What flows best?: stock intake air box or two small aftermarket filters?

[Kane]

Hello all, I’ve been tempted to remove the side panels on my V11 and replace the stock air intake with two small K&N type of filters. I’m thinking it looks kinda cool, more of a stripped-down cafe racer thing, it might afford bettter access to adjust the rear shock, and might save a little weight.

Is there better airflow with two small filters? Any change in performance either way?

Hope everyone’s 20/20 has been grand so far!

Thank you

[JBBenson]

I think you will only introduce a bunch of idle and running problems with near-zero performance gains.

[GuzziMoto]

The stock airbox will flow better than two small pods at most rpms, and as such will make a better spread of power. But the individual pods do look cool.

The loss of performance when switching to pods isn't huge, and it has been done by some. But it is a loss of performance.

If you go with pods, do everything you can to retain the rubber velocity stacks that serve as intake runners between the airbox and the throttlebodies. My Daytona has a really cool set of machined aluminum velocity stacks that were made to convert to pods, and I was able to get them to work pretty well. But if I could fit the airbox back on that bike I would. But it is pretty far from stock and the stock airbox would not fit with the V11 rear subframe and seat.

[pete roper]

What you will achieve is a loss of performance and accelerated wear of your engine. Pod filters, as I stated in another thread yesterday, are utter shit and should be ruthlessly stamped out whenever they rear their ugly, useless, heads!

[Kane]

15 minutes ago, pete roper said:

What you will achieve is a loss of performance and accelerated wear of your engine. Pod filters, as I stated in another thread yesterday, are utter shit and should be ruthlessly stamped out whenever they rear their ugly, useless, heads!

Dang. That’s doesn’t sound so good. I guess looks aren’t everything. I actually like the stock look, but sometimes I wish the bike’s profile was a bit stealthier. Thanks, guys, for cueing me in. The bike’s running pretty good with the stock systems, so I’ll leave it be for now. 

Cheers!

[Lucky Phil]

Removing the airbox on a modern bike and going to pods is about the equivalent of hacksawing your header pipes off 4 inches from the port. People still do it though.

Ciao

[pete roper]

1 hour ago, Kane said:

Dang. That’s doesn’t sound so good. I guess looks aren’t everything. I actually like the stock look, but sometimes I wish the bike’s profile was a bit stealthier. Thanks, guys, for cueing me in. The bike’s running pretty good with the stock systems, so I’ll leave it be for now. 

Cheers!

Oh, and the same goes for 'Flat' replacements for the stock filter by K & N or whoever. Labyrinth filters *work*, again using the word advisedly, by forcing the air to twist and turn around the filter media. The actual 'Holes' in the filter are huge, this is why you can effectively see through them. The way they are supposed to work is that as the air twists and turns through the media any particulate matter having greater mass and therefore inertia will try to keep going straight and in doing so will collide with the oily medium of the filter's structure and stick to it.

Great theory. In practice it's pretty much useless. If you want to dust your motor, short of shovelling sand down the throttle bodies fitting a labyrinth filter is a pretty close second!

[po18guy]

If you want the look, buy one pod filter, cut it in half lengthwise, and hot-glue half to each of the intake boots just upstream of the throttle bodies. Only you will be the wiser.

Seriously, airboxes are big talk even at the EX500/GPz500S forum. That bike uses CV carburetors which need a certain restriction to function properly. All the cool dudes toss the box and put $10 pods on, only to lose tons of mid-range (if 498cc can be said to have that), as well as some top end, as the slides may not rise completely. The EX airbox has a 7 litre capacity and is a very odd shape, fitted into each and every available nook and cranny in the frame. 5 separate pieces and two snorkels. It was most certainly not done for looks - it was done by reading dyno charts at the factory.

[docc]

1 hour ago, pete roper said:

Oh, and the same goes for 'Flat' replacements for the stock filter by K & N or whoever. Labyrinth filters *work*, again using the word advisedly, by forcing the air to twist and turn around the filter media. The actual 'Holes' in the filter are huge, this is why you can effectively see through them. The way they are supposed to work is that as the air twists and turns through the media any particulate matter having greater mass and therefore inertia will try to keep going straight and in doing so will collide with the oily medium of the filter's structure and stick to it.

Great theory. In practice it's pretty much useless. If you want to dust your motor, short of shovelling sand down the throttle bodies fitting a labyrinth filter is a pretty close second!

I have never heard that term "labyrinth" filter ( now, there are LOTS of Pet'es terms of never heard, but the rest are generally, er . . . "discriptives" ). I have heard the K&N types called "oiled gauze" and was taught here a long time ago they are not "foam." I have listened to and read so much of the debate about them and somehow concluded their downfall is neglect. So, I service (clean/oil) mine about every 12,000 miles/20.000 km, but am now having second (fifth?) thoughts about returning to paper (if I can find a ready source).

