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Mid-muffler delete??

11K views 13 replies 7 participants last post by  gotzaRT  
#1 ·
Thinking of doing a mid-muffler delete on my 09 r/t AWD. Will doing this hurt the engine in anyway? I'm concerned about losing back pressure and hurting the engine and losing my warranty.
 
#5 ·
At least on my 2014 there is a slight drone at highway speeds when the MDS kicks in, this is due to the gearing in the AWD vehicles, it just so happens to put the RPM right in the sweet spot to drone. I used a tuner to disable MDS (lost about 2-3mpg in fuel economy), when I was researching the issue a while back I stumbled across a few posts that stated you could put it into manual shift mode once at highway speed and it would handle shifting for you... those posts were from a while ago and unfortunately for me that's not the case (downshifts like normal, but it holds the gear when accelerating up to an obnoxious RPM).

Many people aren't bothered by the drone, and to be fair it's not deafening (I've had to point it out to people riding in my car) but it was getting on my nerves. Otherwise I love the muffler delete, it's the way these cars should've sounded from the factory.
 
#8 · (Edited)
I'd be happy to re-enable MDS and record the drone that my car (which has a muffler delete, but retains the resonators) has on my way to lunch today... The 3.06 rear gearing in the AWD Chargers put the RPM right into that sweet spot at about 75-80 with MDS engaged. Your statement is true of the RWD Chargers which have 2.65 rear gearing. Not trying to be argumentative, just want to provide good info, as it's something I wish I was aware of before I removed my mufflers.

Edit: Also, the purpose of resonators is to alter the resonance frequency of the exhaust to a frequency outside of what the exhaust system is capable of producing. In this case, they're not sufficient in altering the resonance of the exhaust system. You could certainly eliminate the drone by using different length/design resonators or altering other exhaust characteristics. It's akin to a musical instrument, it must be properly tuned to sound right. I will agree that running without resonators would most certainly create an unbearable drone, but simply having them doesn't eliminate the possibility.
 
#9 ·
I'm going to reply again, since it occurred to me that I didn't directly address OP's concern very well. You won't do any damage to your engine whatsoever, and if any dealership gives you issues with a warranty claim they're crazy people (it'd be pretty much unheard of). But, yes the muffler delete will reduce exhaust back pressure, which hypothetically could cause a decrease in engine torque. I don't notice any difference, and without a dyno/more info on how restrictive the mufflers are, I can only speculate... but in my experience large displacement naturally aspirated engines tend to have little issue with a reduction in backpressure, and in some cases it even improves performance numbers. Also, you may notice a slight "wobble" in your RPM at idle for a few days after the delete (it's hardly noticeable unless you're watching your rev counter), but the ECU will adjust to it's new "conditions" and smooth out.
 
#10 ·
But, yes the muffler delete will reduce exhaust back pressure, which hypothetically could cause a decrease in engine torque. I don't notice any difference, and without a dyno/more info on how restrictive the mufflers are, I can only speculate... but in my experience large displacement naturally aspirated engines tend to have little issue with a reduction in backpressure, and in some cases it even improves performance numbers. Also, you may notice a slight "wobble" in your RPM at idle for a few days after the delete (it's hardly noticeable unless you're watching your rev counter), but the ECU will adjust to it's new "conditions" and smooth out.
I'm curious. Why would reduced back pressure cause a decrease of torque? It seems counter intuitive. The whole point of the internal combustion engine is it's basically an air pump. Suck the air in (mixed with fuel), burn it, push the burnt product out. Lower back pressure means more efficient scavenging of the cylinder during the exhaust stroke allowing more air/fuel mixture back into the cylinder during the intake stroke. Isn't that what aftermarket exhaust headers and performance exhaust systems are made to do, decrease back pressure to create a more efficient running engine?
 
#11 ·
The mid muffler delete doesn't reduce any power what-so-ever. I'm still doing consistent 0-60's in 5.1~5.2 seconds before and after this mod. The mid mufflers are a pass-through design as is the straight pipes put on in their place. It also doesn't really drone at all cruising along with 4cyl mode or otherwise on my '16 R/T since I left the rear resonators on. You'll get a little drone when you are under medium or heavy throttle but cruising along you get almost zero.