 12:31 PM
Airman Doors, USAF Airman Doors, USAF is offline
Member
 
Join Date: Feb 2001
Posts: 13,936
Quote:
Originally Posted by Rick
The answer is it may, or it may not depends on the actual requirements of your car, and how you drive. Best to follow the recomondations in your owner's manual.
I subscribe to Car And Driver and they had something about this in their technical questions section. This guy said that he had a supercharged car (which for our purposes is pretty much the same as turbocharging since both force more air into the combustion chambers) and that he would run 87 octane in it, and does this hurt the car?

The response, predictably, is that you can in fact run lower octane-rated fuels in your car, but due to the large volumes of air created by the supercharger it is an absolute necessity to stay out of the boost because the detonation would be very destructive. The car has some safeguards against that, such as advancing or retarding timing, but nonetheless lower octane fuels shuld be used only in situations where the higher rated stuff is unavailable and the lower octane fuel should not be used on a regular basis.

If you have a newer car, this becomes a warranty issue as well. Car manufacturers don't warrant stupidi...err, owner-induced failures. So absolutely follow the recomendations that the car builder makes, and if you can't for whatever reason take it very easy lest you turn your pimpin' ride into a $20,000 piece of junk.
  #14  
Old 05-18-2004, 01:33 PM
bump bump is offline
Guest
 
Join Date: Jun 2000
Location: Dallas, TX
Posts: 15,115
Well, assuming you have a stock car, I'd be willing to bet that even though they recommend 91+ octane gas for best performance, that you can run 87 forever with no ill effects. Your performance will suffer though, due to the knock-sensor retarding the spark to the point where knocking doesn't happen.

With super and turbochargers, often times high octane gas isn't enough- that's why they have intercoolers, water injection, etc...
  #15  
Old 05-18-2004, 01:42 PM
Airman Doors, USAF Airman Doors, USAF is offline
Member
 
Join Date: Feb 2001
Posts: 13,936
Quote:
Originally Posted by bump
Well, assuming you have a stock car, I'd be willing to bet that even though they recommend 91+ octane gas for best performance, that you can run 87 forever with no ill effects. Your performance will suffer though, due to the knock-sensor retarding the spark to the point where knocking doesn't happen.
That's not why they designed those systems. They designed them for the occasional knock during normal operaion, not continuous beating the hell out of your engine. If you depend on them to save your car because you want to get gas on the cheap and they fail, BOOM! And then you'll feel pretty stupid.

Quote:
With super and turbochargers, often times high octane gas isn't enough- that's why they have intercoolers, water injection, etc...
Those are for thermal efficiency, not combustion. The temperature of the forced air will have an effect on efficiency but little to no effect on detonation, which is what high-octane rated gas is designed to prevent.
  #16  
Old 05-18-2004, 02:33 PM
rsa rsa is offline
Guest
 
Join Date: Sep 2001
Posts: 2,108
Techron: Yes it is superior to other gas detergents. I pretty sure there is a thread from way back if you do a search. You can always just buy the additive in a auto parts store and add it to your gas twice a year. Chevron has a patent on polyether amines which is why other oil companies can not offer the same additive in their fuel.

Lower grade gas: Read your manual. Most, if not all modern cars sense knock long before the point where it would do any damage to your engine. My 94 BMW recommends high octane fuel but allows low octane fuel with the only caveat that performance/effeciency may be less. No warranty issues despite some unsupported assertions in this thread.

And BTW, the temperature of the intake air definitely will affect detonation (as well as effeciency).
  #17  
Old 05-18-2004, 03:29 PM
Dag Otto Dag Otto is offline
Guest
 
Join Date: Sep 2003
Location: Las Cruces
Posts: 4,911
Quote:
Originally Posted by filmyak
I've got several q's concerning gasoline.

First, I've heard of a group in SoCal that wants to fight the current price hikes by temporarily getting rid of high octane gas at the pump and replacing it with an additional med octane pump. Now that sounds stupid to me, but here's the question: I have a sports car which, according to the owners manual, requires high octane fuel.

How does this fight the current price hikes? Simply by getting rid of the highest price gas so the 'average' price is lower?

Housing in Southern California could be affordable again if only all those expensive homes weren't on the market!
  #18  
Old 05-18-2004, 04:54 PM
MysteryFellow63427 MysteryFellow63427 is offline
Guest
 
Join Date: Aug 2000
Posts: 3,996
Quote:
Originally Posted by Pork Rind
They do know that the refineries don't actually make any mid-grade gas, do they? The mid-grade at the pump is just a mix of the regular and premium 'made' in the pump.
[Johnny Carson]
I did not know that.
[/Carson]
  #19  
Old 05-18-2004, 05:52 PM
Rick Rick is offline
Charter Member
 
Join Date: Aug 1999
Posts: 16,451
Quote:
Originally Posted by Pork Rind
They do know that the refineries don't actually make any mid-grade gas, do they? The mid-grade at the pump is just a mix of the regular and premium 'made' in the pump.
Sorry, but I gotta call CITE here.
Seeing as how my local filling stations have three count them three fill ports in the pavement. Also I have never seen this in any of my professional magizines in over 30 years in the auto business, my bullshit meter is pegged firmily in the red total bullshit zone.
  #20  
Old 05-18-2004, 06:20 PM
Balthisar Balthisar is offline
Charter Member
 
Join Date: Nov 2000
Location: Southeast Michigan, USA
Posts: 10,284
Quote:
Originally Posted by Airman Doors, USAF
Those are for thermal efficiency, not combustion. The temperature of the forced air will have an effect on efficiency but little to no effect on detonation, which is what high-octane rated gas is designed to prevent.
That's something that he'd really have to check the owners' manual for. My car line had anti-knock sensors added/adjusted for the 2001 model year for this very reason. All the pre-2001 guys have to put in 93. I usually put in 87. The manufacturer recommends 93, but says only performance will suffer a little bit with the 87. Really, I don't notice any difference.
  #21  
Old 05-19-2004, 12:03 PM
filmyak filmyak is offline
Member
 
Join Date: Apr 2001
Location: Hollywood, CA
Posts: 998
Quote:
Originally Posted by Dag Otto
How does this fight the current price hikes? Simply by getting rid of the highest price gas so the 'average' price is lower?
I don't know, but I assume by increasing supply in the low end range (which would lower price). Hey, it was just a blurb I heard on NPR news, they didn't say it was a SMART idea. Hmmmmm.

Thanks everyone for the info. Though I still hate the 9/10 of a cent factor. Heh!
  #22  
Old 05-19-2004, 12:54 PM
Pork Rind Pork Rind is offline
Charter Member
 
Join Date: Jan 2001
Location: Santa Barbara
Posts: 2,168
Quote:
Originally Posted by Rick
Sorry, but I gotta call CITE here.
Seeing as how my local filling stations have three count them three fill ports in the pavement. Also I have never seen this in any of my professional magizines in over 30 years in the auto business, my bullshit meter is pegged firmily in the red total bullshit zone.
Well, I took a look at the gas station up the hill from me (an independant) and they only had two holes. The guy inside had no idea how any part of the operation worked.

Then there's this:

Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 03:07 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright 2017 Sun-Times Media, LLC.

 
Copyright © 2017