b4 I buy...

I didn't read the test on BITOG, but i did note that the cover page says it isn't conclusive at all. And that I couldn't view the graphics from work. All I know is that when I had a K&N on my car it a) did not increase HP and b) did not filter well as indicated by the solids in the oil that did not come from the engine itself. You can tell it won't filter well by a) reading the instructions that indicate that it relies on the dirt it catches to filter b) looking at (through) it and c) reading the intarweb.

Modern engines are optimized to achieve the best fuel economy, power, and reliability that they can make at an economical cost with acceptable NVH charactaristics for the particular vehicle they're put in. Yes, you can get more HP, but you WILL sacrifice one of the above. Cost, NVH, and/or reliability. Given CAFE standards, if there was a gain from a less restrictive air filter, the car would have a less restrictive air filter in it from the factory. If you notice, the air filter is larger than the intake tube. The restriction of the air filter is largely negated by the added surface area relative to the rest of the intake tract.

In my personal experience, there's no significant restriction in flow from a stock paper air filter, even if it's good and dirty. I base this on back-to-back drag strip passes, some with the filter, some without. Why screw around, right? If an air filter that flows well is better than a stock air filter, wouldn't no air filter at all flow even better? I saw no gain in a mark 8 that was already pumping a wee bit more air than stock (cobra intake, long tubes, full exhaust, 6800 rpm shifts) even when I completely removed the air filter.

And yes, I would tend to believe an engineer that I personally know who did testing on test equipment at a filter media manufacturer, WAY before i believe some guy on the internet, even if he is "bob the oil guy".

I've heard of a number of problems now with the replacement K&N or K&N type filters on the Ford 6.0 turbo's where they 'dusted' the turbines in them and Ford refused to warranty them as Ford's stock 6.0 air intake/filter is probably the best there is out there..just another example of maybe the manufacturer knows what's best.

Hey we're off topic and I got my questions answered anyhow. So let's continue with this.
I completely agree with Logres on the fact that manufacturers leave HP and MPG on the table. I think they're in bed with the oil companies on this, but it's coming back to bite them now.

Anyway here is a link to a guy who proves just that. http://www.explorerforum.com/forums/showthread.php?t=137531

I agree thought that the bigger restriction is in the intake tube and silencers that they install and that the air filter is a minimal part of it. Although it is part.

Part of the reason they make it the way they do though is for quiet operation. Just about any aftermarket intake sys is louder than stock. There are a lot of ways to improve mpg and HP at the same time.

Anything that reduces friction or restriction of some sort will be an improvement in both economy and HP. As well as anything that aids in a more complete combustion. (exhaust can be tricky though, some cars need more back pressure than others and there is a need to find a proper balance in this area)

So imagine if you took an engine, any engine, tore it apart (keeping everything stock as far as dimensions go) install roller anything you can, lighter rods, lighter pistons, lighter crank, polished and matched intake and exhaust runners, tuned exhaust sys. top of the line intake (free flowing) a larger throttle body (debatable, but go with me here) increase the voltage for the spark (or go with multi spark) Synthetic fluids throughout (engine, tranny, rear end, power steering, etc. syn. grease in the wheel bearings) Let's even go with an electric water pump and fan lighter wheels and tires (stock size though) tire press a couple pounds over factory setting, re-program the ECU to optimize economy. etc. etc. etc.

Now what do you have? The same size engine you started with, but now you're getting better mpg and HP because it takes less fuel to get the car moving. In reality though you never increased the HP. You only released existing HP. The energy from the fuel was already all there, your just using it much more efficiantly.

If I had the money and time I would like to build a car like this and document everything and then take it to congress to show them what the manufacturers can and should be doing to the cars they already build. But then politics would take over and it would be for nothing. (But really I am an optimist. Just not in our politicians.)

sleeper said:

I didn't read the test on BITOG, but i did note that the cover page says it isn't conclusive at all. And that I couldn't view the graphics from work. All I know is that when I had a K&N on my car it a) did not increase HP and b) did not filter well as indicated by the solids in the oil that did not come from the engine itself. You can tell it won't filter well by a) reading the instructions that indicate that it relies on the dirt it catches to filter b) looking at (through) it and c) reading the intarweb.

