The 447UL could handle the 40-60hp, the 503UL could handle 50-70hp. The 377UL/380F could be built to handle 35-50hp range if turned 6500rpms. The Smaller 185UL would need a few more Upgrades to be more reliable but could be built for 9.4hp-24hp if ran up to 6500rpms. With some other upgrades it can even make more HP. The Rotax 277UL in Stock form is rated With minor Upgrades it can be made even more reliable. Why, go to all the trouble to reinvent a 2 Stroke Engine already built? For Part 103 Ultralight. You might get that result the chances heavily are that you won't." Stir the chicken entrails in the prescribed manner, your mild-mannered, all-purposeĬhuffer will be transformed into a hyper-horsepower fire-breather. YouĬannot treat them as a voodoo incantation, hoping that if you mutter the right phrases and Toward the particular application, before they constitute a genuine improvement. All must work in concert with the basic engine, directed Bigger carburetors, higher compression ratios, altered port timings and expansionĬhambers often do bring an improvement in power output, but more and bigger is not Some success in modifying two-stroke engines, is to believe in a kind of mechanistic "Another mistake commonly made, sometimes even by those who have enjoyed I think it's a pretty safe bet they've found all the easy hp themselves. Rotax has been building engines since 1920. Without either a clue or some trial and error, probably for the worse. Change the relationship between those and power can change, often substantially. They are complex interactions of waves and flows. Outright flow doesn't make hp on 2 strokes. Match your Wye Pipe & Gasket and External Port taking out rough spots, sharp edges.Ībout half of the non-race tuned 2 strokes I've seen have had some ports made smaller. You're basically going to do the same thing to the Exhaust Port. A Cheap Air Die Grinder & Carbide Bit and a Porting/Polishing kit is all you really need. On some Rotax's there are different Size Carb Intakes. You also want to Match your Carb Intake to the Cylinder External Intake Port on the Cylinder. Were Not building a Race Engine, so I'm not getting into all the Port Timing changes you could do if Racing. Could the Standard 335 be Ported to TNT Spec's, Yes, and you have your Port Timing changed doing that. With the different Port Heights 26.5mm vs 29mm, they will have different Port Timing! But can they both be Improved upon, Yes, using the General Rule of Thumb Formula, they can be Widened from 47mm to 51mm. I'm going to show you my Single Skidoo/Rotax 335(78mm x 70mm) vs my Skidoo/Rotax 340 TNT(78mm x 70mm) Intake Ports for comparison. Some 2 Stroke Porting enhancements you can make to make AirFlow better in your Engine with simple tools. Your Bore is a Circle or let's call it a Radius and once you Cut Ports in that radius, there is a General Rule of Thumb Formula on How Wide you can make that Port before the Ring might get stuck in that Port. The Rotax 618UL was rated at 6750rpms! Using 6750rpms vs 6500rpms equals 250rpms is like 3hp difference. Every 2 Stroke Engine is different in what can be done to make more HP, since this thread is about Porting will try to focus on just that aspect! For our purpose's here, 2 Strokes for Ultralights & Kitplanes were not after every last bit of HP we can get, as were not turning them any more Higher then Industry Standard for Planes today which is 6500rpms.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |