Comments on: Coast Gas Prices Vary Dramatically (And Yes, It’s Most Expensive In North Escambia) http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia Local News for Molino, Bratt, McDavid, Century, Walnut Hill, Cantonment Thu, 09 Apr 2026 02:43:27 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: 429SCJ http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia/comment-page-1#comment-102909 429SCJ Thu, 06 Oct 2011 11:47:08 +0000 http://www.northescambia.com/?p=69650#comment-102909 An engines static and dynamic compression ratios are the critical factors in preignition. Clyinder pressures during operation can be increased or decreased by valve timing. Engine operating temperatures are critical as well. There are several aftermarket spark control systems which can vary engine timing, helping to reduce knock. In my old 4wheel drive I mix 19 gallons of 93 octane gas, with one gallon of low sulpher diesel. This raises the detonation temperature of the fuel and provides upper cylnder lubrication as well. This works great in the summer time, offroading up at the gravel lakes. In closing Volumetric Efficiency is the goal in engine performance. An engines static and dynamic compression ratios are the critical factors in preignition. Clyinder pressures during operation can be increased or decreased by valve timing. Engine operating temperatures are critical as well. There are several aftermarket spark control systems which can vary engine timing, helping to reduce knock. In my old 4wheel drive I mix 19 gallons of 93 octane gas, with one gallon of low sulpher diesel. This raises the detonation temperature of the fuel and provides upper cylnder lubrication as well. This works great in the summer time, offroading up at the gravel lakes. In closing Volumetric Efficiency is the goal in engine performance.

]]> By: Scott http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia/comment-page-1#comment-102841 Scott Wed, 05 Oct 2011 17:29:42 +0000 http://www.northescambia.com/?p=69650#comment-102841 Well, it’s good to see that you are for anti gravity transportation too. We can talk about that one some other time I guess. I got to reading everything and I did not take the time to realize that you changed the subject to a diesel engine, this changes the whole aspect of the situation in which you are (right) and I am (wrong). Something else my grandfather and I were discussing this morning about the price of fuel and the energy concept. You can buy more of the cheaper gasoline and fill your car up twice vs spending more money and getting less gasoline. But the higher energy content in 93 octane last longer and your MPG will increase, but you get charged a lot more money. You would think that the gasoline stations could sell more gasoline to more customers if they could afford to buy the good grade fuel. Last time I checked Propane was $2.99 a gallon maybe we could run that, what you think ol mighty Dave ???? Well, it’s good to see that you are for anti gravity transportation too. We can talk about that one some other time I guess. I got to reading everything and I did not take the time to realize that you changed the subject to a diesel engine, this changes the whole aspect of the situation in which you are (right) and I am (wrong). Something else my grandfather and I were discussing this morning about the price of fuel and the energy concept. You can buy more of the cheaper gasoline and fill your car up twice vs spending more money and getting less gasoline. But the higher energy content in 93 octane last longer and your MPG will increase, but you get charged a lot more money. You would think that the gasoline stations could sell more gasoline to more customers if they could afford to buy the good grade fuel. Last time I checked Propane was $2.99 a gallon maybe we could run that, what you think ol mighty Dave ????

]]> By: David Huie Green http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia/comment-page-1#comment-102827 David Huie Green Wed, 05 Oct 2011 15:44:04 +0000 http://www.northescambia.com/?p=69650#comment-102827 REGARDING; "Just retard the timing back about 5 degrees and say good bye to engine knock." One final, probably futile, attempt. Timing is related to when the spark ignition fires. Compression derived knock is related to when compression causes pre ignition. They really aren't related other than the fact that both can cause ignition of the air/fuel mixture. From: http://www.procarcare.com/icarumba/resourcecenter/encyclopedia/icar_resourcecenter_encyclopedia_ignition.asp#timing “Ignition timing is the measurement, in degrees of crankshaft rotation, of the point at which the spark plugs fire in each of the cylinders. It is measured in degrees before or after Top Dead Center (TDC) of the compression stroke. “ http://www.procarcare.com/icarumba/resourcecenter/glossary/icar_resourcecenter_glossary_viewglossary-d-n.asp#k “KNOCK: Noise which results from the spontaneous ignition of a portion of the air-fuel mixture in the engine cylinder caused by overly advanced ignition timing or use of incorrectly low octane fuel for that engine. “ Note: overly advanced ignition timing CAN cause early ignition resulting in knock, but we are talking about low octane related knock. That is unrelated to the electrical system. David also for anti gravity transportation and reality in the mean time REGARDING;
“Just retard the timing back about 5 degrees and say good bye to engine knock.”

One final, probably futile, attempt. Timing is related to when the spark ignition fires. Compression derived knock is related to when compression causes pre ignition. They really aren’t related other than the fact that both can cause ignition of the air/fuel mixture.

