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Air Filters for 2016 T120

13K views 30 replies 11 participants last post by  o0rob0o 
#1 ·
Looking at DNA air filter, claim 39% improvement in air flow. Believable?
 
#3 ·
I am betting not believable. Is the air filter 39% more cross sectional area? Is the air box 39% larger? If no, then the only way to get more air through it is by reducing resistance to flow. Teflon lined pores?
 
#9 · (Edited)
No, that is not quite right.

The air filter is 39% more porous. Given equal testing environments - same plenum size and shape, same pressure drop, same duration measured - 39% more air will flow through the more porous filter. This is a measurable quality of a given filter, nothing deceptive is being stated by the manufacturer.

This should be really easy to visualize. Water and air are both effectively liquids for this experiment (airflow, fluid dynamic testing) so imagine the following:

Take two different colanders, one a mesh strainer, and the other the kind that has holes drilled in it.

Dump a glass water into mesh strainer and time how long it takes for gravity to pull all of the water through it, into your sink.

Now dump an equally filled glass of water into the hole type strainer and again time it. Compare the two times. Which drained the water faster?

This is essentially how these filters are tested, except they test with air, not water. Slightly more involved experiment, but not buy much.

A less restrictive filter material has the potential to flow more air, all other factors being equal (and they are equal, unless you make changes other than just the air filter).
 
#4 ·
They give significantly less restrictive airflow, in the same way K&N do.
If you think it will give your engine more airflow, it won't. The inlet to the airbox is so small, that's the bottleneck, not the filter.
At least you'll save money on new filters though :)

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#5 ·
Oh, and it's not magic. The fibre in the filter has small hairs that catch dirt and dust electrostatically on the oil they're coated with, and the gaps between the mesh are significantly larger than paper ever is, yet they give equivalent air scrubbing.
Clever stuff.

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#6 ·
If performance air filters do not perform any better than stock paper filters, why would all the race teams in auto, bike, boat, etc., insist on using them? Performance gain? And are sport drinks like Gatorade any better than water? Yea, what's up with that?
 
#7 · (Edited)
If performance air filters do not perform any better than stock paper filters, why would all the race teams in auto, bike, boat, etc., insist on using them? Performance gain?
Because @jsobell did't really fully explain it. When he wrote:

They give significantly less restrictive airflow, in the same way K&N do.
He was exactly correct and later explains why: a more porous membrane physically allows more air to pass through. Imagine a screened in porch on a breezy day. Now remove all the screens and put chain link fence in its place. Then imagine a third porch where the screens are made of coffee filter material.

Which porch lets more breeze in? Which porch lets more mosquitoes in? Which gets filthy dirty and needs to be thrown in the garbage instead of being able to be rinsed off with a hose?

If you think it will give your engine more airflow, it won't.
Well, no, this statement is contradictory to the previous one and should be understood to be false, all other things being equal. To use the porch metaphor again, the porch stays the same size and shape and retains all the same windows regardless of which screen material is used. And we'll grant that mother nature is providing a steady breeze that doesn't change much over time.

The inlet to the airbox is so small, that's the bottleneck, not the filter.
The inlet is a bottleneck indeed. The filter is yet another bottleneck. As to which one is more detrimental to flow, that is an engineering exercise you'll have to do for yourself. However, all things being equal (the inlet size does not change, but the filter material does) you should be able to deduce the net result on airflow.

Again, the size and shape of the porch does not need to change for the screen material to have an effect on how much breeze reaches you. Both variables have their resulting effect on overall flow.

Now, if you both modify the inlet and filter, you net a larger increase in flow than doing one or the other alone, granted. I think for most people, leaving the stock air box in place, removing the snorkel, and adding a higher flow filter will result in a bit more air flow. For what should be obvious reasons, porch metaphors or racing teams using them included.

Just keep in mind that racing teams don't so much care for engine longevity as they do max performance, so they will trade some dirt filtration performance for overall CFM performance.

For me, the question boils down to which one: BMC or DNA?
 
#8 ·
I've used K&N before and it seemed to be of good quality and gave my bike at the time (a 2007 Honda 919) a little bit more pep. It definitely made the induction noise more noticeable. I would imagine that the DNA filter would perform similarly on any given model.
 
