Muffler Question

[afp]

My budget needs to recover before I can consider adding an complete exhaust system. I am wondering if there is a muffler out there that will reduce backpressure significantly from the stock muffler. My goal here is better off-idle turbo response and better mileage.

Here's my take....If a freer flowing muffler on the factory exhaust will give me say 60% or more of the gains of a full system, then it's worth it to me to do now. If the "muffler only" won't do that, I'll just wait.

To that end, is there a muffler out there that will do what I want and if so, which one?

Blaine

[tmg115]

you might what to put a straight pipe in. it costa around $30 to do.

[DMAXDiva]

afp:

tmg115 mentioned straight-piping as an option, and it certainly is an inexpensive alternative to a 4inch aftermarket system (I have straight-piped my own truck). However, I have found that the noise is just about unbearable (the resonance at 1900 rpm drives me crazy at steady speed!). Accordingly, I have ordered a 4inch system which should arrive in two weeks (if I can wait that long :rolleyes: ). I do think I saw a Dynomax 6inch muffler that works with the stock setup in a magazine; you might check their website. Another good place to look for muffler options might be the Summit Racing catalog. One thing's for sure, trashing that monstrosity of a stock muffler will sure help no matter which way you go!

[SoCalDMAX]

A lot of the exhaust kits use a straight thru louvered muffler by Allied. Dynomax also makes a similar design bullet style muffler - check Summit for these. I've heard that these mufflers do a surprisingly good job of cutting down the sound, considering you can see right thru the center of them.

Regards, Steve

[ 06-27-2002: Message edited by: SoCalDMAX ]</p>

[Kennedy]

The key is to get the offset incorporated within the dimensions of the OE muffler. With it only being about 25 long and about a 6" offset, that is easier said than done...

[DmaxMaverick]

Simple solution?

Decide which exhaust system you will eventually buy. Purchase only the muffler and adapt it to your current system. When you are ready to upgrade to the new system, order it without the muffler.

It may cost a little more in the long run, but much less now.

[Kennedy]

Since all of the exhaust systems that I am familiar with use a straight through muffler, and the OE system uses an offset, this can be an issue. Couple that with adaptation from 3.5 to 4" and back down and, well, you get the picture...

[afp]

Well I solved the muffler question. Had a SS Magnaflow installed today. It has the 20" body and 4" tubes. They had to use the reducers (3.5" to 4") to fit it to the stock exhaust. It was an easy installation.

According to the tech guy at Magnaflow, the muffler is 75% of the restriction in the Duramax exhaust. He also said the stock pipes were really pretty decent. No doubt, an upgrade to 4" pipes later on will help a little bit, but for now I'm leaving it as is. The tech also said there wasn't any point in having a larger downpipe.

This is the best of both worlds for me. I keep a fully SS system without having to pay big bucks, and get the majority of the benefit of a freer flowing exhaust. If I ever decide I want the 4" pipes, I'll be able to keep the muffler.

The sound isn't bad. It's a little more throaty and deeper under acceleration, has a slight resonance at 55ish (but no louder than engine noise), but the wind noise takes over at about 63 mph and you can't hear the exhaust anymore. To be honest, it has a rather smooth and pleasing sound. The engine is more responsive and the Turbo does spool up quicker. It accelerates noticably harder at WOT. I'll get to check MPG in a few days. The problem is my truck only has 1100 miles on it, so the mileage and power will increase anyway as it get's broken. Those I know with a lifetime of diesel experience tell me not to expect the best power or mileage for at least 10K miles.

Blaine

[ 06-28-2002: Message edited by: afp ]</p>

[FirstDiesel]

Model number??

