Ducati Sporting Club UK > DesmoDue Race Series > DesmoDue - General Questions and Chat > no air box

[chris.p]

Originally Posted by bally71

does the airbox create a reservoir of still air? ..after all it's being constantly drawn

i can imagine with the trumpets in place you could expect the incoming air to be sucked in in a nice laminar fashion .. but with the top hacked off??

Once the air has been drawn into the air box from the previouse induction cycle the air will be still (still as in not swirling around the airbox) this allows maximum induction suction on the next induction cycle.
The stiller the air, the larger amount can be drawn in, the more air the better the fuel air mix and the bigger the bang


Chris

[bally71]

but with this happening a couple of hundred times a second .. hardly a sea of tranquility

how much air is required for max combustion .. think i remember reading somewhere it was 130% of the cylinder volume

so at 9000 revs that's about 120 litres per second (if my maths is right)

[Ghost]

Originally Posted by bally71

but with this happening a couple of hundred times a second .. hardly a sea of tranquility

how much air is required for max combustion .. think i remember reading somewhere it was 130% of the cylinder volume

so at 9000 revs that's about 120 litres per second (if my maths is right)

Do you think any front runners have consulted Einstein on this? They just ride the thing. Its not about the nth degree of HP. Look how Chris Clarke and Spence and me last year mixed it at the front with the A bikes.

The B bikes are 10bhp less than a good A bike. All about corner speed more throttle and less brakes.

[bally71]

i hear einstein was pretty fast in his day

not really after eeking an extra hp .. just like fettling .. and learning

[skidlids]

Originally Posted by bally71

but with this happening a couple of hundred times a second .. hardly a sea of tranquility

how much air is required for max combustion .. think i remember reading somewhere it was 130% of the cylinder volume

so at 9000 revs that's about 120 litres per second (if my maths is right)

So what would it be for a twin cam, 4 valve per cylinder with flowed heads, high lift cams etc.
Must be where Ducati went wrong with their Moto GP bike with the Carbon airbox, the 400 litre airbox was dictating the whole layout of the bike to be wrong.

[bally71]

[bally71]

and i was suggesting the volume of air travelling through the box would suggest the air is never still

although ... you could put it on a trailer .. or maybe a large balloon

[skidlids]

There is a difference between turbulent air and pulsed air, the underside of a 916 tank in conjunction with the airbox is specially designed to use the pulsing to help produce power by way of acting as a Helmholtz resonator, something Shazaam! did a great post on years ago.

Not sure what you think your air useage is

here are a few questions that may help you answer that

A, How many cc's of petrol do you use in a race
B, What air/fuel mixture do you run
c, How long is the race in minutes

[skidlids]

Here's Shazaam's post
http://www.ducatisportingclub.com/sh...ghlight=Airbox

in it Larry mentions 130% of the capacity. so for a 620 thats 803cc so less than a litre between the butterflies and the air filter, for my 1000SS it woule be a figure of 1300cc so as they run the same airbox I doubt if my Class A bike is finding it a restriction

[Spjallen]

Geat post, I've been blowing on milk bottles all morning!