Variable length runners

[Wesmo]

Has anyone experimented with these to increase horse power? We are goin to test a duel stage system this year. It has been used on the R1 I believe with excellent results.

[Wesmo]

Has anyone experimented with these to increase horse power? We are goin to test a duel stage system this year. It has been used on the R1 I believe with excellent results.

[Mikko Ahola]

Yes they have been seen.

UWA used one few years ago. And TU Graz has one in their new car.

But which one would be more useful? Variable intake or exhaust? Of course the later is kind of a tricky one to make properly...

[terra_dactile]

Hi Wesmo
Our 2004 car had a variable length runner intake on a yamaha R6 engine,
UWA has used one since 2005 I Believe.
Waterloo has been using one unit since 2005 as well.

Excellent results, except our 2004 system kept on blowing up, and it was ver diffiult to have it rotate with out having sealing issues.
Our concept was similar to that used a few years back on the BMW 7 series cars. A cylinder with slots in it taht rotated 300 deg to vary the lenth of the runners dynamically.

I would look into the setup used on the Acura NSX or Acura Integra GSR I belive. Two runner lengths, with a flap that switches between the two. Having a totally variable system means the response of the step motor has to be very fast to ensure it is matched with wave legth you require, if it is off just a little you basically have a system that is worse that an effiecient non varaible unit because off losses from gemetry of the system.

Jude Berthault
ETS FSAE 2003-Current
Team Captain & Vehicle Dynamics Leader

[VFR750R]

As far as the graphs i've seen, the R1's system could hardly be described as giving excellent results. There are gains to be had there for sure, but the R1 didn't seem to respond to the system they used; meaning, the other 1000cc bikes have equally wide and powerful engines without the use of any variable length system.

[Brett Neale]

Adelaide had a continuously variable intake in 2005, and we found similar problems to ETS where the rotating inner barrel wouldn't seal properly. In the end it bound up slightly and burned out the actuator. If this is the first variable inlet your team has designed, I would highly recommend restricting it to a more reliable 2-stage system.

[marcus]

to those teams who have run these systems...can you post some horsepower/torque curves?