is there any use in having intake manifolds and velocity stacks???

[kocheroni]

want to replace the airbox on my M1100

saw Radical Ducati is using on their 2 valve engines mainly filters without intake manifolds; e.g. with BMC filters

or this ones

anyone experience with this setup???


besides the problem of finding a new home for the air temperature sensor (17) [what is the thing for anyway?]



do you guys know what the difference in performance is, compared to an 'intake manifold - velocity stack - filter' combination?


Many thanks!

[ungeheuer]

If you do a search you'll find plenty of info on this subject.  It's been said that pod filters alone (that is without the addition of velocity stacks of some kind) will gain you nothing and will actually lose you some HP.

Some interesting work for M1100 airbox elimination going on here >> http://www.ducatimonsterforum.org/index.php?topic=46660.0

And then there's my own efforts >> http://www.ducatimonsterforum.org/index.php?topic=28586.msg738771#msg738771

[64duc]

 Velocity stacks are used to tune the air intake system to maximize performance. Short ones are torquey, long ones are high RPM horsepower.

Seems I forgot to answer your original question. Intake manifolds are used to connect the carbs to the engine. A very necessary function. Velocity stacks go on the outside of the carbs and are used solely for tuning. Yes it is necessary to run both.

[junior varsity]

Should be noted that the some of these K&N/MWR etc style filters are supposed to have some sort of integral bell mouths in some of their models, not sure which ones or the length, etc.

The velocity stack design is the most beneficial. Many race bikes have used open velocity stacks with no filters. The benefit of a well designed velocity stack is the incoming air has smooth edges - no abrupt angles or corners it has to go around on its way into the intake. This has a huge impact on performance. If you research, you'll notice there are lots of high end, various length (or variable length) velocity stacks for the superbikes - obviously fitting inside their airbox.

That's really the ultimate - a big airbox, pressurized by ram air, with well designed velocity stacks. But unless you have a 4v, functional ram-air is very much a one-off custom airbox affair. Those with 4Vs (not superbikes) CAN modify their airboxes with some creativity to really get some whoop-ass out of it, a la the trick pieces from the guys at Bursi Evolution.

[kocheroni]

talked the other week to a tuner who recommended the following solution



in his opinion the non plus ultra of intake mods if your are after performance

[Cloner]

I think the answer you should have gotten is "leave the airbox on it".

Velocity stacks are good (sometimes....if they're the right velocity stacks for your motor and application) for top end power, but can hurt the things that make your Monster fun to ride on the street....bottom end and midrange.  Why foul up the function of your bike to gain some Ricky Racer wannabe appeal?

If you want your bike to be faster, go get riding lessons and leave the mods to those with too much money and enough time to make them work correctly.  If you want a faster bike (though I can't imagine anyone needing a bike faster or quicker than an M1100 on the street), go buy a four-valver.

Lots of bike builders use pod filters to avoid geometric constraints (i.e., they're out of room for the airbox after they messed around with hiding lots of stuff beneath the tank) and that might be what you're seeing with Radical.  Just a guess, but an educated one.

For reference, the fuel injection system uses the air temperature sensor to calculate air density in its efforts to achieve a proper air/fuel mixture.

[ungeheuer]

I think the answer you should have gotten is "leave the airbox on it".

Where's the fun it that?  .

[junior varsity]

I kind of disagree about "saying no" to pod filters, but only somewhat:  large internal volume pods with large surface area filter medium are good, if not better than tinkering with the stock airboxes (many of which have gotten smaller due to emissions related hoses / devices and electronics... i would, however, say that something like the larger volume, larger surface area airbox shown above with MWR style intake would be better still - the benefits of more filter medium for more possible flow, and the benefits of a large volume 'still air' for low RPM and off-to-on throttle response.

aesthetically it really cool to "look through" the motorcycle.   Nothing wrong with wanting to squeeze some top end power out of it if that's your riding style - its not like the 2v airboxes are pressurized by any form of ram air like the SBKs, and there aren't really any kits for sale that I've found (in my meticulous searching of the internet) to retrofit a 2V naked bike with functional ram air to the air box.*

*I qualified that with the limitation of 2V and "for sale", since I have found such ram-air retrofits made in carbon for the S4R (Bursi Evolution) and the Streetfighter (multiple brands, some more effective than others)

[Roaduser]

i dont see why the Bursi Evolution ram air wouldn't work on a 2 valve if you wanted..
http://www.bursievolution.com/ducati/monster/kit-modifica-airbox-ducati-monster-s4rs.html

having said that i have the tpo beast velocity stacks and k&n filters and found no loss of bottom to middle power at all.. small power increase at most. but it definitely made a difference that can be proven as it started to lean pop out the exhaust as soon as i put it on. little touch up of the base fuel adjustment and it runs good.. still not perfect, prob need the likes of a pcv to make it work to its full potential.

they do look great, but the sound takes a little to get used to. i can easily see how some ppl don't like the sound. they do make a harsh thumping inlet noise particularly bad at certain revs/throttle points.

[junior varsity]

i know the 900 era airbox kind of has the divide straight through there - lid versus base - possible, but not as straightforward.


i love the pod sounds personally - i do like the mechanical noisy nature of ducatis too though.

[ducpainter]

Where's the fun it that?  .

'cuz you get to ride the thing?

[Raux]

The only way to tune the Ram air Bursi well would be the PC V with the Autotune out on the road.
I don't think a dyno would give you the correct tune at the upper end due to the lack of pressurization.

also the Bursi concepts are similar to the SF airbox now.

[junior varsity]

The only way to tune the Ram air Bursi well would be the PC V with the Autotune out on the road.
I don't think a dyno would give you the correct tune at the upper end due to the lack of pressurization.

also the Bursi concepts are similar to the SF airbox now.

That's like saying the only way to tune the SBKs would be the same way since they have functional ram air as well.

[errazor]

Maybe putting the air pressure and temp sensor inside the air box will compensate for the ram effect?

[Raux]

That's like saying the only way to tune the SBKs would be the same way since they have functional ram air as well.

honestly. i believe in that too.

I've read some pretty good tech articles about making sure to charge an airbox with the right air pressure for at speed tuning.

some dynos have that, but i seriously doubt you can get a fan to output a 150mph airflow to tune your bike properly.
you would have to have datalogging to go out  at speed, then come back and adjust accordingly.