Variable rate secondaries?

[revhardSHO]

In my hunt for a new motorcycle I came across the Yamaha V-MAX, which apparently demolishes most sport bikes 0-60 acceleration. In reading up on the VMAX engine it has something similar to the secondaries on a SHO engine, where above a certain RPM a series of butterfly valves open to allow for better performance in the top range of the powerband.

Here is the quote from Wikipedia:

V-Boost is a system that opens butterfly valves in the intake manifold between the 1st and 2nd and between the 3rd and 4th cylinders starting from 5,750 rpm. The valves are opened gradually to match the rising engine speed with a signal provided by the ignition system. The valves are at the full open position at 8,000 rpm. A small black box sends a computed signal to a servo motor that pulls a wire to open the butterfly valves. The V-Boost system adds 10 percent to the top power rating of the base engine.[

Got me thinking, perhaps the same method could be adapted to work on a SHO engine? Question is, would there be any improvements to be had? I guess not considering a relatively straight torque curve through the entire RPM range, but I just thought it was interesting.

By the way: Next motorcycle will definitely be a Yamaha. Leaning towards an R6....

 

[luigisho]

You could always try the bmw design continuously variable intake manifold. Their cars call it DIVA or something


https://grabcad.com/library/continuously-variable-length-intake-manifold-1
http://www.temp.speautomotive.com/Awards Modules/2003Awards/Powertrain/intakemanifold.htm

Yamaha had the patent on a 3 stage intake. I forget if it was for the v6 or v8 designed intake. It should be archived somewhere.

 

[NoSlo]

The butterflies are operated by engine vacuum and commanded by the EATC. They are either on or off, and being vacuum-operated, there is no position control.

It would be possible for the most determined to convert the intake manifold to dual servo motor control, and also add a second RPM engine management computer (even an Arduino) to control the opening based on RPM and commanded throttle.

Torque curve charts are disappearing off the web; here's a nearly-stock tune, and if you use your imagination, you can see there might be room for gains between 3600 and 4200 in the top blue torque pull by slowly opening them early.



That only matters for getting 5% more from 20% of the curve of wide-open throttle runs, which is not how we drive our daily SHOs.

Anybody that is holding the pedal to the floor for over the 7 seconds required to go from 0 to illegal in 50 states is probably running boost anyway.

 

[rubydist]

DIVA would be the perfect name for the BMW crowd...