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Straight Pipe vs Muffler on 806 361


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Any thoughts on running an 806 D with a non turbo 361 with just a straight exhaust pipe instead of a muffler.  I am mostly interested in the effect on the engine - better/worse performance & potential damage?  We have pretty nice noise reduction headsets & plenty of free pipe in our shop.  Any ideas or thoughts are greatly appreciated!

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Not sure exactly how a straight pipe might harm an engine?    Should just lower temps slightly from free flow exhaust.   Wil harm your ears though unless you a diligent with those headsets.

Actually I did read a VERY interesting book about sizing exhausts once (back in the 460/454 days) - where a properly sized exhaust results in a moving column of air that almost self-scavenges the engine.  While too small of pipe results in high back-pressure, too large a pipe  actually results in a column that just starts/stops - also raising back pressure!   Made a lot of sense, as it follows basic principles of fluid motion.   But this was on the topic of large gas engines and longer exhausts (like a RV).   I doubt if its very applicable to 3' long straight pipes out the top!   It does make me laugh whenever I see one of those teenagers with the 6" exhaust pipe on their jacked up PU though!

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Not an 806 but a friend of mine used to pull a 560 diesel that was hopped up a little bit.  He pulled it twice one night at the same weight once with a muffler and once with a straight pipe.  He went farther with the muffler. I know its not scientific, but interesting.

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We have a straight pipe on our 856.  Its primarily used for tractor pulling, which is good, because I wouldn't want to listen to that thing bellar and bark all day long for field/farm use.

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25 minutes ago, Dirt_Floor_Poor said:

There are people that claim that a straight pipe will harm an engine. I’ve never seen any evidence of this “damage” whatsoever or any person who has ever provided any proof. 

The only real damage is if there's no raincap or cover over top of the straight pipe, and the tractor is left outside exposed to the elements, and moisture is allowed to run down the pipe, into the manifold, and then in turn into whatever exhaust valves are open at that time.

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59 minutes ago, Dirt_Floor_Poor said:

There are people that claim that a straight pipe will harm an engine. I’ve never seen any evidence of this “damage” whatsoever or any person who has ever provided any proof. 

I always heard that straight piping a DV-550 in a 1468 or 1568 would ruin the valves because they cooled too fast when the engine was shut off. I don’t know if raincaps would help, the whole story might be science fiction as far as I know. My 5488’s are straight piped and I don’t think it’s caused engine damage. But they are not NA engines. 

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Straight piping a naturally aspirated diesel will only cause damage to your hearing.  Many years ago we did all of our corn silage chopping with a 766 diesel. That is a power hungry application, so my brother, looking to get every hp out of that 7, put a stove pipe on instead of the muffler for the season. What a miserable cackle that makes. 

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1 hour ago, ihrondiesel said:

I always heard that straight piping a DV-550 in a 1468 or 1568 would ruin the valves because they cooled too fast when the engine was shut off. I don’t know if raincaps would help, the whole story might be science fiction as far as I know. My 5488’s are straight piped and I don’t think it’s caused engine damage. But they are not NA engines. 

I put over 4,000 hours on a 1568 with DV550 and strait pipes. Never hurt the motor but when I got a 5488 to replace it my life was much improved. 

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Our little three banger D179 has a home-made exhaust pipe.  It uses 18" of 4X4 3/16 wall tube for a muff with 2" pipe in and out. Heavy built for mowing hedge rows. The stock muff and pipe only lasted for the first hedge mowing job. Under  slung so there is no worry about water intrusion.  Sound good to me and all the noise exists behind the operator anyway. I personally like under slung exhaust if the job will allow it, started in my early bam-slang-pow  Deere days.
 

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I prefer mufflers on naturally aspirated engines and straight pipes on turbos.   The only exception is the hydro 100.  To rev the engine up to the proper range for the hydro is way too loud for a straight pipe!

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           I had a straight pipe on my 806 and ran a 4/16 plow with it for a few yeras when I was younger. I finally put a muffler on and like it much better now.

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Doesn’t cost much to try it each way, since you already have the pipe.
We have an 806 with a large turbo on it and it is the best sounding tractor on the farm, with a straight pipe. More whistle, and deeper tone than a 414/436 with a turbo and straight pipe. We put mufflers on them, but the 806 stays straight.  Bought an 856 with an M+W turbo, not as large or free flowing as the Schweitzer on the 806. 856 had the original muffler on it….so I put a straight pipe on it hoping it would sound close to something like the 806. But it wasn’t even close. Totally different. Loud, more like non turbo tractor than anything else.  So I put muffler back on it. 

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Our machines must be pretty close…..so our opinions, or our ears anyway, are just different.  I didn’t care for the tone of mine with just a chrome pipe on it. (But Im keeping pipe in safe spot….just incase)

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I have spent the majority of my adult life looking at the back side of a chrome straight pipe on my 966.

