exhaust systems - torque curve variations
hi fellow gsx-s users, ive had a black widow full exhaust system on the bike for a week or two now, ive been comparing its performance to the extracter i had previously made for the bike, its still running the the same ecu reflash, which i admit wasnt fueling very well in the lower 1-3500rpm range, its apparrently difficult for the brake dyno tuner to get reliable info in that range., im thinking of an inertia dyno run with this b/widow exhaust to get a base run for comparision, we dont have a lot of dyno tuners for m/c's around my location, a couple in two cities a couple hundred km's away
but ive found a few differences with this b/widow ex system, with its decibel killer in the 300mm carbon muffler the lower 3k rpm responds better to under half throttle, 3-7krpm is very muted in its reponse, i.e a hole in torque curve , 7-11500rpm is strangled, power feels down by approx 10hp in this range, without the d/killer its stronger thruout midrange/topend slightly
the pipe i built used the same size header tubes for 165 ft /sec gas speed, but the b/wid has smaller secondary tubes, with fairly basic collecters which are marginally better than standard, i had also die ground the remains of the tig welding internally on the collecters prior to fitting as these have a negative effect on wave reversions. my next stage will be to remove the b/widow secondary pipes, install a proper set of race collecters and lenghtened secondary pioes to remove the hole in the mid-range power as i had with my pipe. ill put up some pic's for you all to see the differences between aftermarket and race built pipes, i.e they are internal not external as looks dont matter to to gas flow, shape does !