Quieting a Monza Muffler

Tim Polzin · 07-24-1998, 12:30 PM

After over two years of putting up with the noise from my Monza muffler, I finally figured I needed to do something. Why the PO bought this muffler is beyond me. Anyway, I cut off and sealed the two inside exhaust pipes. Not only does the thing look better, it is MUCH quieter plus has a really nice tone now as well. I have not noticed any decrease in performance. Any comments?

07-25-1998, 04:16 PM

yeah..i got a comment.....THE LOUDER, THE BETTER

Tim Polzin · 07-27-1998, 12:36 PM

Silly me, all the while I was thinking
Quiet = Good
Noisy = Bad
I'll get this right yet. Actually, I was looking for some technical reason that I shouldn't have done this, so I can justify the money for an OEM style muffler.

07-27-1998, 12:42 PM

technical info....hmm.....how bout..the faster and more exhaust u can get out at one time the faster the engine can and will fire again which in turn produces more rpm's and power.....

JP Noonan · 07-27-1998, 02:53 PM

How about thermodynamics, velocity of the gas, not just volume of the pipes. Flow is MUCH more important then sound (i.e. big a** pipes). Granted at any road race the sound is deafening, but these motors spend their lives at high RPM. Too large a pipe, or a totally open system does not allow the exhaust from one cylinder to "scavenge" the exhaust from the next cyliner in line. This is the idea behind "bundle o snakes" exh systems and also has something to do with the overlap on the cam shaft lobes (intake and exhaust are open at the same time, this way the scavenging effect helps pull in the intake charge). There are other things like keeping the gas as hot as possible for as long as possible to cool the engine and keep gas velocity up. However I'm not qualified to really tell you much besides rehashing old magazine articles.

As for the Monza's, see if the second tail pipe you blocked off goes into the mufler or runs off the other tailpipe. It very well may just be a resonator, and add nothing to performance.Or you may have chocked off your exhaust but don't notice because all you lost was the high rpm range.

Tim Polzin · 07-27-1998, 03:23 PM

Good point. The way the monza muffler is fabricated is with two mufflers, and the exhaust pipes (headers?)from the engine commonly connected in the center (all four) and from there it joins the two mufflers. Two exhaust pipes leave each muffler (or they used to). When we used a torch to cut off the inside ones, sparks came out the outside ones, so I suspect there is no separate plumbing on the inside of the muffler.

unclerichy · 07-29-1998, 07:52 PM

Well, I'll chime in. When I bought my 74 2.0 it had a Monza style muffler and was pretty loud. Since it was getting rusty anyway I opted for an O.E. muffler which cost me $370 AND took 4 months to deliver (I was told that they only come from Denmark). Each seemed to have same performance, but to my dismay the O.E. was just as loud as the Monza.

I guess the point I'm trying to make is that if you can get the same performance with less noise (and save money to boot) go for it.

JP Noonan · 07-30-1998, 02:13 PM

If the stock muffler was just as loud then the Monza, I would check all the connections down the line. The copper gaskets at the head (I use a spray copper coating on them as I do with all my gaskets), and the muffler flang to muffler gasket. All the bolts need to be there as does the muffler support bracket or the weight from the mufler will pull out the exhaust studs in the head. My P.O. had a rusty Bursh muffler on before putting on a Monza type (Ansa? I think) and the car was much quieter with the Bursh.

Wayne 962 · Wayne 962's Garage

Hmm, I'm not sure about the sound level, but a whole bunch of people (myself included) like the look of the stock 2.0L muffler.

Additionally, we have a new one (yes, from Denmark) in our warehouse NEW for $325. Only one though...

I hear that the OE mufflers are pretty good at flow (resembling the design of the 911 mufflers)...

-Wayne

08-22-1998, 08:00 PM

well...i didnt really have anything to say about the monza system, even though i have one, my engine wasnt running. well i got it running and plugged the monza system up and i think, my opinion only, that the monza sounds real good. it has a real deep sound to it, but mines not that loud, it sounds like what i wanted my exhaust to sound like. i dont know if it would make a difference but my engine has a 32/36 carb, unlike most people u have dual carbs, i do know that duals do make the exhaust alot louder. anyways thats just my opinion.