High flow air filter for the MS460

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RiverRat2

RiverRat2

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It's good data, but dyno tests with clean and dirty filters would be
closer to what the goal is (increased power).

If the flow is similar, horsepower should also be, but the lower velocities
that a larger filter can flow the same volume at may come into play (?).

So far, with the flow bench data I'd say the power should be pretty
close to the same with either filter.

How much flow does the saw need (want)?
What would be the maximum flow at top rpm and 100% volumetric
efficiency (if the engine were a perfect air pump)?

That should be displacement x RPM, I think?

:agree2: :agree2: :agree2:

FYI that stihl filter and carb will flow more than you think,,,,,even when its dirty!!!!! :cheers: :givebeer:
 
gemniii

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I was looking at getting a Max-Flow for my 660. I'll save the $$.

so this is basically a bump for an excellent buried thread.

Well guys, I was hoping to get some feedback (others’ first-hand experiences) on carburetor tuning between the stock Stihl HD filter setup versus the Max-flow, but not seeing anything, I took it upon myself to spend some time on the flowbench and provide everybody some objective data on actual flow between the two systems, as well as slight variations to each as well.

If you open up the Word.doc, you'll see a summary of the flow data. I performed my testing at 28"H2O, but for all those more familiar with 25” or 10"H2O, I ran the conversions for those test pressures as well.

There's two sets of data within the document; the first is a set of high flow numbers flowing just the filters on a mounting plate. The mounting plate was machined with a 2 1/2" ID hole. I had this plate available and it fit the ID of the stock filter pretty closely, so I used it. The next set of data was measured through the complete intake system, and is the set of data that is of importance. The plate the intake system was mounted to was machined to match the carburetor bore. Attached to the plate is the carburetor (stock bore), air cleaner backing plate, radiused inlet, etc.

In the results are some generalized observations. I won't spoil the fun; I'll let you throw your thoughts around for a little while and come to your own conclusions.

Also included - if I do this correctly - are photos of each setup. Each photo is referenced to the data in the Word.doc.

Have fun!
 
gemniii

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Bump

The benefits of the max-flow were brought up recently.
Just the facts often don't agree with the hype.
Well guys, I was hoping to get some feedback (others’ first-hand experiences) on carburetor tuning between the stock Stihl HD filter setup versus the Max-flow, but not seeing anything, I took it upon myself to spend some time on the flowbench and provide everybody some objective data on actual flow between the two systems, as well as slight variations to each as well.

If you open up the Word.doc, you'll see a summary of the flow data. I performed my testing at 28"H2O, but for all those more familiar with 25” or 10"H2O, I ran the conversions for those test pressures as well.

There's two sets of data within the document; the first is a set of high flow numbers flowing just the filters on a mounting plate. The mounting plate was machined with a 2 1/2" ID hole. I had this plate available and it fit the ID of the stock filter pretty closely, so I used it. The next set of data was measured through the complete intake system, and is the set of data that is of importance. The plate the intake system was mounted to was machined to match the carburetor bore. Attached to the plate is the carburetor (stock bore), air cleaner backing plate, radiused inlet, etc.

In the results are some generalized observations. I won't spoil the fun; I'll let you throw your thoughts around for a little while and come to your own conclusions.

Also included - if I do this correctly - are photos of each setup. Each photo is referenced to the data in the Word.doc.

Have fun!
 
MaxFlow Flters

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Maxflow Inventor Responds

Well guys, I was hoping to get some feedback (others’ first-hand experiences) on carburetor tuning between the stock Stihl HD filter setup versus the Max-flow, but not seeing anything, I took it upon myself to spend some time on the flowbench and provide everybody some objective data on actual flow between the two systems, as well as slight variations to each as well.

