I got a straight through rear muffler installed on my TL AWD today. Can't really feel any real difference, but I wasn't really expecting anything amazing anyway. It does seem to rev more freely though.

However. I've had it for just 6 hours now and it's driving me insane. It drones right on 2200rpm which is really quite inconvenient. It's really far too loud to live with every day. From what i've read this afternoon I've got two options- replace the rear muffler or add a big louvered (not hotdog) resonator in the centre.

Which option is more likely to work? I don't want to put in a resonator if it's not going to solve my droning and same with changing out a brand new muffler for another that will possibly drone the same anyway.

Do mufflers have a running in stage? I'm hoping if so it might quieten down in a week or so... But I might be kidding myself here?

From my understanding its the way the pipe bends over the rear diff in the AWD's that makes them drone so easily. I dare say the easiest solution would be to change the the rear muffler to something quieter, but I'm really no expert on the situation, I haven't modified the exhaust at all on mine to know what works with these and what doesn't.

Perhaps throw either Alscall or FamilyWagon a PM, I know both of these blokes have spent a fair bit of time doing exhaust work on their AWD's, they might be able to give you some friendly pointers. Alscall's exhaust I know has a pretty decent note to it and doesn't really seem to drone in cabin at all, been a while since I've been in FamilyWagon's so I can't really remember what his setup is like.

What muffler did you get? Might be worth changing it to something larger (and hence quieter). Not sure if a resonator would do much for the drone - even the stock Sports/VR-X exhaust is supposed to have a slight drone at the 2200-2400rpm mark (it's just barely noticeable since the muffler isn't loud).

Leave it a few weeks mate until its bedded in a bit. My muffler did the same, after a bit the drone almost dissapeared

I have the stock sports muffler and it droned untill I fitted HM headers. The drone is not from the rear section. The pipe does not go over the
diff but under the diff. The rear bank piping makes a horrible 180deg about-turn bend (folded overitself) which is the source of the drone and power drain. The HM headers have a nice smooth bend and no more drone plus you get the power/torque that was robbed back.

Don't bother with hot dogs etc. Nothing at all will stop that drone mate.
Hate to say it but the only way you will get rid of the drone is to change the muffler.
If you want quiet again then go back to a stock muffler, or if you want a little bit of note and a very slight drone which is bareable, then go a genuine sports AWD muffler.
I know paying $400 odd for a new muffler sounds harsh, but trust me mate, it is the easiest/cheapest solution.
I have spent many thousands of dollars and wasted so much time going back and forth to a exhaust shop, its not funny.
At the end of the day, the best combo for an AWD for performance and note is HM headers, then stock right through to a Genuine Sports Muffler as found ofn the GTV AWD's.

Dave, i also was told to wait for it to bed in a little to quieten down but it only got louder as i have experienced with over 6 different mufflers i have tried on my AWD.
It is very hard to get a good note out of the AWD because of the pipeing shape but the best is as said earlier, HM headers, stock centre section inc cat and geniune sports muffler.

Mine has a slight drone but as many will tell you, its by no means noisy. When cruising at 80 or 100, the car is silent. No exhaust noise at all, just when you load it up a hill but even then, its not loud and sounds great.

The bedding in of the muffler can take up to 3 weeks, depending on how often the vehicle is driven & how much packing is in the muffler itself.

What size muffler did you get fitted? Was it a stainless or mild steel one? You'll need a pretty large one there to help with the drone. (Think 5" x 11" x 22" at a minimum. Yuu'll fit, at a squeeze, a 6" x 12" x 22" muffler in.) Was the muffler a 'brand' one? Or a cheapie, that may have a dubious amount of 'glass packing, leaving it pretty useless for anything?

What else has been done to the exhaust system? Or is it still stock? There's not much that actually fits in there without losing ground clearance - if that's an issue? A louvred resonator will help, if the louvres are pointing towards the engine, but you'll lose a bit of flow/ performance. They'll still help with the drone if pointing opposite direction, just not as much - although flow will be marginally better. Hotdogs will help, if you've got nothing else there, but go larger than the factory ones, at least 2x 15", although you should be able to get 1x 18" plus 1x 15" in there. (I run 2x 15" in mine & whilst drone isn't an issue the exhaust isn't the quietest!)

Getting headers fitted, regardless of brand, will also help. Hurricanes work for me, HM's for others, but they do help with reduction of drone overall. HM's are stainless & use the factory heatshields etc, whereas the Hurricanes are mild steel & don't use the heatshields. Up to you which way you go, I suppose $$ will be the factor. Both work & until someone shows me the same car doing back to back runs with a set of each headers I refuse to accept/believe one is better than the other.

The genuine AWD sports muffler is the same that is used in all VRX's & can be bought here 2nd hand from Madmagna - you'll just need to get the pipe work chopped off, (if it's a FWD model) & replace it with the AWD pipe to the flange. You may need to replace the tip as well - but will still be certainly a lot cheaper than $400+ for a new one from Mitsu.

Bear in mind, though that the factory system does drone anyway, even if it's only marginal & you'll never truly eradicate it. If there was more space to fit a centre muffler, it'd be a whole lot easier!

Spot on Ascall, I don't know why people by-pass the factory Sports/VRX/GTV/GVTi muffler. It is actually cheaper direct from Lukey (I actually got one for my old KS for $90 but that was because my brother worked there once).

Hey, thanks for the information everyone. It has actually quitened down quite a bit now. Still a little louder than I would have liked, but nowhere near as loud or droning. I do prefer my exhaust to be quiet, so I may still change it in the future, but it's much better than it was. I'm planning on getting the HM headers so with any luck that will quieten it down a tad in the cruise and still leave it with a nice burble.

I guess I was a little to hasty to change it after just a few hours

The burble will be more pronounced with the HM headers.