#11 ·
Oh, and as for which one? Well if you're hoping for extra airflow, the DNA rates the highest between K&N and DNA. There are no published figures for BMC.
I doubt we'd notice any difference between the three, but take your pick :)

They published a video of a full test of a Kawasaki filter on YouTube:


TL;DR results:
• Kawasaki OEM 152 cfm @ 1.5 inH2O
• K&N Filters 161.6 cfm @ 1.5 inH2O
• DNA Filters 184.6 cfm @ 1.5 inH20
 
#28 · (Edited)
Oh, and as for which one? Well if you're hoping for extra airflow, the DNA rates the highest between K&N and DNA. There are no published figures for BMC.
I doubt we'd notice any difference between the three, but take your pick :)

They published a video of a full test of a Kawasaki filter on YouTube:
https://www.youtube.com/watch?v=pGSHtEjYIhc

TL;DR results:
• Kawasaki OEM 152 cfm @ 1.5 inH2O
• K&N Filters 161.6 cfm @ 1.5 inH2O
• DNA Filters 184.6 cfm @ 1.5 inH20
Note that it appears that the amount of actual "air filtering area" is larger with the DNA and the K&N, compared to stock.
So, with respect to particulate collection (or passing), it can't just written off as the material used, "oils", loose fibers and the construction of pleating.....
Also:
The engine CAN NOT "suck" (hate that) any more air through anything other then what the standard day air pressure is outside at any given moment.
It's that outside air pressure that pushes air into and through the air filter, the induction system and ultimately into the combustion chamber.
Everything we do (outside supercharging or turbocharging) is to make that volume fill up better from atmospheric air pressure.
Hence the reason my bikes are starting to become dogs at 12,5000 to 14,000 feet in the mountains here... LOL.
Same with my 180hp airplane.... air density is the limiting factor.
 
#12 ·
@jsobell I know you understand how it works and then some, the metaphor was more for anyone else who was having trouble visualizing it. Probably a waste of words for most members, nothing they didn't already know.

Anyway my plan is x-pipe plus high flow filter (DNA seemingly ahead of BMC) and the official off road tune. Then perhaps after the warranty is over, something approaching this:

http://www.fortheride.com/stories/jason-paul-michaels-racing-the-street-twin-hooligan/

This guy added a full exhaust system, deleted the air box, added a custom intake plenum with high flow filter - and since he's racing (and probably signed an NDA), Triumph gave him a "top secret" tune. They claim substantial power improvements, which is not surprising given the stock 900 cc mill's lower than typical output figures from the factory.

The big gains are to be made on the intake side of the engine, as many have speculated. That official off road tune is as good (aka rich) as you are going to get without resorting to tricking or bypassing the ECU.
 
#13 ·
The factory tune the bike for the stock air filter. I would stick with the stock filter. Plus an OEM paper filter block dirt from getting into the engine better then those K&N style filters. I've got K&N pods on my 3007 and I notice that dirt film get inside the carb intakes. It never did that with the stock paper filter and airbox.
 
#14 ·
No, what you said was correct, and I was just pointing out that the restriction due to noise restriction is more serious than is immediately obvious :)
I try to treat this as an information sharing forum, rather than a "look how smart I am" one, so if I came over that way I apologise.

That 900 is interesting, and Triumph can easily unlock the ECU for tuning if they want to. It would be interesting to know where they got improvements. Removal of the cat alone may have given an extra 10%, but I don't know how much richening they would have done. Certainly the 1200's are not particularly lean under power, and need leaning up at the top end in stock form. Much of the "these bikes run lean" seems to be a rumour related to the fact they run stoich at idle and cruise, and the fuel is almost cut off on over-run.
We're spinning up a Thruxton with the Arrow full system fitted this afternoon, but it's a fairly standard airbox setup. I'm not familiar with the 900's, but it'll be interesting to see if relatively similar improvements are found on those with the cat removed. As you say, I suspect there's more wriggle room for improvement on the 900 engine.
 
#16 · (Edited)
As you say, I suspect there's more wriggle room for improvement on the 900 engine.
I'm not sure I did (or would) suggest that the 900 has more room for improvement than the 1200, but only time and testing will tell.

What I meant to suggest is that the 900 comes particularly underpowered from the factory, and the bulk of the bottleneck is probably on the intake side of things.

The Street Twin exhaust is not particularly restrictive, at least when examining the silencers themselves. The catalytic converter results in more of a restriction by comparison, as evidenced by the changes in sound when deleting the cat versus deleting the silencers alone. Removing only the silencers results in a small sound change, and removing the cat results in a dramatic sound change. Sound is directly related to pressure and air flow.

