The local expert muffler shop installed a 30x7x4" Magnaflow diesel muffler yesterday afternoon. It sure feels like it breaths a lot better. I noticed a difference in throttle response just pulling out of the lot. I decided to stick with the OEM 3.5" down pipe for now; not sure if I'd actually end up loosing some low end grunt without bombing by going with a 4" down pipe...

Noise is pretty minimal in the cab. In fact, crusing at speeds below 2K rpm, it might be more quite than the OEM exhaust. There is a bit of a harmonic disturbance from 2000 to 2200 rpm on the freeway (70-75mph). It's not really a drone or resionation, but it is a little annoying. I'm going to open up the OEM air box with a 3" black plumbing adapter (home made ram air ) and install a True Flow (made by UNI) foam air filter, which may reduce the noise (and improve power ;D)

Just an FYI...if you looking for an Amsoil type foam air filter, Midwest Specialty Products has the True Flow for $54.59 w/free shipping this month (coupon code 122503). Amsoil doesn't have a filter for the 03 & 04 CTDs yet...
http://www.midwestspecialtyproducts....e=5.9L%20Turbo

 

Nice choice on the muffler..

 

That's what I have. I like it too.

 

Ok, i know i have a 2cnd gen truck... but i just couldn't help but notice your post Monkeylips.
I too just had a new exhaust put on my truck (Walker muffler) two weeks ago and i also noticed a huge difference in throttle response...in fact the truck is SO much more peppier now that i was going to write a post asking Why and how my truck , just out of the blue could seem so much stronger when i haven't done ANYTHING except change the exhaust!
... i mean, after all, it's just the exhaust(new pipe and muffler from cat back)
does it *really* make that much difference, or am i just imagining things?!?

 

Those dang OEM mufflers are so restrictive that they are almost a plug. Automakers build them to keep the exhaust super quite. The only way to do that is to super compress the exhaust in the muffler. Some engines require more compression (restriction) that others.

I had a 2002 GMC HD with a 6.0L. It had dual 3" exhaust into a single muffler. On the outside, it looked like a dual 3" in/3" out that dumped into a monster 3.5" tail pipe. After cutting it apart, you could see that on the inside it necked all the way down to a single 2" before exiting in to the 3" tube, which dumped into the 3.5" tailpipe. The second 3" exit tube was a dead tube. They called it a resionation chamber. Man was that thing a real plug!

Edited by Moderator

 

Monkeylips how much did the muffler cost and were did you get it??


[quote author=MonkeyLips link=board=49;threadid=23300;start=0#msg218687 date=1070643557]
The local expert muffler shop installed a 30x7x4" Magnaflow diesel muffler yesterday afternoon. It sure feels like it breaths a lot better. I noticed a difference in throttle response just pulling out of the lot. I decided to stick with the OEM 3.5" down pipe for now; not sure if I'd actually end up loosing some low end grunt without bombing by going with a 4" down pipe...

Noise is pretty minimal in the cab. In fact, crusing at speeds below 2K rpm, it might be more quite than the OEM exhaust. There is a bit of a harmonic disturbance from 2000 to 2200 rpm on the freeway (70-75mph). It's not really a drone or resionation, but it is a little annoying. I'm going to open up the OEM air box with a 3" black plumbing adapter (home made ram air ) and install a True Flow (made by UNI) foam air filter, which may reduce the noise (and improve power ;D)

Just an FYI...if you looking for an Amsoil type foam air filter, Midwest Specialty Products has the True Flow for $54.59 w/free shipping this month (coupon code 122503). Amsoil doesn't have a filter for the 03 & 04 CTDs yet...
http://www.midwestspecialtyproducts....e=5.9L%20Turbo
[/quote]

 

MonkeyLips,
I also have a 2004 HO 48RE. Man that stock muffler looks huge and I had no idea changing it would give a seat of the pants difference! I cruise a lot at about 75, right where you mentioned the noise. Hmmm. I like the sound of that big locomotive under the hood but ....
Also, I wonder if your highway mileage will improve.
Wetspirit

 

The muffler shop (Boise Muffler; the local hot rod guys) charged $200.00 for the muffler and install. They are a Magnaflow, Flowmaster, & Dynomax dealer. They had to use a couple of 3.5" mandrel bend pipe pieces to align the head pipe and muffler. They did a nice job. I thought the price was pretty good. They spent 1.5 hours working on it.

Try Magnaflow.com for dealers in your area...You can also search the Web for Mangaflow mufflers if you want to install yourself.

I understand the mpg should improve 1-2 mpg. I haven't driven it enough to verify that claim yet. The noise at 70-75 really isn't that bad. All 4 of the 5.3L and 6.0L gas GM engines had worse drone with the most quite after mkt exhaust. I guess I'm getting old. Plus, I have a head cold, so that's probably what is causing the annoyance.

We (my family - wife and 2 kids) are taking a day trip tomorrow. They will let me know if it's too much. The last truck I had seemed loud to me, but they couldn't even tell I changed the exhaust. Maybe I'm hyper-sensitive, or again, just getting old ;D

 

[quote author=MonkeyLips link=board=49;threadid=23300;start=0#msg218687 date=1070643557]
The local expert muffler shop installed a 30x7x4" Magnaflow diesel muffler yesterday afternoon. It sure feels like it breaths a lot better. I noticed a difference in throttle response just pulling out of the lot. I decided to stick with the OEM 3.5" down pipe for now; not sure if I'd actually end up loosing some low end grunt without bombing by going with a 4" down pipe...

[/quote]

I dont think you will ever LOOSE grunt by going bigger exhaust on a turbo motor.

 

Sounds like a pretty good deal going with the Magnaflow muffler. Maybe my first BOMBing mod.

MikeyB

 

I did the same thing some time back...just had them cut out the stock muffler and splice in the Magnaflow. Sounds like you have the same one. I like the sound, wife does not. I also had
them weld on the 5" polished Magnaflow tip..looks great.

 

Yeah, that's pretty much what I had done, no tip though. We just go back from our trip up to the mountians. No one noticed any difference. The only time it gets really noticable is when I get my foot in it. No one said a word, so it must not be that loud in the cab.

 

[quote author=03CTDCO link=board=49;threadid=23300;start=0#msg219168 date=1070725624]
I did the same thing some time back...just had them cut out the stock muffler and splice in the Magnaflow. Sounds like you have the same one. I like the sound, wife does not. I also had
them weld on the 5" polished Magnaflow tip..looks great.




[/quote]

This is also the one I have. 4" turbo back.

Mike

 

I dont think you will ever LOOSE grunt by going bigger exhaust on a turbo motor.
I've heard that Mangnaflow says to stick with a 3.5" down pipe unless going with heavy bombing, but they could be refering to the gen 2 trucks. Anyway, I decided to stick with the 3.5" until more information is available...

 

Correction- my down pipe is stock.
Mike