While searching around for either a Donaldson or Nelson replacement muffler for my truck (the stocker outlet pipe rusted out) I found an AP model 3891 -- has same DIMENSIONS as the 51" x 9" round type 1 Nelson and Donaldson, but I cannot find any specifications data on it! They are priced right, at 56.30, but I don't want to get another 320cfm muffler when I could spend 79.50 for the Donaldson and get over 2000! Anybody out there work in muffler shops or ever hear of AP mufflers?? Their website says they make exhaust components for everything under the sun, but the interactive catalogs are all for cars and light trucks, not the Heavy Duty Trucks they also say they make mufflers for. Any help is appreciated!!

 

Well, I called around to all the local muffler shops, and no one has ever heard of AP making truck mufflers. According to the website, they are one of the leading OEM manufacturers of mufflers in the transportation industry, and make a line called TruckEx for heavy duty applications???

The 3rd Gen forums are full of threads for Donaldson and Nelson mufflers, with lots of good data, but I haven't found any crosses to AP. Heck, I don't really know if many people have added a Donaldson or Nelson to a 2nd gen! Straight pipe is too loud, and I prefer the deep, "sleeper" sound the big mufflers give!

I sent an e-mail to the contact address on the AP website, so I will see what I get. The bummer is the shop I found this one at for cheap is about 4 hours away, along the route I have to take for a business trip early next week! Would have been cool to pick up the part while there and save shipping!

 

Well, I bought one to try! I went to Mutual Wheel in Monmouth Il, and the shop attendent took me back to the warehouse and we opened one up. It turned out to have NELSON 8613M stamped on it (no, I am not forgetting any numbers!) Seems that the body at least is the same as the Nelson 86131M, but this one has a crimped over cone like the Donaldson M090544. I also had to give them the Donaldson number for it to cross over, but it came up as an AP TruckEx number 3891. Wierd. Good quality piece it seems, and I will keep posting here how it works out. Oh yeah -- the muffler only cost $59!

 

This muffler rocks!! I had several holes rusted through the stock muffler, and a split starting in the resonator. I used the reciprocating saw to cut off the pipe right at the front of the resonator -- still stock, 3" pipe. The new TruckEx AP3891 replaced the whole assembly -- resonator and muffler -- back to the stock tailpipe location. I re-used the stock tailpipe for now, but will upgrade the rest of the system later when I replace the turbo. Test drive was very impressive!! System is quiet again, but much different from stock. Exhaust tone is much deeper, with more diesel growl than the stock choker allowed. I can't wait to try this system out with bigger pipes, a new VP44, and either a box or injectors!

If anyone is looking for a replacement muffler rather than straight pipe, I recommend this as of right now. I will add to my little one-man thread as I get more miles and some towing trips logged. Stay tuned....

 

post up a link to where you bought it, dude!!

don't keep a secret!