Venturi effect ??????

Message

D-Rider · #16 Post by **D-Rider** » Mon Jul 09, 2012 11:29 pm

Whooshy matters down the TBs and into the cylinder heads but not really in the filling of the airbox - that's a big reservoir and the most important thing with that is the volumetric flow not the ultimate velocity with which air comes in to it.

MartDude · #17 Post by **MartDude** » Tue Jul 10, 2012 12:09 am

I seem to remember reading somewhere that the turbulence around the front of many bikes means that modifications to the air intakes have little effect except at certain speeds, which I now can't remember.

Same applies to position of radiators; remember the funny Benelli (or was it a Bimota) some years ago, which had its rads behind the engine? The reasoning was that there was so much turbulence around the conventional radiator location, that the airflow over/through them was negligible, so it didn't matter where they were. This was explained to me at some length by Peter Williams, but he lost me after the first few minutes.

#18 Post by **Kwackerz** » Tue Jul 10, 2012 5:13 pm

Benelli Tornado tre.. Sam's dream bike and one I almost bought just to shut him up..

#19 Post by **mangocrazy** » Tue Jul 10, 2012 6:29 pm

Just look where the radiator was on the Britten... under the seat! And it was so efficient that they had to tape parts of it up in cool weather to stop it over-cooling the motor...

fatboy · #20 Post by **fatboy** » Tue Jul 10, 2012 6:30 pm

Now here's one for you
Venturi exhaust tuning ! ! !

blinkey501 · #21 Post by **blinkey501** » Tue Jul 10, 2012 7:11 pm

I thought the radiators were placed behind the motor to allow the motor to be moved further forward for better weight distribution

Viking · #22 Post by **Viking** » Tue Jul 10, 2012 10:24 pm

From what I can recall - it's been a few years since I read the books - for better cooling you want a slow-moving, semi-turbulent airflow to absorb the heat from the radiator.

flatlander · #23 Post by **flatlander** » Tue Jul 10, 2012 10:28 pm

D-Rider wrote:Whooshy matters down the TBs and into the cylinder heads but not really in the filling of the airbox - that's a big reservoir and the most important thing with that is the volumetric flow not the ultimate velocity with which air comes in to it.

But wouldn't it fill it quicker So keep it fuller better?

#24 Post by **Kwackerz** » Tue Jul 10, 2012 10:41 pm

You mean squishy wooshy air?

flatlander · #25 Post by **flatlander** » Tue Jul 10, 2012 10:50 pm

Yes eexactly and lots Of it quickly delivered the quicker the better apparently and for that I understand you need sleeker slimmer snorkels

D-Rider · #26 Post by **D-Rider** » Wed Jul 11, 2012 12:07 am

flatlander wrote:
D-Rider wrote:Whooshy matters down the TBs and into the cylinder heads but not really in the filling of the airbox - that's a big reservoir and the most important thing with that is the volumetric flow not the ultimate velocity with which air comes in to it.
But wouldn't it fill it quicker So keep it fuller better?

Not necessarily.

A stream flowing at 20 mph may well deliver a lot less water than a river flowing at 1mph.
It's not the speed of flow but the ability to shift enough volume into the airbox - and preferably in a non-turbulent manner - and slower speeds tend to help that.

Samray · #27 Post by **Samray** » Wed Jul 11, 2012 12:24 am

As a plumber in a previous existence I just love this discussion .... and never get involved in it.

Aladinsaneuk · #28 Post by **Aladinsaneuk** » Wed Jul 11, 2012 5:57 am

if only you knew about what was behind it all....

Sleepyboy · #29 Post by **Sleepyboy** » Wed Jul 11, 2012 6:10 am

So how does all this mean that the black bikes are the fastest???

flatlander · #30 Post by **flatlander** » Wed Jul 11, 2012 6:56 am

As I understand it that has always been the assumption, ... but if I understand it correctly..,. This Venturi business means that this may not be the case as it seems that the smaller snorkels may be better in delivering the air making the less boring colours quicker which would explain why Aprilia chose to reduce the size as a refinement in the later bikes