Need comments from Magna-Flow owners

[John]

Robert,



After re-reading your last post several times I'm not sure it is clear to you my concern (which may not necessarily be a concern to you). As the 22" long (BODY LENGTH) Banks Dynaflow muffler is installed JUST AFTER (i. e. , downstream of) the mid-ship exhaust hanger (clamping to the FRONT of the Dynaflow muffler on the inlet snout), replacing it with the longer 30" body (36" overall length) of the MagnaFlow muffler will not allow the use of any mid-ship exhaust hanger I'm aware of. The hanger is made to attach to 4" diameter tubing, NOT the body of the 7" diameter MagnaFlow muffler. And, as stated before in previous posts, the extra length cannot be made up to the rear because of the bend where the exhaust system starts up over the axles.



Or, am I missing something? Is your Dynaflow muffler installed AHEAD (i. e. , upstream of) your mid-ship exhaust hanger?

 

[Car_nut57]

John,



I didn't read your first post close enough and focused on the SS systems and not the brand. We actually have found that our 4" aluminized system with 4" down pipe, which uses a Flow Pro muffler is our most popular exhaust system for the Dodge Cummins. It is made of 16 gauge aluminized steel which is mandrel bent. After many installations not one report of any kind of drone problem. The sound level is very close to that of the stock system only with a deeper tone. The Flow Pro mufflers are 24" body length and 30" overall if that makes a difference. Also these mufflers are louvered inside with an expansion area in the center. The Banks and MagnaFlow are straight through using perforated metal core which may be part of the differnce as well.

 

[WTBurke]

I selected Banks SS

Guys STOP me if I'm messing up.

I'm going in Monday morning at 8am to have a Banks SS 4" w/5"tip installed. I looked the system over in the factory box at Chico Truck & RV in Chico CA last week. I was very impressed with the fit and finish including the down-pipe that has the Banks factory emblem etched into the SS (for looks). Dan who owns Chico Truck&RV tells me this is the latest from Banks and he refered to this as the new "Serious Tail" exhaust. He showed me a decal that comes with the package and the text reads, "Serious Tail" with the Banks logo just below the text verbage. I didn't see the words Monster Exhaust?



Am I doing the correct thing? Someone said "they are picky" I'm so anal I should seek professional help? My dog thinks I'm an a$$.



Honest guys looking at this I was drooling all over myself... the overall quality of the componants really hit me hard.



Have I not looked at enough systems? I've been reading every post about exhaust systems sence last Dec. of 01... I'm straight piped on factory plumbing now. I'm lucky my wife said I could... I've been having tantrums for a week she finally broke down Friday and said I could :-{}



I gotta have that big HOLE comming out from behind the rear passenger side wheel... . you guys are all at fault..... you made me do it



William

 

[98rammer]

alright, some want to quiet it down, but which 4" system out there creates a great amount of noise with a muffler? i can't go straight piped and i don't want it to sound anywhere near close to stock! rip rooks is a great price though!

 

[RKrueger]

John,
Makes me wish I had a home page so I could post pictures of the belly of my truck
Anyhow, I reread yours as well, but I cannot detect the difference in our descriptions to understand why we disagree that the MF will fit. OK, I'll try again With my trusty tape mesure in hand, I verified that the OL length of the Banks 22" body is exactly 36". This is exactly the same OL length as the Magna-Flow.
My "downstream" hanger from the muffler, anotherwords, -after- the muffler, is welded onto the tailpipe section and is almost directly over the rear u-joint. The next hanger is -in front- of the muffler, towards the engine. It's not a welded hanger, but clamps around the 4 OD portion that consists of the end of the muffler itself, with the end of the 24" Extension piece inserted inside. Because the MF is a 30" body, that means that there is 3" of pipe sticking out each end, enough to go over the tailpipe at the rear, and over the Extension piece at the front.
Still in all, this is pretty simple. If I have a muffler, regardless of the body length, that measures the same as one I'm replacing it with, it has to fit. The only thing MF told me was I would have to use a 4" pipe-expander to open it up a minute amount to allow the 4" OD Banks pipe to slide in. It's an interference fit right now. If we still disagree, send me your email address to -- email address removed --, and I'll take some pictures with my digital camera of the underside. Ok?