Otherwise, I have always been fond of the stock airbox in any one of its natural settings . . .

[Lucky Phil]

41 minutes ago, docc said:

I have never heard that term "labyrinth" filter ( now, there are LOTS of Pet'es terms of never heard, but the rest are generally, er . . . "discriptives" ). I have heard the K&N types called "oiled gauze" and was taught here a long time ago they are not "foam." I have listened to and read so much of the debate about them and somehow concluded their downfall is neglect. So, I service (clean/oil) mine about every 12,000 miles/20.000 km, but am now having second (fifth?) thoughts about returning to paper (if I can find a ready source).

Otherwise, I have always been fond of the stock airbox in any one of its natural settings . . .

There are 2 threads to this docc. Firstly a well designed airbox is designed to harness the natural intake resonance of the engine and feed a cool laminar flow of air to the throttle body. Forget about ram effect for the majority of riding even on the track as it has a minor effect. These days even street bikes use this resonate effect together with ecu controlled variable length inlets to smooth out the torque curve. The V11 also uses intake and airbox resonance to advantage.

Secondly is filtering. I read a long time ago a comparison of elements of different styles and from memory the conclusion was pretty much the same as for oil filters. less restriction means less effective filtering. So at the end of the day you get the choice of free flowing and reduced filtering capability or less free flowing and more effective filtering. You get to choose.

I used to ride bevel drive Ducati's around for a few years with just wire screened intake trumpets. The Nikasil cylinders and pistons used to be ok but the valves and valve seats used to take a bit of a hammering. Back in those days a std Ducati filter was a tin box and concertina hose for each carb and just didnt look cool at all, before the days of inlet resonance tuning. As soon as manufacturers started taking the induction side seriously I gave up on such silliness. 

Personally I'd stick with the paper element and leave the horrible messy oily gauze thing for lawn mowers and such. Of course the only reason they came into being at all was for dirt bikes back in the late 60's where you couldn't be changing a paper filter after every ride. You needed something economical and easy for the owner to service and being most were competition bikes the manufacturers didnt need to worry about warranty claims for high wear rate. It all grew from there.

Ciao 

[andy york]

yep  I don't know if I can get ANOTHER 130,000 miles with me and my pods.

[pete roper]

1 hour ago, docc said:

I have never heard that term "labyrinth" filter ( now, there are LOTS of Pet'es terms of never heard, but the rest are generally, er . . . "discriptives" ). I have heard the K&N types called "oiled gauze" and was taught here a long time ago they are not "foam." I have listened to and read so much of the debate about them and somehow concluded their downfall is neglect. So, I service (clean/oil) mine about every 12,000 miles/20.000 km, but am now having second (fifth?) thoughts about returning to paper (if I can find a ready source).

It can't be that hard or expensive to get air filters surely? The V11 uses the same air filter as the Cali 1100 so beloved by the Corn Cob Pipe brigade. They'd fly into an apoplectic frenzy if air filters weren't available!

GU30113600

Bash that into AF1's site and they're thirteen dollars but because they don't do a lot for older stuff they'd have to order them in.

Lets try MG Cycles? OK, $11.48 from the Cheesers.

Harpers? $13.10 but their website makes it harder to find.

Order from Europe? Well just as an example from TLM they're €9.05

Air filters aren't exactly *Emergency Breakdown* items, sure it is good to keep an extra one hanging around but as a service item they can usually be bought by planning ahead a bit. Like oil filters, gaskets, sealing washers and all the other service dross we need just buy three and keep them on the shelf. Unless you're one of these folks who changes motorbikes like most people change underpants they'll all get used. It's not like they are going to go off like a bag of old prawn heads!

Pete

 

[docc]

Sheeesh. It's wonder my shit-tard old Sport has any compression left at all.

I suppose I will have to get some pleated paper filters on hand for my impending 115,000 mile service. And the 125,000.

That is my goal, as many of you know: 200.000 km.  But it gives me premonitions, worries, weird lucid dreams, and the vision of pulling wildly into one more South'n Spine Raid and this . . .

 

[docc]

 

[pete roper]

Look, people are welcome to do exactly as they please but the two things I did when I first bought the Scura RC now owned by Chuck was to replace the single plate clutch with a twin plater and dump the shitty pod filters and reinstall the airbox.

If people want to run a K & N filter that's fine but if it comes into my workshop expect a torrent of spluttering, incandescent fury and for it to be returned to you in a bag when the service is complete!