Just installed a Donaldson M100465 muffler yesterday. 5" in, 5" out, 51" long. The state of Missouri decided the straight pipe had to go .. although now that it is through inspection it may return.

The first thing I noticed after wedging this muffler under the truck is that it is quiet ... like so quiet I can hear myself think .. which could be a dangerous situation. Also havent experienced any drone in the 100 miles I've put on the truck since yesterday. Performance wise it looks like the egts are up 50-100 degrees but just barely break 1000 degrees under heavy acceleration and high-ish boost (25-30 psi stock hx35). Spool up and throttle response doesnt seem to be affected. I'm driving to indiana this afternoon so we will find out how it does mpg wise.

 

how did the state find out was during a truck inspection or did you get pulled over just curious on what their parameters were for you having to do this duu inspection i get it now but do they just say thats to loud or do they measure the decibals[ wo pretty fancy word for a redneck] just wondering

 

Vehicles in Missouri must be inspected before you can get your license plates renewed .. my plates expired and as such I had to get an inspection. If you have a good common sense mechanic they will usually pass a diesel even if it doesnt have a muffler due to the turbo ... however those mechanics are pretty much extinct in Columbia, Mo so I had to put a muffler on my truck.

As far as I know they dont test the decible level, just do a visual check to see if the muffler is there or not, then they check for exhaust leaks. If I get really wound up and hell-bent to go around the rules (happens from time to time) I may punch out the center of the muffler and weld a section of straight pipe in ... flow and sound of a straight pipe but hey look, it has a muffler it cant be straight piped

 

hey thanks for the info so if you run a straight pipe through them thats good as long as it looks like you have something there

 

I had one of those on a 2006 Mega Cab and loved it. You could pull a trailer and not have that drone make you crazy!! Awesome muffler and cheap too!!

 

Hay now this is top secret information, i suggest not putting it on the internet or the GOV. might catch on haha

 

Grass now hay later ...

Right now I'm not ambitious enough to modify the muffler .. more likely I'll switch over to the donaldson muffler w/ straight flow design ... I like that this muffler kills the drone the old straight pipe had but I miss the rumble when I really get on it. I've heard that the straight flow donaldsons are a compromise between both worlds.