Modern engines are optimized to achieve the best fuel economy, power, and reliability that they can make at an economical cost with acceptable NVH charactaristics for the particular vehicle they're put in. Yes, you can get more HP, but you WILL sacrifice one of the above. Cost, NVH, and/or reliability. Given CAFE standards, if there was a gain from a less restrictive air filter, the car would have a less restrictive air filter in it from the factory. If you notice, the air filter is larger than the intake tube. The restriction of the air filter is largely negated by the added surface area relative to the rest of the intake tract.

In my personal experience, there's no significant restriction in flow from a stock paper air filter, even if it's good and dirty. I base this on back-to-back drag strip passes, some with the filter, some without. Why screw around, right? If an air filter that flows well is better than a stock air filter, wouldn't no air filter at all flow even better? I saw no gain in a mark 8 that was already pumping a wee bit more air than stock (cobra intake, long tubes, full exhaust, 6800 rpm shifts) even when I completely removed the air filter.

And yes, I would tend to believe an engineer that I personally know who did testing on test equipment at a filter media manufacturer, WAY before i believe some guy on the internet, even if he is "bob the oil guy".

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For the most part I agree, however assuming one gets 1-3 hp from the K&N (or removing the filter altogether), you wouldn't see it because with all of the factors that go into strip times, your effective hp will vary by 1-3 from run to run. A temp drop of 1 degree is an increase of about 1 hp, for example.

My other reason to buy the K&N was to have something that wouldn't get torn up in there. I had a FRAM that had a tear along one edge after only 5K miles.

My other reason to buy the K&N was to have something that wouldn't get torn up in there. I had a FRAM that had a tear along one edge after only 5K miles.

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Some paper air filters are crap as far as material and construction. The K&N is at least a well constructed piece. There are other filters out there that filter well and won't come apart, though.

So imagine if you took an engine, any engine, tore it apart (keeping everything stock as far as dimensions go) install roller anything you can,

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Okay, imagining here, one component at a time. Let's use the 4.6 mod motor as a reference point.

Roller everything... already there

lighter rods, lighter pistons, lighter crank,

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Already pretty light, but if you're willing to spend the money you can always go lighter (GM LS7 for example, w/ titanium) but there's a cost tradeoff involved. Don't discount cost as a factor, it's a major factor to the automakers and a major factor for you, because manufacturing cost will be passed on to the consumer, and you'll see it in repair cost too.

But yes, there will be a gain from lighter weight components. Steady state fuel efficiency (cruising on the highway) probably zero MPG gain. Around town, a very slight gain. The motor will be able to spin faster and make more HP, though.

Manufacturers already spend a lot of money optimizing components, though. Lower MPG costs them money due to CAFE standards. Component weight is already well balanced vs. durability and cost.

polished and matched intake and exhaust runners, top of the line intake (free flowing), a larger throttle body (debatable, but go with me here)

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I grouped these all together because they're the same. Yes there will be gains from polishing and matching things, but there's that cost tradeoff again, so you won't see it in manufacturing except on very high-end cars. Going to headers instead of an exhaust manifold can bring HP gains too, but at the expense of NVH and possibly fuel economy (letting more heat out of the combustion chambers). I lost MPG when I installed headers, although my right foot may be partly to blame.

Throttle body has to be matched to the engine size and intake. Too big or too small can cost MPG.

tuned exhaust sys.

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It already is tuned for cost and sound. And surprisingly, for power too. There is a small gain from aftermarket exhaust, a bigger gain from aftermarket cats, but noise and emission regulations are to blame for any extra losses here.

increase the voltage for the spark (or go with multi spark)

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Already done stock. Not much more to gain over a modern stock ignition system.

