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Gas Saving Gizmos & Gadgets
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Comments
Steve, Host
I still like my car a lot, I admit. I've gotten attached to creature comforts like a great sound system, moonroof, room for my friends and stuff without using bungee cords, not having to wear a helmet, :shades: stuff like that. I have a great tool I use to save gas now that the "cheapest" stuff has been costing about $3.21+ a gallon for so long: I don't step on the gas as fast... and I let the transmission shift sooner. I limit my speed. I purposely let people "race" around me (since my car looks the part). I don't let the car idle. When I'm alone I'm frugal with the A/C to the nutty point of using the compressor mostly when going down hills and slowing down, and usually cutting it out when accelerating from a stop (it gets cool soon enough unless it's been parked in the hot sun for a long time). And, I anticipate my throttle changes long ahead whenever I can. By the way, these are big changes for me, because I'm used to driving with a lead foot, and I like it.
Now I drive like a cheap SOB, but I feel like I'm achieving more than saving money, I'm doing just a little to import less oil and damage the environment a little less. With the "attitude changes" the fuel economy on my RX has gone from an average of about 19 to 25 for the past 7 months... that's a big difference to me without any significant outlay or fragile stuff.
Rocky
"If it's too good to be true, then it is too good to be true". As PT Barnum said..."There's a sucker born every minute"!!!!
I guess this is the reason that Ford turned around and installed a Tornado Air Charger system on the Futura Concept that was in a recent Car and Driver mag.
It doesn't work on some vehicle because the manufacturer already has a system like it in place. So if you are looking at one of these check to make sure your vehicle will be able to accept it.
Odie
Odie's Carspace
Oh man, you almost had me good there odie. I like your sense of humor. I was almost convinced you were completely serious until you mentioned that article on the Futura Concept......
Good one...
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I've been testing the following in 1,000 mile intervals, all separately from one another.
1. K&N air filter -- % of improvement on fuel mileage = NONE
2. Synthetic oil -- % of improvement on fuel mileage= 1/2 mile per gallon, consisently.
3. Switching to Premium Fuel --% of improvement on fuel mileae = NONE
4. Inflating tires to 38 pse --% of improvement on fuel mileage = perhaps 1/3 to 1/2 mpg.
5. Installing after-catalytic performance muffler==% of improvement on fuel mileage = NONE
The problem with such small gains in MPG is that one can't really tell if they are just statistical variation or not due to other uncontrollable conditions.
TEST CONDITIONS: Driving same roads in the same way, with no wildly variable climate changes (California), at very low altitudes and temperate weather.
The only tactic that makes a noticeable difference for me is switching off the A/C. Of course, the interior of the car is then in grave danger of sustaining flood damage.
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Rocky
I have yet to see any reliable reports on any of these that make much difference. I hope he did not put ALL his money into this investment. Now I do remember that the he said his dad was also investing in some yellow button company...text yellow pages to your cell phone or PDA... Dang, don't think this guy is going to have a lot left for retirement :-).
I rather doubt premium fuel would raise gas mileage since if it were that easy for an automaker to rise their fleet average they'd require premium in a heartbeat. To improve fuel economy even 1 mpg, automakers spend countless millions of dollars on technology and weigh-saving materials. A 2 or 3 mpg jump would be a tremendous competitive advantage over their adversaries, and they would absolutely lunge at any such "easy way" if it were possible IMO.
I've discovered a trick that I can do with my '85 Silverado, which might save me about 1-2 mpg depending on traffic/weather conditions. When the weather gets warmer, I swap the air cleaner top with something that lets it breathe better. This truck has a tall 5" air filter, and the top of the cover extends down about 3 inches. I put my non-running Dart's air cleaner top on, which is flat, and it opens up the air filter all around.
I think it really helps performnace more than fuel economy, but I have found that it'll maintain any given speed with a bit less pedal pressure, and I don't have to stomp on it quite as hard to get it moving from a standstill.
And when you're dealing with something that normally ranges in the 10-13 mpg range, an extra 1-2 mpg really helps alot!
The air filter does not give noticeable restriction except at WOT. What you are doing to improve mileage is bypassing the air warming system that brings air from the tin shield around the exhaust manifold to the air cleaner. The cold air having more mass than warm air results in a slightly leaner mixture. This is okay in warm weather, but will result in rough idle or your carburated engine, especially with a cold engine, when the temperature falls.
