Well, after picking up my unmolested '05 RT with only 11,000 miles, I read pretty much all the posts here on exhaust upgrades and promptly ignored all of them.

I had a custom cat-back system installed at Loper's High Performance in Phoenix, but strayed from the recommended path - with undesirable results:

I had the stock system removed from the crossover back and replaced with 2.5 inch piping, eliminated the "suitcase" and replaced the resonators with Flowmaster 40 series. Big mistake. Terrible resonance/drone at ~1500-2000 RPM under light load. MDS mode at freeway speeds brings on a high-frequency vibration and unpleasant Honda-esque sounds. I now also hear computer interference - i.e. rev-limiter and some apparent misfiring (computer-driven?) between shifts at heavy throttle.

Suggestions would be appreciated, but I think I'll start by addinga couple of glasspacks where the suitcase was. If that doesn't work, I guess I should replace theFlowmasters with something else. Again, suggestions would be appreciated.

(I'm a newbie to this forum, but not to American V8 performance. I'mChevy guy, but felt abandoned by the lack of a V8 rear drive platform that wasn't a truck. The Magnum fills the void quite nicely, thank you!)

 

A bunch of us have been down that custom exhaust road, trying to fight the drone monster.

I settled into a Corsa catback and haven't regretted one minute of it. It doesn’t drone, is mild tempered when driving around town but once you get on it the exhaust sounds mean.

 

That's why i'd never go to a custom exhaust place instead of buying a catback system for the car. Asystem engineered specificaly for my car with hundreds of hours of testing, or some random muffler(s) and pipes stuck on by arandom mechanic withprobably like 10minutes of testing, pretty easy choice for me to make, plus with the catback system you can avoid the $60+ hour fee to get it install as they aren't that hard to installyourself, if I can do it myself then i'm sure almost anyone could

 

don't got with glasspacks. add the flowmaster resonators. they are very small (about the size of a high flow cat) glasspacks are very resticting to flow.

 

Thanks for the replies.

But, with all due respect, how is a glasspack restrictive? They virtually eliminate backpressure. I can't see how they'd be considered a restriction in any way.

Thanks again!

 

What does everybody think of the JBA stainless catback exhaust. If anyone has it does it sound decent without the drone like they claim or should I go with a different system? I currently have the custom exhaust with two 40 series Flowmasters. Same prob I have a drone at about 2000 RPM. Not too bad but I would like to know if its worth changing. I feel your pain man im in the same boat you are.

 

The biggest concern is the x pipe, make sure you have that!!!! It makes a huge difference, and I am guessing that when you had the custom work done they didnt put one in they just ran straight pipes. try this first, I am sure you can get it done without really changing anything else you have done and see if this has helped .

 

Thanks, er..uh god_c,

The factory crossover is still in place - everthing back is new (and 2.5").

I've been restoring classic Chevys for a lot of years (still have a '70 SS454 Chevelle) and just sold a nice '66 El Camino. I've done a few others plus a couple of old British roadsters. Hot rodders and muscle car enthusiasts have been on the crossover (or H-pipe) bandwagon for ages. I don't recall the exact dynamics, but something about balancing cylinder pulses during breaks in the firing order - especially when the order switches from one head to the other.

Thanks for the ideas, I still haven't done anything yet. I'm told that the car sounds almost "exotic" with nothing but the Flowmasters at the tails. Too bad about the resonance.

One more thing: The guy at Loper's is adament about the "suitcase" being the resonator. He says there's nothing inside that would qualify it as a muffler. Believe it or not.

 

Yates,

Call me crazy, but I just hate undoing something completely (and admitting defeat). I'll leave those Flowmasters on if at all possible. I don't know where you placed yours, but mine are just ahead of the tips - where the two factory units were. My drone is right at 1500 +/- about 200 RPM. Unfortunately, that's where the car spends most of its time in city driving.

That JBA setup adds insult to injury as it's quite expensive. Your call, but I'm going to try adding small resonators upstream where the suitcase was.

 

Desert I hear ya man I spent a nice penny on the custom setup. It was done very good and i have gotten compliments on the sound and looks, but like you there is a drone. My mufflers are placed where the suitcase was in the middle. I found the JBA stainless catback system on a website (High Horsepower Performance) for only 479.00 not too bad, but again that would be admitting defeat and spending more than i originally planned on spending for an exhaust system. Oh well let me know how you make out. I still thinking. Damn that money could be used on so many other goodies though.