| Author | Message | ||
     Sgthigg |
Anyone know how much more free flowing is the xb race can dual outlet. Vs the stock can single out? Also does anyone know if there is a pic out there of the internals in the race can? | ||
| Blake |
It's not so much a flow issue as it is a geometric tuning issue. The race muffler is tuned geometrically to optimize performance in the upper portion of the operational rev range. It sacrifices some performance in the bottom half of the rev range to do this. I don't know of any illustrations of the race muffler internals. There is a dyno chart comparison showing the difference that the race kit makes. | ||
| Dave |
Blake: Can you point me to this chart? I ordered a kit but never paid attention that the trade off was low/middle. DAve | ||
| Rigga |
"race can" is a misleading name for it ...in reality it should be called "noisy can" as thats all the difference between that and the standard item...poss only a couple of horsepower difference at the top end of the rev range,and as already stated a loss lower down.... better off with any aftermarket exhaust,or a reworked standard can,and quite possibly cheaper too | ||
| Sgthigg |
I am wondering how much easily it flows compared to the 12 stock can with the valve. What if someone ran a 12 race can without a race ecm. Would they loose alot because of a huge drop in back pressure? Like people run other pipes without the race ecm. | ||
| Rigga |
cant see how back pressure would alter by running a different ecu? engine will still be pumping the same,fuel and ignition will alter (slightly if anything) but back pressure would be the same as the exhaust would not have changed | ||
| Blake |
I think that he's talking about changing the muffler, not the ECM. Run a race muffler with a stock ECM? The answer is... The engine will run WAY lean right where you need it to run a little rich, up high and at WOT. Really really bad idea to run a race can with a stock ECM. The conventional use of the term "backpressure" is inaccurate. No back pressure is desired in today's engines. The more backpressure (resistance to flow) that a muffler has, the poorer it will run, all else being equal. What REALLY helps modern motorcycle exhaust tracts perform optimally is their geometric configuration and tuning that puts a reflected negative pressure (vacuum if you will) wave at the exhaust valve during the intake and exhaust valve overlap event. The negative wave reflected from the tailpipe, the collector, or other point of geometric discontinuity in between will then help evacuate spent exhaust gasses while pulling in fresh air-fuel charge for the next power stroke. Resistance to flow is never helpful in a muffler. In days gone by it was helpful. In days long past, an exhaust tract that flowed too freely would expose the exhaust valves and their seats to temperatures that were problematic at that time. Newer materials and alloys have precluded that kind of problem. So please, forget all about "backpressure."  | ||
| Sgthigg |
What REALLY helps modern motorcycle exhaust tracts perform optimally is their geometric configuration and tuning that puts a reflected negative pressure (vacuum if you will) wave at the exhaust valve during the intake and exhaust valve overlap event. The negative wave reflected from the tailpipe, the collector, or other point of geometric discontinuity in between will then help evacuate spent exhaust gasses while pulling in fresh air-fuel charge for the next power stroke. I understand the above. It being tuned if you will to the valve overlap would be best. Now its called optimum forward vacuum...lol So if a pipe is free enough flowing it could actualy pull more air(but not fuel) all the way from the intake valve making it run lean?...hummm Im not being sarcastic at all. Im just trying to figure some schtuff out in my head. | ||
| Buellbozo |
JMTCW, A freer flowing exhaust such as yours will allow more airflow than a stock ecm can provide fuel for. Having said that, if you went to Jxn and back without problems you must still be in the ballpark for satisfactory operation-check plugs-.When you install the race ecm and k&n, you WILL be amazed at what that engine wants to do. At least that was my experience with changing all 3 items at once. Dauphin Island this Sunday!!!  | ||
| Pierre |
Hello everyone... I´m new here and i got a question,since you all know a bit more then me,i guess... Will a Pro Series Muffler(65163-02YB) fit on a 2006 XB9SX City X? I´m Selling my old Muffler on Ebay and someone wants to know. Thanks Pierre |
