After exhaust work truck feels sluggish

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

faitdushred

Senior Member
Joined
Jan 29, 2013
Posts
177
Reaction score
8
Location
Ottawa, Ontario
Ram Year
2013
Engine
Hemi 5.7
Hey guys I have a 2013 ram QC single exhaust. I had the muffler swapped out for a 14" magnaflow and didnt think it was loud enough so went ahead and removed the resignators. After doing this the truck is a hell of a lot louder in my opinion but I feel as if the truck is really sluggish of the go. I do have a set of 34's on the truck and a level but had that before the exhaust set up and never found it to be noticable. I was driving around in my buddies truck which has same tires and stock dual exhaust and his seem to just get up and go. My question is am i just crazy or could the exhaust actually be dropping my HP or Torque to feel so sluggish.
 

BlkRamRt

Senior Member
Joined
Jul 11, 2012
Posts
1,837
Reaction score
211
Location
SoCal
Ram Year
2012
Engine
HEMI 5.7
Disconnect your battery for about 30min. It should fix the problem.
 
OP
OP
F

faitdushred

Senior Member
Joined
Jan 29, 2013
Posts
177
Reaction score
8
Location
Ottawa, Ontario
Ram Year
2013
Engine
Hemi 5.7
Read somewhere else about the battery thing. Think I might give it a try when I get in from work. They also said something about driving it like I stole it.
 

Casper

U.S. Navy (Ret.)
Military
Joined
Nov 13, 2012
Posts
4,625
Reaction score
1,446
Location
Springfield, VA
Ram Year
2020
Engine
5.7L
If you somehow achieved no back pressure then you might see a drop-off in low end torque, but there is no way a 14" maggy is going to do that.

Not sure you really changed enough of anything for the battery reset of the PCM to make much difference.

It will however make the PCM unlearn your driving habits and that may give you some different shift points for a while.
 

WhiteExpress

Senior Member
Joined
Sep 8, 2011
Posts
18,185
Reaction score
3,275
Location
Midland, TX
Ram Year
2004
Engine
5.7 Hemi
The net result of a muffler change is ± 5 HP.
You wouldn't feel that.
 
OP
OP
F

faitdushred

Senior Member
Joined
Jan 29, 2013
Posts
177
Reaction score
8
Location
Ottawa, Ontario
Ram Year
2013
Engine
Hemi 5.7
That's why I'm so confused as to why the truck feels so sluggish from the go. I thought for a second it may have been the tires but like a mentioned my buddy has the same tires and his truck feels a lot better from a dead stop
 

audio1der

Senior Member
Joined
Jul 30, 2012
Posts
5,300
Reaction score
1,103
Location
Airdrie, Alberta
Ram Year
2012
Engine
Hemi 5.7
Unplug the battery for at LEAST 30 mins, then drive it like you stole it immediately. The ECU learns, so if you drive like an old lady it will keep that in mind.
 

trikeffex

Senior Member
Joined
Jun 2, 2013
Posts
292
Reaction score
112
Location
Hammond,La
Ram Year
2013 sport ram
Engine
hemi 5.7
i swapped my muffler out the 2nd day of owning my truck so i can't tell you with this 1 but i know for a fact in my 08 tundra that it felt better with the stock setup vs the magnaflow catback.Before the catback the truck would pin you in the seat and after the catback install it wouldn't.The sound was worth the little difference in torque down low.I don't think you lost anything.I believe it just shifts things around where you lose a little down low but gain it up top!!

Charles
 

TylerB

Senior Member
Joined
Mar 7, 2012
Posts
1,711
Reaction score
467
Location
FL
Ram Year
2011
Engine
5.7
It's because the truck is louder now. Seriously, it's your mind playing tricks on you, your brain thinks you should be moving faster for the given decibel levels your ears are hearing. That's exactly why your buddies truck feels faster with the only variable being the exhaust between the two of you.
 

Hemi_Express2013

Senior Member
Joined
Aug 4, 2013
Posts
728
Reaction score
375
Location
Nantucket, Ma
Ram Year
2013
Engine
Hemi 5.7
resignators are meant to create back pressure. It's what helps the exhaust gases to be pulled from the cylinders. More exhaust gases pulled, more charged air enters. Backpressure helps torque low in the rpm range. It's always a trade off. Low or high. Think of this as an algebraic equation and your cylinders the equal sign. What you do on one side of the equation must be done on the other side. Keeps everything in balance.
 

TylerB

Senior Member
Joined
Mar 7, 2012
Posts
1,711
Reaction score
467
Location
FL
Ram Year
2011
Engine
5.7
The resonators on our trucks are straight thru design just like Magnaflow. They're not gonna create any "back pressure".
 

Hemi_Express2013

Senior Member
Joined
Aug 4, 2013
Posts
728
Reaction score
375
Location
Nantucket, Ma
Ram Year
2013
Engine
Hemi 5.7
The resonators on our trucks are straight thru design just like Magnaflow. They're not gonna create any "back pressure".

Then they're not real resonators, just noise modifiers. Didn't know that.