I want to thank the thousands of loggers who have used our system worldwide. We know it works, we hear from satisfied customers virtually every day. I work on the front lines of fires and meet hotshot crews at the fire camps and get first hand feedback on our filters. Fires are possibly the worst environment that a saw will ever see. There is NOTHING on the market that will out perform a Maxflow filter in real world conditions. It is not just about wide open airflow in a flow bench. It is how well a filter flows after 1 or 2 or 50 cleanings. It is how well the lower end bearings will hold in real day to day use. It is how consistent the power will be at the end of the day, not just at the beginning. And it is about having a saw that will make you money by running efficiently for longer periods of time between cleanings, so that you use less fuel, and spend less time on the tailgate.

The Maxflow Filter was developed by a logger and improved over many years to what you see today. And Maxflow Filters are the only filters that are legal to use on Forest Service lands. They aren't pretty, but pretty would double the cost. We chose ugly but effective and affordable.

I see that this is an old post but since I do not use the internet much it has taken a long time for this type of information to come to my attention. This type of unsolicited testing is very constructive and I appreciate the effort that was made to help the end users make an informed buying decision. There are a couple of things that need to be pointed out, because how the information is presented has a huge effect on what it's meaning actually is or should be.
1. The most important mis-information here is that the stock HD filter, without the outer band will outflow the Maxflow system. This is because the stock filter is not actually filtering (much) without the outer band. The outer band is an essential part of the filter. If you were to put our empty cage on the flowbench with a nylon around it, it would far out flow the stock filter, but it also wouldn't filter anything either. It is also pointless to test the flow of our elements without oil. Certainly they will flow more air, but the debris will pass through as well. The Maxflow filter will far outflow any factory filter if they are both set up to the required configuration.
2. The figures for the flowbench are completely different than ours because ours were done at 10 inches of H2O not 28. Also unless calibration is done between two different flowbenches for altitude and temperature, there will never be identical results, even at the same H20 reading.
3. For the results to matter, the amount of air that a saw requires at WIDE OPEN THROTTLE (WOT) must be established. Any airflow over that number will not add to performance or make your saw run any stronger. However the airflow above that number will indicate how much of the filter can be clogged up, and have the saw still run at peak performance. Since there is no reference in any of the testing as to how much air a saw needs, there is no way to show how much filtering capacity is available. Our figures are actually based on how much air a saw will actually use. They were done with the most demanding saw, an 084, which draws 58 CFM WOT. The 066 uses less and the 046 even less. So any saw will run fine with a new CLEAN filter. But the results change dramatically after a filter has been used and cleaned a couple of times. The factory filters drop substantially in airflow once they are used and cleaned. The more cleanings, the less airflow they offer. In the case of the 084, a used, (but cleaned) filter only brings you 19 CFM of additional filtering capacity. Real world tests showed that this excess could be used up in less than an hour. On an 066 the excessive capacity could be used up in 4-5 hours of heavy cutting. On an 046 it would take several days. Even though there would be good top end power, as the filter clogged the responsiveness of the saw would diminish. Continued cutting leads to low power output, high fuel consumption and greatly increased engine wear.
With the Maxflow filter, the element can be reliably cleaned even after running in the worst conditions. After cleaning it returns to nearly 100% of the new filter airflow. Because of the larger surface area there is nearly 300% more excess airflow available for an 084 (even while effectively filtering). Under most conditions, an 084 will cut for several days, an 066 up to a week and an 046, 10 days or more. They may more steps to clean the filter element, but you only need to do it a fraction as often. Since you have 100% of the air needed for the saw to run powerfully 100% of the time, it puts money in your pocket and saves you aggravation as well. And as some of the more astute posters (Mark42) have pointed out, it is not just the amount of air, but the quality of air. The Maxflow filters size and capacity conditions the air, leading to far less carb icing in wet conditions. And the volume of air that is immediately available leads to a snappier saw from the moment it is installed.

I appreciate that someone took the time to test our claims, I understand why, on a smaller saw, with a clean stock filter, the tester might see a limited difference. However; on a larger saw, against a clean used filter, there will be a dramatic increase in performance with the Maxflow installed, and a corresponding carb adjustment for optimal RPM. And as thousands of fallers and arborists attest, when the saw meets the wood for day or weeks or months at a time, the Maxflow filter is far superior and has been for nearly 20 years.

