Just my 2p worth, I fitted my Sp1 with a stainless steel Dominator De-cat link pipe and a nice Scorpion End Can plus a Booster plug (www.boosterplug.com) and PAIR valve delete and it definately runs alot nicer now than it did and more power and noticably smoother. (I will eventually remove Booster plug in favour of a ECU flash this year). Remember the biggest problems with latest Blade is they make them run so lean on low end to pass stricker emmisions test and noise tests. Don't qoute me but I'm sure valves fittted to race bikes are because many tracks have noise limits in paddocks and pit lanes ????
Im not convinced, as advice I've had from Dave Wood Racing is same as info found on reliable sites, but i do understand exhaust scavaging !!!, any way, think I would need a top mech from a BSB team to convince me otherwise. but happy to be proved wrong as its an intresting subject. >>> The following internet quotes seem to be very contradicting both ways, if only there was a definite answer, but for me my Blade does seem to run alot nicer, but that might be the booster plug fooling ecu to add more fuel over the rev range, I know an ecu flash will improve further like it did on myZZR1400 PS, 216 bhp with a peek of 222bhp >>>>> Internet quotes, not mine>>>> In emission control, exhaust gas flaps are used to divert the exhaust gas flow. In this way, they trigger the HC (Hydrocarbon) absorbers or bring the starter catalyst to operating temperature more quickly. What does an exhaust flap valve do? Exhaust butterfly valves are a type of actuator used to silence or reduce noise emitted from certain applications. These valves are commonly associated within the automotive industry, as they will often be found working within cars or motorbikes. (I've learnt that exhaust scavenging is more reliant on length, size and shape of exhaust system, you can loose low down power for road riding for having a too shorter exhaust system) ?????
My bum says the valve does improve scavenging and by some margin and I'd be more than happy to prove that on a dyno if yer payin Thanks for the servo by the way buddy. Maybe you have found a way to get around it with your set up, but using the standard exhaust without the valve working, versus a standard exhaust with it working, the difference is night and day, it's bloody obvious as soon as you twist the throttle, like absolutely OBVIOUS.
Maybe slightly different from the new models, but on the 2008 the exhaust servo seems to help at lower revs, not saying it gives more power just smoother pull off and idle. Who knows the restriction when closed probably increases exhaust velocity and thus scavenging. But what I do remember from my CFD lectures many moons ago exhaust flow is indeed a complex subject, velocity, volume, resonance, density etc, just wish I paid more attention and didn't have a hangover most of the time!
max IMO the valve does all the things you have quoted from the internet plus: with the valve closed, the route/ length is alo different to with it open. This may be why some feeling the power delivery is slightly different (including myself). There is a science to exaust (and intake) tuning, I just label them as black art as I do with acoustics Iside RR8 silencer there is also a second spring loaded valve pre CAT
