Exhaust Mod on my 3725

   / Exhaust Mod on my 3725 #1  

Slowpoke Slim

Elite Member
Jan 6, 2017
Bismarck, ND
Husqvarna YTH24V48 riding mower, Branson 3725CH
Well it's no secret to the regular visitors to the Branson forum that I've been less than happy with my stock exhaust particle filter. I was having constant issues, mostly in the winter time, with not being able to keep my particle filter from clogging up. Most of this was due to not running it with a load on it in winter time. Normally not an issue in summer time, as I run a 6 ft brush hog, which puts enough load (with the warm weather) to keep it clear. But just putt-putting around in winter pushing snow doesn't work the engine, it just loafs along pushing snow. It's the hydraulics and weight of the tractor that gets the work done in winter, not the engine power.

So in winter time, I estimate probably 25-30% of the run time hours on my tractor were taken up just roading my tractor up and down the back roads, trying to put a load on my engine, and get the filter hot enough to burn the particulates out of it.


I was finally able to locate a local exhaust shop that was willing and able to do a little custom surgery for me. I dropped it off yesterday after work, and picked it up tonight after work.

One of my primary requirements for this mod was it had to be a direct bolt in replacement, and I wanted to have the option to put everything back to OEM stock if the need arose (trade in or sell type thing-I'll never put it back just for my own use). Or, I can at least offer the OEM parts to whomever the next buyer would be, so they would have the option if they wished.

I had originally found a replacement tractor muffler locally with a 90 degree inlet pipe on it, that according to the book was for a 2 liter diesel Oliver tractor. I thought the 90 inlet would help with fitting the replacement into the tight quarters against the firewall. The shop that ended up doing the work thought that this Oliver muffler was too small in chamber size, would be loud, and likely burn through quickly due to its small size. After the shop did some measurements, I went to the store looking for a larger replacement and returned the Oliver muffler. The one I found, is a Stanley muffler, P/N: IH-4 in case anyone out there is looking to duplicate what I had done here.

I did stay and help the exhaust guy take the hood off when I dropped it off. I would say its "possible" to do it with the hood on, but not very realistic. With the hood off, there was plenty of room to get at everything easily. The guy doing the work said it was a pretty easy and straight forward job to do the mod.

Here are the obligatory pics:




The OEM flanges on the exhaust manifold, and the bottom pipe were not touched. New pipe was bent to line the inlet and outlet of the muffler up and new matching flanges were welded on. Exhaust shop even belt sanded the new flanges once welded to the pipes, to make sure they were perfectly flat for a good seal. He even painted the muffler (I hadn't asked for this, but thought it was a nice touch), which now looks like it could be a stock configuration. He also did a very good job tying back the wires from the harness. You have to really look to see them, and they shouldn't cause any issues. I fully plan on removing the entire harness, including the data logger, but I confess I plan on waiting until its much warmer out to do this (unheated garage).


On initial startup with the new exhaust, the very first thing that jumped out at me was I was really surprised with the volume of exhaust gas pressure coming out of the bottom pipe. I had nowhere near this much pressure at the outlet pipe with the OEM filter in place. This leads me to believe that my filter must surely be at least partially clogged. There is also a noticeable cloud of smoke on cold startup. Like a "traditional" diesel tractor would have. After a minute this does clear, and I couldn't notice any smoke in the exhaust. The exhaust also no longer smells like newborn puppy pharts, but smells like a traditional diesel tractor engine. No better or no worse than any "pre-tier emission" tractor in my opinion. Also, with the data logger still connected, it is currently flashing the particle filter warning light on the dash. It is my understanding that once I disconnect this data logger from the harness, that light will go out and stay out.

I noticed an immediate improvement in power and pedal response when pulling out of the exhaust shop and loading it on my trailer for the trip home. The pedals were "snappy" again. I did a little bit of snow work when I got home, and can confirm a legitimate performance gain over doing the same function just a couple of days ago.

Side observation on the filter itself, I was surprised on how heavy my filter is. Feels like it weighs at least 50 pounds. And the outlet pipe is heavily caked in thick layers of soot. I may try to see if I can find someone with one of those video camera probes that I can stick in the inlet and outlet pipes, just to see what it looks like in there. More just for my own curiosity than anything else.
   / Exhaust Mod on my 3725 #2  
Congratulations for the successful surgery, hope she runs good for you.
Was she any louder with the muffler instead of the filter?
My 8050 puts out a quick puff of smoke when she starts also.
The only other time I have seen any smoke was following my brother in it going down the road and pulling a grade,
just a tiny bit of a haze just before he down shifted.
   / Exhaust Mod on my 3725
  • Thread Starter
It's probably a little bit louder, but not bad. I'm not sure if I chalk that up to the muffler itself, or the exhaust is just unplugged now. Mine was very quiet with the filter on.
   / Exhaust Mod on my 3725 #4  
Awesome! That turned out really nice and clean! Still has a nice factory look.
I have been meaning to do this to my Branson but haven’t had time or just haven’t clogged my DPF yet. Did they make custom flanges or did they source those from somewhere? That would be the only thing holding me up right now.
I was just going to remove the DPF and make a pattern off the factory flanges.
   / Exhaust Mod on my 3725
  • Thread Starter
These were common off the shelf flanges that the exhaust shop had on hand.
   / Exhaust Mod on my 3725 #7  
Great job! Thank you for the excellent write up!
   / Exhaust Mod on my 3725 #8  
if i were you i would take that old filter and bust out all of the filter screen material as it is made of platinum
   / Exhaust Mod on my 3725 #9  
That's a really nice job! They could sell those as a bolt-on kit. I'm sure they would sell a lot.

Actually that looks very close to the original exhaust on the non-DPF Branson tractors. Here is a picture of one:


Please keep us updated if you notice any performance changes whenever you get more seat time.

Must feel nice to be able to idle the tractor more now and also not having to run stupidly high RPMs and burning much more fuel just to keep the DPF happy.
   / Exhaust Mod on my 3725
  • Thread Starter
Looking forward to using the 540E setting on my PTO again for mowing this summer. I had given that up previously in an effort to keep the filter hot (by running higher engine rpms while mowing). Hopefully can save some more fuel this way, + less overall run time.

But for now, we're supposed to get some more snow Saturday, we'll see if it actually shows up or not. Maybe 6 new inches coming.