Join Date: Nov 2016
Location: near Greenville, SC
Thanked 145 Times in 103 Posts
Feedback Score: 0 reviews
I recently installed SW downpipes in place of the stock pipes with catalytic converters. In addition to the removal of the cats, the SW pipes are 3" dia. to the connection with the stock exhaust pipes where the original down pipes are 2.5". I took a significant amount of time to fit the reducers in a manner that the catless pipes could be removed and cats reinstalled easily. I plan to use the SW pipes in spring and fall when racing and use the stock pipes when not racing. Bung extensions were used to keep O2 sensors out of the exhaust flow. No tuning changes were made and no MIL codes have displayed.
The noise level has increased however it is still quieter than most aftermarket cat back systems. Running in default mode it is only slightly louder than before, the sound system and conversations are only minimally affected. As well there is a drone when under heavy load at low rpm. At WOT it is noticeably louder than stock. The smell of gas is evident when the car is started in the garage and is occasionally noticeable at other times.
Two tuners I communicated with indicated the mod would be worth approximately .1 ET improvement. While my PB has not improved to date, I have equalled the PB and am hitting within .005 of my PB on a regular basis in DA of 1000' to 1500' greater. Since installing the pipes I am experiencing tire spin on almost every run, even on a well prepped track. No question I will need a lower tire pressure than before. On street tires it is much easier to unintentionally spin tires. Don't know if my experience is typical or not but I have definitely experienced a very noticeable performance gain.
OK I'm a bad boy for removing the cats but the car gets limited highway use, is not a DD, and cats will go back on when spring racing is done.
2016 Challenger Scat Pack Shaker
Jazz Blue, Ruby Red Leather, A8, Scat Pack Appearance Group
Tazer, BT catch can, ported intake manifold, Hemifever Tune, Fastman 84mm TB.
SW mid pipes, Performance differential brace, BMR non adjustable trailing arms.