Air filter question
Seasoned HDF Member
Joined: Dec 2004
Posts: 7,934
Likes: 43
From: Bloomfield, NM
Didn't look up all the Dyno runs that are out there cause I just didn't want to take the time, but did find numbers for a 1200 Sportster in HD's catalog. An air cleaner and high flow mufflers gave the following numbers: Hp increase=59 @6,000 rpm to 65 @ 5,000 (9% increase at 1,000 rpm less). Torque= from 62 to 72 (8.5% increase). These results are without modification to cylinders, heads, or anything else. There are a lot of similar results out there for anyone that wants to look them up. FuelMoto has a lot of dyno runs for about every condition you can imagine.
When I totaled my 2012 Limited it had an AC, Rineharts, and a PCV. I replaced it 2 weeks later with an exact copy except stock. When I first rode the new one I thought there was something wrong because it did not have the zip that the old one did. Why anyone would argue that there are no advantages or increases in the face of overwhelming evidence to the contrary is beyond me.
This increase in air is going to result in leaning out an already lean engine, so some kind of device to add some fuel will be necessary.
Bill
When I totaled my 2012 Limited it had an AC, Rineharts, and a PCV. I replaced it 2 weeks later with an exact copy except stock. When I first rode the new one I thought there was something wrong because it did not have the zip that the old one did. Why anyone would argue that there are no advantages or increases in the face of overwhelming evidence to the contrary is beyond me.
This increase in air is going to result in leaning out an already lean engine, so some kind of device to add some fuel will be necessary.
Bill
Last edited by billnourse; Jan 14, 2015 at 08:31 AM.
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Joined: Oct 2007
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From: New England
...but did find numbers for a 1200 Sportster in HD's catalog. An air cleaner and high flow mufflers gave the following numbers: Hp increase=59 @6,000 rpm to 65 @ 5,000 (9% increase at 1,000 rpm less). Torque= from 62 to 72 (8.5% increase). These results are without modification to cylinders, heads, or anything else. There are a lot of similar results out there for anyone that wants to look them up. FuelMoto has a lot of dyno runs for about every condition you can imagine...
...When I totaled my 2012 Limited it had an AC, Rineharts, and a PCV. I replaced it 2 weeks later with an exact copy except stock. When I first rode the new one I thought there was something wrong because it did not have the zip that the old one did. Why anyone would argue that there are no advantages in the face of overwhelming evidence to the contrary is beyond me....
FWIW, every bike, even those identical ones coming off the assembly line, is not identical. That's why there's custom tuning. Each and every intake, head, cylinder, and exhaust of every bike is different...that's why most ECM's learn to a certain degree.
Now those identical bikes do have the same parameters with respect to tuning when they start out but each one is still different. Each manufacturer builds in a rather healthy "safety" margin to their tuning maps knowing each bike has different actual numbers.
What I'm saying here is a lot of guys just buy into the more-is-better marketing line with respect to air cleaners. It would be like saying that your everyday commuter would significantly increase their car's top speed by simply installing a set of "Y' rated (186 mph's) tires...sorry, it just isn't going to happen.
I know no one likes to be tricked and I'm not saying those marketing claims are false. But one needs to read between the lines when it comes to most of this stuff.
Seasoned HDF Member
Joined: Dec 2004
Posts: 7,934
Likes: 43
From: Bloomfield, NM
While I appreciate what you're saying, remember those numbers usually carry a disclaimer somewhere that suggests numbers are calculated, not typical, under ideal conditions, requires changes to tuning constraints, and so on. All terms required by their attorneys so they don't get sued because YOUR machine didn't achieve the desired results.
Sorry to hear about your totaled bike.
FWIW, every bike, even those identical ones coming off the assembly line, is not identical. That's why there's custom tuning. Each and every intake, head, cylinder, and exhaust of every bike is different...that's why most ECM's learn to a certain degree.
Now those identical bikes do have the same parameters with respect to tuning when they start out but each one is still different. Each manufacturer builds in a rather healthy "safety" margin to their tuning maps knowing each bike has different actual numbers.
Sorry to hear about your totaled bike.
FWIW, every bike, even those identical ones coming off the assembly line, is not identical. That's why there's custom tuning. Each and every intake, head, cylinder, and exhaust of every bike is different...that's why most ECM's learn to a certain degree.