[4meseb]

afp,
I too was on a low budget alternative to getting a 4" system. I ended up getting a Dynomax 6" muffler and a magnaflow tailpipe.
Here is a link to where I got the idea.
http://forum.62-65-dieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=001437&p=
Instead of buying the 3.5" pipe, I had the guy cut off part of the tailpipe to make up the difference of the offset and the shorter muffler. I bought a MagnaFlow Tailpipe that was 4" that came made for a 2 1/2" pipe. We just cut it off where we needed to, To make it fit over the existing tailpipe. Total cost for everything and install was $120.
Just my $.02 and I definitely like the sound.
Scott ;)

[afp]

First Diesel,

Here is the website--scroll to the bottom of the page. My local shop used 14771 with two reducers on my truck.

http://www.bestautopartsonline.com/diesal.htm

Blaine

[pepperidge]

AFP,

Was that where you bought it from or were you able to get it cheaper through your local shop that did the work.

Thanks,

[afp]

Pepperidge,

I bought it from the local shop. I happened to be going through the yellow pages when I found a shop that handled Magnaflow mufflers (I had decided I wanted a straight through design like the Mangflow or Dynomax). I also saw they worked on Diesels. They had the muffler and trasition pipes on hand. They charged me $291 installed. On the website I gave, the parts ran about $195. $97 for labor is in the ballpark, so my local shop didn't do too bad. Also, I was hooked by the fact that I could get it done today and quit schemeing about how to do this!

Other options.......
www.a-1performance.com offers an aluminized 4" Dynomax system for under $370ish (not installed), but I wanted stainless. Also, that price is so much under the others I am a tad suspicious. The stainless systems I'm interested in are running $800 plus (like the Banks)--unless John Kennedy's $575 system is stainless.

Blaine

[Idle_Chatter]

afp, do you mean that the muffler replacement was a simple cut and clamp operation? If you can just cut out the stock muffler and install the replacement with two adapters and four clamps I'd love to do that for my truck! :D

[afp]

Idle,

It was a cut and weld operation. If I was more practiced with my small MIG welder, I might have tried myself. It took the guy about 30 minutes to install. He cut the old muffler out "inside" the factory hangers, then welded in the muffler and reducers. I'm not sure clamping would be a good idea (been that route before), as welding is more secure and much more leak proof. The new muffler is on angle due to the offset location of the factory pipes. In fact, it roughly follows the frame line as it slants up toward the rear. It looks fine--when you look under the truck everything looks like it was supposed to be there. The new muffler is no lower at the front than the stock muffler was, and since it angles up along the frame you actually gain clearance as it you move aft.

Blaine

[Idle_Chatter]

Thanks for the added info, afp. I guess I'll have to shop around some of the local custom muffler places about getting a "mufflerectomy!" ;)

[hoot]

I have been driving straight pipe for almost a year now and find no problems with normal driving and sustained highway speeds. Only gets loud under heavy load or acceleration but I experience no resonation issues at cruising speeds.

[01F350SRW]

Hoot I agree

I've got a 5" straight pipe, no drowning sounds or iritating noises cruising, but she'll wake you up when you stomp on it.

Only problem is I have to clean out small animal nest. :D :D

[pepperidge]

AFP,

Do you have gauges yet? I would be curious to see if the better flow of the new magnaflow will reduce egt's enough to not worry about towing with a juice box w/o gauges. I really want a good priced juice box but the box will be all I can shell out for a while so towing with the juice could be an issue(I pull 8,000# daily {well on the three days a week that I do work}) :D :D :D

[afp]

Pepperidge,

No gauges yet, but I have been leaning that way. I'll definitely get gauges if I add a box. I really want the 6th gear next. I actually hauled some stuff in my truck today--about a thousand pounds of rail road ties. My Z-71 would have definitely felt this load, but my DMax just rolled it's eyes at me. It was hard to tell I even had anything back there.

Blaine

[Redhawk]

afp, it might be a good idea if you installed gauges before you make mods so you can get a read on whether what you do later is helping or hurting and how much.

[afp]

Redhawk,

I agree, and plan to install the gauges before I do anything esle. Of course, with hunting season just around the corner, my budget won't allow anything for the truck for a while...

Blaine