Thank you for reading my long post.. Joseph
 
thenline

thenline

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Hi Joseph,

I saw that you PM’d me minutes before posting your comments, asking me to contact you, but since you didn’t give me a chance to get in touch with you before posting, I’ll just post my thoughts below.

First and foremost, I have no vested interested in your product nor any other manufacturer's product – I want that to be perfectly clear. I’m a homeowner with 40-acres of woods that I maintain. I use my MS460 for maintenance and making firewood, and I spend a fair amount of time cutting with it. I don’t cut in fire-conditions and I don’t own or operate an 084. I’ve owned larger Stihl saws but prefer my MS460 w/BB kit and DP muffler.

Before continuing, let me give you a little background on myself. I have an engineering degree and worked in the high-performance powersports industry for many years. I worked for an engine manufacturer as a project engineer. There, I did fuel calibration and development, engine controls development, exhaust emissions testing, noise testing, etc. I helped to develop and/or test intake systems, carburetors and fuel injection, internal engine components, as well as complete engines up to 160ci. I was even involved with creating – from scratch – a wet flow bench to test carburetors and intakes. Said flow bench used a 30HP Siemens pump to mimic the real-world vacuum present in real-world running conditions.

Again, I have no experience cutting in fires, nor pretend to. Personally, I consider cutting in the woods, not cutting in forest fires, real-world (or at the very least, more common and realistic) conditions for a chainsaw. That’s just my opinion, and I have nothing against those who do cut in fire conditions – in fact, I thank said individuals for doing so when the need arises. They are to be commended.

Regarding your performance after “1 or 2 or 50 cleanings” comments, I cannot directly comment on that with your specific product, as that was out of the realm of my testing. I have tested and have seen test results from other foam filters (both oiled and not oiled) for on- and off-road products and know how they compare to other filtering media. I will refrain from getting into those results at this time. Personally, though, I clean my saw each and every time I use it, regardless of how many tanks of fuel I run through it with each use. I haven’t had an issue with the longevity or performance of my HD filter. I have seen what can happen to the HD filters when they don’t get cleaned – and the effects on engine performance when it happens – but I have also seen the same thing happen with foam filters in other applications.

I do take offense to you stating that I provided “mis-information”; I did no such thing, Joseph. You state that it’s mis-information, yet agree that the HD filter w/out wrap does in fact flow more. As an engineer, I wanted to provide objective test results for as many combinations that I could think of which other forum members might want to see. Just because it flowed higher doesn’t make it invalid data or mis-information. Would I run that set-up on my own saw? No, of course not. Would I suggest others doing so? No, but the data was collected and presented. Testing with the nylon was a perfect example of testing with different combinations/configurations; another forum member mentioned it in the thread so I thought I’d test it as well. Try to picture the look on my wife’s face when I asked her for one of her nylons…

As for the test pressure the testing was done at, I provided data at 10inches of H2O as well as 25 and 28. I chose to perform testing at higher pressure, as that’s industry standard, but whether tested at 10, 25, 28, etc., the % change is what is of interest. The same goes for flow bench to flow bench comparisons. No two flow benches will provide the exact same CFM results, but again, CFM numbers are not what I was after. I was researching the % change found between products and configurations. “CFM” and “inches of water” are labels and should be treated as such. The percentage of increase or decrease is what’s of importance.

Regarding extra filtering media, I couldn’t agree more. It goes without saying, the larger the filtering area available, the longer it takes to get clogged. I’d be interested in hearing about how you measured (again, measured, not calculated) your 58 CFM value, though. What type of flow meter(s) and data acquisition equipment did you use to obtain a measurement of 58CFM on a running 084?

