Octane for the Hemi
#21
12-19-2006, 08:50 PM
Captain
Join Date: Dec 2004
Location: New Castle Delaware
Posts: 679
Likes: 0
Received 0 Likes
on
0 Posts
RE: Octane for the Hemi
ORIGINAL: truckin151
You have it backwards. The higher the octane the faster, hotter, andcleaner the burn is which results in a power gain and because your engine is not working as hard to produce the the power anymore you usually end up with a slighly higher mpg (depending on how you drive).
The higher the octane the slower the fuel burns in the cylinder
#22
12-19-2006, 09:12 PM
Grand Champion
Join Date: May 2006
Location: Gilbert, Arizona
Posts: 6,041
Likes: 0
Received 0 Likes
on
0 Posts
RE: Octane for the Hemi
ORIGINAL: Silver Eagle
wrong answer ,High test burns slower, That's how it produces more power to the cylinder It does run hotter that's where the extra power comes from, as for it burning cleaner no way. I know this if your take your truck to DMV for inspection ,it has a better chance of passing the emissions test with regular then high test. .Check it out. If I use 93 oct. in my 04 hemi it's just like someone punched a hole in my gas tank. . As for it burning cleaner ,it all depends on the Additives. And each grade of Gasoline uses the same additive package. Now here's something else to think about. The oil companies are allowed to slide on the octanes by three teenth of a gallon and still be legal. So if you get 89 oct. it can be 88.7 or if you get 87 oct it can be 86.7 Thats a federal regulation.that allows that. In Maryland the companies push to make it as close to the whole number a prossible because that have state labs to check the octane. I worked in PA and we had to do the same. In NJ there private labs and in Delaware they have no testing labs at all. By the way ,my nick name was Mr Octane. because when we did the round robin testing I was alway in the top three labs in the country. A round Robin is a test where 60 labs around the country woud test a one gallon can of gasoline and only the refinery who sent the sample knew what the true octane number is. No one else knew the results until two weeks after the final results were in. But since then I have retired to play with my Truck and my two customized PT cruiser's.
ORIGINAL: truckin151
You have it backwards. The higher the octane the faster, hotter, andcleaner the burn is which results in a power gain and because your engine is not working as hard to produce the the power anymore you usually end up with a slighly higher mpg (depending on how you drive).
The higher the octane the slower the fuel burns in the cylinder
#23
12-20-2006, 08:27 PM
Captain
Join Date: Dec 2004
Location: New Castle Delaware
Posts: 679
Likes: 0
Received 0 Likes
on
0 Posts
RE: Octane for the Hemi
Let me tell you a little story about Alcohol. Ever since unleaded gas has been around there has been Alcohol in gasoline. Way back in themid 70'sthe refineries were using synthetic Alcohol. and all that means is that it's made from crude oil not corn. as it is today. Usually they keep the blend below 15%.Now that grain Alcohol is out they still use the synthetic but not as much.Your right it does burn cleaner but it reduces your gas mileage by 10% on an average. In the winter the refineries use a lot of Butane as well. It has to do with vapor pressure .In the summer it's 7.0 percent allowed and in the winter it's 15%.It just makes the gasoline burn quicker. It has to do with arir Quality.. One think I didn't say before is is you live in high country the octanes needed are lower in Debver they used to sell 85 oct and 87 was mid grade. So 89 was high test. I don't know what it is today I haven't been to Denver since 1995. WhereI live is at sea level. So the Fuel burns different here then in the mountain areas of the country. Denver is a mile higher above sea level. This makes a big differance. Whats it like in Arizona?
#24
12-20-2006, 08:58 PM
Grand Champion
Join Date: May 2006
Location: Gilbert, Arizona
Posts: 6,041
Likes: 0
Received 0 Likes
on
0 Posts
#25
12-21-2006, 03:55 AM
Record Breaker
RE: Octane for the Hemi
[
I sometimes qustion when I'm gassing up if the Mid grade pump is conected to the Mid grade tank in the ground, or the Supreame, You can't pull out a chemistry set and check the octane on the spot.
Who's to know if the high buck gas is not reguler with a higher price. And who watchs out for this? in Canada/U.S.A.
For the cost of 104+ octane boast, over 6 bucks Cdn, dosent make it woth while for 350 ML of go spark
ORIGINAL: truckin151
Now here's something else to think about. The oil companies are allowed to slide on the octanes by three teenth of a gallon and still be legal. So if you get 89 oct. it can be 88.7 or if you get 87 oct it can be 86.7 Thats a federal regulation.that allows that.
Now here's something else to think about. The oil companies are allowed to slide on the octanes by three teenth of a gallon and still be legal. So if you get 89 oct. it can be 88.7 or if you get 87 oct it can be 86.7 Thats a federal regulation.that allows that.
