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Air Box

Wasn't as bad as I thought, I used a Custom choppers battery box, 20 deg off set filters, KN air temp and crank case filters.
 

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Discussion Starter · #26 ·
I am at odds with this mod but because where I live it rains a lot. Other bikes do have trouble riding in rain with HF filters here...I love it but I am afraid I will have to let it pass.
 

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I am at odds with this mod but because where I live it rains a lot. Other bikes do have trouble riding in rain with HF filters here...I love it but I am afraid I will have to let it pass.
Same here, too much rain and while I like the idea of opening up the frame, the snorkel cover looks out of place with the K&Ns. Not every mod is for every one.
 

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I actually ordered both the catless Akra headers and K&N conical filters through my dealer, but he and his mechanic told me that the engine tuning will auto-adapt itself with the sensors... I know some of you told me here the contrary... Am now lost! :(
Could you help with understanding the real pros and cons?
Thanks a lot.
 

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Has anyone had any experience of the [Pier City Customs kit, tips on shortcuts on fitting. The instructions supplied are a bit sketchy to my mind.
 

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The dude at PCC, Rory, has said there are shortcuts to had, but he's on his holibobs. So Im bothering you lot instead.
 

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Has anyone who's done this dynoed their bike? Hopefully before and after. Just curious how power is actually affected.

Please spare us the usual parrot like responses and hopefully someone will have actual data.
 

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When I had my R9T remapped at Hilltop in the UK he said it was one of the strongest he'd seen . . . no reason for that (as far as I know) other than perhaps the fresh BMW air filter (not K&N) and extra four or five holes I drilled in the side of the air scoop behind the side panel which hides the scoop. I looked at the opening at the front of the scoop and it's tiny, I don't have the figures to hand but something like a third of the surface area of the air filter, so as I've done in cars where the air box is there to mount the filter and reduce noise, I opened it up a little - probably doubled the area available for the air to enter. (No holes in the air box, just the side of the scoop next to the filter) Seems to have worked - or at least not had any negative effect at the very least. Gained 17bhp at the top end in conjunction with the remap and I can certainly feel the gain on the road.

Not sure how this helps with this thread but thought it might be interesting background !
 

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When I had my R9T remapped at Hilltop in the UK he said it was one of the strongest he'd seen . . . no reason for that (as far as I know) other than perhaps the fresh BMW air filter (not K&N) and extra four or five holes I drilled in the side of the air scoop behind the side panel which hides the scoop. I looked at the opening at the front of the scoop and it's tiny, I don't have the figures to hand but something like a third of the surface area of the air filter, so as I've done in cars where the air box is there to mount the filter and reduce noise, I opened it up a little - probably doubled the area available for the air to enter. (No holes in the air box, just the side of the scoop next to the filter) Seems to have worked - or at least not had any negative effect at the very least. Gained 17bhp at the top end in conjunction with the remap and I can certainly feel the gain on the road.

Not sure how this helps with this thread but thought it might be interesting background !
Firstly can I declare that I know next to nothing about tuning, but what little I think I've picked up points to the airbox volume being a specific size for the engine to help with power/torque. Losing the air box/filter would disrupt this and could affect (possibly adversely) the power curve of he engine.

Personally I'd be wary of losing the air box, even if it does look cool.

I do however like the idea of increasing the airflow to the filter, which doesn't directly affect the design of the air box. A caveat would be a remap to take account of the increased breathing capability.

Would you possibly be willing to take photos of your modification and share it in a new thread in this forum section?
 

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I'll take some photos this weekend, it's not pretty . . .but probably works !

I agree about losing the airbox and the two large trumpets inside - it will certainly change the power delivery, but that might suit some people ? As John T said we need a proper dyno test to know for sure.
 

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...what little I think I've picked up points to the airbox volume being a specific size for the engine to help with power/torque. Losing the air box/filter would disrupt this and could affect (possibly adversely) the power curve of he engine.
Our current crop of superbikes definitely have carefully designed tuned intakes / airboxes. They also have frames etc designed around the necessarily large volume airboxes required. Our R Nine T's look like they have something that's more a matter of convenience to adequately silence the intake and they did the best they could with the limited space available for the airbox. Our throaty exhaust comes at the expense of a necessarily very quiet intake as the noise limits are for the bike as a whole.

That's why I was curious if anyone had dyno results with individual filters and no airbox.

Didn't Wunderlich(?) used to offer a "hi-performance" larger cross section intake snorkel for the boxers?
 

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Pier city Rory

I like the look of the Pier city kit. The finished look of the bike looks SO right to me!

It would have been great to see before and after dyno charts. But alas, none seem forthcoming.

IMHO, the R9 motor should be fine without an airbox. It's a big, old stool, relatively long stroke 4 stroke motor. Many variations of such motors run perfectly happily sans air boxes. I would venture to hypothesis that the primary function of the airbox on these bikes is silencing and emissions (ensuring full burning of any crank case gases expelled via the breather system).

Rory seems to have the installation down to a fine art and offers a very reasonable 'all in' fitted price.

The more I look at my airbox, the more wrong it looks!

I'm very tempted...
 

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I like the look of the Pier city kit. The finished look of the bike looks SO right to me!

It would have been great to see before and after dyno charts. But alas, none seem forthcoming.

IMHO, the R9 motor should be fine without an airbox. It's a big, old stool, relatively long stroke 4 stroke motor. Many variations of such motors run perfectly happily sans air boxes. I would venture to hypothesis that the primary function of the airbox on these bikes is silencing and emissions (ensuring full burning of any crank case gases expelled via the breather system).

Rory seems to have the installation down to a fine art and offers a very reasonable 'all in' fitted price.

The more I look at my airbox, the more wrong it looks!

I'm very tempted...
I'm not so sure, the boxer in the R9T is actually a highly developed engine, 12:1 compression ratio, large pistons and bore, strong con rods and reasonably long cam profiles to get 110+ bhp and 88lb/ft from just two cylinders and 1170cc. That's not an easy ask and the fact the new water cooled engine only makes an extra 15bhp shows that BMW have taken the oil/air cooled engine quite a long way. The air box will be an important part of that.

It will work fine without the air box but you need to understand first what the air box contributes and therefore what you will lose without it. I've got some books you can start with :)
 
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