From:
http://www.procarcare.com/icarumba/resourcecenter/encyclopedia/icar_resourcecenter_encyclopedia_ignition.asp#timing
“Ignition timing is the measurement, in degrees of crankshaft rotation, of the point at which the spark plugs fire in each of the cylinders. It is measured in degrees before or after Top Dead Center (TDC) of the compression stroke. “

http://www.procarcare.com/icarumba/resourcecenter/glossary/icar_resourcecenter_glossary_viewglossary-d-n.asp#k
“KNOCK: Noise which results from the spontaneous ignition of a portion of the air-fuel mixture in the engine cylinder caused by overly advanced ignition timing or use of incorrectly low octane fuel for that engine. “

Note: overly advanced ignition timing CAN cause early ignition resulting in knock, but we are talking about low octane related knock. That is unrelated to the electrical system.

David also for anti gravity transportation
and reality in the mean time

]]> By: Scott http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia/comment-page-1#comment-102798 Scott Wed, 05 Oct 2011 12:13:20 +0000 http://www.northescambia.com/?p=69650#comment-102798 REGARDING and combustion caused by compression rather than the spark in a spark ignition internal combustion engine is called knock, which you DO NOT want in the compression stroke, rather you want it in the power stroke which follows the compression stroke Just retard the timing back about 5 degrees and say good bye to engine knock. Scott for anti gravitational propulsion :) REGARDING

and combustion caused by compression rather than the spark in a spark ignition internal combustion engine is called knock, which you DO NOT want in the compression stroke, rather you want it in the power stroke which follows the compression stroke

Just retard the timing back about 5 degrees and say good bye to engine knock.

Scott for anti gravitational propulsion :)

]]> By: Everett http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia/comment-page-1#comment-102792 Everett Wed, 05 Oct 2011 10:44:16 +0000 http://www.northescambia.com/?p=69650#comment-102792 The Raceway station and BP station in loxley has regular for $3.15 The Raceway station and BP station in loxley has regular for $3.15

]]> By: David Huie Green http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia/comment-page-1#comment-102789 David Huie Green Wed, 05 Oct 2011 10:24:26 +0000 http://www.northescambia.com/?p=69650#comment-102789 REGARDING THE RESPONSE TO: "Compression ignition of gasoline is called knock." WHICH WAS: "No David, it is called Combustion." and combustion caused by compression rather than the spark in a spark ignition internal combustion engine is called knock, which you DO NOT want in the compression stroke, rather you want it in the power stroke which follows the compression stroke David for everything in its place REGARDING THE RESPONSE TO:
“Compression ignition of gasoline is called knock.”
WHICH WAS:
“No David, it is called Combustion.”

and combustion caused by compression rather than the spark in a spark ignition internal combustion engine is called knock, which you DO NOT want in the compression stroke, rather you want it in the power stroke which follows the compression stroke

David for everything in its place

]]> By: Scott http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia/comment-page-1#comment-102751 Scott Wed, 05 Oct 2011 00:10:46 +0000 http://www.northescambia.com/?p=69650#comment-102751 Regarding You can avoid knock with low octane gasoline by using low compression ratios but then you have less power to go VROOM VROOM with. One of the ways that Chevrolet avoided knocking was to engineer a reverse rotation water pump on their LT-1 and LT-4 engines. Instead of the cool water flowing through the block first and to the heads last like the old gen 0 and 1 350 CI engines, it flowed through the heads first and through the block last. The advantage was that they could run lower octane fuel and advance the timing further without damage to the pistons, valves, etc. Today’s engines regardless of engine size use this same design to increase engine life. Regarding Compression ignition of gasoline is called knock. No David, it is called Combustion. It’s almost like an explosion inside the combustion chambers, but in a more controlled smaller form. Combustion of the Air/Fuel is the driving force that forces the pistons in a downward motion. This is called the compression stroke. This is where you want the number one piston to be at if you ever have to manually set your engines timing. No science here, just simple mechanics. Regarding
You can avoid knock with low octane gasoline by using low compression ratios but then you have less power to go VROOM VROOM with.

One of the ways that Chevrolet avoided knocking was to engineer a reverse rotation water pump on their LT-1 and LT-4 engines. Instead of the cool water flowing through the block first and to the heads last like the old gen 0 and 1 350 CI engines, it flowed through the heads first and through the block last. The advantage was that they could run lower octane fuel and advance the timing further without damage to the pistons, valves, etc. Today’s engines regardless of engine size use this same design to increase engine life.

Regarding
Compression ignition of gasoline is called knock.

No David, it is called Combustion. It’s almost like an explosion inside the combustion chambers, but in a more controlled smaller form. Combustion of the Air/Fuel is the driving force that forces the pistons in a downward motion. This is called the compression stroke. This is where you want the number one piston to be at if you ever have to manually set your engines timing.

No science here, just simple mechanics.

