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View Full Version : What is Dual vs. Semi Dual vs. Single Exhaust




spoonerock
11-21-2005, 03:03 PM
ChargerSXT asked me this question on another thread, so I thought it might be appropriate to address this topic as a separate item:

Spoon,

First, let me say that I am not trying to be a smart a$$ here. I just want to clarify something for my own edification (and possibly others that may also be confused). I am confused about the correct definition of a "true dual" system. :confused: The MOPAR dualy catback system replaces the "Y" pipe (from the OEM single exhaust system) with a muffler that has 2 inlets and two separate outlets that exit through dual resonators and tips. Is that not a "true dual" system? Again, I'm not trying to be sarcastic, so I appologize if my question comes across as such...

BK

I know this is somewhat a confusing subject. One that only us V6 owners seem to have to deal with.......I am by no means a subject matter mechanic expert on this topic, so I would welcome any further clarification or corrections to my limited knowledge on the subject, so here goes:

What is a "true" dual exhaust cat back system?

The goal of a performance cat back system is to create as much free flowing exhaust from the engine as possible (minimizing back pressure on the engine). Less pressure = more HP.

Like our V8 HEMI bretheren, the V6 has two cylinder heads, two exhaust manifolds, and two catalytic converters. A true dual setup creates an independent exhaust system for each engine head. Exhaust passes from the Catalytic Converters to an "X" pipe, then to two muffers that exit to two tail pipes. These systems may, or may not have an additional resonator for each depending on how aggressive sounding the owner wants the system to be.

What is a "semi" dual cat back exhaust system?

The exhaust from the two catalytic converters is channeled into a "Y" pipe that enters a single muffler. The muffler has two exhaust exits that run back to the exhaust tips. As before, these system may, or may not have resonators. A caveat to this scheme would be, instead of a "Y" pipe, the single muffler has two sets of exhaust inlets and outlets.

The reason these system are not available on the Hemi engines is because of increased back pressure on the engine, and resulting reduction in HP.

What is a "single" cat back exhaust system?

The exhaust from the two catalytic converters is channeled into a "Y" pipe that enters a single muffler. The muffler has one exhaust exit that run back to a single tips. Most of the system I have seen for this set-up do not have resonators, so they tend to be very aggressive sounding.

The reason this system are not available on the Hemi engines is because of increased back pressure on the engine, and resulting reduction in HP.


So here is the $100K question.....Why are there so few "true" dual exhaust systems for the V6?

With out knowing for sure, I would speculate that the V6 doesn't generate enough exhaust (or back pressure) to require one. Put another way, you probably wouldn't get much more free flowing exhaust to add any additional significant HP.

With all that said.......a "true" dual set-up looks and sounds cool, but there is a performance ceiling that the set-up cannot take advantage of because of the engine.

The "semi" exhast set-up looks cools, and takes full advantage of the performance gains, but may be less aggressive sounding because the exhaust note (exhaust pressure) is divided by the two tips.

The "single" exhaust set-up looks wierd (yes I admit it), but sounds very cool while enjoying the probable same performance gains as the "semi".

Don't know if this makes things any more clear, or if the waters are now more muddied? :happy:




BetoMXL
11-21-2005, 04:39 PM
Excelent explanation... thnks!!!

Kim+Charger
11-21-2005, 06:48 PM
Thanks for taking the time spoonerock. I have learned something today.

charger Bill
11-21-2005, 07:37 PM
Spoonerock: The only thing I would add is that on the Mopar "semi" dual system they do not use a single in dual out muffler but a single in single out muffler that goes thru a "Y" pipe into 2 tail pipes. Other than that your explanation should clear up a lot of questions.

Paradog
11-21-2005, 08:26 PM
Spoonerock: The only thing I would add is that on the Mopar "semi" dual system they do not use a single in dual out muffler but a single in single out muffler that goes thru a "Y" pipe into 2 tail pipes. Other than that your explanation should clear up a lot of questions.

