I was told that the Tower cannister muffler would produce better performance than stock mufflers for an OS .46 AX and an OS .55 AX. My question is if that is true, and what performance changes I should look for. I have the Tower muffler, just never got around to installing it on an engine. Thanks

I have used the GMS 47 muffler, which is similar to the Tower. On a 46AX and found the AX picked up some power in the upper rev range. It's claimed peak rpm will also increase and while I didn't tach the engine it did seem to have the often quoted 300-800rpm extra. I'd say mid range improves slightly, throttle response generally, and upper end is the main improvement.

The biggest improvement you'll note is that you won't be losing any more of those AX mufflers because of their hopelessly inadequate through bolts.... [:@]

As the GMS/Tower mufflers are generally longer, keep an eye on mounting space. Side mounts with the muffler running under the bottom of the fuse may foul wing saddle mounts etc.

Those long cannister mufflers are half wave tuned pipes. They tend to give a noticable boost at high rpm. They still make good mufflers even when proped out of tune.

I think that the GMS and Tower mufflers are the same item, but the GMS is about a dollar cheaper.

I have the Tower muffler on an Evolution 46NT and I tached a 1000 RPM gain with it. To me they are worth the money.

Just got the GMS 47 muffler for my 46AX. Pretty much the same as Tower 46 (if not exactly). Fit like a glove. Will also work on 55AX and many others. Good luck.

Interesting. What are the differences that you saw?

There's no real difference between the Tower and GMS mufflers, apart from the fact that the GMS has the letters "GMS" cast on the header.

Both work really well at giving your average 46-sized engine a boost.

Can someone measure the overall length of the expansion chamber of these mufflers?

I've been thinking about making an aluminum insert for my stock mufflers to increase the volume and reproduce the effect of the Tower/GMS mufflers. I just don't know how long to make it!

Thanks,
Jeff

a person can't buy the materials and do the machine work for the price of the tower muffler, then you have the bolt to also consider.

Cyberwolf, You're right, MOST people couldn't even attempt it. It is a good thing I'm not most people. I have the ability, knowledge , and in this case - the materials to do pretty much anything I set out to do. I've been making mufflers, headers/spacers, and adapters for several years. Finding the right size aluminum tubing was easy (actually, I already had it). The bolt is a no-brainer. I just need the length.

Most people with your ability would tune the length themselves.

Yeah, I'm a perfectionist at heart. I don't have the time to mess around experimenting. All I asked for was a simple measurement.

Never mind, I got it from Tower:

SPECS: Diameter: 1.6"
Length: 6.3"