No more pods ! ! !

[Agemax]

You can tell that they don't work worth a darn by all of the race bikes running around using the stock airboxes.
Nice charts BTW.

Just sayin'

Eric

true, but an awful lot of race classes require the standard airbox to remain.
its whats inside them that you cant see would probably be far from standard

[Steve]

You can tell that they don't work worth a darn by all of the race bikes running around using the stock airboxes.

If you want to compare, just make sure you are comparing the proper items.

Race bikes are built with one purpose in mind, to maximize the airflow through the engine and to get the resulting power to the ground in a controlled, predictable fashion.

Street bikes are not designed with that purpose in mind. They have several other constraints, including having smooth, predictable idle and mid-range response, as well as decent power when wide open.

Try running any of the winning race bikes on the street in day-to-day riding, see how they do. My guess is that they will do as poorly in "street" riding as a stock bike will do on the race track.

.

[Griffin]

I've run GSes completely stock, with pods and aftermarket exhaust, with stock airbox and K&N oem style filters (stock and aftermarket exhausts). All these configurations were tuned and made to run with excellent street manners. Some configurations take more fiddling than others.

My current favorite setup is with a Dynojet Stage I kit, stock exhaust, stock airbox, and K&N style filter. Every bike I've done this with has run at least as well as stock for street use, but has been far better at cold starting and shortened warm-up times.

Perhaps the best improvement was on my GS700ES. It was one of the last GSes made, and was jetted horribly lean at idle and low rpms in order to meet stricter EPA requirements (they cracked down in 1980, and then again in 1983). The GS550s from 1980-on (CV carb-equipped units) were also horribly lean in stock configuration.

The Stage I kit and K&N filter is probably the single best thing that can be done to one of these models to make for a happier relationship between bike and rider.

Note: Installing the Stage I kit with a normal paper element improved starting and warm up, but made my GS700 slightly rich at mid rpms and really rich at high rpms.

[Nessism]

You can tell that they don't work worth a darn by all of the race bikes running around using the stock airboxes.
Nice charts BTW.

Just sayin'

Eric

Use pods if you want. No worry. Simple fact is though that K&N's let more dirt though to your engine than a stock filter. Why do you think K&N's flow more air? Answer: they filter less. And yes, it's possible to get a bike to run decently with pods. Sad fact it though that many people can't figure out how to do it.

[Griffin]

Does anybody have the specs for the level of particulate filtration (expressed in percentage of particles at a certain micron level) of oem paper elements? What does K&N claim for their packed-fiber elements? What about Uni-style foam elements (which were also oem on some GS models)?

Don't assume that just because a material passes air with a lower pressure drop that it doesn't filter particulates as well as a material with a higher pressure drop. 'Tain't necessarily so. Packed fiber elements have filtering surface areas (what traps particles) thousands of times higher than paper elements. They therefore can have a larger void volume (what allows air to pass through) than a paper element, yet still trap more and just as fine particles.

I personally do not know if that is indeed the case with a K&N filter, but it is technologically possible.

All filter elements allow dust particles into the engine. If they were truly dust-tight down to something on the order of 0.01 microns (a human hair is about 120 microns thick), they'd either be horribly expensive, or wouldn't work well beacause they would restrict air flow to an unacceptable level. So everything with element design is a compromise. An element needs to remove particulates down to a size small enough to prevent unacceptable wear to the engine, yet allow enough air flow with a low enough pressure drop to ensure adequate performance.

This brings us to the first pertinent question on the subject:


What particulate size is acceptable to pass into the engine without causing unacceptable wear rates on moving components?

Without knowing that requirement by the engine designers, the question can't be answered here. If somebody here designs four stroke internal combustion engines for a living, please weigh in with your knowledge. Absent such an event, we therefore must try to answer other questions pertinent to the topic. Such a question might be:


Does anybody know the claimed filtration level of the oem paper, oem foam, and K&N packed fiber elements?