Now those identical bikes do have the same parameters with respect to tuning when they start out but each one is still different. Each manufacturer builds in a rather healthy "safety" margin to their tuning maps knowing each bike has different actual numbers.
After putting the AC, PCV and pipes on the new bike, it runs like the old one did. These mods achieved the desired and advertised results.
You can continue to argue your point till hell freezes over, but it does not alter real world facts and results. Dyno results and "seat of the pants" feel carry more weight with me than your theories.
Bill
Last edited by billnourse; Jan 14, 2015 at 09:31 AM.
Road Master
Joined: Jun 2009
Posts: 932
Likes: 14
From: CENTRAL IL
A good reason to upgrade the air filter imo, is the cost of the 1 time big sucker/reusable cleanable upgrade vs the cost of replacement stock filters. Couple air cleaner changes you are already money ahead on the high flow air cleaner , and any hp increase is just a added free benefit.
Extreme HDF Member
Joined: Jun 2011
Posts: 14,731
Likes: 2,536
From: Mountain Top, Alabama
A good time to upgrade the A/C is during a planned performance upgrade.
Dyno runs recorded before and after to bring together the total package will show YOUR BIKE'S improvement.
And, like Bill expressed, the seat of your pants will agree with a little more zip in your doo dah!
Dyno runs recorded before and after to bring together the total package will show YOUR BIKE'S improvement.
And, like Bill expressed, the seat of your pants will agree with a little more zip in your doo dah!
Outstanding HDF Member
Joined: Jan 2008
Posts: 3,328
Likes: 15
From: Pacific Northwest
And why do you say that?
A stock 103 TC at about 4000 rpm will flow approximately 135 cfm's. At about 5000 rpm, the cfm's "jump" up to about 143.
Here's MK's previous post...
Of what value does an air cleaner that flows 250, 500, or even 1000 cfm's provide?
Seriously? Remove the air cleaner on a running motor and tell me just how loud it becomes? I dare say that unless a decibel meter is used, no one would hear any difference.
That last part is not exactly correct either. The motor will flow only the amount of air that is "allowed" based on the design of the entire system.
Here's a little hint that MIGHT help you understand air flow...there's a LOT of things that reduce air volume into the cylinders that's well after the air cleaner. I'm not saying the air cleaner plays no part but it's not what causes any significant increase in air volume if nothing else downstream is done to improve air flow.
For example, smaller port creates more velocity, which in turn creates more inertia. The principle of inertia is to pack as much into any given area before it stops. The more inertia, the more force it develops, and the more mass it will pack before it stops.
So, when you figure in inertia (velocity squared x volume or cfm), it becomes apparent that velocity is more important to cylinder fill than volume. And unless you've made significant mods to the intake, heads, pistons, and so on, you won't get any significant benefit from just going to a "high flow" air cleaner.
The marketing for all these "high flow" systems generally fail to mention that in order to take advantage of their bigger numbers, the motor has to be modified to the point is can begin to draw much larger volumes of air. It is far cheaper to manufacturer, market, and sell $125 systems then it is to sell $2000 mods to take advantage of that new air cleaner.
A stock 103 TC at about 4000 rpm will flow approximately 135 cfm's. At about 5000 rpm, the cfm's "jump" up to about 143.
Here's MK's previous post...
Of what value does an air cleaner that flows 250, 500, or even 1000 cfm's provide?
Seriously? Remove the air cleaner on a running motor and tell me just how loud it becomes? I dare say that unless a decibel meter is used, no one would hear any difference.
That last part is not exactly correct either. The motor will flow only the amount of air that is "allowed" based on the design of the entire system.
Here's a little hint that MIGHT help you understand air flow...there's a LOT of things that reduce air volume into the cylinders that's well after the air cleaner. I'm not saying the air cleaner plays no part but it's not what causes any significant increase in air volume if nothing else downstream is done to improve air flow.
For example, smaller port creates more velocity, which in turn creates more inertia. The principle of inertia is to pack as much into any given area before it stops. The more inertia, the more force it develops, and the more mass it will pack before it stops.
So, when you figure in inertia (velocity squared x volume or cfm), it becomes apparent that velocity is more important to cylinder fill than volume. And unless you've made significant mods to the intake, heads, pistons, and so on, you won't get any significant benefit from just going to a "high flow" air cleaner.
The marketing for all these "high flow" systems generally fail to mention that in order to take advantage of their bigger numbers, the motor has to be modified to the point is can begin to draw much larger volumes of air. It is far cheaper to manufacturer, market, and sell $125 systems then it is to sell $2000 mods to take advantage of that new air cleaner.