Guess I was used to it, didn't think it was that bad. 

A couple of years ago I bought a 1486. 

Kinda semi retired the "9"

After feeding with the 14 all winter I crawled in the 9 yesterday to bank windmill tanks. 

Now I know it is NA vs Turboed but holy buckets, that 966 is loud now. 😄

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I always figured if I straight piped a tractor I would do the exact same thing Maynard did!  I did run a 4 ft long 2 inch diameter chrome straight pipe on the '39 H for a short while, but about all we did with it was get an occasional load of hog feed from town 5 miles away, haul water to the hog lots, mow & rake hay & straw.  It got replaced with a stock Farmall 460  muffler, which got transferred to the SH till the bottom rotted out.  I do have two nearly new Stanley mufflers off the M & SH I will never use, both tractors have 2 ft long stainless 2-1/2" pipe and rain caps. For as little as I run them a straight pipe is fine. And those short straight pipes fit under my short roll-up shop door.

     I did straight pipe my '96 F-250 with 7.3L PSD,  when I finally removed the "catalytic converter" as people called it and replaced it with 3-1/2" aluminized muffler tubing it really started sounding nice.  THE truck was only a couple months old when I took the muffler and tailpipe off and welded up a side exhaust pipe that exited right ahead of the right rear wheel. I drove it 24 years and 300,000 miles that way. Once the "Cat" was gone it had a great whistle, no drone, no hum, still had stock down tube, it sounded so nice around 2000 rpm I'd run with the passenger door window open an inch or two even in Below Zero temps, that truck had a great heater!

     SON put an after-market down pipe and a 4" aftermarket exhaust that exits behind the rear wheel.  I GUESS he hit his shin on my exhaust outlet, it stuck out 8-9 inches so I didn't soot up my Alcoa wheel! I only cleaned soot off it once.  Guy was standing outside when I pulled in the lot at work and idled to my usual parking space, He Hunted me up and claimed my truck sounded like a semi, and he liked it.

     I read a book on engine tuning too, 2 stroke racing motorcycles.  A too small exhaust not only reduces performance but substantially increases piston temperature, which can stick piston rings, makes pistons brittle, I cracked a chunk off a 125 CC piston once running a slightly too hot spark plug,  but running it Wide open way too long, the piece of piston and ring got chewed up in the engine and ruined the needle roller rod bearing which pretty well ruined most of the engine. Took a second O/S piston & rings, new conn rod, new crankshaft crank pin, half a new crankshaft, new seals & gaskets, probably should have got some new crank bearings too.  It actually got rebuilt TWICE about 3 months apart.

   On an 806 diesel I'd put a 3 maybe 3-1/2 ft long chrome straight pipe with angled outlet aiming ahead or to the side but partly forward, whatever size fits snuggly on manifold outlet pipe. Probably wouldn't be that much loader than the stock muffler.

 

 

 

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When dad had a cab put on his 806 in 66 the dealer put a 4' straight pipe on it. I blame my being hard of hearing a lot on that tractor with the old Full Vision Cab with the doors tied open and that straight pipe blareing. We put lots of hours on that tractor and when i got the 856 it never had a straight pipe until i had a m&w turbo put on it and it was not bad at all

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i have read somewhere that on straight pipes for top performance, was to put the pipe on then run the unit hard and where it turned  the pipe blue that is where u cut it off.

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8 hours ago, rustred said:

i have read somewhere that on straight pipes for top performance, was to put the pipe on then run the unit hard and where it turned  the pipe blue that is where u cut it off.

That's about as good of advice as the old racers wives tale about cutting off a header collector at the white ring that forms inside of the pipe.
But, after you run it hard again, there's a new white ring just ahead of the outlet.

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On 5/9/2022 at 3:42 AM, Maynard said:

That's about as good of advice as the old racers wives tale about cutting off a header collector at the white ring that forms inside of the pipe.
But, after you run it hard again, there's a new white ring just ahead of the outlet.

well i am sure if you keep using a new pipe to see where it turns blue the blue will be in the same spot every time. so if its cut at the top of the blue what more do you want?  i have seen for my self the pipe just dont turn blue it entire length.  so your saying if you install a new pipe the same length as the one you cut off it will turn blue lower down , as yes it has to. run with out a pipe and you see flames, put a pipe on and you dont see flames.

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On 5/6/2022 at 1:12 PM, Dirt_Floor_Poor said:

There are people that claim that a straight pipe will harm an engine. I’ve never seen any evidence of this “damage” whatsoever or any person who has ever provided any proof. 

  I believe that thanking comes from valve failures with bad manifold gaskets. That would be on something like a gas burner straight truck with sodium filled valves. The type that would have manifolds glowing orange when you came off the road and opened the hood at night. If you turned the engine off, it kicked back and sucked cold air past the gasket, that could bust an exhaust valve.  Not a concern with our tractors.

  

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