I have a ZDZ 80 super engine, there is no way this engine will go over 5900 RPM with a BOLLY 26x10 prop and a SUPER SONIC MUFFLER, it has about 8 galons of fuel allready, the engine has good iddle, starts great, good transition ect, but it just wont go over 5900 RPM. The way I found out the engine is not giving it´s power, it´s because there is a guy at the club with the same engine mounted in the same airplane I have mine in, with the same muffler and prop that I have, and we went flying together, and when I saw his plane fly, I noticed he had a ton of power more than me, specialy on pull outs from hover. I said jesus man wath did you do to that engine, he said nothing, actualy his engine has not even finished the break in yet, so I told him lets start the engines and chek RPMs and we didi it and his engine did 6400 RPM with the BOLLY 26x 10, both even with the same fuel, and mine did not go over 5900 RPM, we even checked the neddles to see if mi engine was to rich and nope! we checked if the throttle was opening completely, and yes it was. besides that, the engine is perfect on all other aspects. Could this have to do with me being to easy on the engine? I mean I never dive without first cutting on the throttle, I never fly horizontaly at full throttle, I have never exeded 7000 RPM in the air with this engine, could the engine still be tighted up steel do to this reason? I apresiate anyones sujestions. thanks.

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They can have different power outputs for many reasons. I have two ZDZ 50 NG's and many people are getting 7200-7500 where I am only at 6900. I haven't done a full peak test though. I may be rich. I had a DA 50 that would pull 300 more RPM's with a different carb (the same exact model carb, but I had a spare).

You should get in touch with Dick Hanson on here. He's spent lots of time with a super 80....perhaps he can help you get it solved.

Try switching props with him. See if there is a difference. Go from there.

I tried his prop, his muffler, his fuel, and nothing, I even have another Super 80 at home, one that I got completely rebuilded from RC Showcase and I started it and the RPMs on this one are the same as my other engine 5900! So my friends engine is special or something, The only thing I have to try is his ignition, he has one of the newest ones which I know they have been modified and improved! Maybe that could be doing it!!!!!!!!!

I'd be very interested in hearing how things turned out for you. I have almost the same setup and problem except that I cannot get past 5700 with a TBM 26 x 10. Something wierd is going on.

My buddy had 2 of them... couldnt get past 6200 with a PT 26x10 and 4 gallons. Both of them started around 5900 new with the same prop.

Keep in mind that D.H. usually puts a tuned exhaust set up on his ZDZ'z and does not use a Bolly prop.

The first thing I would do is remove the Bolly. If you can find a Menz in the same size, and right now you might not, try that. Perhaps a 3W or RCS prop in the same size. A PT would be another good alternative. No Xoars!! They all seems to provide lower rpm counts and less thrust that I think they should. I don't believe the ignition has any influence in this case, either new or old style. You might also try using a little better gas. Try some premium just to see what happens. In any case, try only one thing at a time and see what each item does for the performance.