Comments on: 87, 89, 91 … What’s the difference in fuel grades? http://www.laurenwantstoknow.com/2010/03/87-89-91-whats-the-difference-in-fuel-grades/ Changing the way people look at cars ... Thu, 05 Jan 2012 00:03:35 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: bsnow0707 http://www.laurenwantstoknow.com/2010/03/87-89-91-whats-the-difference-in-fuel-grades/comment-page-1/#comment-223 bsnow0707 Tue, 20 Jul 2010 08:19:12 +0000 http://www.laurenwantstoknow.com/?p=817#comment-223 who ever told you higher octane burns hotter needs to go back to school. 87 oct, has about 150,000 btu per gallon 93 has about 140.000 btu,s per gallon, 93 octane burns slower and cooler, if it had a fast burn it wouldnt drive the piston back down very effeciently, octane does not cause compression, ~bob who ever told you higher octane burns hotter needs to go back to school. 87 oct, has about 150,000 btu per gallon
93 has about 140.000 btu,s per gallon, 93 octane burns slower and cooler, if it had a fast burn it wouldnt drive the piston back down very effeciently,

octane does not cause compression,
~bob

]]> By: Lauren McCarthy http://www.laurenwantstoknow.com/2010/03/87-89-91-whats-the-difference-in-fuel-grades/comment-page-1/#comment-108 Lauren McCarthy Mon, 05 Apr 2010 19:23:03 +0000 http://www.laurenwantstoknow.com/?p=817#comment-108 Tim, Higher octane takes more heat to burn - which causes more compression - which equals more power. You are correct! Nothing seems to be simple these days! ... haha ~Lauren Tim,
Higher octane takes more heat to burn – which causes more compression – which equals more power.
You are correct!
Nothing seems to be simple these days! … haha

~Lauren

]]> By: mathstud http://www.laurenwantstoknow.com/2010/03/87-89-91-whats-the-difference-in-fuel-grades/comment-page-1/#comment-107 mathstud Mon, 05 Apr 2010 16:45:58 +0000 http://www.laurenwantstoknow.com/?p=817#comment-107 To Scott: To make sure I understand you, you're saying: "More air + more fuel = more power" as opposed to my claim of: "more air + higher octane fuel = more power"? Thank you for clarifying. I suspect you know the topic better than I do. I did a little more digging and found the following the following article: http://www.corvettefever.com/techarticles/corp_0402_corvette_fuel_octane/index.html And specifically the following line - "An engine's octane requirement is directly related to the engine's compression ratio..." I didn't take into account the fact that Corvettes and turbo'd four-bangers run higher compression (more air pressure) than your daily driver. It then said that with higher compression it needed the higher octane to combust safely. The way I had understood it was: "more air + higher octane fuel = more power" Is this a better explanaition? More air (via forced induction) = more air pressure (Compression); Higher Compression (which needs high-octane fuel) + More Fuel = more power. (So much for a simple answer!) -Tim To Scott:

To make sure I understand you, you’re saying:
“More air + more fuel = more power”

as opposed to my claim of:
“more air + higher octane fuel = more power”?

Thank you for clarifying. I suspect you know the topic better than I do.

I did a little more digging and found the following the following article:
http://www.corvettefever.com/techarticles/corp_0402_corvette_fuel_octane/index.html
And specifically the following line – “An engine’s octane requirement is directly related to the engine’s compression ratio…”

I didn’t take into account the fact that Corvettes and turbo’d four-bangers run higher compression (more air pressure) than your daily driver. It then said that with higher compression it needed the higher octane to combust safely.

The way I had understood it was:
“more air + higher octane fuel = more power”

Is this a better explanaition?

More air (via forced induction) = more air pressure (Compression);
Higher Compression (which needs high-octane fuel) + More Fuel = more power.

(So much for a simple answer!)
-Tim

]]> By: Lauren McCarthy http://www.laurenwantstoknow.com/2010/03/87-89-91-whats-the-difference-in-fuel-grades/comment-page-1/#comment-105 Lauren McCarthy Fri, 02 Apr 2010 20:23:25 +0000 http://www.laurenwantstoknow.com/?p=817#comment-105 Hey Tim, I appreciate any advice & tips you have for me! I love learning new stuff! Thanks so much. :) ~Lauren Hey Tim,
I appreciate any advice & tips you have for me! I love learning new stuff!
Thanks so much. :)
~Lauren

]]> By: scott_o http://www.laurenwantstoknow.com/2010/03/87-89-91-whats-the-difference-in-fuel-grades/comment-page-1/#comment-104 scott_o Fri, 02 Apr 2010 16:02:17 +0000 http://www.laurenwantstoknow.com/?p=817#comment-104 In a non-specialized tuned car higher octanes will not benefit you one iota. It has nothing to do mathstud with air flow levels. More power when combined with higher volumes of air in a constant air to fuel ratio means you are burning more fuel - thats what gives you more power, not the octane. Lets check what the American Petroleum Institute say about octane. http://www.api.org/aboutoilgas/gasoline/gasoline-octane.cfm paragraph #4 "Ordinarily, your vehicle will not benefit from using a higher octane than is recommended in the owner’s manual." From Wiki - Octane rating does not relate to the energy content of the fuel (see heating value). It is only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. Where octane is raised by blending in ethanol, energy content per volume is reduced. I think I will take their explanation In a non-specialized tuned car higher octanes will not benefit you one iota. It has nothing to do mathstud with air flow levels. More power when combined with higher volumes of air in a constant air to fuel ratio means you are burning more fuel – thats what gives you more power, not the octane.

Lets check what the American Petroleum Institute say about octane.
http://www.api.org/aboutoilgas/gasoline/gasoline-octane.cfm
paragraph #4
“Ordinarily, your vehicle will not benefit from using a higher octane than is recommended in the owner’s manual.”

From Wiki –
Octane rating does not relate to the energy content of the fuel (see heating value). It is only a measure of the fuel’s tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. Where octane is raised by blending in ethanol, energy content per volume is reduced.

I think I will take their explanation

]]> By: mathstud http://www.laurenwantstoknow.com/2010/03/87-89-91-whats-the-difference-in-fuel-grades/comment-page-1/#comment-103 mathstud Thu, 01 Apr 2010 15:11:03 +0000 http://www.laurenwantstoknow.com/?p=817#comment-103 I have been riding motorcycles and driving 4 cylinders for almost ten years, so I'm always looking to squeak out a little more performance from my toy- er, vehicles. In my Yamaha V-Star I put the high 93-octane because it will ride rough with the 87-octane. At KCIR (the local dragstrip) I tried putting 111-octane racing fuel into a stock Pontiac Grand Am but didn't notice a significant power gain than normal. Call me boring, but I'm going to go with car-tuning 101: higher octane fuels will provide more power when combined with higher volumes of air to maintain air-fuel ratios. Performance cars feature improved air intake systems to actually make use of the higher octane to push out the power (improved intake manifolds, cold-air intakes, blowers, turbochargers.) I feed my stock Civic 87-octane (from QT - no exceptions!) because it can't suck in the air necessary to use the high grade stuff. Hope this helps. And I love the site Lauren. - Tim I have been riding motorcycles and driving 4 cylinders for almost ten years, so I’m always looking to squeak out a little more performance from my toy- er, vehicles. In my Yamaha V-Star I put the high 93-octane because it will ride rough with the 87-octane. At KCIR (the local dragstrip) I tried putting 111-octane racing fuel into a stock Pontiac Grand Am but didn’t notice a significant power gain than normal.

Call me boring, but I’m going to go with car-tuning 101: higher octane fuels will provide more power when combined with higher volumes of air to maintain air-fuel ratios. Performance cars feature improved air intake systems to actually make use of the higher octane to push out the power (improved intake manifolds, cold-air intakes, blowers, turbochargers.) I feed my stock Civic 87-octane (from QT – no exceptions!) because it can’t suck in the air necessary to use the high grade stuff.

Hope this helps. And I love the site Lauren. – Tim

]]> By: Lauren McCarthy http://www.laurenwantstoknow.com/2010/03/87-89-91-whats-the-difference-in-fuel-grades/comment-page-1/#comment-102 Lauren McCarthy Thu, 01 Apr 2010 14:06:26 +0000 http://www.laurenwantstoknow.com/?p=817#comment-102 Well, thank you! (and thank you) Well, thank you! (and thank you)

]]> By: nddhawk http://www.laurenwantstoknow.com/2010/03/87-89-91-whats-the-difference-in-fuel-grades/comment-page-1/#comment-101 nddhawk Thu, 01 Apr 2010 01:36:16 +0000 http://www.laurenwantstoknow.com/?p=817#comment-101 Great information, Lauren (and gorgeous smile). Great information, Lauren (and gorgeous smile).

]]>