I need to get an exhaust system for my truck. I have put it off for a long time because I haven't been able to hear any different systems. There just aren't any Duramax's around with 4" exhausts.

First and foremost I want something that is not too loud. I don't mind a bit of a different sound or a bit more rumble but I don't want it to be abnoixious and I definately don't want ANY drone at all in the cab. I don't want it to sound like crap or like a 16 year old kid drives it.

The only exhaust system I have ever heard anyone say that it was queit was when Mike L was speaking of the TTS exhaust. Can anyone give me their experiences with the TTS exhaust? Currently TTS doesn't offer a cat replacement pipe (to my knowledge) so I will have to use another manufacturers pipe for that (Probably MBRP). So keep in mind the fact that I will not have a cat on my LLY.

Does anyone know of any other systems that will meet my needs?

Sound clips? :uhoh2:

I've driven a TTS equipped truck, been in another TTS truck, and it's pretty subdued. Didn't notice any drone. If quiet is what you seek, you should be happy with it.

I have a TTS exhaust on my truck. It works fine. There is a low rumble at idle and it is louder than stock (but not by much). Once under way you barely notice the exhaust has been changed. This exhaust system will not interfere with any conversations you would have in the cab.

The TTS exhaust as installed on my truck has a very slight drone from 1600 - 1800 RPM. It is not loud, but it is there. There is also a naturally occuring drive line resonance at the same RPM on my truck. Maybe my ears are more sensitive to this than others.

The TTS exhaust uses a Donaldson 85171 muffler. The specs for this muffler can be found here:

https://dynamic.donaldson.com/webc/WebStore/search/item_detail.html?section=10210&item=22723

This is a commercial heavy duty muffler. Very similar in design to mufflers used by large OTR diesel trucks. The muffler has very low restriction as you can see in the specs and barely fits in the confines under our trucks. If this muffler is too loud for you, it would be possible to substitute a quieter Donaldson muffler that is designed for the DMAX, Cummins and Powerstroke diesels as shown at this link:

https://dynamic.donaldson.com/webc/WebStore/search/item_detail.html?section=10210&item=235839


I hope the above helps.

My front pipe back mbrp is pretty awesome...I think the in cab noise level is very acceptable and I have no drone. The kennedy system sounds like a winner as well. There is sound clips of this one...I am gonna try and find it and post the link....give me a minute.

I found it

http://dieselplace.com/forum/showthread.php?t=20845&highlight=bmdmax

The TTS exhaust uses a Donaldson 85171 muffler. The specs for this muffler can be found here:


While Donaldson does make our muffler it is not a 85171. It is a custom muffler built for us by them. We do use some of the off the shelf parts within the muffler to keep the cost down but it truely built to our specifications. We spent close to a year with Donaldson to get the noise level the way we wanted it and try to keep the cost down. By useing some parts they already had in high production it allowed us to get what we wanted.

The part number stamped on the muffler is 85171 (at least the one I have). Not sure if they make variants off this part number. It sounds like they did for TTS, as Steve mentions above. Maybe they used the case from a 85171 muffler. Anyway, it looks to be well built and of commercial quality. Donaldson is a large company that builds many exhaust products for OTR trucks, etc.

I am very happy with the Banks. Not loud and no drone. Installs very quickly. I still have the CAT on mine.

The lly in general has a much more subdued tone to it. BMDMAX has done some nice audio clips for me, and now after his 2 truck trek (too long for his trailer) to Suncoast could comment on the sound differences.

I am very happy with the Banks. Not loud and no drone. Installs very quickly. I still have the CAT on mine.
Judging from past threads it seems as though the trucks equiped with cat's are the ones that report no drone. Seems like all the other systems w/o cats do experience some amount mid RPM drone. I guess it depends which are worst and what can be tolerated. Some do appear to be much better than others. Might be a good idea to run a poll on the different brands, listing with and without the cat and put it out there as a simple Yes/No question. Drone or not.

Sound is such a subjective thing it would be hard to make a decision for yourself based on other peoples opinions. Many moons ago, I did a noise study with a decible meter. We were trying to open a motocross track near the city and while wandering in peoples back yards I showed the home owners (with the DB meter) that the sound of the sprinkler hitting the window or door was noisier (subjective term) than the bikes in the distance. One of the homeowners was a former mayor who opposed the track and his pool house was 3 times noisier than the bikes but all he heard was the bikes.

Judging from past threads it seems as though the trucks equiped with cat's are the ones that report no drone. Seems like all the other systems w/o cats do experience some amount mid RPM drone. I guess it depends which are worst and what can be tolerated. Some do appear to be much better than others. Might be a good idea to run a poll on the different brands, listing with and without the cat and put it out there as a simple Yes/No question. Drone or not.

You're probably right. I picked up a minor drone when I removed the cat and just ran the stock muffler.

The solution is probably a resonator or glass pack in the intermediate pipe. These have almost no restriction, but they absorb some of the pulses from the exhaust.

I also have the TTS flange back exhaust and have been pretty happy with it. It was louder than stock between 1600-2000rpms, but moving the tip in a bit moved it to 1800-2000rpms. Steve had mentioned that some people have been able to "adjust" the sound by moving the tip, which did work for me. I purchased a front pipe from Mark Craig as well as a resonator and installed it in the front pipe to get rid of the extra noise. There is enough room to do this without clearance problems. The 1800-2000 rpm noise, droan, whatever you want to call it was reduced, just did not happen right away, took a couple hundred running miles... The exhaust is very quiet now and I am very happy with it...:ro)
Bob

Maybe they used the case from a 85171 muffler. This is exactly what we did as well as a few of the interior parts from other applications. The final design uses parts from three other mufflers they produce in high volume and only a few special parts for us. This really helped keep production cost down.

Geo - I agree about the subjectiveness of sound. For instance I live fairly close to Lake Erie and the sound of dozens of wave runners can drive me crazy. Not loud, just annoying. (Please, no angry PM's from the wave runner crowd!) Someone with an unmuffled big block or a Harley can rumble by and it doesn't bother me a bit. Psychological tolererance........

Truck configuration has its effects too, regular cab, Xcab, crew, long box and short box. I have a Xcab short box with a 4" exhaust, I rode in a Xcab long box with the same exhaust, the sound quality/drone in the cab was noticable better in the long box. The muffler being further from the cab, or maybe just the extra length of pipe changing the natural frequency of the system?

I have the TTS, I initially logged approx 2500 miles with the TTS and factory cat. I was concerned about the increased noise level while towing a trailer(13.5k lbs gross) on vacation. Although I noticed a slight increase in exterior exhaust noise know one traveling with me noticed or complained. Upon arriving home from vacation I installed a 4" Dynomax intermediate pipe, again a slight increase in exterior noise and little if any increase inside the cab. Quieter than than a stock 04 Powerstroke, both inside and outside.

Max Power,

If you remove the cat you WILL get more noise period, no way around it! We sell tons of MBRP every day and get no significant noise increase on an LLY if the cat is left in place, no matter what system you get if you remove the cat you will hear it some.
Give us a call and we will be glad to help you with questions.

I would suggest you get the system without the cat test pipe and then see what you think. You can always get the test pipe and add it at any time.

Mark @ DPPI

I understand removing the cat will increase noise but the LB7's had no Cat so it can't be too drastic. The cat is gone no matter what.