It may increase gas flow at high rpms, but you may find low rpm performance adversely affected. The valve is similar to the one fitted some years to the Gen I FZ1 and it wasn't there just for noise suppression.Has anybody disconnected the exhaust backpressure valve yet?
I would think it would increase performance a little, and increase the noise a little.
It acts as an exhaust system tuning device by altering the back pressure. You'll find a lot about it, but a lot of that is misinformed forum posts regarding noise and emissions, often based on stories from dealers who want to sell after-market full exhaust systemsCan someone please explain what the exhaust valve does?