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The following is from someone who has designed motocross pipes for old school big bore motocrossers using both MOTA and ECcalc14: I have given a lot of thought to the analysis of both MOTA and ECcalc, what each has to offer especially concerning pipe building, and after a lot of experimenting, I would have to say that ECcalc has some advantages over MOTA. Here is why; 1) ECcalc has a large body of supporting literature that answers many of the questions a person getting into pipe building would have. 2) ECcalc uses simple visual sine waves to display what is going on in the pipe. Though MOTA has a more complex analysis of the effect of the boost created by the pipe, in the end the power band calculator function of ECcalc is realistic and accurate. I have compared several different expansion chambers on both ECcalc and MOTA, and they both closely correspond with regard to peak boost and peak RPM. 3) One of the very first questions ECcalc asks is what is the real upper RPM range and what is the power band width. These questions are essential to building an effective pipe. I have made the mistake of having the baffle wave land too early in the RPM range, trying to get more mid RPM boost and when it came to testing, the pipe would shut down because the baffle wave landed too low in the RPM range. I have also encountered this problem with a MOTA designed expansion chambers, in that the software doesn't "understand" that a two stroke motor will not run well much past max baffle pressure at exhaust close. This is an essential trick to making pipes. This may be a common mistake easily made by a novice and I have done it twice. ECcalc design begins with defining the peak RPM as a baseline to build the pipe around and has the vital ability to target the RPM where the peak baffle wave should land, thus ensuring a successful pipe design. 4) With big bore two stroke pipes often the effects of the baffle and diffuser wave are spread out over a larger RPM width. One way this is done is by using low degrees of taper say 4-5 degrees. The other way the effects of the diffuser and baffle are spread out over a larger RPM range is to lengthen the belly. With ECcalc I have analyzed many pipes to understand what makes a successful design. With ECcalc I can enter a known successful pipe geometry and get exact times the diffuser and baffle arrive, peak, and crossover. This takes all the black magic out of pipe building and shows you in milliseconds exactly whatÕs happening with various expansion chamber designs. MOTA software can show you the effects of such pipe variations in complex hypothetical telemetry that can teach a lot about the complicated inner workings of a two stroke. The MOTA software is a great tool for learning about two stroke motors but if you want to make a pipe and it has to work, ECcalc along with the library of free information that informs it is a great pipe makers tool. |