Synthetic fluids throughout (engine, tranny, rear end, power steering, etc. syn. grease in the wheel bearings)

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Synthetics themselves won't provide measurable gains, but lower viscosity will. This is already being done to some extent. Notice that Ford now recommends 5w20 in almost everything. The lower viscosity reduces losses from pumping the oil around and provides a small gain. Bearing design and manufacturing of all the components in the driveline have improved over the years, and there's not much gain to be had over stock in this arena. Again, CAFE is driving the manufacturers to optimize here.

Let's even go with an electric water pump and fan lighter wheels and tires (stock size though)

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Those things will definitely offer an improvement, at least in city driving. On the highway, not so much. The electric water pump still gets power from the engine through the alternator, it's just a matter of having an efficient design to the pump. Lighter wheels are easier to accelerate but don't reduce the energy needed to keep it rolling on the highway. They also present durability issues for OEMs. People have had lightweight aftermarket wheels break on them.

tire press a couple pounds over factory setting,

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I already do that for handling purposes. Have to watch tire wear, though.

re-program the ECU to optimize economy. etc. etc. etc.

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Improvements can be had in fuel economy by running leaner in certain situations, but you run into durability issues. OEM's could do this, but it will affect emissions so they won't.


Overall, what do we have? Yes, there are a number of areas where improvements could be had over stock, but the gains are minimal and in most cases, the OEM's are already doing these things. If you're optimizing for one thing, you can always do better, but manufacturers have to balance power, cost, durability, emissions, and fuel economy requirements, and the resulting design will always be a compromise. For the most part, manufacturers balance these things well, although there will always be areas for improvement.

I think they're in bed with the oil companies on this, but it's coming back to bite them now.

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I don't buy that for a minute.

Anyway here is a link to a guy who proves just that. http://www.explorerforum.com/forums/...d.php?t=137531

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I don't think he proved much of anything. Sure, with a light foot and an engine running dangerously lean, you'll get better highway fuel economy. Let me know when he posts about the hole in his piston.

I'll make this a little shorter. I guess I don't agree with you on the fact that The manufacturers are doing most of these things already. Some maybe, and using the 4.6 is probably not a great example of what I mean because it is pretty well built engine from the start. Other engines are not so well engineered.

The torque monster headers available for the 5.0 in the Explorer's boasts a documented 3 mpg gain with no other mods. That's pretty significant to me. Also more power. The main problem there is the fact that the factory manifolds are junk. A great example of the manufacturers not doing what they could.

As for Aldive's mileage monster explorer. He did these mods roughly 4 years ago I believe and puts on 20,000 miles a year. His 32 mpg is running on the highway at an avg. of around 72 mph as documented by gps. I don't call that a light foot. The thing weighs more than the Mark and is a lot less aerodynamic, yet it gets better mpg. (not that much less power either, he has 200 rwhp) If he were to blow a hole in a piston he probably would have by now. Going from a factory mpg of about 21 (that's at 55 I would say) to 32 at 72. I'd say he proved a lot.

As for emissions, if you're getting better mpg, how is it that you're putting out more emissions? Burning less fuel means less emissions.

And for synthetic. I have yet to hear of anyone that pays attention that hasn't seen an increase in mpg. That's only talking about the engine. Then when people put it in the tranny and rear end, they do even better. I have seen a number of people on other forums that see as much as a 20% increase in mpg going syn throughout. These aren't isolated cases either. There are a lot of them out there. I'll be switching to syn in the trans of my Cruiser soon and I'll see what happens to mpg.

And spark, some are good, some aren't, I feel most could be better. The factory plug wires in my PT Cruiser are junk and I was able to smooth out the idle a great deal by switching to Crane wires. Mpg gradually increased as we drove it more and more. Then the tranny crapped out at 20k miles and ever since that was replaced with a factory unit the mpg dropped back down almost as bad as when we bought it with 10k on it. I recently installed a new set of plugs (Halo plugs, 90 day money back guarantee - I figured what the heck, I can't really lose) I've seen about a 10% gain in mpg from those. So these are more real world examples of the manufacturer not always doing what they can.

I planned on this being short, but oh well. You sound like you are alot more educated than me on a lot of this. But I'm paying attention to real world scenarios and not what's on paper.

I guess we'll have to agree to dis agree on this