Who's to know if the high buck gas is not reguler with a higher price. And who watchs out for this? in Canada/U.S.A.
For the cost of 104+ octane boast, over 6 bucks Cdn, dosent make it woth while for 350 ML of go spark
#26
12-21-2006, 04:02 AM
Record Breaker
RE: Octane for the Hemi
With Desiel Flue, thiers a tint ( purpule, Red ) to use for on Road/off Road, esp. in the southern states, Last time I was traveling with my Kin, down yee a younder in Gritt's counrty, Us Canayydians were derailed By some Fine Southern Finger sticking Law enforment officers who determined the Desiel Flue in the truck was the right refignment for highway use.
#27
12-21-2006, 09:32 AM
Professional
Join Date: Sep 2006
Location:
Posts: 168
Likes: 0
Received 0 Likes
on
0 Posts
#28
12-21-2006, 10:56 AM
RE: Octane for the Hemi
You can not reliably predict whether a gasoline blend burns faster or slower based on octane. Methane is extremely fast burn and rated 120 octane. Toulene is slow burn and rated 110 octane.
You can not reliably predict what MPG you can get based on octane either.
The best way to guess which gasoline will give the best MPG is to buy one of those 1 gallon gas cans and weigh EXACTLY one gallon. A gasoline blend that weighs the most for 1 gallon (density) will probably give the best MPG too.
want more info?
http://www.epa.gov/orcdizux/rfgecon.htm
has a survey of how many BTU's of heat were actually in gallons of gasoline bought many different places, and during the season of 'summer blend' and winter blend.
You can not reliably predict what MPG you can get based on octane either.
The best way to guess which gasoline will give the best MPG is to buy one of those 1 gallon gas cans and weigh EXACTLY one gallon. A gasoline blend that weighs the most for 1 gallon (density) will probably give the best MPG too.
want more info?
http://www.epa.gov/orcdizux/rfgecon.htm
has a survey of how many BTU's of heat were actually in gallons of gasoline bought many different places, and during the season of 'summer blend' and winter blend.
#29
12-21-2006, 03:40 PM
Captain
Join Date: Dec 2004
Location: New Castle Delaware
Posts: 679
Likes: 0
Received 0 Likes
on
0 Posts
RE: Octane for the Hemi
ORIGINAL: cyclone429
[
I sometimes qustion when I'm gassing up if the Mid grade pump is conected to the Mid grade tank in the ground, or the Supreame, You can't pull out a chemistry set and check the octane on the spot.
Who's to know if the high buck gas is not reguler with a higher price. And who watchs out for this? in Canada/U.S.A.
For the cost of 104+ octane boast, over 6 bucks Cdn, dosent make it woth while for 350 ML of go spark
[
ORIGINAL: truckin151
Now here's something else to think about. The oil companies are allowed to slide on the octanes by three teenth of a gallon and still be legal. So if you get 89 oct. it can be 88.7 or if you get 87 oct it can be 86.7 Thats a federal regulation.that allows that.
Now here's something else to think about. The oil companies are allowed to slide on the octanes by three teenth of a gallon and still be legal. So if you get 89 oct. it can be 88.7 or if you get 87 oct it can be 86.7 Thats a federal regulation.that allows that.
Who's to know if the high buck gas is not reguler with a higher price. And who watchs out for this? in Canada/U.S.A.
For the cost of 104+ octane boast, over 6 bucks Cdn, dosent make it woth while for 350 ML of go spark
#30
12-30-2006, 03:58 PM
RE: Octane for the Hemi
Thanks stump_breakerfor your response. You've got it correct. Its related to the compression ratio of your engine. Sure the temperature is a bit higher with higher octane but thats not was gives you more power. Octane is the compression thatthe fuelcan take. If you run low octane in a high compression engine it will cause a premature explosion in the cyclinder which causes uneven burning and pitts in the cylinder wall. Thats where all the crap comes from. Sure, your safewith higher octane but if your engine isn't designed to force more air and fuel into the mixture to achieve a higher compression then its waisted money and you don't get much more power for your money. I race bikes that have to run at least 110 octane. If I don't it will destroy the engine. If you have remaped your fuel injection with a computer and are allowing more fuel and air into the cylinders I would be careful running 87. You can install an air intake but, once you've remaped your computerfor more horsepower, keep in mind your forcing more air and fuel into the cylinderfor that power which raises your compression, which in turn requires you to raise your octane. Every variableis related to the other. Your debating single aspects of the whole process. Some of you may have mods and some may not. When I race bikes in the mountains I use a different fuel injection map which adjust for lower air pressure. If I don't I will loose a lot of power. Its not magic, its physics and its the same principles with all internal combustion engines.