Truck Trend claims 10% more MPG with K&N in 2009 Ford F-150 after bogus road test

[Christ]

Originally Posted by jamesqf

No, I don't have a flow testing setup in my garage. (Nor a dyno, alas.) Now how much would one of those cost? And how much time would I have to spend setting up a test?

As for how I know they need to be changed, I think the manufacturer's recommended interval is a good clue. Or I could just drive until they get black with dust & crud...



Plus shipping, if you order on-line. They don't (or didn't) have them at the local parts store.

A flow testing setup can actually be built for very cheap, honestly. It takes a little math and engineering study, but you basically build a setup that will pull water through a tube, pop your filter in, flip on the fan, and see how many inches you pull the water. You can convert known airflow from the fan when free-spinning into max airflow through the filter. As long as that figure is at least 50% of the max potential flow of the engine, you're still OK to use the filter. I don't think I'd go any less on flow, though.

Yes, you have to pay shipping if you order online. Many times, it's not that bad, and you get the same shipping price if you order more than one. You can get a few changes' worth for less than buying them locally, because you also don't pay state sales tax on purchases that originate from outside your state.

The MFR's recommended change interval is based on severe duty service, and "the average driver", which you most certainly are not, unless you have an ulterior motive on this forum...?

The fact that you frequently are driving in Nevada's sand storms does lend to changing the filter a bit more often, though. I wasn't aware of that to begin with.

Often times, like I said before, the color/appearance of the filter is not a good indication of it's available media or flow rate.

[ALS]

There is a piece over on TurboBricks (Turbo Volvo web site) on intake restriction. Full article

Restrictions to airflow cost you power and efficiency. When air is on its way into the engine of a Volvo 700 series, there are a number of items that cause restriction, thereby reducing airflow. Obviously, the first efforts for the tuner should be directed to the highest restrictions, but as we'll see below, many people just guess where the restrictions lie and throw money towards fixing what are in fact the smallest restrictions (the excellent OEM paper filter, or the OEM throttle body).

BOTTOM LINE:
Many may not care how this testing was conducted, so let's cut to the chase. Here, following the natural flowpath that air takes to get to the intake manifold, are the pressure losses on my 1987 B230FT 740 at 5500 rpm and 10 psi of boost:

*Airbox snorkel (ie, from the "outside" to the "dirty" side of your filter) 5.0 inches of water

*Paper air filter (just the loss across the filter element) 1.0 inches of water

*Air filter lid & AMM elbow (ie, from the "dirty side of the filter to the AMM) 9.0 inches of water

*AMM (loss across the Air Mass Meter) 5.5 inches of water

*Pipes to compressor, and from compressor to intercooler 0.0 inches of water

*Intercooler 38.0 inches of water

*Pipe from intercooler to throttle body, including 90 degree bend 0.0 inches of water

*Throttle body 0.5 inches of water

WHAT NOT TO DO:
Where is the LAST place I'd recommend you spend your money? Replacing the piping, the paper air filter or the throttle body. And remember, your replacement filter or TB would not have 0.0 inches of water pressure across them, so you're looking at one of the most expensive bang-for-the-buck mods that I can see.

[blueflame]

'Restrictions to airflow cost you power and efficiency'

Then why are all highly restricted motors designed for economy and not power?...Everything is a compromise but tuning an engine isnt about having your cake and eating it too

[tasdrouille]

Originally Posted by jamesqf

No, I don't have a flow testing setup in my garage. (Nor a dyno, alas.) Now how much would one of those cost? And how much time would I have to spend setting up a test?

All you need is a a drill, some fittings, a ruler, some water an empty soda bottle and a flexible clear pvc tube.

[Christ]

Originally Posted by blueflame

'Restrictions to airflow cost you power and efficiency'

Then why are all highly restricted motors designed for economy and not power?...Everything is a compromise but tuning an engine isnt about having your cake and eating it too

Because when you say "highly restricted", you're thinking in terms of maximum airflow, which isn't even remotely the case with engines based for efficiency. Those engines with maximum efficiency are tuned so that they reach that maximum efficiency under normal circumstances, not some bogus unreachable series of events. Therefore, if you use an engine that was based on efficiency for performance, you'll obviously be left lacking. They're not "restricted", they're tuned.

