Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Ducati Race Airbox Filters

[rockhopper]

He means place something at the side of the bellmouth, where the radius is, not in front of it.
If you can get hold of a copy of David Vizards book "Tuning BL A series engines" its well worth a read. He did a whole series of flow bench tests whith various configurations of flat edges, radius etc and it clearly shows that the shape at the edge of the intake is critical to the airflow peformance.

Hope this doesnt breach any copyright!!

[DC]

Originally posted by rockhopper
He means place something at the side of the bellmouth, where the radius is, not in front of it.
If you can get hold of a copy of David Vizards book "Tuning BL A series engines" its well worth a read. He did a whole series of flow bench tests whith various configurations of flat edges, radius etc and it clearly shows that the shape at the edge of the intake is critical to the airflow peformance.

Hope this doesnt breach any copyright!!

That book is a blinking good read. It helped me many years ago when i was tweaking my mini.

One thing i learnt was the different shapes of belmouths and the effect they can have on engine performance.

[skidlids]

I thought the support arms for the injector on a 998 were at the side of the radius.
Shazaam has previously done a excellent post on the draw backs of fitting a large filter inside the airbox as the Helmholtz effect of the airbox is compromised, so suggest this is not the ideal way to go about filtering your air supply, trouble is if you have carbon airtubes without a filter option what do you do. These may well be the answer, so as I see it they are well wort trying.
I also don't totally take for granted what Dynos tell me. When racing my TL1000S I fitted a TFi fuel injection unit. Had a before dyno run, took it racing and played with the settings where I managed to improve the drive out of corners, it pulled strogly down the straits and my lap times dropped. Put it back on the dyno after and apparently had a few horsepower less, which is the opposite from what I felt I got in the real world with speeds in excess of 140mph

[Felix]

The answer is in the RS style tube filter, skidlids. Only problem is it's expensive, but then what isn't. I've just installed them on mine where I was previsouly running without any filter (on tracks only).

[chris.p]

Kev,
Can not remember who`s filters they are, will go through my mags, but they fit over the the ends (somehow) of the ram air entry tubes as they enter the airbox. From all the work we did on the ZXR ram air system the larger the filter size the better, as it will pass more air, so the only filter I have seen so far is the one that is cylyndrical & is attatched to each ram air intake tube as it enters the air box.

BTW, how is your mate after his spill???

Chris.

[skidlids]

Chris I know the filters you mean and they look like the ideal solution for the shower injection bikes. On my 916 Strada race bike I have been running without filters or the gauze at the entrance to the airtubes (have seen one of these wedge open a throttle butterfly once) but as The bike is no longer going to be raced I was looking at fitting a filter, these look like a simple solution and worth trying, so I have a set coming and I will try them on my road going 916 along with fitting the air tubes off the race bike and see what differences I notice if any. I'm not after any extra power, but want to give these a try as I see them as a possible solution to filtering when running Carbon tubes with no filter option.
I know one person using them and he has given me good feedback.
IF anybody else has tried them and compared them to a JHP filter or Pipercross, K&N or standard filters I would be interested in their views, otherwise consider this as a product test.
As for Gordy he appears to be recovering fine, but the bike maybe a write-off, if the insurance guy agrees with the shop then he will soon be shopping for a new bike.

Kev
PS Chris I'll try and give you a call tomorrow and catch up on your hospital visit.

[Flanners]

I have the carbon air scoops and a foam filter over the stacks. What real world power loss are we talking about?
The induction roar is now awesome and the foam is to prevent flies, grit and small children being sucked in!

[antonye]

Originally posted by Flanners
I have the carbon air scoops and a foam filter over the stacks. What real world power loss are we talking about?

To summarise Shazaam's previous postings (if I'm reading it right! )...

It's all about volumes of air, both filtered and unfiltered, that the engine can suck in.

Basically your bike works better when it has plenty of air to suck in. However, you need to filter that air to remove the dust, grit and small animals. Sucking air through an air filter is harder than sucking it straight in - therefore some "effort" is required to filter the air, which means something loses out.

The way Ducati set up their bikes with a very large surface air filter in the tubes means that air can be sucked into the airbox quite easily, so you end up with a large volume of filtered (clean) air in the airbox ready to be sucked in.

If you put a smaller surface area filter over the belmouths, this filtered air all but disappears - air has to be drawn through the filter as there is no "reserve" of filtered air in the airbox.

You will mainly notice the difference in throttle response rather than outright power.

From the diagram that Rockhopper posted, you can see just how fickle the engine is at drawing air into the belmouths with different designs of belmouth edge - think of the effect that putting a filter on top of this has!

For me, the ideal setup would be Pipercross MPX038 stock-replacement filters. These have better filtration than stock filters and are reuseable too - a bargain at around 18 quid a pair.

If you want to get really picky, spend the extra few quid on carbon tubes that take stock filters and use the Pipercross ones.

You can see Shazaam's original article here:
http://ducatisportingclub.com/contro...d.php?tid=1701

[Felix]

I think your summary is pretty accurate, Antonye. The filter in the tube is by all accounts the best approach. It provides a large surface as you say. Whether the filtration effectiveness of the stock filter foam is good enough for you, is an individual judgement, I guess. The piper cross replacement foam is certainly a finer foam, but will undoubtedly increase the "effort" slightly of pulling the air through it. How much difference this makes in terms of engine performance in the real world is questionable. It's most likely a worthwhile trade-off. I can tell you that the RS race filters are the same approach as the stock filters and the foam is very similar to stock if not the same. The advantage you gain with the RS setup is a very quick change of filters. Again, not really that important for street bikes.

I agree with you Antonye, using the stock setup with the Pipercross foam is the way to go. Just make sure the tank-to-airbox seal is sufficient. If you're worried about sucking in gravel, if the tank comes of in a crash, fit a tip-over cut-out switch.

[Flanners]

Great posts has sorted out all my questions going to leave it as is. Cheers