Of course this is unquantified conjecture without AB testing on a dyno, but we know enough about general engine dynamics from countless other applications to know what is likely to apply here.

What I do know for certain is that Triumph's own off road tune for the 900 engines assumes a cat delete, and therefore must be richer than it is leaner. So anyone considering both intake and exhaust flow improvements probably wants to experiment with that tune, as it has the most potential for more power by way of delivering more fuel than the stock tune.
 
#19 ·
Basically, an internal combustion engine is an air pump. Make it pump more air and you will get more HP. You will NOT get 39% more air through the engine by installing a DNA filter. You can remove the air filter completely and you will not get 39% more air through the engine.
 
#20 ·
I am not suggesting 39% more air flow "through the engine" and neither is DNA. Their numbers measure the filter itself, nothing more.

Having said, more air through the filter per cycle is exactly what allows an air pump aka engine to create more output. The amount of which is determined by a lot of variables in the form of the rest of the engine south of the air filter.

Are we really in disagreement here?
 
#21 ·
:D
I think Delta has correctly addressed the original question "Looking at DNA air filter, claim 39% improvement in air flow. Believable?". The answer is definitely yes.
I already mentioned that the airflow into the engine will be almost unaffected, so let's accept that we're all correct and move on.
 
#23 ·
Almost unaffected? A small change in air volume can result in measurably more O2 in the compression cycle.

When the cylinder drops, and creates vacuum pressure, the void must be filled. The pressure is essentially a constant, assuming healthy piston rings, valve seals and heads.

Given that constant pressure, the variable is how much O2 can be drawn per cycle. This is where that 39% figure is important. It represents increased potential.

This notion that a better flowing air filter is not going to be of much use seems be at odds with what we are actually agreeing on. It sounds like you are suggesting that while a filter can flow more air, it somehow won't make it into the combustion chamber.

If that last part is true, why is this so?
 
#26 · (Edited)
@jsobell Definitely looking forward to your results of the Arrow system testing. Is @Fenech the guinea pig again this time?

Regarding which end of the intake matters more - the bellmouth inlet to the atmosphere versus the filter air inlet to the TBs, that is an interesting discussion. Clearly the inlet to the atmosphere matters - it is the primary inlet point, which all downstream points are affected by. However the downstream flow variables - of which the air filter is one - play a role in determining just how much of a downstream pressure drop occurs, which is what is informing the atmosphere just how much air is being asked to be sucked into that primary inlet.

But like you mention, just improving one variable (less restrictive filter) is not going to do much all by itself.

Makes you wonder if that Free Spirits air box breather kit is really worth +8 HP like they claim. Could be, but I am skeptical.
 
#27 ·
No, @Fenech is not the victim this time :) He's too sensible to stick a relatively untested system on his bike.

Yeah, the Free Spirits claim looks like complete bullsh*t. Combined with a decat possibly, but the decat would be 7hp of that :)


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#29 ·
FWIW I put the DNA filter on my Street Twin a couple weeks ago and I did notice it to be a bit more responsive. I rode it just prior to and just after installation. Not suggesting there actually is an increase in power but it did feel more eager to accelerate.
Placebo? Maybe, but I do feel like it did something.
I then added the Vance and Hines a week later went for another ride and did not notice any discernible difference except for the sound without the baffles.
 
#30 ·
Airbox mod

I have a 2016 ST with a Tec Cam and K&N filter. Also have custom exhausts with a DB killer and X pipe. A while ago I had thought of making a replacement airbox cover with these 2 pods fitted in to try and squeeze a little more grunt from this bike.
Question - would it make a difference since I already have a K&N fitted? This would be more air coming in from the airbox cover over and above the K&N airflow. Also will it be a problem in the rain?
Getting a booster plug in a couple of days just to make sure it doesn't run lean.
 

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#31 ·
K&N Air Filter for 2016 T120

I installed the K&N filter on my bonnie black last month, also running Motone X-Pipe, and have noticed a considerable difference. Revs a lot more freely but also crackles and pops on the over run.

The main question I have relates to a new noise I've noticed since installing the filter:
When shutting off throttle and pulling the clutch in at high revs (like switching from 1st to 2nd) I notice a sort of burping noise as the revs fall before releasing the clutch again.

Any ideas? Seems related to the airbox mod as it's definitely a new thing.
 
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