[mwebb]

restricted air filter

testing has been done by two groups that i am aware of , the conclusions were the same - restricted air filters have zero affect on fuel economy

IATn test results are by subscription , but the US government testing results are in agreement with IATn results

if you run out of bathroom reading material , print this ,
page 37 has the conclusions

conclusions on page 37
"4.1 CONCLUSIONS
The goal of this study was to explore the effects of a clogged air filter on the fuel economy of vehicles operating over prescribed test cycles. Three newer vehicles (a 2007 Buick Lucerne, a 2006 Dodge Charger, and a 2003 Toyota Camry) and an older carbureted vehicle were tested.
Results show that clogging the air filter has no significant effect on the fuel economy of the newer vehicles (all fuel injected with closed-loop control and one equipped with MDS). The engine control systems were able to maintain the desired AFR regardless of intake restrictions, and therefore fuel consumption was not increased. The carbureted engine did show a decrease in fuel economy with increasing restriction. However, the level of restriction required to cause a substantial (10–15%) decrease in fuel economy (such as that cited in the literature3,4) was so severe that the vehicle was almost undrivable. Acceleration performance on all vehicles was improved with a clean air filter.
Once it was determined how severe the restriction had to be to affect the carbureted vehicle fuel economy, the 2007 Buick Lucerne was retested in a similar manner. We were not able to achieve the level of restriction that was achieved with the 1972 Pontiac with the Lucerne. The Lucerne’s air filter box would not hold the filter in place under such severe conditions. (It is believed that this testing exceeded the design limits of the air box.) Tests were conducted at a lower restriction level (although still considerably more severe than the initial clogged filter testing), allowing the air filter to stay seated in the air box, and no significant change was observed in the Lucerne’s fuel economy or the AFR over the HFET cycle.
Closed-loop control in modern fuel injected vehicle applications is sophisticated enough to keep a clogged air filter from affecting the vehicle fuel economy.
However for older, open-loop, carburated vehicles, a clogged air filter can affect the fuel economy. For the vehicle tested, the fuel economy with a new air filter improved as much as 14% over that with a severely clogged filter (in which the filter was so clogged that drivability was impacted). Under a more typical state of clog, the improvement with a new filter ranged from 2 to 6%."
http://www.fueleconomy.gov/feg/pdfs/...02_26_2009.pdf

[dwtaylorpdx]

I've used K&N filters for a long time, mostly so I could re-use them.

But on measuring the flow,,, Yes I did. On my 1600 CC Bug motor switching to a top-hat K&N from the factory abomination, It made a 1" difference in vacume pressure.

The car also got about a half a mile to the gallon better on the highway. It was a BAJA bug so used in really nasty dusty conditions. I also had a rally computer in it and was able to really track my mileage.

As far as effective filtering, the original study from a mining company that used the Caterpillar engine labs for evaluating a K&N in place of the factory filter for a large mining operation showed the K&N filter had equal filtering efficiency except with certain silica rich soils, but the material that made it through was small enough to basically pass through the engine, on extended runs they started finding more of the silica in the oil which is the root of all the K&N bashing. testers determined the particles WOULD harm the turbochargers.

Back when Mt St Helens Erupted I lived 10 miles from the mountain, saw it blow.
The ONLY thing that worked for keeping ash out of our trucks was a pair of womens nylons wrapped around the air cleaner element, and ourt mileage sucked with it in there...

Dave

[dwtaylorpdx]

Lol,,, because of the K&N talk, we have K&N adds below the forum pages tonight... HAHAHAHA

Dave

[Frank Lee]

Originally Posted by jamesqf

Ever been to northern Nevada? The climate's not all that different, especially when it comes to dust.

I read the K&N "flows better" because the holes in it are bigger? Then I especially wouldn't want to use it there.

And if that's not the case, why does it "flow better"?

[Piwoslaw]

Originally Posted by Frank Lee

I read the K&N "flows better" because the holes in it are bigger? Then I especially wouldn't want to use it there.

And if that's not the case, why does it "flow better"?

If the holes are the same size, but there are more of them, then the flow will improve (larger area, less resistance) while keeping the same amount of dirt out. On the other hand, larger holes may increase flow, but also let more dirt in.

Originally Posted by tasdrouille

It all comes down to filtration and flow. This study proved that K&N flows better. Yes, by a huge 2 inches of water at 350 CFM. That sure is good enough for a 10% in fuel economy. It also does not filter very well.