I just purchased an 07 Ram Laramie with the 5.7 Hemi Multi Displacement System. I had intended, as I do with almost all my new trucks, to have a set of custom duals made and installed, probably using Flowmaster mufflers. Then I remembered something. This is my first Ram with the Multi Displacement Hemi....and I began to wonder if when the engine cut from 8 to 4 cylinders the exhaust tone changed dramatically....or if you could even hear it at all.

So my question is: For those of you who have dual exhausts systems, or single exhausts sytems with a more aggressive sounding muffler, and who also have the Hemi Multi Displacement enging...What effect, if any, have you noticed on the exhaust tone/sound when the engine cycles from 8 to 4 cylinders?

Thanks in advance for any responses.

 

I don't have MDS, so I may not be the best suited to answer this question. Anyhow from what I have heard MDS only kicks in when you are at a cruising speed with very low RPM's for a certain amount of time, I don't know all the details. But usally this means it is only going to kick in on the highway at lower RPM's, so I don't think you would really notice it much since your running at low RPM and not producing a loud exhaust note at the time anyway. That's my two cents

 

DelawareDon,

I have an '06 with MDS. I recently had a 50 series Flowmaster installed, replacing the stock muffler. I kept the front resonator and had the rear one removed.

With the stock muffler you never notice the MDS cutting in. With the Flowmaster or any other louder muffler you can hear the MDS cut in. It's not bad and you will get use to it. It is much more noticable when driving at a constant speed between 40 - 60 mph. Switching over to the Flowmaster did not gain me anymore power, just the healthier exhaust note I was looking for.

With the single 50 series Flowmaster, my truck idles quietly and sounds very healthy when pushing on the go pedal.

 

I second what berg501 said,as I have the same set up.

 

I have an '06 with 2 Super 40s and yes you can hear when the MDS kicks in, but it's nothing to not get the exhaust you want on it. It's off and on for maybe not even 3 seconds. If you have the radio on you would probably barely notice it.

 

Mine goes from an allready low rumble to an even lower pitch rumble when the MDS kicks in.

 

With the radio off, nobody talking in the vehicle, and if I'm really paying attention to it, yes I can tell when the MDS kicks in. With the radio on, I never notice.

 

Have a 2006 with MDS and recently installed a Borla exhaust system. Can't even hear when MDS kicks in.

 

I have an 06 Ram 1500 QC 5.7L w/ MDS and I put on the Flowmaster 40 dual exhaust on about 2 weeks after buying the truck. In a word if you have MDS stay away from Flowmaster. On a few other websites the typical poll is that MDS & Flowmaster owners hate it when the MDS kicks in. Even with the Series 50. The guys who have Magnaflow and Aero Exhaust seem to have great results mainly due to the design of the muffler.

After doing quite a bit of research I've got an Aero Turbine 3030XL on order and will have it installed in about a week. This one has the built in resonator so that I can get rid of the noise inside the cab (which is not great on the ears when I'm pulling the boat). I would suggest checking out www.aeroexhaust.com for more info on their product.

Also if you're going to upgrade the CAI I have a K&N Series 77 CAI w/ a metal intake tube. There are some strange noises that also kick in from the MDS that are not very favorable. If you're planning on installing a CAI go with one that has either a non-metal tube for the CAI (like the Series 63). The only downside is the Series 63 is not street legal in CA so I have to just live with the noise. That should help you save some $$$ on a few expensive mistakes that I've made.