Exhaust Mod on my 3725

[Slowpoke Slim]

Oh, and I looked at my soot cooker again today. I had it backwards. The heavily sooted up pipe was the inlet to the filter, not the outlet. Kind of makes sense. I may try to take some pictures of it Sunday, depending on what the weather actually does.

 

[450]

Slowpoke, if you don’t mind, what was your total cost? I would like to have a setup like that just in case mine clogged. We really only have a Midas up here and they don’t like doing anything outside the box. It would be nice if you could just buy one.

 

[Slowpoke Slim]

I bought the muffler at a local store for $38. You can probably fine it online, Stanley muffler # IH-4.

Then it was just labor and materials at the exhaust shop. That bill came to $330, includes removing and reinstalling the hood, removing filter, sensor lines, tying back wiring harness, fabricating and welding on a mounting bracket on the new muffler that bolts to the original filter mount, fabricating the inlet and outlet pipes (needed to be mandrel bent due to tight bends/tight clearance), welding on the flanges, painting the new exhaust, and of course bolting everything in place and leak testing it afterwards.

It was worth it to me, as I can see the quality of this guy's work, both in the welds he did, and the bends in the pipe he made. Kind of hard to explain, but you can tell by looking at it once it's finished.

I'm not sure you could have one premade, without using your own tractor as a template. It's not just the bends and length of pipe, but also the angle and rotational timing of the flanges that has to be spot on, so the flanges seal properly, and the bolt holes line up.

 

[450]

Slowpoke, thanks for the info. I could do everything myself but bend the pipe.

 

[JonnyRed]

Not trying to be a smart azz here, but you could simple gut the DPF and put it back on for no cost. Granted, that would eliminate the opportunity to return it to factory stock if you were interested in having that option. I gutted mine and plugged everything back in the way it was and have no lights on the dash. Smokes visibly at startup and some under labor but nothing unusual.

Btw Slim, that exhaust guy did a **** of a job on your muffler. I would rather have that in my engine bay than a gutted DPF just for the extra room to navigate around in.

 

[450]

I would just like to keep the original one for warranty purposes.

 

[Slowpoke Slim]

Thanks Jonny, I'm not taking it like you're being "smart xxx".

I really thought about it for quite a while first. I guess I wasn't looking at it from the warranty side of things, but more along the not knowing what the future might hold kind of thing. I talked to my dealer several times about it, and he made it clear to me that removing the filter wouldn't do anything to my warranty, and he would have no problem with servicing or repairing my tractor once I did the mod. But I was more concerned with the "what if"... like what if the bozo's in Washington pass another EPA rule that says tractors can't be sold or traded without all their original emission equipment tested and working. May never happen, hopefully it doesn't. I doubt those kinds of rules would be something to worry about in this rural part of the country anyway. Maybe in the big cities, but this is "fly-over" farm country. But my crystal ball is out of charges, and who knows what changes could happen in the next 20-30 years.

What if I decide to upgrade tractors? Go with something bigger, or just different? It would be nice to have the option to hand the dealer the box with all the "stuff" in it and say, "Here, this goes with it." Then the dealer can put it all back on if they want to, or have to because of "rules" at that point. And I don't take a trade in "hit" for not having it.

The more I thought about it, the more I liked the idea of being able to put it all back *if needed*.

I'm certain I won't be putting it back on just for my own use though. That thing can sit on a shelf in my shop until the end of time as far as I'm concerned (unless trading, as above).

And I do get the same startup smoke that you describe on yours. But it's ok with me. Any "pre-Tier" tractor will do the same.

 

[ericm979]

Slowpoke, thanks for the info. I could do everything myself but bend the pipe.

You can buy exhaust pipe bends from Summit Racing (or the local auto parts store or many other sources). Flanges from the same place. It's common to make exhaust systems without a bender that way. More welds but if you make the joints smooth the exhaust does not care. I've seen entire 4 cylinder headers done this way.

When I am buying a used vehicle I value one that's stock (or can be put back to stock) higher than one that's irrevocably modded and requires expensive parts to return to stock. Especially if it's a mod that I would not have done.

 

[Slowpoke Slim]

I wanted to post an update to this thread, I hope this is ok, instead of starting a new thread, and just referencing this one again. I thought this would be simpler.

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It finally dried out enough around here that I could regrade my driveway yesterday. Got started last night after work. Made the first pass with the box blade, rippers down, and cutting a full front blade. Had to put the HST in 1st and engage the front diff when I found a small tree root with the ripper blades (was pulling a full box of dirt in HST 2 at the time). I had no lack of power in HST 2, even pulling along at 1500-1600 rpms, but I did stop the tractor (it didn't stall, just started spinning the one back wheel).

Once I finished the first pass, I flipped the rippers over, set the front blade higher, to not cut, and just let the rear blade do the re-spreading of my pulled piles of dirt. I was back to doing this in HST 2 with the front diff disengaged again. And back to running at 1500-1600 rpms. Again, no lack of power at all.

Anyway, the weather was so nice, low 70's, slight breeze, partly cloudy. I had both side doors open, and the back window open while running, just enjoying the beautiful weather. Since the mod up until now, I've been running it with the side doors and back window closed, and with the fan running (usually with heat).

What I was able to notice (hear) was that my new exhaust definitely has a deeper, resonant tone to it. Especially when running at lower rpms (while pulling the full box in HST 2). Once I changed gears, and upped the rpms the deep tone got a little higher, and the resonance quieted down. I can't say it was too loud, but it was definitely noticeable. And it sounded like a much larger machine working hard. Maybe this is what it was supposed to sound like all along? I don't know, but it was pretty obvious it was breathing deeper and heavier than it ever could have done with the dpf on it (at least mine anyway).

I did make one pass with the cab closed up, and turned the cab vent fan on, and noticed a drastic reduction in perceived noise through the cab.

I did not notice any smoke coming from the exhaust, (other than the start up smoke I get every time I start it), it was running clean the whole time. Even chugging along with the full box at moderate rpm, and when I stopped it on the root. No smoke.

So, summary time. I think if you had an open station tractor, you would notice the "new" exhaust was louder and deeper when under load, especially at moderate rpm levels. But up at max-2500 rpms, it runs quieter, without as much deep resonance to the tone.

If you had a cab tractor, with the cab buttoned up and possibly the fan running, I doubt you could notice much difference at all.

Thanks.

 

[ericm979]

The sizes of the chambers in the muffler and the sizes and lengths of the tubes or openings between them affects the sound frequencies that the muffler suppresses. Unfortunately it's difficult to get that information from muffler companies.