More go for the buck

[Donald Stahl]

Todays gas prices are dropping, but what will they be next Spring? Experimenting with some items to improve gas mileage, I have tested and come up with thoughts which I would like to share with you.

There are three things I have found to be effective increasing mpg. Firstly, I have installed a K and N air filter in our Odyssey. That added about 2 miles per gallon. Secondly, each month I pour a small amount of Lucas Fuel Treatment in the gas tank, that cleans the fuel injectors.

The third thing was a recent addition, that of synthetic oil, same weght recommended by the manufacturer. That added yet another 3 -4 mpg.

On a recent trip to Phoenix from Show Low, 6400 ft. down to 1000 ft, got a solid 30.5 miles per gallon. The drive back home registered 28.9 mpg.

Haven't yet tested at highway speed on the flat, but expect to do quite well. Next Spring will tell the story if there will be an increase towing the Casita.

For those of you who drive Odysseys, the 2004 model is rated at 25 mpg, that being the results by EPA at 55 mph on level ground.

One plus with synthetic, even though it costs more, 5000 miles can be done between changes. As for the air filter - never need to buy another one as it can be cleaned with a special solution available at auto parts stores, and that between 50,000 and 100,000 miles.

[Larry B]

Donald
when I went from show low to phoenix I just shut the engine off
and coasted not much for gas but the new brakes sure cost alot...
seriously thanks for the good hints.

[Roger H]

I do the same things... I use full-syn oil and have a K&N on the Excursion. Believe it or not, at 55mph I have gotten an average of 19mpg over one trip of 130 miles with it! Usually, though on average it's at 13-14 mpg, which is probably still significantly better than average for an Excursion.

A caveat on the K&N though... there are some significant arguments against using them in terms of the grit your engine can suck down. If your driving is primarily on paved roads and not a lot of dusty areas, I think you're probably good. If your vehicle spends a lot of time in areas with blowing dust or sees lots of non-hard surface road time, I'd recommend you stay with the best (most filtration) air cleaner and your stock system.

The argument is that these newer vehicle intakes are computer controlled for the maximum air intake anyway, so if that's the case, how can the K&N allow more air in than the computer allows the mixture to call for? Further, the K&N (and clones) don't filter as fine as the stock and better aftermarket filters, allowing more fine particulate grit to enter the air intake and subsequently the combustion chambers.

Intuitively, that argument is sound. The real question is, how much, if any damage do those particulates really do, and what is the volume of them really anyway? I dunno... and frankly, between the syn oil and the K&N there really is a noticeable increase in gas mileage!

I also use K&N racing oil filters on the Ex and on our '92 Mitsu 3kVR4. I use Wix oil and air filters on everything else.

Roger

[Bill Abbay]

On my old '93 GMC, after installing the K&N air filter, going to synthetic oil, adding two different oil additives, installing a magnetic fuel vaporizer, a catalytic fuel atomizer, adding injector cleaner to my tank, installing a HiTech electronic ignition, and using a couple of anti-friction additives, I had saved so much in gas usage that I hardly ever needed to buy fuel. And, while going up hills was ok, going down the other side was a problem. I'd have to pull over from time to time to drain off the extra gas. It became such a hassle, that, after two tickets from the Highway Patrol, I had to sell it. The new owner says he never drives it; just leaves it idle in his front yard and sells gas to his neighbors. That last sound fishy, but the rest is true, I swear.

[Donald Stahl]

Good points about particle filtration, however dust is not a factor where we live. The Phoenix valley? Plenty of dirty air there. As for turning off the engine and coasting? Lol !! The distance is about 180 miles with many hill climbs in between ! (Just to let you know if you are planning that route on your trip).

Any of you notice any difference pulling your respective trailers? I mean, as opposed to what you got before the mods?

[Brian B-P]

I use synthetic oil in my (relatively) new van, and have used it in the past for better winter performance, and in severe duty sitations (racing). Towing our trailers is certainly severe duty use, and I think a good fully synthetic oil is a good idea, but I would not extend oil change intervals based on its use. The oil needs to be changed due to contamination and exhaustion of the additives, not so much because the oil itself is breaking down.

While the correct viscosity of synthetic oil might reduce engine drag, particularly at low engine temperatures (while warming up, the synthetic oil flows more easily than conventional), Donald's large change in fuel consumption is surprising. A number of vehicles come from the factory with synthetic oil (often Mobil 1), and if this kind of economy gain could be realized with a switch to synthetic oil, I'm sure virtually every vehicle would be so equipped. While Mobil's web site mentions "excellent fuel economy" in the product description for Mobil 1, none of the detailed information or Frequently Asked Questions mention it again, and no specific claim is made, which makes me think that they do not really expect an improvement under normal conditions.