]]> By: David Huie Green http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia/comment-page-1#comment-102743 David Huie Green Tue, 04 Oct 2011 22:56:52 +0000 http://www.northescambia.com/?p=69650#comment-102743 REGARDING: “Just to point this out to everyone. 93 & 89 octane gasoline burns a lot hotter and slower requiring less liquid mass to do the same amount of work. 87 octane burns a lot cooler and faster which requires more liquid mass to do the same amount of work.” Lots of people believe that, even President Carter, once a nuclear engineer in the Navy. However this is wrong (as he so often was). For example, ethanol has an octane rating of 113 but has much less energy by mass than any form of gasoline. Octane rating is simply a measure of the tendency to ignite by compression rather than by spark. Compression ignition of gasoline is called knock and is hard on spark ignition engines. You can avoid knock with low octane gasoline by using low compression ratios but then you have less power to go VROOM VROOM with. This DOES NOT mean the gasoline has less energy than high octane fuel, though. You can add tetra ethyl lead or ethanol to heptane and get performance equal to 100% octane without increasing the energy content of the fuel. Note: if you inject the fuel at the end of the compression stroke, you effectively have a diesel engine even if you're burning heptane For an independent source on the subject you might try: http://auto.howstuffworks.com/fuel-efficiency/fuel-consumption/question90.htm David for truth REGARDING:
“Just to point this out to everyone. 93 & 89 octane gasoline burns a lot hotter and slower requiring less liquid mass to do the same amount of work. 87 octane burns a lot cooler and faster which requires more liquid mass to do the same amount of work.”

Lots of people believe that, even President Carter, once a nuclear engineer in the Navy. However this is wrong (as he so often was). For example, ethanol has an octane rating of 113 but has much less energy by mass than any form of gasoline. Octane rating is simply a measure of the tendency to ignite by compression rather than by spark. Compression ignition of gasoline is called knock and is hard on spark ignition engines.

You can avoid knock with low octane gasoline by using low compression ratios but then you have less power to go VROOM VROOM with. This DOES NOT mean the gasoline has less energy than high octane fuel, though. You can add tetra ethyl lead or ethanol to heptane and get performance equal to 100% octane without increasing the energy content of the fuel.

Note: if you inject the fuel at the end of the compression stroke, you effectively have a diesel engine even if you’re burning heptane

For an independent source on the subject you might try:
http://auto.howstuffworks.com/fuel-efficiency/fuel-consumption/question90.htm

David for truth

]]> By: Beegee http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia/comment-page-1#comment-102738 Beegee Tue, 04 Oct 2011 21:37:00 +0000 http://www.northescambia.com/?p=69650#comment-102738 We just got back from Tennessee and the price of gas was $3.11 !!!! We just got back from Tennessee and the price of gas was $3.11 !!!!

]]> By: Scott http://www.northescambia.com/2011/10/coast-gas-prices-vary-dramatically-and-yes-its-most-expensive-in-north-escambia/comment-page-1#comment-102710 Scott Tue, 04 Oct 2011 17:55:59 +0000 http://www.northescambia.com/?p=69650#comment-102710 David Just to point this out to everyone. 93 & 89 octane gasoline burns a lot hotter and slower requiring less liquid mass to do the same amount of work. 87 octane burns a lot cooler and faster which requires more liquid mass do do the same amount of work. An experienced driver can feel the difference in engine acceleration with 87 octane burning faster giving the driver more acceleration vs 93 octane burring slower giving the driver a little slower acceleration. If you have a car that gets an average of 28 MPG on 87 octane, using 89 will bump that up to 30 mpg. If you use 93 octane you will be looking at about 32 to 33 mpg. I have noticed this in my fiance's 1997 Chevrolet Cavalier. An engine with a compression ratio of 10 to 1 or 10.5 to 1 will require 93 octane no matter what kind of budget you are on. The reason is when the compression ratio is raised the gasoline will try to ignite faster once on the compression stroke. If low octane fuel is present in a high compression engine, the fuel will try to ignite before the spark plug fires causing pre-detonation. David

Just to point this out to everyone. 93 & 89 octane gasoline burns a lot hotter and slower requiring less liquid mass to do the same amount of work. 87 octane burns a lot cooler and faster which requires more liquid mass do do the same amount of work. An experienced driver can feel the difference in engine acceleration with 87 octane burning faster giving the driver more acceleration vs 93 octane burring slower giving the driver a little slower acceleration.

If you have a car that gets an average of 28 MPG on 87 octane, using 89 will bump that up to 30 mpg. If you use 93 octane you will be looking at about 32 to 33 mpg. I have noticed this in my fiance’s 1997 Chevrolet Cavalier.

An engine with a compression ratio of 10 to 1 or 10.5 to 1 will require 93 octane no matter what kind of budget you are on. The reason is when the compression ratio is raised the gasoline will try to ignite faster once on the compression stroke. If low octane fuel is present in a high compression engine, the fuel will try to ignite before the spark plug fires causing pre-detonation.

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