A Real resonator works thus When a wave hits the hole, part of it continues into the chamber and part of it is reflected. The wave travels through the chamber, hits the back wall of the resonator and bounces back out of the hole. The length of this chamber is calculated so that this wave leaves the resonator chamber just after the next wave reflects off the outside of the chamber. Ideally, the high-pressure part of the wave that came from the chamber will line up with the low-pressure part of the wave that was reflected off the outside of the chamber wall, and the two waves will cancel each other out. In this process, a stronger wall is created with this escaping volume of gas. Creating increase resistance in exhaust flow. No matter how slight. I'm not an automotive engineer but I think that's the extent of a real resonator.
 
Last edited:

Cowboy345

Senior Member
Joined
Oct 30, 2012
Posts
302
Reaction score
39
Location
Kentucky
Ram Year
2011
Engine
Hemi 5.7
There real resonators lol. They do not create back pressure, if they do it's a insignificant amount. However, what you said about the waves is correct but it's just that, that just alter (quieting,lowering) exhaust note, tone, and loudness. All the back pressure is in the pipe diameter it's self but more so in the muffler. There's not much backpreassure on these 5.7 hemi's. It's ment to be that way. While you do need back pressure to keep from burning valves out and maintaing performance removing a resonator is perfectly fine and you actually probably gain a slight increase in power from it as they do generate a small amount of turbalance.
 

Caldwell

Senior Member
Joined
May 11, 2012
Posts
1,031
Reaction score
178
Location
Philadelphia
Ram Year
2013
Engine
Hemi 5.7L
I look at it in the sense that you didn't lose power, you just adjusted where you feel the power within the RPM range. I bet that truck pulls like a mother up top when you punch it.
 

Hemi_Express2013

Senior Member
Joined
Aug 4, 2013
Posts
728
Reaction score
375
Location
Nantucket, Ma
Ram Year
2013
Engine
Hemi 5.7
I don't disagree with either statements. Im just having a hard time thinking that our resonators are straight thru, not that they're not but whats the point of it. There must be a way that the pressure differential is reflected. Look, its about volume of the entire exhaust system. If you change the volume of gases in the system, you change the torque curve. The OP said he swapped out the school bus muffler and resonators and felt low end torque sluggish response. Most of us have swapped our mufflers out with any low end torque/ responsive issue. I think mine felt great, more responsive. Bu, I left the resonators in. My reasoning was the volume of gases the resonators held was the deciding factor. But if they're straight thru like a regular exhaust pipe, then there's no more loss of volume in gases. MYbe he has a leak somewhere.
 

dodge dude94

Millennial Boomer
Joined
Sep 5, 2013
Posts
27,745
Reaction score
6,426
Location
East Texas
Ram Year
1998 Ram 1500
Engine
5.9 Magnum
2nd gen guy here.....going off of what little I know about 4th gens...BUUUT....aren't the resos mounted on the tailpipes after the axle on these trucks? In which case you could look down the pipes and see.
 

kkreit01

Senior Member
Joined
Nov 12, 2012
Posts
1,133
Reaction score
258
Location
Olathe, KS
Ram Year
2018
Engine
Hemi 5.7
Without a before and after dyno, we can all speculate. However, I felt the same on my previous 4.6L Sport Trac. It had 2 large OE mufflers. I removed them both, welded a Maggy in. I felt like I lost torque as well. I was tempted to remove my resonator on my Ram (already have 22" Magnaflow), but now I think it will stay.
 

Cowboy345

Senior Member
Joined
Oct 30, 2012
Posts
302
Reaction score
39
Location
Kentucky
Ram Year
2011
Engine
Hemi 5.7
I don't disagree with either statements. Im just having a hard time thinking that our resonators are straight thru, not that they're not but whats the point of it. There must be a way that the pressure differential is reflected. Look, its about volume of the entire exhaust system. If you change the volume of gases in the system, you change the torque curve. The OP said he swapped out the school bus muffler and resonators and felt low end torque sluggish response. Most of us have swapped our mufflers out with any low end torque/ responsive issue. I think mine felt great, more responsive. Bu, I left the resonators in. My reasoning was the volume of gases the resonators held was the deciding factor. But if they're straight thru like a regular exhaust pipe, then there's no more loss of volume in gases. MYbe he has a leak somewhere.

They are straight through but there a larger diameter. They do change pressure but they don't create back pressure. Its possible he has a leak which will create a loss of power but it there's a leak it will backfire!
 

JohnD72

Senior Member
Joined
Sep 22, 2013
Posts
776
Reaction score
411
Location
Charleston, SC
Ram Year
2012
Engine
5.7 Hemi
There are so many things wrong with some of these replies, it's beyond funny... and I'm not about to jump in the middle of that fiasco.. lol

I'm more inclined to agree with Tyler's comment. I've seen first-hand how changing the sound of a vehicle can make it "feel" like it's driving totally differently.

I can't tell you how many times I replaced fan clutches on different kinds of cars, when I was a mechanic, and had the owners bring them back complaining that I screwed up the transmission because it wasn't shifting right anymore. ("it revs much higher before it shifts, now")
I actually had to re-install a couple of bad clutches and let the customer drive their car to prove to them that nothing was wrong.
If you somehow managed to modify the exhaust enough to make any difference to the computer (not likely), simply disconnecting the battery as mentioned will do the trick.
 
Top