Well I finally bit the bullet and decided on a 51 inch Nelson. I was worried about drone when towing and didn't want to do it twice. I like the straight pipe osund but not the drone. I called NAPA and they cross referenced a muffler to the Nelson. When it showed up it had a baffle (shouldn't have had one). But after looking at it I figured I could open it up with a sledge hammer and pipe. The baffle was an extension of the perforated pipe, that was crimped in four places to close it off. That then opens up into a packing free area that is the resonator. After about 30 minutes and two pieces of pipe and a modified piece of wood I finally got it opened up completely. I paid $65 to have it installed. Sounds great! Nice rumble at idle and quiet with no drone cruising. If I get on it, the sound really comes out - definitly noticeable from the cab. I also have a 5 inch slip on stainless tip. I went ahead and removed the silencer ring and muffler from the turbo. You can really hear the turbo whistle now - sounds like a big rig. Overall one of the best mods I have done. Very satisfied. The egts have dropped about 150 deg. when stomping on it and spool up seems to be quicker.

 

sounds good, what year truck do u have?

 

It's an 03 HO. No cat - didnt have one from the factory that year.

 

yea, i miss my 03 cause of that

 

deere nut:
i ordered the donaldson 51"...i think its the same as the nelson. i dont want any drone what so ever. do you have any drone at all? i think the donaldson also has the center piece your nelson had and i wonder if i can knock it out or if i have to leave it in?

 

I left my baffle in unknowingly and haven't had any problems or drones what-so-ever. Course I don't have guages yet so I couldn't say if my temps have dropped any. Mine sounds as quiet as stock on the highway.

my .02
Jamie

 

I bought my 51" Nelson 86131M Muffler from a Cummins Atlantic shop near Kenley NC right on I-95. The 86131M does not have a baffel it is 4" in and 4" out. When you look in one end you can see out the other end. It has a nice sound and does not have a drone even when I pull my 10,000 lb. travel trailer.
I had to shop around for a muffler shop that would install it for me. It does hang down a little, but I painted it with high temp. black paint so it is not very noticeable.

Bill

 

Bill,
Did the kitty fall off or do you have the muffler on with it? if so, does it still have a nice rumble outside?

 

thanks deere nut...guess if my muffler comes with a baffle its getting knocked out...good to hear all drone is gone, cause i HATE it!!!!!!

 

I still have my cat.

 

Absolutely no drone even with the baffle opened up. Louder than stock at idle and cruising but not a whole lot.

 

Does it sit where the original muffler was (I know it's longer), and what is the diameter?

 

I just got the 51" Donaldson installed and boy oh boy am I pleased! I wanted to improve flow, thus lowering EGT's and still have a nice quiet ride with better performance and economy. There is no drone anywhere-at all!
I DID leave the perf'd baffle in and see no problem at all. I felt it was better to leave it and not risk damaging anything else inside not knowing for sure the strutcture inside.

Just FYI, for those looking to decide between Nelson or Donaldson....the flow rate of the Donaldson is higher than the Nelson, with the baffles left in, so that is another reason I left it there. I believe they are both great choices.

Overall, this is the best mod I have done for well under $200.00 on any vehicle I have ever owned. Nice "sleeper" kind of setup....quiet when light footed, but comes alive much better than stock with more rumble from the back end, but not overbearing. Turbo seems to spool up quicker too.

Have fun!

 

Look in my gallery , I did the 41 in Donaldson , straight thru flow 4 in. in and out. and tuck up as far forward it could be located. sounds great and no drone. I believe the number was a 85171 , I could find it again if anyone wants to know. very high flowing numbers.

 

Yes it does sit where the stock muffler was. The stock muffler was an offset oval style and the Neilson is a round straight style so the installer had to let the front hang down a little to get everything to fit right. Like I said I just painted it black so it is not very noticeable.