smoother running

higher temps, faster warm up time

  milage dependent on driving style, as most people that have an engine that is woken up with premium have a difficult time staying away from the loud pedal,

  results will vary per vehicle, would recommend doing a baseline on one, with 87, then do the same driving (as much as possible) in that same one with premium, just as a comparative reference.

  found mine (in sig) likes mid grade the best.

 

Explain how all of that will happen Mike! I predict only an emptier wallet.



Do you understand what higher octane means? You'll gain nothing by simply changing gas.

Here, read this:

http://www.straightdope.com/columns/read/2565/whats-the-difference-between-premium-and-regular-gas

 

Higher octane only helps prevent detonation. If you wanted a real test try fueling up at different brand gas stations

 

For an '85-up 318 89 might be slightly better but for any stock motor that doesn't have a big cam with a lot of timing or high compression anything over 87 is a waste.

 

if they took the ethanol out of the 87 i would be happy running it more often. the ethanol increases the octane rating a couple of points so they can give you crappier gas. i was running 91 octane gas which is ethanol free up till the last top up. my ramcharger took a fairly big dump as far as far as gas mileage goes so i decided it would be a good idea to run 87 till summer rolls back around.

 

Never really looked into but, but I believe the rumours are true. It's not like Shell, Esso, ect.. have special access to brand specific oil wells/ come on get real;they all share the same resources, they might have there own additives. Cant remember if it was Shell or Esso bragging/ promoting nitrogen additive as a better fuel, helps in cleaning the fuel system and engine components. Come on it's an inert gas, what's up you cant aerate the fuel any more, octane numbers is what people look at

 

but up here in Canada pretty much every shell gas station offers ethanol free 91 unless it states otherwise on the pump. i don't think there is a nitrogen additive. i would think just running without the ethanol would help the engine burn cleaner.

 

Best additive is gasoline.

 

but up here in Canada pretty much every shell gas station offers ethanol free 91 unless it states otherwise on the pump. i don't think there is a nitrogen additive. i would think just running without the ethanol would help the engine burn cleaner.

I am up here in Canada and remember it was Shell pushing the Nitrogen enriched fuel, an old/older guy at work brought in a pamphlet from Shell and was bragging how he was getting the best fuel for his yota truck. I dont see how an inert gas cleans a fuel system. Havent seen that stupid commercial or talk about it in the last couple years

 

Maybe if you changed your timing, to take advantage of the increased octane, you might see a tiny difference. But without any changes, different octane will not change a thing.

I used to laugh, no matter what car she had, my Mother in law, always claimed that it needed premium, or would not run right.

 

Maybe if you changed your timing, to take advantage of the increased octane, you might see a tiny difference. But without any changes, different octane will not change a thing.

I used to laugh, no matter what car she had, my Mother in law, always claimed that it needed premium, or would not run right.

Modern fuel injected engines are constantly adjusting the timing, and retard it as soon as knock is detected. Premium fuel reduces knocking which allows for more advance. I've found regular gas to be low quality and possibly even lower octane than advertised with sometimes 10% alcohol added which decreases power and mileage, whereas premium is a higher quality fuel without the alcohol as well as higher octane. Ive found most vehicles run better with premium fuel and improves mileage too.

 

Modern fuel injected engines are constantly adjusting the timing, and retard it as soon as knock is detected. Premium fuel reduces knocking which allows for more advance. I've found regular gas to be low quality and possibly even lower octane than advertised with sometimes 10% alcohol added which decreases power and mileage, whereas premium is a higher quality fuel without the alcohol as well as higher octane. Ive found most vehicles run better with premium fuel and improves mileage too.

So how does Dodge detect knocking? chebys have a knock detector mounted low on the engine, but Dodge either uses something else, or uses a much less aggressive timing curve.

My MIL, never had anything but a carbed car. this was quite some time age.

 

Most if not all modern engines have knock sensors including Dodge. His carbed engine obviously doesn't but I was just saying that modern engines do adjust the timing to take advantage of the increased octane. I would recommend advancing the timing on his engine as well. I am interested in the experiment and I predict his engine will like the premium fuel and the mileage will increase and it will just feel all around smoother and more responsive. keep us posted

 

i know magnum engines do not have knock sensors. dont know if the 4.7/5.7 does or not.  i predict the only noticeable difference will be from, as already mentioned, the possible lack of ethanol in the fuel. interested in hearing the results but not expecting any shocking results

 

If you have carbureted engines if you want more fuel mileage you buy better fuel and lean out the mixture and adv your timing exactly How fuel trim in new engines work. That is the only way you'll see any sort of difference but you also have to factor temperature in.

