Variable Inlet trumpets

[VFR750R]

http://www.motorcycle-usa.com/Article_Page.aspx?ArticleID=3819&Page=1

They did it, now there's going to be a stock system to use/benchmark. Anyone out there like me wondering why it went on an R1 first and not the R6. I mean, yeah, any bike could benefit but the 600's seem like a more likely candidate for a powerband widening feature like this.

I bet next year R6's, and 3 years from now every new sportbike will have something like this.

[absolutepressure]

Wow, what a smart and simple solution. I bet one could implement that technology in an FSAE car. The plenum volume would have to be huge, though, to contain the secondary trumpets and the actuator. Would obviously have to leave the tb's off. It would be interesting to see if the gains of the wave ram tuning would offset the losses of a huge plenum.

[Wesley]

I was talking with a senior member of our team about variable geometry intakes, and he raised a very valid point about the usefulness.

In the acceleration runs you may gain some points because they would give you some power in a nice straight run under basically constant load.

However, with the tightness of the courses the FSAE cars run, and the way drivers are constantly on and off the throttle, the servo would have very little time to cycle back and forth, and the air would also have very little time to gain momentum anyways, before you were back off the throttle and into the next turn.

If you were to implement a variable intake system I'd imagine a flapper-type would be the easiest to setup on an FSAE car without making the plenum huge.

Given the pound or two you'd add (and the hours of R&D and testing,) implementing such a system for a few points on the acceleration probably wouldn't be the best use of manpower, or so it seems to me.

Not that that the technology isn't cool. It's the simplest variable geometry setup I've seen. Makes you wonder why it hadn't been used before.

[repeatoffender]

I guess you could say thats a two stage version of the old formula one variable intakes before they were banned.

http://scarbsf1.com/gallery/inlet_pict0020.jpg

http://scarbsf1.com/gallery/inlet_pict0019.jpg

[AK UT]

I thought it was funny when F1 switched to the V8s and banned the variable trumpets some reporters asked the Cosworth guys how they were coping without the variable intake trumpets and they just said "oh we never had them to begin with"

[JerryLH3]

Mazda's R26B four rotor that won LeMans in 1991 had completely stepless variable intake trumpets. In previous years they had two or three different lengths.

So, this sort of thing has been around for quite awhile.

[Bryan Hagenauer]

MV Agusta has been doing the exact same thing for a few years. Even better, the variable intake is only an option on the Tamburini model, so you can compare to the regular model.

Although, at $50k and only a handfull built per year, I guess Yamaha still gets to claim to be the first to production.

http://www.mvagustausa.com/web-mvagusta/F4-1000_Tamb.html

[Ben Inkster]

Wow, I find both of those variable intake systems very unique for a dual length design! Both designs are actuating the entire mass of the secondary length rather than a conventional design that just actuates a valve for two different air paths. They must have found that the flow restriction was too great with the convoluted designs used for most conventional dual length systems (probably becuase the flow velocities are so much higher than a car).

If the throttle location rule changes maybe this would be viable for fsae? not sure about the weight and size though?


I was talking with a senior member of our team about variable geometry intakes, and he raised a very valid point about the usefulness.

In the acceleration runs you may gain some points because they would give you some power in a nice straight run under basically constant load.

However, with the tightness of the courses the FSAE cars run, and the way drivers are constantly on and off the throttle, the servo would have very little time to cycle back and forth, and the air would also have very little time to gain momentum anyways, before you were back off the throttle and into the next turn.

If you were to implement a variable intake system I'd imagine a flapper-type would be the easiest to setup on an FSAE car without making the plenum huge.

Given the pound or two you'd add (and the hours of R&D and testing,) implementing such a system for a few points on the acceleration probably wouldn't be the best use of manpower, or so it seems to me.

Not that that the technology isn't cool. It's the simplest variable geometry setup I've seen. Makes you wonder why it hadn't been used before.


Wesley, I think the real benifit of a variable intake is in the enduro, not the acceleration run, because of the increased drivablity of the torque curve, but I think this is a long discussion in a very grey area. But yes it is possible to actuate the intake at an appropriate rate for race conditions, and the transient build up of harmonics occurs too fast for the drivers to even notice. However, I can't argue that the manpower could be better spent somewhere else though.

appologies for any statements made without technical backup, no time at the moment.

Cheers
-Ben

former UWA

[mtg]

The R1 probably has a higher profit margin than the R6, and putting the variable intake on the R1 first could help recoup the develop costs quicker.

Just a thought...

[Bill Kunst]

Recouping costs, maybe. That funny homo word, yes. I am talking about homologation. It's still happening, especially in the motorcycle world. Maybe this is the reasoning on why it is on the R1 before the R6.

[Wesley]

Originally posted by Ben Inkster:
appologies for any statements made without technical backup, no time at the moment.


I understand completely. I don't even have the know-how yet to make or understand such computations anyways.

[illiterate]

Heard there is a dynamic intake system on some BMW's as well. Something by the name of DIVA. Haven't seen anything about it though. Anybody with a little more info?

[TG]

Originally posted by illiterate:
Heard there is a dynamic intake system on some BMW's as well. Something by the name of DIVA. Haven't seen anything about it though. Anybody with a little more info?

The BMW V-12 N73 engine has infinitely variable length runners and the V-8 N62B48 (the latest 4.8 liter) has dual length runners. http://en.wikipedia.org/wiki/List_of_BMW_engines

Automotive Engineering International did an article on the multibody analysis of the runners and valve system of the V-12 when it first came out a few years back.

[overdrive535]

The car our school ran in 2003 had variable length intake runners on a Yamaha R6, so no, it's not new technology