Quoted from Rogue:
The 2-1 exhaust fad
I disagree with the entire premise of this more midrange power with a 2-1
update: the dyno charts are proving me right...
I have seen many 2-1 systems yield better topend hp & weaken the mid-range like on the Erion Superhawk & numerous Hawk GT systems. That's not to say that with enough piping & tubing you could get just about any result ya want, but it will most likely be a point of diminishing return as the overall power output will most likely be significantly lower (if you were to purposely build an exhaust just to prove a point)
I firmly believe that on the HRC Superbikes that the extra length of piping is taking the jerk out of the mid-range making it a less powerful hit of power & thus more useable, but not "more" mid-range power. Along with that I suppose that top-end may be suffering some, but with 190hp on tap I guess you could stand to lose a couple here or there.
Either way I think alot of people are going to be dissapointed when the final product comes around & it doesn't give you this miraculous mid-range power gain that you have all been dreaming about.
Several manufacturers are currently working on 2-1 exhaust for the RC51, once some of them are on the open market & we can test them then I may need to revise this page, but until I am proven wrong I will stick to what I learned over the years.
Update 06/05/02: The Erion 2-1 full exhaust on the 02 bike is producing dismal power curves even worse than stock & has several issues with overheating the motor as well as scorching the single cannister.
Update 07/18/02:dyno charts of the Erion 2-1 with a terrible mid-range dip
Jardine has admitted that they are having problems with the mid-range with their 2-1 system & Arrow is being very tight lipped about their 2-1 after having made a big showing of the prototype many months ago which to me is most likely indicative of their failed attempts or at least performance issues stemming from the design.
UPDATE: Jardine has released their 2-1 full system & the performance numbers aren't bad, nothing spectacular, but no major drops in performance either. A few owners have commented that it leaves a flat spot in the mid-range, but overall with a price tag of $499 it sounds like a pretty good deal for those that want more performance than stock, less weight (credible reports have it at a whopping 19lbs of weight savings & a price tag of $390) & something fairly unique dyno chart for Jardine 2-1 another dyno chart for Jardine 2-1 supplied by an actual owner (the mid-range dip is pretty severe on this one). There have also been numerous issues of the welded tab breaking off on them as seen here 2-1 Jardine broke.