I recently purchased and installed the Magnaflow 16612 SI/SO system on my ‘o6 CC 5.5. I picked up a whopping .6 MPGs. (every little bit helps!) Everything fit nice and the sound is great,…..but I have a question. Instead of taking the new system’s 2.5 pipe all the way to the end of the “Y” pipe, it connects to the end of a 20-inch factory pipe clamped to the “Y”. Why not eliminate this factory pipe by extending the length of the muffler forward 2.5 diameter pipe all the way from the muffler to the end of the “Y” ? The 20-inch factory pipe is squashed oval for some reason. This correction would simplify the install and eliminate what seems to be another opportunity for a restriction. Can Magnaflow manufacture a longer pipe for this section as a post sale item? Can anyone else recommend an alternate source for a pipe like this?

 

In my opinion, (for the most part), once exhaust gases reach the muffler, and are restricted there, anything beyond the muffler isn't much of a restriction. OR, better yet, you won't pick up anything by making mods after the muffler. *disclaimer for those that want to argue...9 times out of 10, your stock piping is ok for your stock engine.

 

I noticed the same thing when I installed my 16612 on my SCrew 5.5 bed. I thought that was kind of strange as well as slightly disappointing considering how much the system cost. Oh well, it still sounds great and made a noticeable increase in power.

 

The Magna flow rep wrote me that the 16612 is the system that will fit my '06 S/Crew with a 6.5' bed, too? How can those additional 12" of wheelbase between the 5.5' bed (138.5" WB) and the 6.5' bed (150.5" WB) not matter?

 

Same lack of possible replacement of restritction with the 15821 from Magnaflow ! Really disappointed in Magnaflow as they said that is just the way it is designed. I am going to go with custom exhaust next time, since I plan to get long tube headers soon and will run true dual exhaust. It is sad to see how carelessly they designed a system from what I thought was a great brand name. My first Magnaflow purchase and more than likely my last and I will certainly not recommend it to anyone else either. There are other companies out there, maybe just use the magnaflow exhaust !

 

There are two intermediate pipes included in the kit that go from the "crimped" factory tube to the magnaflow muffler. One is for the 5.5 bed, one is for the 6.5. So now I got an extra piece of 3 inch mandrel bent tube with a hanger already welded on. Haha!!

 

It seems like this should be a wake up call for MAGNAFLOW on this 16612 kit. The directions were obscure. Posters here are cutting welding and replacing parts on the kit. I had to leave a squashed piece of easily replaceable stock pipe on my '06 CC 5'5 bed. It connected the stock muffler to the rear of the Y pipe assembly. I would have paid more $ for the kit if it had a longer pipe from the Magnaflow muffler to the Y pipe, even though I thought I paid for a complete kit!