In conclusion, again, this testing was done because after doing A-B-A testing out in my real-world cutting conditions, I saw no difference between the two filter systems on my MS460 – subjectively, while cutting – nor – objectively, while measuring RPM with a tachometer. After reading your company’s claims and purchasing your product, I had hoped to find increased HP performance. After finding no such thing in the woods, I had hoped to get some feedback from forum members, but because I received none specific to my question, I conducted controlled testing to determine a valid explanation. The data presented from the testing was accurate and included as many configurations that I could come up with in the time I had available to do said testing in one sitting. I didn’t provide the information to direct potential customers to or from either product. I provided it as a forum member to follow up the question I had posted.

Tom
 
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MaxFlow Flters

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Hi Tom,

Unfortunately after I posted my response I saw some errors and could not correct them because I'm new to the forum.

First, mis-information is the wrong word. I meant to say mis-understanding of the data presented. I only brought it up because of a post above where someone commented on the stock filter without a band as being something of a valid comparison to an actual filter ready to perform. I understood what you were doing.

The second point I wrote incorrectly was that we tested at 9 inches, of H20 not 10. We used a Superflow 110 and our test looked like your setup, except used custom plates with exact hole openings. We used 9 inches because an 084 at wide open throttle would only pull 9 inches of water without bogging down as we measures its airflow. We made a special plate and built tools to get an accurate reading on a running chainsaw. We used that to calibrate the Superflow so the test had some validity. We did many different tests over months of innovation and then built filters, and then went and used them logging for several months on each prototype. At the beginning we were happy to just double the time between filter cleaning, and as time went on we arrived at what we sell today. We also found that many loggers just loved the sound of their saw screaming at peak power with a Maxflow filter installed, especially with a DP muffler.

As you found on your saw, there is virtually no performance change verses a new filter, they both flow much more than what the saw can possibly breathe. And if you clean your filter daily like you do, you will never experience a degradation of performance with a stock unit when you are woodcutting. So for you and the majority of homeowners using an 044, the stock filter is more than adequate. But for professionals who cut for hours every day, it is a whole different world. An 066 that is working down on a stump and in a cloud of dust will clog a stock filter in half a day or less. Carrying one or two extra filters just to get through a day is problematic. One of our filters will get you through days where the factory filter can't and the inside of the filter cage will still be spotless. Two stroke saws are amazingly sensitive to air flow restrictions, much more than motorcycles. There is no comparison between other motors and chainsaws which run basically wide open all the time. This is especially if you are working in the mountains where the air is a bit thin anyways. The longer a saw can suck clean unobstructed air, the longer it will perform at peak.
The other advantage of the Maxflow filter is that by having more surface area, we allow the air to enter at low velocity through a broad area of filter media. A stock filter has less area and as the surface fills with debris the velocity through the remaining area is higher, which draws dirt into the inside of the engine. Fire service is the most severe example of how to test this.

If you read the label on our kits, it talks about how long the filter will run, and all the CFM calculations reference the extra cleaning capacity that we offer. We do not advertise anywhere that we will add horsepower to a saw. I would like to know where you believe we "claim" this. What we do claim is that with our filter you will be able to produce a saws maximum horsepower for far longer between cleanings than with a stock filter. We then made sure that professionals and woodcutters could legally run them in the woods, something that no other aftermarket air filter has ever done.
We also found that many saws were being run with "cleaned" filters that were already restrictive. Unless you constantly put new filters on, you were not even getting rated horsepower. For these users, putting on one of our filters gives increased airflow, resulting in a need to richen the mixture. This immediately increases the output back to stock peak performance and keeps it there. We tried for several years to develop a test to put the air filters into a dirty environment, under "lab" conditions, to actually measure how much debris a filter could hold without degradation of power. In the end, we found that loggers, using the saws in actual conditions, provided much better feedback on longevity. We still hear this today.

As I said in my PM to you, I really LIKED your test. I was amazed that someone took the time and had the knowledge and equipment to generate neat numbers like that. Bench test results are interesting, but must be paired with work in actual cutting. It is real world work where Maxflow filters have earned their deserved reputation for long life. Maxflow filters are much more than numbers generated on a sheet of paper.