Wtburke,
Well, maybe this is a new system. The Banks outfir has a good reputation, so maybe they have modified the original Monster Exhaust for the better, and renamed the whole package. I'll check it out on the web.

 

[RKrueger]

FWIW,
Trying to help Banks resolve this noise problem, I have done two weeks of research into muffler and resonator design. I have spent literally hours on the phone to various people involved in silencing exhaust systems. Here's the result.
While any flow-through will always be a little louder than the normal redirected flow type of muffler (standard muffler ), there is a design configuration which has proven to be the most efficient type. When I saw the post by Dave regarding Flow Pro, I recognized this as a perfect example.
According to one engineer that designs exhaust systems for a wide variety of industrial applications, the most efficient type is composed of two important considerations.
The first is length. Every engine has it's own particular exhaust pulse length, or wavelength, dpendant upon the cylinder configuration. A V8, like the Ford, produces a shorter pulse or acoustic wavelength. A six cylinder inline diesel, like the cummins, produces the longest pulse, or wavelength. The muffler must be of a length equal to, or longer, than the longest acoustic wavelength that the engine produces, or that portion of the frequency, usually the lowest frequency, exits the muffler with no change. Magna-Flow recognizes this. That's why they supply different length mufflers dependant on the vehicle on which it is to be installed. That is also why they went to a 30" body length instead of a 24", to cure resonance at the low end the customers were experiencing.
This is also why a six cylinder gas engine is more difficult to silence than a similarly sized V8.
The second is the design of the muffler itself. Regarding a flow-through system, the most efficient type is the "muffler within a muffler". As the exhaust pulse ( heated, compressed gas ) passes through the muffler, it is allowed to expand into an "inner chamber" through louvers, or holes of the correct size. This expansion completely alters it's acoustic properties, and shortens it's wavelength.
On the outside of this inner expansion chamber lies a good quality sound absorbing material that absorbs this shortened acoustic signature.
It is important that the sound deadening material be correct, and not packed too tightely. If it's jammed in there, it trasmits the sound instead of aborbing it. This is how the FlowPro is designed. However, it is vitally important that the length be correct, as well as the dual chambered design, as they complement each other to break up the exhaust pulse and deaden the sound. This design, if done properly, is also the most expensive to produce, which is why most don't.
The resonator is a perfect addition when trying to attain the most reduction in noise. It's design is even simpler still, but similar. A true resonator is a louvered or multi-holed grate, surrounded by a empty chamber than allows the heated, compressed gas pulse to expand prior to entering the muffler. A resonator, properly designed, will lower the entire broadband noise level a minimum of 3 - 6 db.
This the information I have given Banks, but I doubt it will have much, if any, effect on their design, but I hope I am wrong.

Like I said, FWIW

 

[Big White Beast]

I had a drone that would deafen......

I had the Jardines exhaust with the magnaflow muff. Had to add a resonator to kill the drone. Didn't like the sound afterwards. Now this is a heavy truck 11K lbs. daily. Load increases drone.



On the 02 I installed Rips 4" exhaust but mounted the muffler forward of the middle hanger right after the first straight piece. I figured if that's where a resonator works why not just put the muffler there. No drone from that truck and I really like the sound of the Allied truck muff.



So I put one on the 01. Took off the resonator and muffler from magnaflow and mounted the new allied forward and also have no drone now. I do believe it's placement more than what type of muffler. If you can get your system apart try moving the muffler first. I bet that will knock out your drone issue.



Garrett

 

[RKrueger]

I have no doubt you are correct. That's probably one reason why the Magna-Flow's are reportably drone-free, as they mount their muffler in the forward position also. I also realize, and I've tried to convince Banks' of this also, that there is too much open pipe length from the turbo to the muffler, which is the ideal setup for harmonics, or "drone".
Where did you get this Allied muffler?

 

[Big White Beast]

Rips the man.........

