The muffler on my ST 45 came off in flight yesterday and we could not find it. I lost the entire muffler assembly and am looking for a relpacement. Should I Just buy a stock ST muffler and manifold or are the Macs mufflers a good replacement? I really don't like the look of the standard, so if the Macs provides good performance, I will probably buy one of those. Any one have any experience with the Macs or is there another muffler I should try?

A bit of a rant here, but too bad engine companies don't have some industry standards for parts sizes. I have a muffler off an old OS 46fx that almost fits, but the screw mounts are a couple or millimeters off. No matter how hard you try, you just can't stretch aluminum.

Hi Buz......

Sorry to hear you lost the muffler. I've scattered a few around the weeds in my years too. It happens.

The muffler patterns are sorta standardized. The european engines and 'eastern' engines use different spacing.

In the 40-50 size range.... Webra, ST (as well as Jett ) use the same 38.5 mm bolt spacing. OS, TT, Tower, Irvine, ASP, Magnum (and other similar clones) use a 37mm bolt spacing.

A suggestion if you are replacing the muffler. Consider a Jett-Stream muffler. It works very well on the ST engines, and is a one-piece bolt-on design. It will not come apart. No adapter or modificiation... its provided with the correct bolt pattern for your engine, and suitable bolts. It will also increase the engine rpm quite a bit. The resulting performance gain will most likely put a big grin on your face Price wise, it may be a few $$ more than some other options, but its not much more, and its wise to consider all of the factors. More info and performance data is available on the web site

I hope this is helpful
Bob

A lot of people throw the ugly ST mufflers away. You can probably buy an ugly muffler cheap if it wasn’t thrown away first.

I have used Macs mufflers on other engines and like them.

Safety wire (fishing leader line, insulated wire, etc.) can prevent a muffler flyaway. I usually put a thin metal strap under the pressure fitting with a hole for the safety wire.

ST mufflers stay on fine if you do not use the gasket. If you use the gasket it will fall of every time.

Hobbsy is correct....don't use the manifold gasket on a Tiger, use
the black high temp silicon for exhaust manifolds. When the manifold
loosens, it starts beating up the small manifold screws as well....and
then you can have problems when the screws strip out.

My manifold and muffler fell off this used 3000 one time when the
weakened screws pulled out.....notice I said "one time".

I re-drilled and tapped the cylinder, and made some studs, like on a
motorcycle. I used plenty of lock-tite on everything, as well as locking nuts,
and lock washers. I don't think it will fall back off....any time soon.

FBD.

I think the Macs muffler for my .61 Bluehead is gorgeous. Give it a try.

I have a st 51 that came with the macs ( black ) muffler, runs very good, cant compare it to the stocker though as far as performance goes.

If the Macs for the ST is the same as the results (generally) for the OS-46FX/SF they have similar performance compared to stock and you might pay $30 bucks for another ugly one or for a Macs, whereas the Jett-Stream is a huge performance booster (bolt-on power) as is the Ultrathrust-

"A lot of people throw the ugly ST mufflers away. You can probably buy an ugly muffler cheap if it wasn’t thrown away first."

That is FUNNY BillS!

My new (used) ST G-90 came with some sort of boat-anchor bookend 2 piece steel-belted heavy duty all purpose muffler and a Bisson strap-on muffler (which I will use-)

Dave- I got a Tower-75 on my Funtana-46, what pop you thinking for low and slow? 13x4W maybe? (Not speed I know, that is why I am confused- the 10x10 APC may not be the perfect match for that airplane-)

Cheers!

Thanks for the feedback. The LHS has a Macs in stock so I am going with that. The Jett looks like a great option, but not available locally and I want to fly this week.

I may never understand how the Italians with such a strong love for beauty over function allowed a butt ugly muffler to be put on a very good engine. One might guess that the design was farmed out to an eastern block country without supervision. However that does not excuse ‘UGLY’ nor explain why the US marketing people have not insisted on correction. Surely the US marketing people understand that the sell rate is probably less than half its potential and with reduced margins.

Notice that the advertising sometimes presented here never shows the muffler.

Bill

Marketing 101 and ST mufflers

wife: Why did you buy that dress for me?

Engineer: It is a very well constructed dress.

wife: It is ugly.

Engineer: The workmanship is better than any other that could be found.

Wife: The dress is worse than ugly.

Engineer: But.

Result: Rather than immediately throwing the expensive dress in the garbage it was never worn and quietly given to goodwill presumably because of the workmanship.

Not enough to do or something. Bill

>>> In the 40-50 size range.... Webra, ST (as well as Jett ) use the same 38.5 mm bolt spacing. OS, TT, Tower, Irvine, ASP, Magnum (and other similar clones) use a 37mm bolt spacing..........

Ahhhh, so Webra mufflers and pipes will fit the Super Tigre? That is good to know if correct!

Ernie

Here's what happens to those unloved ST mufflers when people who don't want them pass them on to me. The engine on the left is a Russian Zeus .61 that came with a very small restrictive muffler, the engine on the right is an OPS .60 that came new with an incomplete muffler.

Way to go, Hobbsy....I'll bet they run sweet....

Razor....I don't know, I've never run one low and slow....

FBD.