I gather that the latest final word on tuning favors a ~32 inch header length merging into

a 2 into 1 collector and then into a muffler. So, in the interests of standarization for our
bulk buy on spintech mufflers, I guess that we are looking at a 1 into 1 cruiser muffler and a 2
into 1 collector independant of the muffler. There is a question of having a 2 into one
collector built into the muffler, I'll also get clarification on this.

I'm getting a price on a 2 into one merge collector from spintech, and will keep the group

posted. We have about 13 individuals on the bulk buy list at this time.

Brian Trubee

Try putting the muffler 11 inches beyond the collector.

Paul Lamar

Was hoping someone would ask this question before i couldn't stand it any longer and risked

the possibility of making a fool of myself by asking:  is it practical to use this muffler
(Spintech) or any muffler with a turbo?

thankx,    Rick

Our collective experience is the rotary snacks on mufflers. The Spintech is thick 321 SS
as I recall and tracy has a couple of hundred hours on one mounted under
the fuse.

Paul Lamar

Rick Bettmeng wrote:

Wasn't clear with my question.  see, i want quiet.  am somewhat aware of the fact that a turbo
does some of what a muffler does in breaking up sound waves and such.  question is:  is it worth
the weight penalty to install a muffler (Spintech) in conjunction with a turbo (TO-4) for the
decrease in the exhaust note it would give? is it practical if space is not an issue?
Are you installing this muffler with your turbo?
thankx again,   rick

The big question is: high quiet is "quiet"?. 90 db is quiet for an aircraft engine.
Right now we are closer (and that includes Tracy) to 100 db, 30 feet away
on takeoff.

The majority of the noise emanates from the prop. The way to make the 
prop quieter is slow the tips down, widen the blades and/or the increase the
pitch to absorb the HP. Use a 2.85:1 PSRU if possible so you
don't compromise the engine HP and net thrust.

I have all sorts of other alternatives to quiet the turbo engine noise. One 
of which is installing a fish mouth on my turbo down pipe. I have a tig 
welder and I can weld SS fairly well. SS is one of the more easy metals 
to weld.

Another factor is turbo exhaust are much cooler so just about any
off the shelf muffler would work with a turbo. Also please
note turbo's don't like back pressure so be prepared to give up
a little HP if you are using the stock turbo with a muffler.
If you are building a turbo system from scratch you can always install
a slightly larger diameter compressor to compensate for this fact.

Paul Lamar
 
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