Harry
I'll probably put the proper air cleaner top back on around late September/early October. I think that's when I swapped it back last year.
My favorite gas-saving gadget is a rock glued to the back of the pedal.
Regarding your experiment with this filter, please keep in mind that UOAs from K&N equipped cars over on the BITOG web consistently show higher silica (sand) readings than cars fitted with the OEM filter. That and the hot wire used for measuring intake air density is often damaged by the oil used in the K&N filter element.
Good luck with your test, keep us posted.
Best Regards,
Shipo
Changing the shape and resonant length of the intake tract will cause substantial changes to the engine's torque curve. This has been documented repeatedly in dynamometer tests. If you have a manifold vacuum gauge on a car, you can quickly see how much difference changing intake length makes. And this is why motorcycles, race cars and hot rods have those long intake extensions on their engines. Stock air intake systems are usually designed primarily to reduce sound levels, which often creates a system that is a very poor match for the performance characteristics of the engine. There is a 'small' company in Southern California called Edelbrock, which has become famous by designing performance boosting replacement intake manifolds for popular engines, which change the shape and length of the intake passages to tune them to match the engine's breathing characteristics. And there are now a half dozen other companies which also make such parts.
Now that awareness of the importance of intake tuning has become widespread, filter manufacturers like K & N have gotten into the act, by applying the same engineering principles to air filter assemblies. And even the after-market exhaust manufacturers are finally becoming aware of the scientific principles of controlling pulse reversion, which they've long overlooked. So we're all getting wiser; and as a result, engines now run better.
But you are right; just adding a low restriction filter in the stock location won't do much of anything. It's those long pipes and the cold air that make all the difference.
I'd also like to mention that the increase in sand getting into the engine which you mentioned, is probably more related to fact that ram air systems move their air pickup point away from the relatively quiet and protected under-hood environment, and place it right out in the wind and dust that bombards the front of the vehicle, than it is to any lower filtering efficiency (unless the filter is not oiled, which is lately becoming a common practice). Unfortunately, all too many people either don't oil their K & N filters at all; or else over-oil those filters when they service them. And both of those practices cause different sorts of problems.
So, as far as I'm concerned, if you're not wiling to learn and practice properly maintaining a K & N filter, then you'd be better off with a ram air system that uses a paper filter.
For the record, my argument is that a K&N modification to the intake system of virtually any recent vintage of car will cause the engine yield a bit more power at wide open throttle (WOT), both due to the lower restriction of the filter element and the new plumbing, and any theoretical differences in induction resonance. That said, I'd wager that a K&N system doesn't do squat for the induction resonance.
Further, it is my argument that the addition of a K&N system cannot and will not improve fuel economy, as the system does nothing to the fuel injection system, a system that weighs the intake charge and dispenses the exact amount of fuel necessary. If (and I say "if" only for the sake of argument) the K&N system allowed in more air during a steady state cruise, then the fuel injection system will simply supply more fuel keeping the air to fuel ratio exactly the way the designers of the engine specified. Net result, the fuel economy doesn't change one wit.
Best Regards,
Shipo
My work with the Metro builds on years of previous experience with tuned intake and exhaust systems on both motorcycle and car engines.
My point is that I know from hands on, direct experience that ram tuning DOES A WHOLE LOT for the induction resonance. So your theoretical arguments to the contrary just don't move me.
I do concur that changing the volumetric efficiency in a modern fuel injected engine will not alter the air/fuel ratio. I'm glad that is the case, because these engines fuel mixtures are already set for best economy.
The increased economy from a ram tuned intake does not come from leaning out the mixture. It comes from the increased torque, which enables the engine to operate at a smaller throttle opening while cruising at speeds that previously required more throttle. A smaller throttle opening means less air will be drawn in, which in turn means less fuel will be injected. And that creates better economy.
To say that I'm skeptical is an extremely gross understatement. In my experience, changes upstream of the throttle body don't amount to anything at a steady state cruise. Statements such as yours regarding the throttle setting and less air simply makes no sense from an engineering perspective. Volumetric efficiency is simply a measure of how much air and fuel can be crammed into a combustion chamber. Pack less air and fuel into the chamber and you'll get less power out of the engine.
