ANSA Mufflers

8/7/2019 ANSA Mufflers

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want to cut open my mufflers. The standard ANSA mufflers have a smaller inlet

pipe than the GTS mufflers and adding to their flow restriction are discs that are spot

welded into the front of the exit pipes. These discs close off the front end of the exitpipes and force the exhaust through small holes drilled in the pipes.

View of Dave Bells GTS ANSA muffler cut open showing the internal perforatedpipes, baffles and location of the discs on the standard mufflers. The discs can beseen buy looking down the fluted exit pipes with a small flash light. The standardANSA mufflers have the area between the two baffles packed with a sound deading

material that looks like fiberglass.

View of the exhaust flow route through the stock ANSA muffler. The flow is inthrough the inlet pipe to the back of the muffler case, then through the holes in the

exit pipes and out the fluted tail pipes. Not a very free flowing system!

I wanted to find a way to increase the flow without cutting open the mufflers sodecided to focus on how I could increase the flow to the exit pipes. Some people

have knocked out the exit pipe discs by ramming a pipe down the tail pipe or

sometimes the spot welds rust apart and they fall inside the muffler. But thatsolution causes the loose disc to rattle around inside the muffler or you must cutopen the muffler to remove the disc.

My solution was to buy a 3/8 drill bit that is 12 long to drill holes in the disc from theback of the fluted pipes. The drill bit was purchased from Lowe's.

I was a little concerned that the 3/8 holes could cause a whistling or chirping soundbut that was not the case. I started by drilling one hole in each disc to find out how it

sounded. As I drilled more holes I could tell that the sound level was louder. Iended up drilling five holes in each disc being careful not to drill through the side of

the exit pipe or the spot welds holding the discs. That's ten holes per muffler.Unfortunately it is too dark inside the muffler to take a picture of the holes I drilled.


www.panteraplace.com/page200.htm 2/5


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The idea is to drill holes in a pattern like this but it is hard to control the hole

positions with the long drill bit.

From my calculations the ten 3/8 holes in each muffler increases the open area by1.044 or about 46% of the inlet pipe area . That area along with the existingperforations in the exit pipes opens it up quite a bit. The exhaust tone is louder, but

not too much and I expect the holes help reduce some exhaust back pressure.

March 18, 2007 - Update

Being a typical Pantera owner I can never stop tinkering. After I drilled the holes in

the disc, I could see that the muffler had a couple of small vent holes in the backbaffle and I could see the deading material behind the baffle. I got a longer 3/8 drilland drilled five holes in the back baffle. The deadening material turned out to be

steel wool and I was able to remove it by drill ing holes in it and pull ing it out with

piece of coat hanger with a hook on it.

After removing the deading material I was then able to drill a few holes in the frontbaffle so that the exhaust flow now works like this:

When drilling the holes in the front baffle, make sure that the angle of the drill will

place the hole in the baffle and not in the bottom of the muffler. It worked fine for

me but I can see that depending how the holes are drilled it would be possible tomiss the baffle. The inside of my muffler now looks like Swiss cheese and is a lotlouder.

Removing the steel wool and adding the extra holes in the baffles made the exhausta lot louder outside the car and also inside. The famous Pantera 1900 to 2300RPM harmonic resonance is way louder so do not make this mod if you do not

like the sound. I've always thought that the harmonic resonance could only be

heard inside the car but after extensive testing in our local underground Wal-Martparking area I discovered that it is loud outside the car too. My car has always been

good at setting off car alarms but now it does an excellent job!

March 6, 2010 - Update

After giving more thought to my muffler modification, I decided to take it a step




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further by cutting 1 3/8" holes in the muffler tip cap and the front and back baffles. A

total of six cutouts per muffler. The 1 3/8" cutter fits inside the tip with just enough

clearance to make the turn into the perforated part of the pipe.

I used the following Ace Hardware tools to cut the holes:

1. 1 3/8" wood and metal hole saw - part number 20223 - $10.49.

2. Vermont American mandrel that matches the hole saw - part number 25536 -$16.99.

3. Starrett 12" mandrel extension - part number 206103 - $23.49.

To make sure that the cutter did not get disconnected from the extension I cut anotch in the mandrel shaft and replaced the straight slot set screw with a hardenedhex head set screw so I could really torque the set screw down very tight. Having thecuter get disconnected from the extension inside the muffler would be a major

problem so be very careful. I retightened everything after each cut and used oil on

the cutter teeth. Most of the cutout parts stuck to the cutter teeth when I pulled it outof the muffler. A couple are still in the muffler but they don't seem to be rattling.

The following are my area calculations for the openings in the muffler:

1. Main 1 3/4" OD tailpipe that connects from the header to the front of the muffler

has a ID area of about 2.074"..

2. Perforated main pipe inside the muffler has about 210 3/16" holes for a total areaof 5.88". I don't believe a perforated pipe would actually flow like it had an area of

5.88".

3. The two 1 3/8" holes that go from the exhaust tips through tip plug and bothbaffles. The total area of both holes is about 2.97".

After cutting the large holes I found that there was some steel wool left in one of themufflers and I was able to pull it out in pieces.

The larger holes made the exhaust somewhat louder and the exhaust has a bit of abark to it now at RPM. The system has lost a lot of the characteristic ANSA airy

sound. At this point the muffler should not be creating much or any restriction whenyou consider the small size of the inlet.

Images of the tools.

I expect that I'm getting the best flow possible now, without cutting the muffler apartand removing the perforated pipe and baffles.

It is kind of hard to see with the flashlight in the way and the poor camera focus, but




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in this image you can see with the 1 3/8" cutouts there is a clear view all the way tothe front surface of the muffler from inside the exhaust tip.



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ANSA Mufflers