brisson 3.2
 

a brisson 3.2 with a mejzlick 22x8 what is the static rpm? mine tach's out at 7200rpm does that seem right???:eek::eek::eek:

RE: brisson 3.2
 

That is right about where it should be. I turn a MSC at 7050 consistently and the PT models prop (Mezjlik clone) right at 7200. When Gary owned Brison, he said to keep these between 6800 and 7300 for the best power and he is correct

RE: brisson 3.2
 

Seems low. My Brison 3.2 with Slimline Pitts muffler and Mejzlik 22x10 turns 7300 rpm.
The 22x8 Mejzlik should turn a good bit more rpm.

RE: brisson 3.2
 

You guys are getting better #s than my Brison with BCM pitts and a Menz 22/8 S prop. I'm lucky to get 6900.

RE: brisson 3.2
 

Gotta to compare apples to apples. A Menz and Mejzlik is apples and oranges
FWIW My Tarus 52 will turn a Zinger Pro 22x8 @ 7600,,,, and a XOAR 22x8 @6700. The Xoar flys better

RE: brisson 3.2
 

My Brison 3.2 with Slimline Pitts turns the Menz-S 22x8 prop 7200 rpm. Could be your muffler. Try running it open stack and resetting the high speed needle and see what it turns.

RE: brisson 3.2
 

your pitts style muffler is costing you about 400 rpm.

RE: brisson 3.2
 

7200 rpm isn' so bad. Is the engine broken in, how many gal through it? What kind of muffler are you running?

RE: brisson 3.2
 

HI torqmeister , the engine is new not flown yet, the muffler is a bisson pitts muffler and the oil is ams oil 80 to 1. rpm seems steady there just wasn't sure. i can only get 6900 out of my zdz 50 and 6935 out of my da 50 with the same prop just seemed high to me. everybody told me that brisson engines were less powerful.

thanks for the help and much appreicated:):)
tailheavy

RE: brisson 3.2
 

My Brison 3.2 engines are just as powerful, if not more than a DA 50. My blue-block mechanical advance would turn a MSC 22x8 7000 rpm, turns a Menz 22x8 7300 rpm. A powerhouse for sure. Don't let the DA owners blow smoke up your tail-pipe. :)

RE: brisson 3.2
 

marzo91 , AMEN TO THAT !!
I have 3 of the Brison 3.2's and all run strongly NX 22x8 now getting 7100 rpms 22x10 6900 rpms and steadily increasing with time . I get some RPM changes
from time to time between the 3 engines sometimes as high as 7250 on the 22x8 . There are alot of variables that can change a tach reading
Dont worry about it !! tune for reliability , Not to compete in the RPM bragging game .

RE: brisson 3.2
 

Diablo, When you say open stack, do you mean to try it without the muffler? I cut off the restrictive tips as many have suggested and as it is now the pipes are 2 and 3/4 inches long and extend about an inch and a half below the fuse bottom. I was thinking of taking another inch off the pipes, Do you think I would gain any power by doing this? A little extra "punch out" giddy-up wouldn't upset me!;) I realize my muffer is more retrictive than most but I do like the fit and sound of the BCM pitts.

RE: brisson 3.2
 

thanks you all for the help i flew the plane about 3 hours ago its a great planes yak54. what a great engine/ plane combo. flys great even at 16 lbs all went well exceped i lost a 4-40 bolt that holds down the canopy. hey ill take that any time. the brisson ran great no proplems starts easy and it is smooth i think i will buy another for something else down the road. thanks for all your input guys. smooth sailing:):D:)
tail heavy

RE: brisson 3.2
 

There will be zero gain in power levels by cutting the Bisson muffler tips any farther up that what it takes to remove the crimped tips. All you'll get is shorter stacks.

7,200 +/- a little is about right for the Mejzlik 22-8, a little lower for the wood Menz-s is also about right. As the engine breaks in there will be a continual rise in the rpm until the break in process is complete. That rise will not be a lot. Better to tune the engine for reliability and best power that to try tweaking it to get the last possible rpm out of it. That's how engines get fried. That and a lot of ground running at high rpm levels.

Don't forget that no two people will ever have the same rpm numbers with similar engines and prop. Density altitude plays a large part is the maximum performance output. If it's hot and humid you will not get as much power as when it's cool and dry.

RE: brisson 3.2
 

I re-read your original post. A new 3.2 with your setup turning those r's is great. And, BTW, I haven't seen another 50cc engine out turn a Brison 3.2 yet. I've got two of them, & because of the power & reliability, I am a loyal owner.

RE: brisson 3.2
 

I am the same way. I posted my numbers when it was new and I was testing which prop I like the best on the plane it was installed into.

I'm well over 10 gallons on mine and it has really improved. I know it slowly breaks in over time but it was like I noticed it all at once in the course of two days. It seemed like on one day it was running like it had always did, then two days later when I flew it next it seemed even more powerful.

I just ordered my second one, this one has auto-advance. Hopefully it will run as well as the mechanical advance I already have.

One thing for the 3.2 engines. Over in the "will Brison Survive" thread, Gary states that if your engine has an "S" stamped near the fuel inlet, start with your needles set at 1 1/4 turns. He states he usually ends up at 1 turn each. Once I did this, the engine really came alive. I could not tell you exactly where I am at as I really do not want to change the needles to check them, but I'm sure I am stiull on 1 turn on the low, but something like 7/8th's turn on the high

RE: brisson 3.2
 

Menz "S" 22x10 6800 rpm
Bambula 22x8 6800 rpm

Amsoil 50-1, TNC tach, Bisson W/A pitts w/1" pipes
Excellent performance

Good Luck
John