With that being said...would ChargerBill's setup be a less attractive option due to the increased back pressure on the engine? (if that question made sense I might have actually learned something about engines today!)

charger Bill
11-21-2005, 10:53 PM
Paradog: Having been in the high performance industry for the last 25 years I have learned a little about that subject. Companys like Magnaflow & Edelbrock both feel with fairly stock engines that they can make more horsepower with a single exhaust than with a true dual system. This would hold true until you get very high horsepower engines with long duration cams and/or large displacement. It than becomes a matter of having a large enough exhust system to handle the larger volume of air, though for maximum performance some back pressure is needed. Hope this clears this up a little.

spoonerock
11-21-2005, 11:16 PM
Spoonerock: The only thing I would add is that on the Mopar "semi" dual system they do not use a single in dual out muffler but a single in single out muffler that goes thru a "Y" pipe into 2 tail pipes. Other than that your explanation should clear up a lot of questions.
Help me out here Charger Bill! Look at ChargerSXT's decription of his Mopar exhaust system below:

The MOPAR dual catback system replaces the "Y" pipe (from the OEM single exhaust system) with a muffler that has 2 inlets and two separate outlets that exit through dual resonators and tips.

Do you think Mopar might have differing versions of their system out there? I wouldn't think there would be a significant difference between the two variations??

charger Bill
11-21-2005, 11:39 PM
Spoonerock: Not sure if there are 2 systems or not. Only thing I found was that my dealer and a dealer in Upland both found 2 part numbers, but one was prefixed by an "E" which would make it a replacement part, according to the parts guys. I know for sure my system came with the single inlet and single outlet setup. Also someone, whom I don't remember, posted some photos of the Mopar system and it also was single in/single out type muffler. I might try to research this some more thru my guy in Upland. I also have a friend who is a field rep. for Mopar, I might give him a try also.

ChargerSXT
11-22-2005, 06:49 AM
OK,

First, mad props to spoon for explaining things for me. After reading your initial post and then Charger Bill's post, I have to admit that I was thoroughly confused. So, once I got to work this morning, I had to go out (in the rain and with a thrown-out back) to take a look under my car at my MOPAR exhaust. Needless to say, I am quite embarrassed with myself. :embarrese When I looked, I noticed that I was incorrect with my initial assessment/description of the MOPAR system. It is, in fact, as Charger Bill states, a single in/dual out muffler. The original "Y" pipe is still there. I don't know how I missed that the first (and only time...until this morning) that I really looked at the entire system. I even went back and looked at the pics that I posted of my system. Knowing what I do now about it, I can make out in one of the pics that it is in fact a single inlet muffler. My only excuse is that I must have been on an emotional high when I picked up the car and looked at the system, and I wasn't paying attention to it when I took and posted the pics. :nervous s

I appologize to all for any and all confusion. I'll go back into my corner now.... :silenced:

ChargerSXT
11-22-2005, 09:04 AM
I now have a question about the MOPAR system. I had originally thought that I might remove the resonators sometime down the line if I wanted a louder system. Now, I'm thinking that I would see about having the "Y" pipe and muffler removed and replaced with a "X" pipe, and have only the resonators in place. What do you think that setup would be like (sound, etc.)? Also, especially for those of you in VA, would that setup pass state inspection?

OU812
11-22-2005, 09:29 AM
The X pipe is only going to insure a even balance on the pressure & flow. I am not sure that we would gain much with the V6's. What do you guys think?

ChargerSXT
11-22-2005, 09:47 AM
Maybe that would be a good thing to do when I install my new Paxton supercharger... :wink:

JBthe3rd
09-09-2006, 01:42 PM
Paradog: Having been in the high performance industry for the last 25 years I have learned a little about that subject. Companys like Magnaflow & Edelbrock both feel with fairly stock engines that they can make more horsepower with a single exhaust than with a true dual system. This would hold true until you get very high horsepower engines with long duration cams and/or large displacement. It than becomes a matter of having a large enough exhust system to handle the larger volume of air, though for maximum performance some back pressure is needed. Hope this clears this up a little.


what about if you install a CAI ....does this hold true?? ..becasue i have a SE and i was thinking about the "SEMI" setup with a cold air intake or would that be pointles ???would the cold air intake ad a better sound or horse power and would the extra airflow be pointless ?

ZMagnum
09-09-2006, 09:21 PM
The X pipe is only going to insure a even balance on the pressure & flow. I am not sure that we would gain much with the V6's. What do you guys think?

I recently read somewhere that V6 engines are even firing. The gains from and "X" pipe on an even firing engine is unknown.

I know that my dual Zoomers are not as loud as a single Zoomers pipe probably due to the amount of exhaust generated. But just from my own observations there is quite a bit of exhaust coming out of both pipes at idle.

arfur
09-12-2006, 06:35 AM
The X pipe is only going to insure a even balance on the pressure & flow. I am not sure that we would gain much with the V6's. What do you guys think?
Also aids pressure wave tuning/scavenging - so the X pipe has benefits (if designed into the system and not just chucked anywhere willy-nilly). :)