gasoline prefrence

[chatcher]

i read apost just now and it got me wondering
i myself have always run sunoco 94 in my car and my bike now niether one is a daily driver which of course makes shelling out alittle more cash for a fill not so hard on the wallet
my ? is is it worth it
i read once in muscle mustangs and fast fords an article where they were dynoing modded mustangs to see diff hp changes and they made a point to say that they had run 94 octane for all the runs
now i really dont know the dif from 87 to 94 so if you do let me know what you guys think and of course what you run

[Maroon 5.0 LX]

The stock 5.0 recommended fuel octane is 87. The only performance difference you'll see using a higher octane is a decrease in spending cash in your wallet.

[chatcher]

maroon im no so much concerned about perfomance i am wondering if the octane level helps at all is there any test that has been done that says one is better than the other for any reason also my bikes manual says to run 91+ but does not really say why if i am doing nothing but wasting money i wonder why they offer diff grades at all

[1BAD89]

If your stock, always run what the manufature recommends! As far as your bike, if it says run 91+, you better run 91+! If it is a newer street bike, it'll run like **** with 87 in it, and you could have possible engine damage. I just don't understand, even if you decided to use 87, the current crop of streetbikes get like 40mpg, why use 87, you'll be saving maybe $.50 each fill up, and it's BAD FOR IT!! I'm assuming a street bike?? Different motors are set-up to run on different octane ratings. If the manufacture recommends 87, and you don't bump the timing or anything, your wasting your cash on anything higher than 87. Chevy says only premium fuel in my 2000 SS, if I use 87 octane, I will be rewarded with " knock retard" by the computer to compensate for the lower octane, and I would probaly lose around 20 hp, because the computer sets itself up in kinda like a "safe mode."

i read once in muscle mustangs and fast fords an article where they were dynoing modded mustangs to see diff hp changes and they made a point to say that they had run 94 octane for all the runs

Mod'ed is the keyword there.

[7000rpmisheaven]

http://www.howstuffworks.com/question90.htm

[chatcher]

1bad89 the bike is an f4 and it only gets 94 my real ? is about my car not that im worried about the extra couple bucks i will prob continue to use 94 in my car regardless and it is slightly modded i was just trying to figure out what the advantages were if any for keeping only one type of gas of the same high octane in the tank at all times i only use sunoco 94 in all my toys

[chatcher]

ok 7000rpm that kinda helps that article would tend to make me belive that i prob dont need to run 94 in my car but i prob will still use it anyways next ? does any fuel keep the fuel delivery system cleaner or in better shape

[7000rpmisheaven]

Using a higher octane does nothing if you don't set the timing to take advantage of it. Most believe that the higher octane gas is actually better or cleaner. Somebody correct me if I am wrong but won't it actually leave more deposits if you are using it unnecesarily.
Since I am not worried about the difference in price I set the timing higher and run the higher octane all the time.

[Mr 5 0]

I've run 15 degrees initial timing on my '90 LX since I've owned it (12 years - bought it new) and I've used nothing but Sunoco 94 octane gas. Never a ping or gas-related problem in 115,000 miles.

Of course, I change the gas filter every 15,000 and use (Ford) injector cleaner once or twice per year, which doesn't hurt. I could probably get by with a lower octane gasoline but I like the Sunoco Ultra 94 and I'm willing to pay the (slight) extra cash to use it and have total peace of mind.

To each his own, but if gas money was a problem, I'd buy a Civic.

[chatcher]

mr 5.0 how does timing help in using a higher octane

[curtis73]

Higher octane levels slow down the burning which in turn slows down the flame front. A proportional advance in timing is recommended so the flame front still hits the piston at the same time. Using higher octane than is recommended can hurt top end power because the fact that the compression is too low for the slow flame front qualities will make the flame front too slow. A complete re-curving of the timing would compensate for this because the piston speed increases, but the flame front doesn't. but why re-curve and spend too much for fuel when you don't need to? Higher octane is recommended at times when compression is high enough that it causes overly fast flame fronts and pre-ignition/knock. If you don't have the compression to require the octane you're running, it may actually reduce power. WHEN the spark happens won't compensate for HOW FAST the flame can physically travel. Your owner's manual is a good guide for stock engines. Depending on your setup, it actually matters very little. Some guys say that the octane you use should be ten times your compression (i.e. 8.7:1 can use 87 octane) with obvious adjustments for aluminum heads and EFI. This is a pretty vague guess and there are extreme variations. My Impala SS LT1 with iron heads used 87 octane and had a 10.5:1 static ratio. My Honda Shadow VLX 600 has 7.9:1 compression under aluminum heads, but needs 92 octane (and it still knocks like a woodpecker)

These days, fuel companies fill your head with big brand-names of cleaning gasolines. Usually, its the alcohol that they add. I used to help out with the tankers up around Oil City, PA. Shell, Sheetz, Hess, Amoco, Exxon, Texaco, Mobil, and countless others all fill their tanks (at least motor oils and gasolines anyway) from the same exact pipelines in Altoona. Base motor oils and Gasolines are usually only separated by their additive package. Motor oil is potentially very different. Gasoline's additive packages are usually a powdered dye dropped in the tank before the fuel truck dumps fuel into it. That "clear" supreme fuel that is so special? Just 93 octane without the corporate dye. Some actually add detergents, but they do no more than a bottle of 65-cent fuel injector cleaner that you find in the parts store. If you think about it, gasoline is very specific about what it can and can't contain. Anything else would change its specific weight and that perfect 14.7:1 air/fuel ratio would be lean or rich depending on what brand you used. The government wouldn't allow that.

