Straight pipe on a NHC-250

[scooter01922]

A straight piped cummins 5.9 is a sweet sound. Really nothing else quite like it

 

[jwaller]

I ran my 818 straight for about a day after I sold my muffler. dont do it unless you have to. it's loud. about 150db's if I had to guess. does nothing for performance either. have I have an egt.

 

[StreetbikeDepot]

So did your EGT drop any? I didn't figure it would gain any performance, I mostly wanted to know if it hurt it any with no back pressure from a muffler or turbo?

I ran my 818 straight for about a day after I sold my muffler. dont do it unless you have to. it's loud. about 150db's if I had to guess. does nothing for performance either. have I have an egt.

 

[StreetbikeDepot]

A straight piped cummins 5.9 is a sweet sound. Really nothing else quite like it

Not only does it sound good, but it runs like a scalded ass ape too. 05 2500 2wd auto tranny with straight pipe with AEM intake, BullyDog Power Pup with Crazy Larry download, needless to say it would boil the hides off of it from a rolling start! Not much could hang with it, stupid fast.

 

[jwaller]

So did your EGT drop any? I didn't figure it would gain any performance, I mostly wanted to know if it hurt it any with no back pressure from a muffler or turbo?

didn't drop any egt. didnt raise it either. same old 25,000lb slow truck.

 

[StreetbikeDepot]

didn't drop any egt. didnt raise it either. same old 25,000lb slow truck.

LOL.....I think I would be completely happy with that truck if it had a different tranny, a Roadranger would be nice. My biggest beef is the RPM drop between gears, kinda sucks when your pulling a load up hill from a standing start at the base of a hill.

I guess while on the subject.....has anyone known of a succesfull tranny swap in a 5 ton?

I bet there would be a length problem with the transfer.

 

[ARMYMAN30YearsPlus]

I need to work on my M818 when I finally get home and I plan on welding in replacement parts and patches if the metal is still solid enough. I can do a lot of that with a wire feeded before I fork over $400 plus shipping and disassembly reassembly work. I am just hoping my wife has not thrown away the fuel selector switch I ordered and my son did not scrap the slave cables I ordered as well. It is hard being a country boy married to a city woman.

 

[DaveP]

I gutted the muffler on our XM818 when I installed the pyro.
No idea if it helped anything but it really barks! ear plugs are a must. I wear them anyways whenever runing these down the road.
the inside of the muffler had a screen of sorts that looked like it would limit the flow. no more.

 

[WillWagner]

Everyones definition of loud is different......have any of you owned a Dodge 24V 5.9 cummins that was straight piped? I do and it sounds great (ofcourse it dumped at the rear of the truck....LOL), people outside hold their ears when I throw the coal to it though!

855 cubes is ALOT more than the puny 359 cubes the MoPar has. Mucho more noise!

 

[StreetbikeDepot]

855 cubes is ALOT more than the puny 359 cubes the MoPar has. Mucho more noise!

That is true!

 

[bbf]

i cant hear anything in 813 with a stock exhaust its so loud

 

[poppop]

I blew the whole end out of mine on a trip to North Ga. By the time I got home $400.00 for a new muffler was not a problem.

 

[Andydieselpower]

I've always wondered what the NHC 250 would sound like without the muffler. Some engines such as a Ford NA 7.3 diesel without a muffler in my opinion actually sound worse and more gas engine like. Make sure you get a sound clip of this modification after your install. I figure if you are going to wear earplugs while driving might as well make your vehicle REALLY obnoxious.

Andy

 

[98hd]

I was thinking about doing this as well, mostly for EGT's when the fuel gets turned up. Although it sounds like there isn't much gain to be had.

For those complaining about noise, you could gut it and pipe it out back by the tires like the 5-ton gassers.

One thing I HATE about the original muffler is that it is huge and takes up alot of space under the hood.

 

[StreetbikeDepot]

i cant hear anything in 813 with a stock exhaust its so loud

See thats whats wacky.....my 818 is just the oposite, its fairly quiet, way quieter than a deuce. I can talk to the passenger if need be and my muffler is even rusted out some in the bottom.

 

[No.2Diesel]

A friend of mine in my ATHS club has a 49' Mack LJT with a stock NH-220 (743ci) routed to twin stacks w/no muffs.

Ditto to what DaveP described: It barks!! I think it sounds great and it isn't that loud. At idle it burbles and is pretty quite.

I would say go for it!

(the 819 w/400 will be run with no muff)

 

[M1075]

Here is a shot of an M813 with chrome pipes

 

[FreightTrain]

Ewww,that is sweet!!!!!even though I bet the Port pipe does't smoke any.Look how they T-ed off the main pipe.If your going to twin stack it then try to keep the pressure even in each pipe or you will have one stack smoking and one just sitting there for look....and will look goofy.As for straight pipes,I say go for it.Loud pipes saves lives.Louder is better to me.If push comes to shove,try one of those $20 weld in race mufflers(basically a ring with holes stamped in it that welds inside the stock pipe).No more than what those things actually are,they do change the note a substantial amount on a 2.3L I4 Dirt track motor.

 

[StreetbikeDepot]

Ewww,that is sweet!!!!!even though I bet the Port pipe does't smoke any.Look how they T-ed off the main pipe.If your going to twin stack it then try to keep the pressure even in each pipe or you will have one stack smoking and one just sitting there for look....and will look goofy.As for straight pipes,I say go for it.Loud pipes saves lives.Louder is better to me.If push comes to shove,try one of those $20 weld in race mufflers(basically a ring with holes stamped in it that welds inside the stock pipe).No more than what those things actually are,they do change the note a substantial amount on a 2.3L I4 Dirt track motor.

I kinda thought the same thing....I can always put a resonator on it if I wanted too.

Not sure what to say about the chrome stacks though.....not my taste.

 

[StreetbikeDepot]

Here is a shot of an M813 with chrome pipes

DANG! anyone else notice the front duals!