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Episode III: The Phantom Menace
I decided just cutting the suitcase out of the picture wasn’t good enough. Those so-called resonators -- which are really mufflers when it comes down to it -- were still on there. They must die.
OK I'll admit that I like modding my Magnum, and I probably could have left this alone and ended this saga after Episode II. However I just wanted to squeeze a little more out of the system, and I still didn't have the in-town mean/nasty burble I wanted when driving in the city. I wasn't sure I could do it without destroying my cruising speed sound with drone, but I wanted to give it a try anyway.
So the next step was to go back to the muffler shop and hack off those resonators. Once they came off, I was amazed to discover they weighed like 12-15 pounds EACH. I wasn't sorry to lose 25+ pounds of dead weight off the car.
In place of the resonators we welded on straight pipe. Now, if you know anything about exhaust systems you know we lost a whole lot of backpressure by doing this. Perhaps so much that this move will cause a performance decrease... and maybe a big decrease at that. The decision to do it anyway was twofold.
First of all, I had listened to plenty of other Magnum owners talk about their results while doing this. It appeared that the only time a backpressure issue was encountered was when someone hacked off the resonators AND went to bigger pipe. Those who did go with 2 1/2" or even 3" pipes wound up necking the system down somewhere to scavenge some needed backpressure.
Next, we decided to neck down the pipes to 2" at the point we cut them off, and to furthermore use a press-bend instead of a mandrel-bend on the length of new pipe that replaced the resonators.
At the tail end, some short rolled-edge chrome tips were put on to finish up the project.
Total cost for this modification was $110, bringing the total project cost to $375.00.
 Results
I loved the sound before we even put the tips on. After the resonators were cut off, we brought the car down from the lift and started it up. The sound was *exactly* what you would expect from a 1960's or 1970's muscle car. A truly beastly, low burble.
In terms of performance, 1/4 mile times stayed roughly the same -- and the temperature in early May was 20 degrees warmer than the 1/4 miles run in February. So here again I figured that I had not lost anything, and maybe gained some added performance.
Driving around town, the car drew the kind of attention it deserved. Startups in parking lots drew head-jerks. Quite satisfying overall. This is the sort of sound that strikes terror into the heart of the Mustang in the next lane, and maybe even gives a few of the bigger kids out there reason to skip a challenge (which is good because a station wagon is not going to beat a Corvette without a lot more than some exhaust work).
Now for the bad news...
Well, I can't say I wasn't warned. Pretty much everyone who has gone straight pipe out the back of this car has reported drone, and lots of it, in the 1800-2200 rpm range. At idle the car was a wonder but driving it was another story. I knew immediately what drone was (having heard it only described before) and that I had it. I will say that you do get used to it, and its not so bad after a few weeks of learning to live with it... but you had to learn to live with it. Driving around town I was able to minimize its effects -- and enjoy the sound of the exhaust -- by rolling all of the windows down. However thats not going to help much in the winter time. And if you've ever heard of the "wife test" rest assured this is one mod that will never pass it unless she's an extreme gearhead like you are.
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What is "Drone"?
Drone is a harmonic resonance inside the cabin that occurs at certain points on the power curve when the sound emanating from your exhaust turns into a wave of undesirable sound. The air in the cabin seems to almost vibrate and you can almost feel it pressing your eardrums. Someone with sensitive hearing would be very uncomfortable.
Its LOUD and not an "exhaust" sound.
Kind of like sticking your head inside of a tuba thats playing a continuous note.
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So despite my love of the sound in town during the summertime, the price to get it was too high ... even if I got used to the sound, occasional passengers sure didn't. So while this system is probably very good for the unmarried purist who is willing to pay the price for the perfect muscle car sound, that ain't me.
Next... Episode IV: The Empire Strikes Back
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Personal BS
