JHP air box filter
 

Hi
After much fafing around with air filters and carbon air tubes I think I've decided to go for a JHP airbox filter.

Anybody got a spare one that they no longer need that I could buy off them?

Nice way to sap power

Believe me I've looked at all the options and if I want to go with the bling I've no other real affordable option.
Will I really notice a 3bhp loss?

NOPE!!

Mr C next time you are in the Midlands please call into the shop and I will show you the flow readings from my flow bench, with std filter, with JHP filter and without filter. without doubt a fresh engine without filter flows marginaly better than a fresh engine with JHP ( or std ) filter but the fresh engine without filter is very soon a worn engine with poorly seating valves and considerably down on power to a filtered engine. Of course if money and frequent rebuilds are no problem go without filters ! jhp john

Looks like I'll have to buy a new one from you then John.
Looking for a good price? :lol:

Hello Col996S
No problem 10% to all DSC members for most spares, just quote your membership details.
Best regards

jhp john

Only problem with the ITG/JHP filters is the space that is taken up in what is designed as a pressured airbox. I have used the in tube PiperX ones in the past But in this case he cant use them.
What kind of time scale untill things become worn? Surely not unless you live in the desert running without a filter wont hugley add premature wear to valve seats??
I know of some who have used high denier tights as air filters!!
Big plus point if the JHP type filters are if you end up upside down and tankless in the gravel there is less chance of kitty litter ending up down the inlets.

Funny you should say that but I was thinking the same. What would be wrong in stretching them over the holes where the pipes join the airbox? I'm being serious.

im just imagining you going into a shop and asking for a pair of tights................"NO, NO NO, there for my bike, honestly!"

"Of course Sir, special party at Christmas is it?":lol: :lol:

They go up in flames if you get a back fire thru the throttles..... I'm being serious ;)

I wont even go near something that sounds like singe!

Filter
 

The main reason I did the air filter way back in 94 was after removing the tank on the 1st 916 I ever worked on I found the air box lined with grit etc which had got right past the original air tube filter then of course the next step is straight into the motor, after considering every which way to go and with the knowledge that surface area for any type of filter is the most important thing to avoid suffocating the engine the JHP filter was borne. One advantage with that type is that it does not impeed the volume of the air box (just think of how much water is displaced when you put a sponge in a bucket of water) is also has little to no effect on pressurising the air box, in fact as the air tubes are not resticted it is better than the original.
As for Chris B's comments I can't stop laughing which is always a good way to start the day !

jhp john

Its true ya know.
Back in the days of when I was an impoverished grass track racer,I made an airfilter from my mums old tights.I could'nt afford one of those fancy foam jobbies.Now big singles running on methanol are a bit of a b*****d to start,and sure enough she backfired through the carb,.....:eek:
I managed to put the fire out before the frame and seat got too badly damaged.:lol:
"Hello,is that Trackstar equipment?One foam airfilter please!":lol:

While it's true that foam does not impede or change the effective volume of the air box, it does change its resonance characteristics. You can prove this to yourself by first blowing across the mouth of a bottle to hear it's tone, and then repeating this after partially filling the bottle with filter foam.

Filters located in the air box take-up space which changes the resonance of the intake system at various engine speeds. Air box resonance helps to fill the cylinders with air, and it’s important to note that factory engine development work to smooth-out the power and torque curves is done using the stock filters. In particular, air box filters degrade throttle response, the ability to smoothly accept changes in throttle, by reducing the volume of “free” air located in the space between the filter element and the throttle plate. The volume of “free” air should be at least 1.5 liters for the best throttle response for liter displacement bikes.

http://www.ducatisportingclub.com/sh...ad.php?t=41331

Now what do I do?

And here's me trying to explain things simply, well in reality on both the flowbench and the dyno + keeping things to a resonably affordable level the foam airbox filter works very well without any drop in performance over the original type and it certainly filters the incoming air to a better level than the original.
On our BSB winning bikes we have used two types of JHP filter one being the foam in airbox type before the shower type injectors were employed and I think if they were good enough to win BSB races in the past then they can't be to bad !

Regards jhp john

Hello

I have, and always fit the ITG/JHP to my bike,
soley because over the years I have noticed lots of stone debirs in the airbox.
Maybe not a good enough reason, but Nelly set my bike up some years ago when I first fitted one,
and the bike ran just fine.;)

each to their own I guess.:)

TopiToo

To be fair you would be hard pushed to notice much difference which ever route you go down. Like John says you will have better protection for your engine internals.
Get one ordered fit it and forget about it.

I am.
Thanks to everyone.

Does anyone know the correct way to fit them?
Do you just sit it on top the belmouths and try and align the holes in the filter to the centre of them or are you supposed to insert the "trumpets" inside the filter holes, if you see what I mean.

They fit over the trumpets.Fiddly,but has to be done!

Thanks Jasper. The front one looks a pig to get to.

Hello Col996s

The trick is put your fingers just inside the first hole of the filter,
push it down into the airbox so you palm is now over the first trumpet,
As you pull your hand out, feel around the trumpet making sure its still
covered, the second one is alot easier, it's fiddley but you will know
when its right.;)

Oh . . just thought did you get a spray for it? I seem to remember mine was sprayed wih a coat of oil.

TopiToo

I like filters that cover the bellmouths they prevent things like small bolts that are supposed to be holding the front tank mount on dropping down there don't they Tim (Well I think it was Rattler that suffered this woe)
Been using them on my 996 for years, bit awkward on my 998s as the Shower injectors get in the way.

The holes are offset to line up with the bellmouths. There's usually a "front" marking on the filter to, as the leading edge isn't as thick as the rear.
Put your hand inside the filter, thru the rear whole and work the front hole over the bellmouth from inside. As you pull your hand out, fit the rear over the second bell mouth.

DIRTY BOY! :o

No I was told by JHP that it was pre-treated and did not need spraying.

I've got a small tin of Pipercross spray that came with my in-carbon-airtubes filters if you ever need some ;)

I have a set of Piper-X filters in the carbon air tubes on my 998R, got to keep the **** out of the engine some how

Blimey!!! - you're right, that was my lovely old 996SPS - but she was sorted under warantee!!! ;)