Exaust and Body

Pierce Arrow factory mufflers and pipes were ENGINEERED just for PA. The mufflers were what is called in the industry double wrapped. That is they had a muffler inside a muffler. ( Made them very quiet.) They basically were straight through with very little restriction. Also, all the pipes were mandrel bent. That is to say not crushed down to a smaller diameter when being bent in the machine. Thus the system was very quiet and had almost no back pressure. Unless you have a system custom made this way, you car will not run, perform, or sound correctly. An incorrect exhaust of modern manufacture that is run on 95 percent of the cars in the PAS from the Classic era causes the car’s performance to be reduced by about 15 percent by my best estimation. Long story short almost every car in the 29 – 38 time frame is too restricted and suffering a large performance deficit due to incorrect and over restricted exhaust systems.

Richard, could you send me some better photos of your factory system. We have been collecting patterns for many years as we like to make our exhaust just as it was new. Thanks, Ed See photo below for a 36-38 set of correct pipes. They are huge, and flow better than anything else made today.

David, that is fun story. Copper at the scrap yard is worth a fortune!

Ed, I agree with your comments about exhaust flow being critical and it is good to see ‘factory spec’ being reproduced. Do you know of someone making accurate mufflers for PA?

Enjoy your holiday!-John

John Cislak had about a hundred mufflers made. He still has some left for the 36 to 38 cars. I think he is going to do the earlier car in the near future. Give him a call. I am shure he will post an ad whan he is going to make them.

Mr. Minnie…Those pipes are gorgeous! I need them for some plumbing I’m engaged in. Are they available?

For Richard Leroy: The engine setup is what determines which side of the car the exhaust runs down.

For all Pierce straight 8’s, the exhaust manifold is on the right side, the passenger side of the engine. The exhaust runs down the right side of the chassis, inside the frame rails.

On the ’25-’28 Series 80 and 81 cars, the exhaust manifold is on the left side, the driver’s side of the engine. The exhaust runs down the left side of the chassis, inside the left frame rail.

Greg Long

A second layer of steel can be wrapped around a muffler to deaden the ‘ring’ from the muffler’s single thickness skin. Brazed or welded onto to the muffler. It definitely makes a difference in the sound of the car when running. Much less ‘radiated’ sound from under the car.

Greg L

I just measured my head pipe, which I don’t think was replaced. It is 2.250 OD x .065/.069 wall (16 ga) and is either seamless or drawn tubing, as there is no weld bead. It is obviously mandrel bent.

John’s pipes look really good.

Bill

Greg,

I also think you are a font of info–maybe a Helvetica or a Times Roman.

But, maybe a fount of knowledge too?

Bob

Fonts, fountains etc.

I went through a time when I was trying to quiet down an aftermarket exhaust system on a diesel truck, it had some weird drones and an odd tinny sound at idle.

One of the things I noticed was the aftermarket muffler was half the weight of the original equipment one. But about the same size.

I had a rusted original so I cut it open and it had a double outer skin. No insulation, just two layers of thin steel, with many spot welds keeping the two attached to each other.

I duplicated the idea, I just added a second skin, of 16ga steel, rolled so it had to be expanded to slide over the muffler, I just tack welded it in a few places and then tested the idea for a few trips to the airport. I had gotten pretty serious about this noise reduction project and had a Db meter. The double skinned muffler was noticeably and measurably quieter. and the dinging and tinny sound was gone when the truck idled.

I finished attaching the second skin with a few more welds and welded the lengthwise seam closed, Eventually this muffler succumbed to Michigan salt and rusted out, I bought a Stainless steel system next, and inquired of the manufacturer/seller how thick the skin on the muffler was, he asked why? I told him about my double skinned muffler for noise reduction, He offered to make a muffler for me out of 14 ga SSteel, instead of the standard 16ga. And it was plenty quiet.

So, I believe either a second skin, or a rather thick and heavy single skin will change the radiated sound from just about any muffler. You can experiment quite inexpensively with the correct diameter chimney flue pipe, and two or three large diameter hose clamps. just open the metal flue pipe at the seam, put it around the muffler, and hold it in place with two or three hose clamps. See if you notice any difference. Most flue/chimney pipe is either 24 or 28 ga. Rather thin, but it should make some difference in the radiated sound. You can use the results of the experiment to see if you want to go with a real double skinned muffler or not.

Greg L.