While I'm not questioning Donald's individual experience, I do not understand how reducing the restriction of the engine's air intake system could make a (roughly) 10% difference in fuel consumption. While the high-load condition of towing is the situation in which filter restriction would be most significant, I just find it hard to believe that there is that much restriction in the stock filter. Again, as with most easy-gain modifications, if it were truly that easy I think Honda would ship Odysseys with an equivalent filter - much money is spent by the manufacturers for much smaller gains.

With the ever-increasing criticality of clearances in modern engines, I would be very concerned about any change which might increase dirt intake into the engine. I used a K&N for many years on a Toyota car, and had great engine life, but I was quite careful to maintain the condition of the filter. I only used the K&N to save money compared to buying disposable filters. For the current van, I am using stock filters and have no plan to change.

[Steve C.]

I have used K&N air filters in four vehicles, and don't think I will bother installing any in the future. I never noticed any significant gains in mileage or performance, even though I was hopeful for some change. Lately, I have removed and discarded the K&N on my chevy PU after I began to discover fine grit in the throttle body. I installed a Napa filter, again with no noticable change other than the throttle body remaining clean. If I remember correctly, the Napa was around 8 bucks verses the $40 or so for the K&N. When you factor in the cost of cleaner and oil, as well as time wasted, I think it will take many many years berfore the K&N will "pay" for itself.
Currently I have only one remaining K&N, installed in my old Corvette, and absolutely no plans to drop one in my newer Envoy. I believe the risk of contaminating the MAF sensor with oil is too great, and the relatively poor filtering performance is not reassuring.
I have used synthetic oils for years in all my tow vehicles, mainly because they will retain viscosity and lubricate during severe use. A little added insurance against component failure. Cannot say I have seen any great increase in mileage so far, but will monitor it more closely when I convert the Envoy to synthetic engine oil at its next oil change.

Steve.

[Pete Dumbleton]

Simplistically put, if you make the holes in the filter bigger, you get more air thru but you also get more debris -- If you leave the holes alone, but manage to get more of them, by clever folding of a larger filter sheet or by a larger filter, then you can increase thruput of air and still restrict debris.

Regarding syn oil, my brother had a fleet of vehicles in Vermont (he was the port engineer for a ferry company) and they did routine oil testing, changing when either needed or at one year, whichever came first -- There were Toyota pickups in his fleet with over 400,000 miles on them -- The contaminants were in the oil, but weren't breaking down the oil (they were using the commercial version of Mobil One) -- One truck was not allowed out of the yard because the rest of the truck was so rusted they were afraid it would collapse around itself on the ruff streets.

Another unadvertised plus for syn oil is that in the event of a cooling system breakdown, the syn oils generally have much higher temps before they break down, so you are less likely to do damage to the engine.

Also, of course, was that the trucks would start regardless of how cold it was because the syn oil still flowed.

[Craig Nold]

Pete,
I have to agree with your assessment of the benefits of using synthetic oil but not just for the added safety factor in the event of cooling system failure. In recent years, manufacturers have resorted to building engines that run at higher temperatures to meet emission standards and from what I have been reading in the automotive news, that old engine killer, "SLUDGE", is back. I thought sludge was history like smallpox but apparently not. Consumer Reports has been keeping track of those engines that seem to have the worst problem with the formation of sludge. They recommend using synthetic oil and changing it according to the “extreme use” schedule in the vehicle's manual.
While neither of my Toyota trucks is on the list, I began using synthetic oil when I made my first Alaska trip because I expected to go over the recommended oil change interval. Even though I put 5,000 miles on the oil in less that a week, towing across North Dakota in 120 degree temps would have to be considered extreme.

Sludge Report

[Dan Meyer]

If all of these items had any effect on fuel economy, either indivually or in concert, automakers would use them at the factory to increase their CAFE numbers.

Since the automakers do not use these items (except in circumstances where using them helps boost sales), I can only conclude they have little effect on economy of operation.

-- Dan Meyer

[Donald Stahl]

Dan,
Respectfully, on what do you base your conclusion? I am here to testify that I have had a 5 to 6 mile per gallon increase on our buggy. Is what the manufacturer does or does not do relevant?

Prior to using a full synthetic oil, I called the service department at the dealership where we bought our van. I was told to not waste my money on synthetics, if they worked as claimed, all their service mechanics would be using it in their personal vehicles. If I heeded this advice, I would not have discovered for myself that synthetics can increase gas mileage.