If I get off at an exit and I'm looking for fuel, I always (without exception) go to the cheapest place regardless of brand, appearance of the station, or how dirty the pump looks. The federal government keeps such close tabs on the condition of every single tank, pump, hose, and filter, that getting "bad" fuel is a very rare occurence. Even if you do get dirty fuel, chances are that the worst it will do is clog up your filter.

Another little tidbit. Gasoline contains no actual Octane. Octane is very hydrophyllic, meaning it absorbs water very easily. Octane was used very early on, but rusty tanks and rapidly degrading fuel lead to the use of tetraethyl lead. Boy, those were the days. Lead was good stuff.

Just my opinion from my short experience with those companies in PA.

In my experience, the cheaper fuel is probaby no different than Exxon, and may have even come from the same source.

Curtis Mittong

use the best gas you can run,I run premium 91 or above all the time

[Mr 5 0]

Curtis:

Thanks for the informative octane info.

I've found that raising the initial timing from the factory stock 10 degrees to 12 -15 (depending on the engine condition & mods) is usually worth a good tenth of a second off the quarter-mile et, sometimes more and this little adjustment almost never fails to produce this result.

Using higher octane gas after this timing advance simply avoids potential problems with detonation and is easily worth the peace of mind.

It has nothing to do with gas company ads or anyone's misconceptions, just real-world track experience and buying a cushion of safety for your engine.

I don't care to experiement with how low an octane I can run or how cheap I can find some gas with my beloved 5.0

On my wife's bone-stock Mazda 2.0 with stock timing, I'm not so fussy. 87 octane is fine and I have no brand loyalty at all.

As I stated, I don't care about brands, Sunoco just happens to have the highest octane available in my area and I prefer to stay with that. Price is a minor consideration and for what it's worth, after 115,000 miles, my injectors are still clean and I've never had a deposit on the plugs or any gas-related hassles.

Works for me.

[drudis]

In Detroit, Sunoco is 10% gasohol.

With alcohol being 50% as much BTU (energy) as gasoline... You are paying for 90%Gas + 10% alcohol (which is really 5% gas sort'a), so you really only get 95% of the gasoline you are buying.

(Did that make sense?)

[PKRWUD]

Originally posted by drudis
In Detroit, Sunoco is 10% gasohol.

With alcohol being 50% as much BTU (energy) as gasoline... You are paying for 90%Gas + 10% alcohol (which is really 5% gas sort'a), so you really only get 95% of the gasoline you are buying.

(Did that make sense?)

But, alcohol has a slower burn rate, which supports higher compression and/or more ignition advance. Does that mean that gasoline that has gasohol added has the same benefits as other manufacturers gasohol-less gasoline with a higher octane rating?

[curtis73]

MR 5.0.......... Ah, quite understandable.

I come from PA, so I'm used to poopy gas in the winter. So what did I do? Bought a diesel and moved to Louisiana where there is so much parafin and crap in the diesel. I can't win. Down here its so frustrating. Whereas up north many times stations will just switch to the good #1 diesel in the winter, they sell it as a super premium diesel down here. When the weather man predicts a "hard freeze" as they call it (which means 34 degrees...that's not a joke) the "premium" diesel prices skyrocket. Fuel is cheap down here right now at just under a dollar for 87 octane unleaded and about $1.01 for #2 diesel. When the weatherman says cold weather, the $1.14 price for #1 diesel jumps to about $1.35. I laugh and go to the cheap pumps. I usually don't look for #1 diesel until about 15-20 degrees for sustained periods.

Curtis

PS. now that its getting nice here in LA, I'm moving back to PA where its cold. I'm not a very smart man.

[joe4speed]

I use 93 in the Stang, 93 in the Ninja, and 89 in the Olds!

[Chevyguy]

When I was towing my big block back from Mi with my mustang, I ran into pinging problems when I hit the uphill grades on the NY thruway. The Gas that I had filled with was 87 octane with 10% ethanol. Even though alcohol has more octane, it also has less btu/gal and burns at a lower air/fuel ratio. something like 6:1 vs 14:1 for gas, this is why alky carbs have giant jets. So.. adding 10% alcohol to gas is like watering it down, and can cause some leaning out. I had to fill up with some 94 Octane before I got to Mass since there is a high elevation pass.

Running more Ignition lead will feel like more compression since it builds cyl pressure. But.. it is different, the fuel is still burning longer, and more compression does probably give more power than low compression and more timing.

[chatcher]

so mr5.0 running 94 with an advance in your opinion is better than running stock with 87 is that the general consensous

[Coupe5oh]

Tell ya what, i know 93 octane smells alot stronger than 87 octane, my dad works on gas pumps, i used to help him when i was younger, you would be surprised bye how much water those in ground tanks hold on the bottom of the tanks, i think it is 8 inches where the sub pump picks up, I checked water levels before, and found up to 7 inches of water.....not good, so I try and choose a well established company that you know maintains their equipment, such as chevron, texaco, ect...I have gotten bad gas before at some quicki mart, luckily that was not ran through my mustang, down here the agriculture department just checks the calibration of the actual pump, not gas quality, that is probaly inspected once it leaves the refinery.

I hear the fresher gas is, the better, more accurate the octane is, I sometimes see a truck dumping fuel in the ground at a store, i try and get gas there the next day.

I only run 93, sometimes vp 99, cuz timing is at 16* 99 octane doesnt improve, or degrade performance in my car, it just insures me i wont lose a gasket to detonation, really good to run on a hot day.