Ive been searching for a lil while now and havent found any fool that has run their down pipe to the stock catback.
Im wanting to use the stock muffler just so it stays nice and quiet. I dont like loud.
I had 2 big magnaflow mufflers on my STS rear mount years ago and it still wasnt quiet enough.

Been thinkin bout just puttin a cutout before the collector so it can breath when i want it to. And for daily driving 100 miles a day i like the quiet.


So what genious is with me on this?

 

y not get a Dura factory exhaust. should be plenty quiet. and 3.5" is way better than 2.75"

 

I'm running the exact setup you speak of. My exhaust consists of this... 3.5 turbo down pipe all the way back into a QTP 3.5 cutout right before a factory 3.5 6.2 Catback. I'm the same way I like my truck to be quiet when I'm cruising but still have the ability to open up when I need it too.

 

To go from the stock exhaust. A midpipe is needed.
Slips on the down pipe, the pretty straight to the 2 bolt flange mid truck. And the rest of the stock exhaust.

Cut out in the mid pipe. Not sure what opening will help/hurt tuning. ???

 

I was going to say the same thing, with a cutout, the catback shouldn't matter

I'm going to do a boost activated cutout myself with a stock catback (on my f body, but same principal).

 

I like my 24" long case 4" inlet outlet Magnaflow. Plenty quiet and flows like a sewer pipe.

 

I dont see the stock cat back really holding back a ton of power with just 6psi.

If i wanted to turn the boost up the cutout will take Care of the flow.

But mostly for towing and DD.

 

I'm working on something similar for my truck. I didnt really enjoy riding around in my slow truck when I had some loud slowbasterds.
Sounded prolly just as loud as my ss but half the power.
This kit I'm working on allows for a quiet non obvious easy to install kit with stock like catback sound. Unless pop open the cutout. I got a tc78 Im gonna try with it.
But yea, I understand I like the truck to be a quiet ride but still want the

 

I personally think the stock muffler would be a significant restriction. I bet that you have a noticeable difference in AFR's when you open the cutout, so much so you will probably need to tune for it with the cutout open leaving a bit of a rich condition when its closed. I like the idea of a boost activated cutout as that would eliminate tuning issues if it could be implemented to work very precisely and reliably. It should be easy to build the mid pipe though, I would put a v-band on the end of the DP to connect to the mid and the cutout should fit easily with a Y.

 

If theres a big difference, it should flow less so should be in a different portion of the VE table. Correct?
One way to find out
Well after i find my money tree