Said another way, until you've convinced the auto industry at large of your miracle skills at induction plumbing, I'm not buying.
Best Regards,
Shipo
Thanks for your interest!
Joel
Failing the above, you can argue all you want, until you come up with more specifics about how you managed to coax more power out of any given unit of intake charge simply by changing the plumbing upstream of the throttle body, I'll remain extremely skeptical. Keep in mind, as a general rule folks who offer only oblique references and illogical arguments have typically been found to have the same credibility as your run of the mill snake oil salesman. Your existing arguments seem to bordering on that realm.
Best Regards,
Shipo
Joel
I am looking into buying a 96 Geo Metro and was wondering what kind of improvements you've had with your ram air system.
But bear in mind that my 1990 has the 3 cylinder engine, while some of the newer ones used 4 cyl engines. The system would also be adaptable to the 4 cyl, but it would probably require some retuning.
If you want to discuss this in more detail, we'll need to work out a way to communicate more directly and privately.
The Geo I am planning on buying is a 3 cylinder, I think that was the last year they build the 3 cylinder.
THANKS!
Hmmm, apparently the real world that isn't always correct. In aviation circles it has been long known (as in many decades) that by heating the intake charge to at least 40 degrees Fahrenheit, the engine will propel the plane further per pound of fuel consumed.
Best Regards,
Shipo
In this case, it seems that each of you is referring to a different truth: Heating the intake charge will insure optimal atomization of the fuel, which can raise economy. There were several famous add on devices that heated or totally vaporized fuel; which were claimed to dramatically increase fuel economy. The most well known of these was developed by a Canadian inventor named Charles Winton Pogue. He built an elaborate fuel vaporizing device, which he installed on a Ford V-8. Newspaper accounts reported it got over 200MPG. More recently, a Texan named Ray Covey redesigned this device, and sold kits to convert your car to vapor fuel. He also claimed economy of 50 to 150MPG on big sedans and vans. But carrying a tank of vaporized fuel under the hood involves a great risk of explosion.
The other side of this coin is that, when you heat the intake air/fuel, the charge density is reduced; which leads to a lowering of the maximum power potential. That is why professional drag racers use refrigeration cans to cool the fuel before it reaches the engine. This is also why high performance turbocharging systems use intercoolers to cool the intake air that has been compressed by the turbo. And this is why ram air systems pick up their incoming air from a point that is not in the warm underhood atmosphere.
The legendary engine tuner Smokey Unick built an experimantal car that integrated these two opposite principles. He took a 4 cylinder Pontiac and installed a heat exchanger to vaporize the intake charge. He then ran the vaporized mixture through a turbocharger (or supercharger-I don't remember which it was). The result was a car that got 40-50 miles per gallon, and was much more powerful than the original.
So, like in so many issues, there is more than one truth to consider.
Joel
The problem is that you didn't qualify your earlier statement, you simply said, "...the lower your ambient temperature(air temperature) is, the more efficient your system will be.", and to that I completely disagree.
Now, if you're talking about "volumetric efficiency" then yes, I agree with your statement. The colder the intake charge, the heavier the charge; the heavier the charge, the greater the power output from any given combustion event (assuming the mixture is rich enough).
The above said, combustion efficiency suffers when the charge gets too cold.
Best Regards,
Shipo
Nothing really new there. Pratt & Whitney ran very similar studies back in the 1930s on their "legendary" radial engines and produced very similar results.
"So, like in so many issues, there is more than one truth to consider."
Quite true.
Best Regards,
Shipo
In the 1930s P&W pioneered a methodology of fuel injection that was downstream of one supercharger (or turbocharger) of any design and immediately upstream of a second low ratio centrifugal supercharger. The resultant atomization of the fuel made a huge difference in the smoothness and power of those large radials (imagine trying to get even fuel distribution to a 2,800 cubic inch, 18 cylinder engine). In fact, even though those engines were developed some seventy years ago, they are still among the most efficient intermittent combustion gasoline engines ever built (as measured by the BSFC).
Best Regards,
Shipo
Agreed. I might even buy a tad more than that.
"And yes, getting even fuel distribution in an 18-cylinder, 2-row radial at altitude is difficult!"