By the way, I really liked your pre-filter sock. Perhaps you should offer them on the internet as a way to prolong the life of the element from tearing in brushy conditions if a cover isn't used.

Joseph
 
thenline

thenline

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If you read the label on our kits, it talks about how long the filter will run, and all the CFM calculations reference the extra cleaning capacity that we offer. We do not advertise anywhere that we will add horsepower to a saw. I would like to know where you believe we "claim" this. What we do claim is that with our filter you will be able to produce a saws maximum horsepower for far longer between cleanings than with a stock filter. We then made sure that professionals and woodcutters could legally run them in the woods, something that no other aftermarket air filter has ever done. .

Joseph

Hi Joseph,

It's almost 1:00am here, so I'm past ready for bed and am going to make this abbreviated.

Thanks for your kind words on my testing and on my pre-filter sock. If I wasn't busy enough the way it was, I might have to take your suggestion on the sock!

As for your question above regarding the claim, as of 10/31/12, 12:55am CST, it's right on your website (copied directly from the site and posted below). I don't have a copy of my original instructions handy but could check for it on them as well.

"MaxFlow air filters trap the smallest particles while flowing twice as much air as stock air filters. This helps your saw breath better, resulting smoother running and more power"

Tom
 
MaxFlow Flters

MaxFlow Flters

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Hi Joseph,

"MaxFlow air filters trap the smallest particles while flowing twice as much air as stock air filters. This helps your saw breath better, resulting smoother running and more power"
/QUOTE]

Hi Tom,

I though that it would be seen in the context that a filter that breathed better while trapping the smallest particles for longer would result in more power. Since I can see how you read it I have changed it to read "MaxFlow air filters trap the smallest particles while flowing twice as long as stock air filters. This helps your saw breath better, resulting smoother running and more power"

Hopefully this clears up any confusion, thanks for bringing it to my attention.

Joseph
 
thenline

thenline

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Hi Joseph,

"MaxFlow air filters trap the smallest particles while flowing twice as much air as stock air filters. This helps your saw breath better, resulting smoother running and more power"
/QUOTE]

Hi Tom,

I though that it would be seen in the context that a filter that breathed better while trapping the smallest particles for longer would result in more power. Since I can see how you read it I have changed it to read "MaxFlow air filters trap the smallest particles while flowing twice as long as stock air filters. This helps your saw breath better, resulting smoother running and more power"

Hopefully this clears up any confusion, thanks for bringing it to my attention.

Joseph

Hi Joseph,

While your new statement is more accurate, I'm guessing it will still be interpretted in different ways by different people. Of course there's not much you can do about that, unless you phrase it something to the effect of "MaxFlow air filters trap the smallest particles while flowing twice as long as stock air filters. This helps your saw breath better after prolonged use in adverse conditions, resulting in smoother running and more power." I'm happy to see, though, that you removed the "flowing twice as much air as stock air filters" reference from your statement, as that of course was not the case, as shown in the testing, if referring to CFM. Replacing it with "flowing twice as long as stock air filters," if indeed validated in your testing, is great, and kudos to you for supplying a product that is able to do that.

All the best,
Tom

Thanks for the info fleebay bud. I'm just gonna stick with my HD2 filters. They do the job for me. I gave ya some rep too.

Thanks, Chad, I appreciate it.
 
MaxFlow Flters

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I'm happy to see, though, that you removed the "flowing twice as much air as stock air filters" reference from your statement, as that of course was not the case, as shown in the testing, if referring to CFM.

In our testing our filters DO flow twice as much CFM as a stock filter. That your tests show different CFM figures where the CFM is closer only proves that our filters shed debris far better than the stock filter, partly due to the reduced velocity, partly due to other factors, and this allows the saw to flow more air for a longer period. This can really get into interpretations and splitting hairs.

