ryontd

My Feedback: (40)

Guys I need some help. I am getting ready to put together my Cap X and I am putting an OS 160 in it. What Pitts style muffler is the best to use, and also what Pump should I use? Thanks, Ryon

flipstart

don't know about the pump, but I have my 160FX with Bisson Pitts muffler and its great-good sound-the exhaust tubes are rounded over on ends, so I get enough pressure-

Marcol

I agree,
Go with the Bisson everytime. A guy in our club uses a Slimline muffler on his DA 50 and it is the loudest gas engine I have ever heard.
I use the Bisson on my ZDZ 50 and I turn the same prop at the same speed but much , much quieter.

We made some outlet restrictors for the Slimline to try and get the noise down but the revs just fell away.

So in my opinion there is no choice really

ryontd

My Feedback: (40)

Another Question,

What size Prop should I use on this motor and What size Spinner do I need?

Checklst

I don't use a pump on my OS160 (Seagull SS 120) it has slimline pitts muffler with no mods for back pressure, my 160 is as quite as any 160's at our field, but a high rpm bank turn will sing the prop into making a lot of noise. I fly a MAS 18/6 classic great prop, but a little noisy at full throttle. My last Bisson on this 160 I don't recall it being any less noisy, I purchased the slimline after breaking off a pipe on the bisson during a gear up belly landing.ouch!![8D]

ryontd

My Feedback: (40)

Hmm,

I have heard some people say that they have had problems with running a Bisson pipe (having to block one of the exhust ports). But I don't know, thats why I want alot of opinion from everyone. Also what size spinner are you using? I have never used spinners before, just use spinner nuts.

Ed

The Bisson has a larger expansion chamber, which will allow your 1.60 to breathe better. So much so, that it may not produce enough backpressure. But that can be easily fixed by blocking one of the exhaust pipes. Remember, the stock muffler only has one exhaust pipe. Regardless, the Bisson is a superior muffler.

Here is the criteria that you are looking for if you install a Bisson. If you cannot get the high speed needle rich enough within 1 1/2 - 2 turns from the bottom, then you will need to block off one of the pipes.

> Jim

ryontd

My Feedback: (40)

What do you usually use to Block off one of the ports?

alan0899

G'day Mate,
Run the motor in with a Bisson pitts muffler, a couple of tanks rich & leaner rich & leaner, on the ground, until it hold a steady setting. Remember it must be run in some, before it will richen up, as the crankcase suction improves it will run richer & then can be leaned out some, until it will hold a sready setting, then fly it.
DON"T crimp off or block an exhaust outlet, & run 10% nitro fuel with Coolpower oil at 18 to 20%, OS #8 plug, use muffler pressure, no need for a pump, just make sure your tank height is correct, & use a 16x10 or a 17x10 prop, OS recommend nothing less than 10" pitch, on the 160FX, it is flat out at 10,000 RPM, so don't under prop it.
And it will be the easiest motor to start & run sweetly, that you have ever had.

Checklst

I'm using a 2 3/4 spinner on the SS120 it matches the planes cowl best, a 3 would also work. As for the Bisson needing to plug a tube for back pressure or not, it appears some need to do this ...not sure why.....one would think if Bisson knew this muffler had a back pressure problem they would fix it. It would only require a baffle to be added inside the muffler. BTW my bisson did not require a blocked tube to run my 160, both motors were mounted sideways, tank center line was on the crankshaft center line, this mounting method(on these planes) makes the carb on the center line of the tank and the thrust line of the plane............I also used a smaller tanks on both set up's(this is what I had on hand) maybe my setup compensated for the BP on the bisson and allowed me to run with out tube blocking, I have also read that tank size has an effect on internal tank pressure.........Just a thought.

BTW I have not got a problem with any solution that makes an engine run better.......