Hey everyone! So I’ve had a magnaflow tru x in replacement of my rear-center resonator and then swapped my mufflers for flowmaster bottle resonators. Let me tell you it sounds amazing, but the drone is absolutely terrible. I’ve already installed sound deadening material all over the car and it helped but not by much.

My question is what do you guys suggest I do next? I wanted it louder than stock but DO NOT want drone. Mild drone is fine, but nothing terrible. I guess I just want a balance between both. Not the loudest, but not any obnoxious drone either.

i was looking at magnaflow and borla mufflers to swap the bottle resonators, but didn’t get which one to go with.

Also I’ve had this setup since last November and I cannot stand it now. It’s Undriveable for me

 

I would say to find yourself some offset 50 series mufflers by flowmaster. That should keep the exhaust flowing freely and give you an increase in exhaust note volume, but drop the drone that you have.

If you are still having issues, then you may want to consider trying to angle the exhaust towards the ground to let it drive itself into the ground and be absorbed there.

 

I’m looking at this one, what do you think? It claims to have almost no interior noise, which is what I’m looking for

 

You need some turbo style mufflers out back or have a some that have valves that open up so you get the loudness when you open it up but can close the valve and it will go through the it’s chambers to be quiet. I would take measurements and see what fits and go through the summit racing and Jegs catalog for what fits. Straight flow with no resonator is a recipe for disaster when it comes to drone. I’m not a fan of flow masters when it comes to flow for high HP and boosted applications.

 

I was thinking about that, but I just want something simple and want to keep it close to OEM style. I’m sold on the flowmaster mufflers Thermo told me about, I just need help weather I should get Offset OUTFLOW or Offset INFLOW. Thank you for your help!

 

After years of experience modifying exhaust systems including both my XFS and XFR I have learned two things if you want to prevent or at least minimise drone but still get good sound, flow and performance:

1. Do NOT delete any resonator(s) in the system, that is why they are there, to minimise drone. At the very least if you chop out the resonators then replace them with others.
2. If you must have "straight through" rear mufflers (for flow/performance reasons) then get the biggest you can that will physically fit. Biggest in all directions to maximise volume.

Like the OP I fitted an H-pipe and small straight through after-market rear mufflers to my XFR, it sounded great under WOT but the drone was unbearable. Not real bad from the driver's seat but one day I sat in the back while SWMBO chauffeured and it was 'orrible. I whacked the stock rear mufflers back on the next day!

 

i definitely agree with you on this one! Learned the hard way lol

 

Sounds good but those 50series don’t flow so well, I was always a fan of the sound flowmasters made in 80s and 90s car but engines are making a lot of power and that chamber technology only goes so far. Mind you the stock mufflers are likely chambered but more of turbo style chamber.

Take a look at some flow comparisons. I’d take a Dynomax super turbo over a flowmaster any day. You need insulation to tame the drone. Empty chamber mufflers are marginal, albeit 50 series are quieter have you seen a cutaway of the paths the gases must make to exit, again for high performance boosted mills they only go so far. But if sound is all you care for that might do the trick.

https://www.corvetteforum.com/forums...mparisons.html

 

Supercharged Jag, yes, that would do what you want. Like was said, measure and get the biggest that you can. Stick with the offset inlet, centered outlet. I have had good luck with my Flowmaster muffler on my truck. Been using it for 20 years. Granted, the Jag is a different beast.

 

+1 on the Dynomax. Flowmasters have always had some type of drone, no matter what you got, IMO.

 

I left both the stock crossover, and resonator in place, and just put a set of Borla muffs on. Got exactly the throaty sound I was looking for without excessive drone or vibration in the cabin. My favorite place to hear it is when my wife leaves the house and is motoring around the subdivision before pulling out on the main road. Such a statement of power along with the luxury!

Note: I first tried deleting the rear resonator, but the drone was unbearable. Leaving things all stock back to the new Borla mufflers was the way to go for me. The shop I use was nice enough to test fit three different Borla examples up to the car, and run it on the lift, so I could hear the differences and select the one I wanted. Dynomax also sound great, I used to run them on an old Corvette.

 

Ths only issue I see with Dynomax is its over 18 inches long. The space for the muffler on the car is max 17.5 inches roughly. The flowmaster is 17.25.

I have an appointment with my muffler guy on Friday to see what the exact measurements are.

Thanks!

 

That's literally what I was thinking about trying lol! I was gonna put my original resonator back in place and just mess with mufflers.

Which Borla mufflers are you running?

 

If you are willing to put back the stock resonator you will be in a better place to run straight flow mufflers. Magnaflows and Borla ProXS are a good choice. But remember what you hear at first will get slightly louder after packing starts to wear in. The larger the body the better your are off. Also offset inlet outlets will fare better, the sound collides in the inner tube due to the change in angle.

Another choice is to put the stock mufflers back and run cutouts with a mechanical vacuum valve.

 

My apologies, I went back and re read the specs for the Dynomax and the actual body length is 16 inches which is perfect. I was looking at the overall length (end to end), which was 18 or 19 inches.

I will confirm with my muffler guy on Friday and update back here.

Also, the other great part about the Dynomax is they’re cheap! $90 for both!!!

Thank you!

 

Only one stainless option is offered on the super turbos, Aluminized ones will not last very long. The factory exhaust has a resonator after the cats, almost all resonators are chamber design, so the frequency that produces drone cancel out. If you eliminated the stock resonator you are allowing such frequencies to make it through. The super turbo puts back the chambers to help in that department, but still allows a smith flow of gases with its S shape design. But if you put the stock chamber resonator back the a straight flow with a good size body might work well. Good luck with the outcome, it’s trial and error with exhausts.

 

Thank you very much for your help! I will update back on here frequently.

 

Just to clarify, the resonator behind the cats was not touched, but the one in front of the axle was replaced with a magnaflow resonated x pipe, and the mufflers that connect to the exhaust tips were replaced with (short) bottle resonators which was stupid on my part lol. Then again I have no knowledge of exhausts

 

The silencer before the axle appears to be insulated tubes. Similar to cherry bombs, I’m not entirely sure but they don’t seem to connect internally, my educated guess and just theoretically speaking, is that you might have brought the drone sound frequencies back by using an magnaflow X after the front resonator already took care of it in the first place. Sounds do funny stuff like that. I would scratch the straight flow idea and stick to the super turbos if you want to continue running the X muffler. Unless someone has tried it it’s tough to tell the outcome of modifying the exhaust. And sound is subjective, makes it even tougher.

 

yeah that’s what I’m gonna do is just stick with the turbos since they’re cheap enough anyways. And you’re more than likely right with the drone part, it was dumb on me and I should’ve just swapped them long time back lol. Oh well. I just wanted to clarify what I did

Also you are right about the other resonator as well. It’s just two resonated straight pipes in side. They don’t connect inside.

Thanks!