Doug Thorley Cat Back Droning

[maxse01]

@abuck99 - mine has headers and customer cats/mid pipes....just the DT catback is much more subdued.

 

[ukaviator]

The DT Catback was $550 shipped, then I spent about $500 getting the custom work done on the mid section. They're 2.5 inch pipes with flomaster hi flow cats and o2 spacers. No CEL, and it runs great. Much more noticeable low end power. Where it would have previously had to grab 4th on the highway for passing, it will just stay in 5th and accelerate. I'm very happy with the power gains of the entire system, I would estimate that I made up for the 33's and all the armor I've added. It feels just as quick as my wife's stock 100, but sounds MUCH better.

If you want some more clips I can get them for you. 1 thing I will admit, it is somewhat drony on the highway at slow speed (under 2,000rpms). If you're going faster than that it's ok, but you still know it's there. I might have a resonator put in somewhere at some point to take the edge off a little bit.

YES more clips! Sounds great!

 

[jLB]

An aftermarket cat back exhaust system, that provides a minimal HP gain, along with a highway drone....

Say it ain't so!


(Nice work on trying to correct the issue Daskoff.)

 

[outdoor7or24]

How did this work for decreasing the drone on your trip?

Here you go - per info I glean from the ole interwebs the bends should be mandrel bends and much smoother. I needed it fast and this fixes what I wanted and it cost me $150 at a local muffler shop. It really is amazing, not only did it get rid of the droning but also quieted the overall system. You can still definitely hear the exhaust but not every little accelerator input. Still haven't tested it on the highway but I will report back as I am going to trailer a couple of bikes to Sturgis starting tomorrow.

Also please don't mind the rust on the frame - I only had this truck for a few months and have already sunk a ton of money into it. Next on the list this fall will be the underbody rust which I will treat with a rust convertor and then POR15 or something like that.

Back to the main issue. Yep dosen't look exotic but it certainly works and am happy with the sound now. Wish DT offered an option like this which would most likely be way more elegant.

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[Daskoff]

How did this work for decreasing the drone on your trip?

I still hear some drone on the highway depending on the RPM but as someone mentioned in a previous post in this thread...it might be I am just getting to old for this. It definitely sounds "musclecar-ish" but am getting kind of tired of it. My buddy who came on the trip thought it was fine. I've read that the system should not affect performance any (i.e. no extra power) but it certainly feels move lively. Maybe it's psychological only. Next year I may swap out the muffler for something more quiet.

 

[LateOnTheBrakes]

I'm having a similar issue with highway drone. But what bugs me more is almost a tinny resonance that is RPM dependent. I hear/feel it more of a vibration in the rear, passenger floorboard than I do as a drone.

I actually prefer the old system. I removed the stock muffler and kept the stock resonator. It was slightly louder at low RPM and much less drone at highway speed.

 

[LateOnTheBrakes]

The weird resonance I hear at lower RPM almost sounds like metal on metal. Not sure if the exhaust tip is vibrating against the bumper, the exhaust is hitting against the OEM muffler heatshield, or if the heatshield is just flapping and giving off a harmonic.

 

[LateOnTheBrakes]

I loosened everything up and shifted the tailpipe forward to get more clearance with the rear bumper. It got rid of most of the noise. However, there is still that weird resonance/drone around 2,000 RPM. I was able to replicate it as ~50mph and ~2,000 RPM. See video below. Anyone have similar issues?