I do not. If anyone has seen published data, please share it. Lacking verified published data, we are then left with this question, the only one that we might possibly have relevant data to provide a reasonable answer to:


We all acknowledge that packed fiber elements allow more air flow with less pressure loss than oem paper elements. Do the packed-fiber elements filter out particulates at a level fine enough to provide an acceptable engine life?

On this, we have some anecdotal data upon which we can draw conclusions. There are thousands of riders out there who have put tens of thousands of miles on their motorcycles using packed fiber elements. Those bikes still have good compression, don't knock, nor have twisted cranks. This isn't new technology, packed fiber elements have been a popular choice on street motorcycles for at least forty years.

I have not heard of a rider properly installing and maintaining a packed fiber element on his engine, and reporting excessive engine wear that had a proven cause of excessive particulate contamination of the engine through the intake system.



Anecdotally from a personal side, my GS700 has had either V&H pods or a K&N oem-style element mounted on it for the last 40,000 miles or so. Still runs fine, no smoke, no noises. Billy Ricks has had pods on his GS700E for years as well, and it still runs tip top.

My conclusion:

Properly installed and maintained, a packed fiber element (or pods) filter out fine enough particles for our bikes' needs for many tens of thousands of miles with no observable ill-effects.

To me, the benefits and ease of installation and use by this type of element with a jet kit more than outweigh any theoretical (although not proven, nor documented on this thread so far) drawbacks.

My $0.02.

[Nessism]

Griffin,

Have you read this air filter test (as posted earlier in this thread)?

http://home.roadrunner.com/~jbplock/ISO5011/SPICER.htm

There are all kinds of tests showing how much dirt is being trapped, let though, pressure drop, etc. I'm not sure if it answers your questions, but there is lots of good information.

Bottom, K&N's let more dirt though. Is this extra dirt going to wear out your engine sooner, and if so, how much sooner? I don't know. Personally though, I'm not inclined to take chances.

[7981GS]

Can we combine this with a "Which engine oil to use?" thread?

Eric

[Griffin]

Griffin,

Have you read this air filter test (as posted earlier in this thread)?

http://home.roadrunner.com/~jbplock/ISO5011/SPICER.htm

There are all kinds of tests showing how much dirt is being trapped, let though, pressure drop, etc. I'm not sure if it answers your questions, but there is lots of good information.

Bottom, K&N's let more dirt though. Is this extra dirt going to wear out your engine sooner, and if so, how much sooner? I don't know. Personally though, I'm not inclined to take chances.

I didn't see that earlier. Thanks, it provides some data that, although for a different application, can probably be used for some rough comaparison evaluation.

The test was performed on diesel engine filters, and used different brands with essentially three different styles:

Foam (Uni)
Packed Fiber (K&N)
Paper (various brands)

As for my first question, the filtration rating, the test didn't completely answer it, but did provide usable data. The dust media is described as ranging in size from "under 2.5 microns" to "greater than 80 microns". I don't particularly like that description, because it doesn't really tell us anything. A hydrogen atom is "less than 2.5 microns", and a red giant star is "greater than 80 microns". So we can't get a true rating for each filter, which would read in this format:

Rated 99.6% entrapment down to 1 micron at rated flow.
Rated flow 80 scfm @10" H2O - 24" H2O

That rating means that a filter will capture 99.6% (by mass) of all test media passing through it that is larger than 1 micron, with initial (clean) pressure drop of 10" H2O and saturated (dirty) pressure drop of 24" H2O, passing no more than 80 standard cubic feet per minute of air. The filter will capture some particles below 1 micron, perhaps a lot, but it hasn't been tested with smaller media.

Anyway, the testing pretty much confirms that the K&N has the least pressure loss, but allows more dirt through than paper. Interesting to note that the foam type of filter (in this case, Uni brand) allowed about the same amount of dirt through as the K&N, and had a higher pressure drop (about in the middle of the paper elements).