And they figgered all that stuff out on slide-rules and SOTP testing. I read one account of an engine balance test (the R-2800 I think) with a full size propellor where the prop broke off the engine and went through a multi layer cinderblock and brick wall. Yikes!
Best Regards,
Shipo
Ohhhh, would I love a job like that. ;-)
Best Regards,
Shipo
That same type of "seat of the pants" R&D still takes place today. A few years ago, Harley Davidson wanted to build an EPA legal version of the engine in their VR1000 racebike. They tried, but were unable to solve the engineering challenges of integrating sound control, performance, and durability. So they farmed the project out to Porsche. Porsche built a whole series of V-twin test engines, and ran them on the autobahn until they either broke, or didn't perform as desired. They then disassembled those engines, analyzed the parts for signs of wear, and redesigned them. They eventually came up with a design that met their specifications. And that engine is now used in the Harley Davidson V-Rod.
Some things to consider.
As was stated, the less air you pack into the cylinder, the less efficient it will be, the less power it will make. That's physics.
Also, if your fuel and air is not balanced to what the computer wants, fuel economy suffers.
Guys adding cold air intakes, re-usable filters designed to "create more airflow" and other bolt on addons aren't going to gain much without re-programming the computer to the changes that those add ons make.
As for the heat exchanger for the turbos.
Diesels have had them for years. Diesels call them prechargers. They are designed to cool the air before it gets to the turbo. Smokey wasn't the first person to test the theory.
Here is an article on fuel economy and add-ons which hits the mark nicely.
http://www.batauto.com/Forums/index.php?topic=3.0
As for intake after the throttle body. A statemtent was made once that smoothing out the intake gives better air flow. It may, but it also causes problems with fuel atomization. You see the fuel needs the turbulents to help keep the fuel atomized or cause it to further atomize.
Correct placement of where the turbulents are, is also very important.
Ok, I'll go back to my corner now. :P
Here again you need to define "efficient". If you're saying the amount of power generated for any given amount of air and fuel in the proper ratio will suffer, I absolutely disagree. If you are saying the maximum amount of power from the engine at WOT, then we are in complete agreement.
Best Regards,
Shipo
Sorry about that, to clarify.....
Most instances, my mindset is always at peak horsepower.
So, yes.
But, at any rpm, the air fuel ratio must have the optimum balance or efficiency and power suffer.
You can have too much air, too little air or too much fuel or too little fuel. At rpms above off idle to before WOT, this is especially critical.
But I want to address several misconceptions. One of them came from the article you referenced, where the author claimed that the 6mpg loss from installing a free flowing exhaust system on a vehicle was due to the increase in the volume of air that was pulled through the engine, and the corresponding increase in fuel which the computer had to add in order to correct the air/fuel ratio.
First of all, potential changes in the volume of intake air required to compensate for a free flowing exhaust are not great enough to cause a loss of 6 miles per gallon IF THE AIR/FUEL RATIO IS KEPT AT THE MANUFACTURER'S RECOMMENDED SPECIFICATION. As long as the mixture is correct, you can vary the total volume within that kind of range and not see much change in economy. Increasing the total mixture volume while holding the air/fuel ratio constant will just result in needing to use a smaller throttle opening at a given speed. The reason free flowing exhaust systems (and radical camshafts) sometimes ruin mileage is because the changes they create exceed the compensating capabilities of the fuel injection computer. When that happens, the air fuel ratio does not remain constant; it becomes way too rich. That's why the exhaust from modified engines often smells so bad.
Another issue which sometimes happens is that when someone installs a free flowing exhaust system, they also remove the oxygen sensor. And this disables the fuel injection system's ability to monitor and correct the mixture.
Fuel injection computers are designed with a limited capability to adjust the mixture. They work fine, as long as the engine is kept stock. But some modifications, particularly to the exhaust and camshaft, create changes which are too much for the computer to handle. And that's why the EPA and CARB approve mild performance add ons, but outlaw radical modifications.
The other point I need to make is that the heat exchanger in Smokey Unick's Pontiac was used to heat the mixture until it was well vaporized. The diesel heat exchangers you spoke of do the opposite; they cool the air to make it more dense.
I'm glad you enjoy this discussion.
Joel