Surely you understand the positive aspect of having an A/C that flows more than a motor needs under full power - there IS no such thing as too much. There IS such a thing as too little and hitting the perfect flow number for a given motor would be an exercise in banging your head against the wall.....not impossible but pain WILL be involved.
Yes, the EPA uses machines to measure sound levels, but take the A/C off of any motor and rev it up and you WILL hear the difference. Evidently you never have or you wouldn't make such an ignorant remark.
And while you speak like you might actually know something all you're really doing is picking nits. A motor has to be able to get enough air to generate the velocity needed to fill the cylinder(s). That free flowing air does not come from a choked up stock A/C. The factory left quite a bit of power on the table for those of us that want it. But it takes a free flowing A/C, exhaust, and some tuning to get it.
And finally, just because an A/C flows more air than needed does not mean that one HAS to build a hot rod motor OR take full advantage of all the air flow it provides. It's enough that it can flow more air than the stock A/C so one can tune for the maximum power that even a pretty stock motor can provide.
Man, get out in the real world and stop drawing conclusions from a few articles in some magazine. You have much to learn - go do some racing and see where your air flow theories get you (back of the pack....way back).
Road Warrior
Joined: Oct 2007
Posts: 1,468
Likes: 4
From: South Carolina
Ok, now I'm confused. I know that if I put too big a throttle body on my bike it will get too much air, CFM, and run like ****. I keep reading posts that are saying there's no such thing as too much air. did I have a stroke last night or are they meaning that for the correct throttle body a filter wont flow too much air?
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Joined: Oct 2007
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From: New England
Spend maybe 3 minutes in a garage with REAL professionals and see how much head banging they do. Unlike your method (head banging), the pros do simulations with various parts under various conditions. What you won't see is their chief mechanic on the phone with some marketing dude getting tricked into buying something that won't provide any real benefit.
Sorry guys, you bought into a slick marketing campaign...but hey, it's your money...waste it any way you like!
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Outstanding HDF Member
Joined: Jan 2008
Posts: 3,328
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From: Pacific Northwest
Can you provide an example? If so, put if your own words instead of simply regurgitating some cheap marketing campaign...
Banging one's head against the wall is probably something they did decades ago. But here's a news flash for you...they have computers today...no need for head banging.
Spend maybe 3 minutes in a garage with REAL professionals and see how much head banging they do. Unlike your method (head banging), the pros do simulations with various parts under various conditions. What you won't see is their chief mechanic on the phone with some marketing dude getting tricked into buying something that won't provide any real benefit.
Sorry guys, you bought into a slick marketing campaign...but hey, it's your money...waste it any way you like!
Banging one's head against the wall is probably something they did decades ago. But here's a news flash for you...they have computers today...no need for head banging.
Spend maybe 3 minutes in a garage with REAL professionals and see how much head banging they do. Unlike your method (head banging), the pros do simulations with various parts under various conditions. What you won't see is their chief mechanic on the phone with some marketing dude getting tricked into buying something that won't provide any real benefit.
Sorry guys, you bought into a slick marketing campaign...but hey, it's your money...waste it any way you like!
This site is chock full of examples man, wake up and smell the coffee.
An example you want, an example you get - here we go, pay close attention:
Back in '06 I bought an EFI Street Glide. I installed Rinehart TD's, a Big Sucker A/C (I run it uncovered), and a PCIII. It gained about 10 hp/10 lbs ft of torque. Now that Big Sucker flows way more air than that 88" motor actually needed (here's where you need to concentrate) but it still made more power than it would have with the stock A/C.
My motor is now 95" with 577 cams, head work and 10.5:1 pistons that easily cleared 100 hp and 100 tq. Still has the same exhaust and A/C. The A/C still flows more than even the 95" motor can use, but you just can't argue with results (well maybe YOU can).
So.....the logical conclusion one draws is that having an A/C that flows more than a given motor needs is a positive thing.
If you still don't believe me just ask ANY engine builder. The want unimpeded air flow no matter what kind of numbers their engine makes.
And here's one more thing: I double dog dare you to find an A/C that exactly fits the air flow needs of any motor you can find. Go on, start banging your head.
I'm done now - all out of patience. No more explaining simple concepts to someone unwilling to accept what is normally taken for granted by everyone else.