How did I get 15.5 MPG?

[Efrain]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">

I get 10 mpg on long trips and around 8.5 mpg around town. Believe it or not, if I have a strong head wind I will get as low as 6 mpg. </div></BLOCKQUOTE>

PhilD, your mpg's seem more reasonable to me. after 10 months, I still can't shake off the 10.9 mpg average I'm getting. Either my H2 was made on a Monday or those guys are just plain lucky. Also, this is the first time I read (in this forum) about higher octanage giving you higher mpg's. Wouldn't the owner's manual say,"Use 87 octane gasoline unless you want better gas mileage, then use 97 octane" What gives?

[Jeff Jackson]

2006 Lux H2

Dealer told me removing the roof racks would improve mileage 1 mpg
Did not remove because I like the look

Replacing the exhaust system and air intake system would improve mileage 3-4 mpg
Had that done. More power but mpg remains the same.

Put in BP 89 octane instead of 87 octane
Noticed a marked improvement in performance and mpg

Read this forum and today I put in Sunoco 94 octane
No change in performance but gas mileage actually DECREASED!!!

I'll try one more tank of higher octane and post the results.

[OrangeCrush]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PhilD:
Octane will make no difference to fuel efficiency. </div></BLOCKQUOTE>

Phil,

I have to politely disagree with this statement. A lower octane gas burns slower and produces more power. (providing it's not knocking)

For OVER a year, I ran premium gas in my Honda 954 motorcycle. I reset the trip odometer (since most sportbikes don't have fuel gauges) and I CONSISTENTLY got 140-150 miles till the low fuel light came on. I did that for over 15K miles.

For the last 6K miles, I have run 87 octane EVERY time. I CONSISTENTLY get 160-170 miles till the low fuel light comes on.

Now, granted, this is on a motorcycle so because of it's weight, aerodynamics and rolling resistance, it may make a much more noticeable difference, but nonetheless, I have noticed this in bike after bike that I have owned.

Lower octane burns slower and produces more power os I can't see how the statement "octane will make no difference to fuel efficiency" can be true. Over the last 20 some years of riding, I can't tell you how many people I have discussed this with came back and couldn't believe the results.

I too was under the impression I was giving my vehicle " a taste of the good stuff".

Just my opinion... well, actually, the Federal Trade Commission's opinion also. Here's part of the article from them.

The Low-Down on High Octane Gasoline
Are you tempted to buy a high octane gasoline for your car because you want to improve its performance? If so, take note: the recommended gasoline for most cars is regular octane. In fact, in most cases, using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner. Your best bet: listen to your owner's manual.

The only time you might need to switch to a higher octane level is if your car engine knocks when you use the recommended fuel. This happens to a small percentage of cars.

Unless your engine is knocking, buying higher octane gasoline is a waste of money, too. Premium gas costs 15 to 20 cents per gallon more than regular. That can add up to $100 or more a year in extra costs. Studies indicate that altogether, drivers may be spending hundreds of millions of dollars each year for higher octane gas than they need.

Here's the entire article. Federal Trade Commission



Mark

PS. Driving easy with my H2, I can get 13.6-14 mpg in town. Driving it normally like I tend to do, it gets 11'ish mpg.

[OrangeCrush]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> No change in performance but gas mileage actually DECREASED!!! </div></BLOCKQUOTE>

Though I hadn't read all the posts, Jeff's post confirms exactly what I was saying. Try another tank Jeff, I think if everything is the same, you find the same results.

Mark

[Poseur]

Another opinion to back up Orange and Phil. Lower octane gas actually combusts more violently than higher octane. It is less resistent to ignition and therefore fires off faster then high octane. On a modern, computer controlled vehicle you might see an increase in performance with higher octane because the computer will allow the timing to advance due to the increased resistance to detonation. If the engine isn't exceptonally prone to detonation with a lower octane fuel,(ie. lower compression) than this benefit is only imagined. In an engine such as a rotary which has a much lower tendency for detonation you actually see increased performance by using a lower octane.83 octane was the choice of racers for years until the sanctioning bodies made it illegal to level the field. Forced induction changes these rules and in that instance you need the higher octane to prevent uncontrolled detonation and engine damage.
At 40,000 miles our 04' has an overall average of 11.5 mpg. I always use 87 octane and have had no issues with detonation. I can average 13-14 on the highway at 70-75 but as soon as there is any stop and go I'm back down to 11.5. On a trip to Savannah where we drove kinda fast 80-90 we averaged about 10. Seems this is about normal for the H2.

[HUMMERcustoms.com/TAZ]

If You will do a search for Octane You will find allot of info and one will be MY lecture on octane and what it means and why it can be different than what the pump says due to how long or how short of a time it has been in the tank at gas station. I have Buddy in the oil business and actually works with the octane quality etc. he is a chemical engineer with a major oil compnany.
Or You could look up My soapbox lecture and see what He told Me. But, Phil is correct in what He says about octane not helping MPG and that low octane is extremely violent burning that is why You have to go to higher octane to prevent detonation when you switch to forced induction.
Also if You should go to a high flow head as I'm doing later this year You should get one that will flow more air and not increase compresion. If You raise compression with forced induction You are looking for trouble unless you do the bottom end work along with the heads.
Stock rig should do just as well on 87 octane as any of the other and You save money.

TAZ

[OrangeCrush]

Boy, don't I feel like a dumbass. Phil, you and I are saying the same thing.... that octane rating does NOT increase fuel efficiency.

I must have misread your statement... I don't know how I missed the word "NO" in your statement that said "Octane will make no difference to fuel efficiency. "

I apologize completely. You and I are saying the exact same thing. It was getting late and I must have misread it.

Sorry.

Mark

[OrangeCrush]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Worst things have happened, at least you didn't call me a self lubricator </div></BLOCKQUOTE>

Well, I was going to tell you to get ....LOL Is that close?

Thanks bud.

Mark

[DeBest]

So now that the myth regarding higher octane gas improving MPG has been put to rest is there any little tweak that might help to get better MPG's?

[Albie]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DavidAragon:


Now, I have an 05' SUV with the stock air filter, box and on a trip from WA state to CA, I was getting 15.5mpg...



</div></BLOCKQUOTE>

its very simple. If you look at the following map. you will see that Cali is down hill from WA. Thus giving you 15. mpg

[Nixxxster]

13 mpg in the city?? you must drive really slow, live it a total flat land, and have very few traffic light....