 

a real test is buy some 100 or 105 octane. we can get this stuff at our pumps out here idk if you can but anyways try it and bump the timing thats how you will get some mpg and some power.my 93 f150 was stock at 10 btdc and on pump junk i could run 13 btdc and with 100 or 105 i could get 16 btdc. so to stay on track with the post fill it full with 93 and bump the timing till u get ping then back 1 degree

 

a real test is buy some 100 or 105 octane. we can get this stuff at our pumps out here idk if you can but anyways try it and bump the timing thats how you will get some mpg and some power.my 93 f150 was stock at 10 btdc and on pump junk i could run 13 btdc and with 100 or 105 i could get 16 btdc. so to stay on track with the post fill it full with 93 and bump the timing till u get ping then back 1 degree

One of the things I miss, from growing up 15 minutes away from Charlotte Motor Speedway - racing gas!

Starvin' Marvin near UNCC on U.S. 29 used to have "TurboBlue - 109.5 octane." Of course, it also had lead, but it ran great in my old '68 Mercury Monterey, with a 390 SuperMaruader. You could also get 110 Octane leaded at the little mom 'n' pop Union 76 stations around Mooresville, as the dragstrip was there off Rt.150.

I haven't seen a racing gas pump at ANY station, since at least 1990 though. Maybe add a QUART of avgas to a full tank? That stuff is powerful though - somebody who KNOWS something better weigh in on THAT; I just know it's around 170 octane, and will MELT your engine in under 5 minutes if run straight!

 

Tune the carb to be lean and turn up the timing. Hell I'm running 23* static and can't get these low compression pigs to detonate.

 

Explain how all of that will happen Mike! I predict only an emptier wallet.

higher octane by my understanding requires more heat to ignite, and burns quicker than lower octane fuel at a slightly higher temp,

some vehicles require it, some run better with it, some that don't need it or shouldn't use it can get up to operating temps sooner, there is also a theory that because it combusts quicker, it can produce greater cylinder pressure, which is inline with prematurely wearing components, or wreaking havoc on components that are already worn.

I do know, when I tried it in my 99 fraud escort, worn and beat 2.0l it came up to operating temps sooner than running 87 or 89 octane. in my vehicle/fuel testing, I go to the same station for all my fuel for a period of 4 tankfuls per grade, and take note of any differences during the 3rd and 4th tanks.

 

higher octane by my understanding requires more heat to ignite,

Then where would that heat come from? Does the engine detect higher octane gas and decide to turn up it's own heat?
Basically, your above (quoted) statement is correct, but there is plenty of heat from the ignition to do it. Higher octane only lets it take a little longer to ignite so the fuel is ignited by the ignition and not chamber heat, but by itself it will not create more heat and make the engine run hotter.

 

One of the things I miss, from growing up 15 minutes away from Charlotte Motor Speedway - racing gas!

Starvin' Marvin near UNCC on U.S. 29 used to have "TurboBlue - 109.5 octane." Of course, it also had lead, but it ran great in my old '68 Mercury Monterey, with a 390 SuperMaruader. You could also get 110 Octane leaded at the little mom 'n' pop Union 76 stations around Mooresville, as the dragstrip was there off Rt.150.

I haven't seen a racing gas pump at ANY station, since at least 1990 though. Maybe add a QUART of avgas to a full tank? That stuff is powerful though - somebody who KNOWS something better weigh in on THAT; I just know it's around 170 octane, and will MELT your engine in under 5 minutes if run straight!

Avgas is usually mixed a few gallons to a full tank of pump gas for a mild street engine. It's about 100-110 Octane (Straight) depending on the type you get. Pretty much all the high octane stuff like 130 has been phased out and replaced with 100LL.

I ran straight Avgas in an old Dodge D50 a few times when I was a teenager, it didn't melt down the poor old abused 2.6L engine. I've also got a few engines that would run on straight avgas (and reap the benefits of it), but its too damn expensive to do that Those particular engines run on a milder mixture, with Methanol Injection added to the vehicle to keep it streetable.

 

It's always been my understanding that running higher octane gas in a vehicle not designed to take advantage of it by retarding timing or other means, accomplishes nothing. The only point of high octane gas is to allow for higher compression without detonation to increase power.

The difference in % or lack of ethanol in it may make a difference though. I don't know how much of a difference it would make. It would probably be difficult to attribute it directly to the lack of ethanol vs possible different driving conditions from one tank to the next.

 

Well i was going to try 100 octane but i pulled into the pump lastnight and forgot the crap was 7.30 a gallon lol

 

http://video.foxbusiness.com/v/2000862202001/

 

have a local station that sells 105 octane no lead, and 112 oct low lead,

  been told that av gas is going in a similar direction, have to ask for unleaded if you need it.