He made me a new straight section and sold me the muffler. I needed the section after taking out the muffler resonator combination.



The allied has little half moons inside the flow pipe. You can mount it two ways and the sound will be different. I've only tried it with the moons facing back because I wanted it louder. If noise outside the truck is a problem you could try it the other way.



Garrett

 

[John]

William (Burke), although I have one of the earlier Banks Monster Exhaust systems (well all except for the Dynaflow muffler... NOW), they do produce a really nice stainless steel exhaust system.



However, MagnaFlow produces a higher quality, better sounding exhaust system, period.



Robert, I believe (as does Rip) that two MagnaFlow mufflers (in my case, a 24" long and a 14" long muffler in series) is superior to one 30" long MagnaFlow muffler... and he has the noise data to prove it. The forward mounted 14" muffler was installed for three reasons:

1) to break up the sound signature of the exhaust

2) by placing a second muffler ahead of the first with a pre-determined space separating them, this WILL reduce or eliminate droan over a single, strategically placed muffler

3) I have 38" of muffler (combined) whereas, the 30" supplied muffler is only that, 30". The only down side I can see is the cost of the two mufflers as opposed to the single 30" muffler.

Either way, all the aforementioned mufflers are of straight through design. Contrary to what others have written on the subject, anything OTHER THAN a straight through design WILL cut horsepower... end of story! And please don't tell me about Flowmaster's secret to horspower success... what a joke! Test them for yourself on any dyno. Although they sound really nice, they WILL lose horsepower!

 

[John]

Robert, after re-reading (again... ) your post dated 8-18-02 @ 3:51 PM...



I have determined that your Banks Dynaflow muffler (the 22" portion of the 36" long weldment) must be mounted AHEAD or upstream of the mid-ship exhaust hanger (which is located near the passenger side rear shock). In which case, Banks changed their exhaust system! The FRONT of my 22" long Banks Dynaflow muffler was JUST behind the mid-ship exhaust hanger. I'm willing to bet Banks found out that placing the muffler ahead of the mid-ship exhaust hanger reduced droan. Rip found that out through his own testing... long ago I might add!



PS: The other reason I decided to go with two MagnaFlow mufflers as opposed to the one 30" long unit (other than what I stated before about not being able to purchase the one with the hangers attached to the muffler body), was because I didn't want to chop and weld the living s**t out of my Bank$ $tainless $teel exhaust system. This way, everything, and I mean everything, worked out for the better!



signed, one happy camper!

 

[RKrueger]

John,
Boy, am I glad we cleared that up Oo.
I couldn't figure out what the difference between the two systems really was. Anyhow, now I'm sure you know how i intend to mount the two MF's. I just received the 14" one today.
And BTW, in regards to Flow Pro as mentioned by another member, I made no claims of performance, quality of the unit, or anything else. The discussion was in the context of design criteria.
The dual chambered design like I mentioned may in fact cause a loss in HP or torque due to the exhaust becoming intercepted and being able to expand inside the inner chamber. It actually does make sense that a power decrease might be a result. But I stand by my point that this is the best type of design for muffling a flow-through system.
I'm going to give your buddy Rip a call after I finish this post, see what he has to say.

Robert

 

[Big White Beast]

Freebie's.......

Speaking of mufflers. I was just cleaning the garage and need to get rid of the magnaflow ones I have.



I'll give the 7" round 24" long magnaflow to anyone who pays shipping. I had to cut slits in one side to get it off. the other side still has a piece of pipe in it, it will come out with a work. Best used if you weld your system together.



The resonator is 13½" and oval. I'll take $10 and shipping for that. It was installed with strap clamps and has good ends on both sides.



Niether has very many miles on them.



Garrett



EDIT: they are gone, thanks all who replied.

 

[RKrueger]

Hi John,
Quick question. When you coupled the 14" MF to the 24" MF, how much distance between the two is there? I'm going to install the 14" in front of the Banks muffler on Monday to see what difference it makes, if any. If I don't get good results, I'll order the other MF muffler.
I gotta spend the $36. 00 labor to find out.

Thanks,
Robert