How does the power output with the standard, quiet, and dustbin silencers compare for the .91? I don't want to run a pipe and noise is not a consideration. Do the dustbin silencers have a pressure tap? Thanks.

JVB,


The muffler options currently available for the MVVS .91 are the #3255 standard silencer, #3255A quiet silencer, the #3253 tuned silencer, the #3250 tuned pipe and the #3298/10 'dustbin' silencer.

The tuned pipe and silencer can be used with rear, or side header, long and short. The .91 responds to the full length pipe better than it does to the tuned silencer.

Non of my customers has ordered the #3298/10 'dustbin' silencer, so I have not actually seen it yet.
I can ask if it has a pressure nipple and be back to you.

Dar, I hope you don't mind me adding to your thoughts since I can't make a post here.


The dustbin has a pressure tap and is not very loud considering that it has no baffles in it. Is has a deep sound rather than the usual loud crackle.

Thanks Dar.

Any idea of engine performance using the dustbin silencer? There is also a square silencer (box style) listed. Looks like the type of silencer used on weed wackers. I am trying to find an in-cowl option other than a pitts.

JVB,


One of the reasons not too many order the dustbin is that it is rumored to leak a little oil sometimes.
It is the only OEM silencer to have an 'in-cowl' option, even if the cowl is not very big.

Another strong plus is that it is very attractively priced and not too suffocating for the engine.

On older .91 engines, that came with the 'butterfly' carburettor, it was included for free, but this is no longer the case.


MVVS engines are timed to make best power with one of the tuned silencer options.

They also run well with a standard silencer, but many would want to use this quality and most MVVSs that I have sold did include one of the tuned mufflers.

This engine doesn't need any more than 5% nitro.

JVB,


With a little help from Dave, I got this photo for you.

It includes both the dustbin muffler and the quiet A muffler and as you can see, the dustbin does have a pressure fitting installed.

Is there a website where one can view these various silencers and pipes? I am about to purchase a MVVS .91 for a SA Excelleron 90, and I need to review the relative sizes of the various pipes for this airplane. I plan to use it as a RE, and prefer a tuned silencer, as it should fit with the least modification to the bottom of the wing, but would use a tuned pipe if it can be fit without major surgery.
Can anyone say who makes the correct RE fuse-top header is for this engine?

Rick

Rick,


You can see these silencer options in the [link=http://www.mvvs.cz/hl_strana_cz.html]MVVS Czech language web site[/link].

Use the 'Katalog' link and then the 'Vyfuki' link and scroll down to the 10-15 cc section.

The .91 has a considerable advantage when using the full length pipe over the tuned silencer.

You must select the exhaust configuration (side, or rear), and modify the engine accordingly, before first starting it and doing the break-in.

I looked on the Czech site and saw both tuned pipes. I did not see any dimensions listed for either pipe, the 3250 or the 3253 short pipe. Is there any place I can get these pipe length dimensions? I need to do some measuring to the Excelleron to assess available room for the pipe, as it will likely affect my choice between the two pipes.
Your quick response so far is much appreciated.

Rick

Rick,


The full length pipe is about 18" long and the tuned silencer is about 11" long.

Add to both the 5.5" long rear header.

The tuned silencer has a larger external diameter than the pipe.