So...what does it mean for your engine?

Probably not a whole lot as far as wear and tear, your oil filter will catch the dirt. Remember, Suzuki used foam elements on several GS models, and it appears to filter about on par with a packed fiber element. Evidently Suzuki decided it filtered well enough. Your oil filter will not last as long, but I think that we tend to change our oil filters (every 1,500-2,000 miles seems to be the norm here) long before it is necessary anyway, at least in general street riding.


To each his own. I prefer the increased rideability that is afforded with packed fiber filters, and have a track record of engine durability to not worry about the increased dirt loading on the oil filter.

If using the finest (and in this case, I'm referring to particle size) filter to eliminate as many particles as possible from entering your engine at the possible expense of rideability is the most important aspect to you, then use the paper.

On my GS700, the original Suzuki element is oiled foam. With stock jetting, it flowed too much air, particularly at low rpms. With a Stage I kit, it didn't flow enough air at mid and high rpms, hence the switch to the K&N.

The Stage I kit changes the bike from a wheezy, cold blooded beast that took five minutes to warm up on cold mornings (even when brand new), to an instantly fired-up charger that was ready to go in less than a minute. To me, that change is well worth the reduced filtration level. I wish I'd done it twenty years earlier.


And by the way, yes, one aspect of my job is evaluating, sizing, spec'ing, and applying filters in industrial applications.

[Billy Ricks]

Every time the K&N topic comes up I have to bring up something K&N used to include in all of their literature. Their filters actually do a better job of filtering particulate when they build up a layer of dirt. You don't clean them every time they look dirty either, you knock off the loose dirt and re-oil right over the dirt left behind. I've had my K&Ns on my bike since it was about a year old. 26 years later and about 70,000 miles and it still runs strong, even stronger than new.

As for the dyno charts, if I just throw a set of pods on any bike and throw some whopping mains in it I'd expect to lose power over proper tuning. Whoever set that test up should be shot.

[gearhead13]

Griffin,

Have you read this air filter test (as posted earlier in this thread)?

http://home.roadrunner.com/~jbplock/ISO5011/SPICER.htm

There are all kinds of tests showing how much dirt is being trapped, let though, pressure drop, etc. I'm not sure if it answers your questions, but there is lots of good information.

Bottom, K&N's let more dirt though. Is this extra dirt going to wear out your engine sooner, and if so, how much sooner? I don't know. Personally though, I'm not inclined to take chances.

Cant believe everything you read, or so they say.

[Nessism]

As for the dyno charts, if I just throw a set of pods on any bike and throw some whopping mains in it I'd expect to lose power over proper tuning. Whoever set that test up should be shot.

Joe Minton ran that test. A highly respected tuner guy from the 70's and 80's. The mixture was not optimized for each pipe, so there may be some extra power being given away, but I suspect it was within a jet size or so.

Cant believe everything you read, or so they say.

Okay, so show me some creditable test data what shows K&N's filter better than a good paper filter.

[gearhead13]

Okay, so show me some creditable test data what shows K&N's filter better than a good paper filter.

99.999% of racers cant be wrong? Show me a racer using a paper filter.
Besides, they are reusable, and (most) everybody says they are better
Maybe that Minton guy is as stubborn as you.

[7981GS]

"Figures lie and liars figure"

Do you also trust the propaganda that you hear on the national news stations?

Just sayin'

Eric

[Buffalo Bill]

"Figures lie and liars figure"

Just sayin'

Eric

Yea, that's right, and that's what everybody says up and down the pits at every MotoGP event!

Just stupid'

[Billy Ricks]

You can tell that they don't work worth a darn by all of the race bikes running around using the stock airboxes.
Nice charts BTW.

Just sayin'

Eric

If you're talking about modern bikes yes, they are running pressurized airboxes fed by snorkels in the fairings. Vintage race bikes would have been running stacks.