Exhaust overhaul

SwampmanLA · Jan 9, 2010

I have not posted in some time but I read this board almost daily. I get great info and ideas for all of you. Thanks!

It's cold as heck down here in South Louisiana, some folks think **** is freezing over cause the Saints may finally go to the Super Bowl, so I am pulling my winter maintenance. I'm doing mostly routine stuff but one thing I am doing is overhauling the exhaust on my 422. I got really tired of the excess heat generated by the standard PT exhaust system and the noise so I'm trying a little custom stuff.

What I landed on is a piece of 1 5/8" exhaust pipe, two 1" nipples, and two generic 1" screw on mufflers, the big round ones. What I am doing is cutting the PT square tubing just past the second cylinder and will sedge up the 1" to the 1 5/8". That runs out the same notch that is cut in the cover. Once outside the cover I built a manifold with the two nipples welded into it and the mufflers will attach there. I figure I am at least doubling the exhaust path by doing this. I also picked up some exhaust wrap and plan to wrap the whole exhaust manifold out to the mufflers.

I should have pictures in a day or two and will post them. I'm hoping for a much cooler and quieter 422. Wish me luck!

SwampmanLA · Jan 10, 2010

OK, I did a bit more today. Here is what I have so far. With a bit more welding I'll be ready to try her out. So what do you think?

Willl · Jan 10, 2010

Looks good.

That's alot of weight out on the end of that, you thought about some type of support ?

Marks481 · Jan 14, 2010

It probably weighs quite a bit less then the OEM PT 1/4" steel box muffler he took off.

DCWhitley · Jan 25, 2010

How did you make out, is it quieter than the OEM muffler? I would love to find something quieter.

westcliffe01 · Jan 25, 2010

You need some volume, preferably something with some fiberglass inside to take the edge off. Take a drive to the exhaust shop and try a 3 way muffler, and if possible add an outlet pipe 2 feet long. If the muffler can be connected to the engine with flex hose, this allows the muffler to be hard mounted on the frame, perhaps with a vertical stack.

Alternatively, look at places like smallenginewarehouse.com for mufflers off the Honda and Robin engines. They have better mufflers out the box.

SwampmanLA · Jan 25, 2010

Well I finally finished this up over the weekend and tried it out. It is a bit quieter but not as much as I had hoped. The tone is much better and I must say the engine runs better. It is easier to start, seems to run cooler and has no backfires! I'd say it was worth it.

ponytug · Jan 26, 2010

Dear SwampmanLA,

Many congratulations! It sounds really successful. Are you going to post photos?

An engine that starts easier, runs cooler and doesn't have backfires sounds like a great reason to have done it.

On a separate thread, I saw a home video of someone that had welded a cheap $20 automotive muffler on some flex hose to connect it to his generator with a slip fitting. It knocked 30-40dBa off the generator noise. I have a similar model that is loud at the 60' distance.

All the best,

Peter

SwampmanLA said:
Well I finally finished this up over the weekend and tried it out. It is a bit quieter but not as much as I had hoped. The tone is much better and I must say the engine runs better. It is easier to start, seems to run cooler and has no backfires! I'd say it was worth it.

jaquetarr · Jan 27, 2010

I had to build a muffler for a 6 wheel swamp buggy I had one time. We used pipe stuffed with metal shavings. I believe they were SUS. The over size & shavings dropped the pressure & the shavings cooled th gas flow a little. Worked pretty good. The engine was quieter than the drive chains. The shavings might last longer than fiberglass.
Rgds,
tim