Again, I ask on what certain conclusions are based. There may well be unpublished reasons why such oils are not in the owners manual to begin with. Honda sells it's own brand of oil. Could that be a reason? Profit?

There is testamony given here by others which points to mileage increases. It is not from my imagination that I write of mine.

Incidentally, I just inspected my air filter, found no particulates inside the throat of the carb. Of course, that doesn't say anything conclusive either - it just may be that air borne particles are very few where we live. Or, it may be that the filter is doing it's job.

I think I will stay with what I am doing and enjoy the rewards. Don

[Lizbeth]

Also make sure your tires have enough air in them. Simple but true!

[Steve C.]

There are some independent air filter tests at
Air filter test 1
Air filter test 2
These tests confirm that a K&N filter will have, at least when new, a slightly lower restriction than a paper filter. Unfortunately any increase in HP will be minimal and then only under full throttle operation at redline RPM.
This is an advantage for racing engines at the track, but not for towing applications. The tests also confirm what I have seen, the K&N is one of the worst at removing grit. Since grit removal is the primary function of an air cleaner, I will choose to keep OEM style air filters in my tow vehicles.
Steve.

[Kent]

:4: The main difference between stock replacement K & N filters and ordinary filters like Fram is the material that they are made of. Your typical paper filter will over time clog with dirt and swell from moisture restricting the airflow. These types of filters are known as surface loading. Contaminants are captured on the surface and as the surface loads up less air gets thru. The many layers of oil impregnated cotton material that K & N is made from will not clog like paper; it is known as depth loading and actually captures more dirt than stock filter. This type of filter can hold more dirt per square inch without restricting airflow. This type of filter will have the least improvement on mileage and horse power though. There main advantage is saving money over time because they are cleanable and reusable with modest improvements in mileage and performance.

You’re biggest and noticeable changes will happen when you install a Cold Air Intake System. This replaces the restrictive air box and plumbing up to the air intake of the engine. The stock box is very restrictive and the first thing you will notice about the stock air intake system is the flexible ribbed tube that allows you to lift up the lid on your stock air box to replace the stock filter. These ribs disrupt airflow, any airflow that is smooth and flows freely will improve performance this is the basic principle and reason for the aftermarket Cold Air Kits. Their tubing is smooth walled allowing a smooth flow of air which equals more efficient air flow to the engine. Add a more efficient air filter and you improve the airflow. It is same principle for smooth fuel intake manifold passages. The reason they are called Cold Air is that they typically seal off the filter area from the engine compartment forcing cold or cooler air into the filter area. Colder air is denser, denser air means more air.

For manufacturers it is give and take with fuel economy, performance and what the average Joe will pay for. Installing a high end intake system would only raise the price and the average person doesn't want to clean their air filter. They just want to buy a new one and throw the old one away.

Using my Explorer V8 as comparison, 22 gal. Fuel tank, cost of fuel at $2.09, 13 mpg and 15,000 miles a year would equal $2411.54. With just a 1 mpg gain in mileage that would reduce the cost to $2239.29 per year, a savings of $172.25. A 2 mpg gain would equal $321.54 per year. Now throw in a 7 horsepower gain in performance by adding a Cold Air Intake it is a win, win situation.

As far as synthetic oils it is proven to improve performance and mileage when you change engine, transmission and differentials to synthetic oil. It is simple physics, less friction equals less work to do the same job. As with everything you have a trade off, synthetics are more expensive.

Winded aren't I! :4:

Picture of Cold Air Intake

[Steve C.]

:4: The main difference between stock replacement K & N filters and ordinary filters like Fram is the material that they are made of. Your typical paper filter will over time clog with dirt and swell from moisture restricting the airflow. These types of filters are known as surface loading. Contaminants are captured on the surface and as the surface loads up less air gets thru. The many layers of oil impregnated cotton material that K & N is made from will not clog like paper; it is known as depth loading and actually captures more dirt than stock filter. This type of filter can hold more dirt per square inch without restricting airflow.

Please take the time to read through the impartial tests (especially #2). In the past, I also blindly believed the advertisements and installed several K&N air filters, the first 12 years ago. Any miniscule HP gain was unnoticable, but the grit deposits in the throttle body over time were very obvious.
Revising the entire air cleaner intake structure for smoother airflow and access to cooler air will increase power, but the drawback is a huge increase in intake noise. This intake howl often persuades people into believing a big change has occurred. The reality is that it is only a few percent more and, if it wasn't for all the racket, it would be unlikely you would feel it "in the seat of your pants." This is the primary reason manufacturers do not employ this system on everyday grocery getters. But hey, if you like the sound - go for it!
Steve.