Our tests do not match your tests, but both can still be valid depending on many factors. The point being is that my only concern is how they work in actual use, not how they look on paper. We field tested dozens of filters, some flow great on paper, but get rain soaked in an hour. Some freeze up in icy conditions. Some are hard to install, or difficult to clean or catch on everything in sight. Some can't pass the USFS requirements for an aftermarket filter. Stihl is an amazing company, making one of the best chainsaws in the world. Trying to improve on their product is difficult at best, look at how few aftermarket parts there are for them! Loggers are some of the most demanding customers anywhere and they are only going to pay so much and the dealers must make a profit as well. They work hard and expect their equipment to do the same. Maxflow filters have been the replacement choice of professionals for a very long time, and this is not by accident.

Joseph
 
Tree Sling'r

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In our testing our filters DO flow twice as much CFM as a stock filter. That your tests show different CFM figures where the CFM is closer only proves that our filters shed debris far better than the stock filter, partly due to the reduced velocity, partly due to other factors, and this allows the saw to flow more air for a longer period. This can really get into interpretations and splitting hairs.

Our tests do not match your tests, but both can still be valid depending on many factors. The point being is that my only concern is how they work in actual use, not how they look on paper. We field tested dozens of filters, some flow great on paper, but get rain soaked in an hour. Some freeze up in icy conditions. Some are hard to install, or difficult to clean or catch on everything in sight. Some can't pass the USFS requirements for an aftermarket filter. Stihl is an amazing company, making one of the best chainsaws in the world. Trying to improve on their product is difficult at best, look at how few aftermarket parts there are for them! Loggers are some of the most demanding customers anywhere and they are only going to pay so much and the dealers must make a profit as well. They work hard and expect their equipment to do the same. Maxflow filters have been the replacement choice of professionals for a very long time, and this is not by accident.

Joseph


I have been a professional timber faller for just under 20 years and will not run stock air. I will either use a foam filter with a velocity stack or the Max Flow with the orange cage. Reason being, the after market filters are less work to maintain and they hold up. Just my 2 cents...
 
thenline

thenline

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In our testing our filters DO flow twice as much CFM as a stock filter. That your tests show different CFM figures where the CFM is closer only proves that our filters shed debris far better than the stock filter, partly due to the reduced velocity, partly due to other factors, and this allows the saw to flow more air for a longer period. This can really get into interpretations and splitting hairs.

Joseph

Hi Joseph,

This will be my last post regarding claims, test data, etc., as it's cutting into my other priorities.

If your filters do flow twice as much CFM as a stock filter does, as you state (even though I showed on the flow bench they don't, whether when flowed through a large orifice plate - which would represent a larger displacement saw - or when flowed through the complete intake system of my MS460), then I have to ask, why did you state on this forum earlier today that you're removing that claim from your website, and changing it to "flowing twice as long?" In addition, my testing and CFM figures showed absolutely no such thing regarding your filter "shedding debris better than a stock filter". My data showed - documenting multiple test pressures - that flow data between the two clean filtering systems was actually quite comporable, regardless of whether the filters were flowed by themselves on a plate or when flowed through the complete intake.

If customers prefer running your product due to prolonged use between cleanings, that's understandable. Me personally, cleaning my saw after each use and seeing no performance enhancements at all when both filters were clean and run on a saw, as well as when flowed in the lab, would rather run the OEM product. Again, that's just my preference, as I find it easier to clean the OEM product than I do cleaning/re-oiling foam filters.

All the best,
Tom
 
openloop

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For a given airflow if two filters are tasked to filter the same amount of dirt... the only way one would show better "dirty performance" would be by increased surface area or with less effective filtration. Two filters of the same surface area that flow differently obviously have very different filtration capabilities. Do the filters in question have a radically different filtration area? If not then the only way one will allow better flow while being dirty would be to allow particulates to pass through the engine. I personally would much rather ensure the proper filtration than ensure consistent power levels well after I should have been cleaning the filter.
 

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