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This page is about the various exhaust mods done to the Avenger.
My header is a generic POS from eBay, and the slip joint on the downpipe leaks, even after I put a clamp on it. I got it used, and it is intended for a 1995 Avenger, which I assume has something to do with the extra EGR fitting on it that is blocked off. It has a 3/8" flange, 1 5/8" primaries in a 4-1 design going into a 2.5" collector. The primaries are crimp-bent and short, with unequal lengths. Do not ever buy a header like this. It's useless. The downpipe is 2 1/4". The only nice things about this header are that it is ceramic coated and has an actual factory-style flex joint in the downpipe. These pics are in chronological order from the install:
As you can see, I ordered all new hardware from the dealer, including bolts, nuts, gaskets, etc. because this is one of those things that you hate to stop in the middle of. Also in that undercar shot, you can see my catalytic converter and the Bosal exhaust system as it was delivered and originally installed (by me).
A fun sidenote is that I did not have the hardware to bolt the downpipe on at the shop where I was working, so I drove all the way across Coralville and Iowa City with an open header. It was pretty freaking loud... aka, awesome. I bolted the DP on by pulling the front tires up on the curb at the auto parts store, crawling underneath and doing the job in the dark parking lot.
Now for everything behind the header downpipe:
A long time ago, I rigged up a glasspack with a crimped 45 degree bend and an ugly tip from the parts store. The whole thing cost about $50, but it sounded like butt becuase the clamped joints leaked, as did the oversize bolt-on tip.
After driving around that way for awhile, I decided that it was not quite..... "sophisticated" enough, so I plunked down a fair chunk of change for a Bosal catback system, which is one of very few systems availible for the Avenger. Looking back, buying this was stupid. I was immediately disappointed to find that the Bosal muffler was not straight-through, but chambered (and don't tell me that small engines need backpressure; just leave your stock muffler on if that's what you think). Also, it did not come with most of the hardware that I needed to install it. The muffler body is huge (and heavy). The dual 3.5" tips are overkill, to put it nicely, not to mention that they had rubbed off paint in the first 10 minutes that I drove around, because of the way the system is designed to touch the rear fascia. I ultimately replaced the rubber hangers with aftermarket ones to lower the tips away from the bumper, but that put additional strain on everything else. While I am at it, I should mention the fact that for no apparent reason, there is a short section of pipe right behind the cat that is smaller than the rest of the system. And, I hated the way it sounded. It was louder and relatively low-pitched at lower speeds, but the sound had no character because of the backpressure effects of the muffler. Ironically, the muffler was just free-flowing enough that it allowed an annoying "zip" sound to escape from around 2500-4500 rpm (which also could have been cured if Bosal had installed a resonator like the factory one). Anyway, here are pics of the Bosal system from the box, compared to what was on there, and installed:
Two things to notice in the last shot: the lowered tips, and the mammoth size of the Bosal muffler.
Well, after driving around for a year thinking about how I hated my exhaust system, I finally decided to do something about it, so I ordered a Dynomax Ultra-Flo muffler (p/n 17283), a 45-degree mandrel bend, a 3" SS tip and some 2.5" piping from Summit Racing. While I was installing this stuff, I learned several things, such as:
