[Liquidstone]

What is your guys take on the factory exhaust, in terms of flow (restriction) with long tubes. I get that there is the crimped section. Does anyone have long tubes to factory exhaust and how was the gains? as suppose to full cat back. The only reason why i ask is because i find that this setup is loud but not crazy obnoxious. Would a axle back help at this point or not?

[Can'tHave2MuchHP]

It's perfectly adequate for flow with a proper LT Headers + long X pipe. If you get something like the ARH Long or Kooks + X Pipe (necked to 2.5" at the back) it will delete the crimped section + eliminate the entire factory X pipe.

Attached two pics that may help for reference. A long header system will end right where the red vertical line is at the back, around the rear axle/diff area.

Also attached a picture showing the internals of the NPP. In track mode it's nearly straight through.

[mdmoore23]

Just an fyi. It was tested once and the "crimped" section has no effect on power. The test car made the same power before and after the section was removed.

[Liquidstone]

Originally Posted by Can'tHave2MuchHP

It's perfectly adequate for flow with a proper LT Headers + long X pipe. If you get something like the ARH Long or Kooks + X Pipe (necked to 2.5" at the back) it will delete the crimped section + eliminate the entire factory X pipe.

Attached two pics that may help for reference. A long header system will end right where the red vertical line is at the back, around the rear axle/diff area.

Also attached a picture showing the internals of the NPP. In track mode it's nearly straight through.

Appreciate the pictures! My plan was to run Kooks Long tubes w/high flow cats, into factory exhaust. Therefore i can still keep NPP and its not a Raspy sounding and CRAZY loud. My last car was a 2017 Shelby GT350 with cat-less long tubes, into borla atak..........it was stupid loud....couldn't even carry a conversation in the car with someone lol. Im sure those secondary cats would have to go too tho..... :(

mdmoore23 Just an fyi. It was tested once and the "crimped" section has no effect on power. The test car made the same power before and after the section was removed.

Beauty! I was hoping to hear that answer!

[Markoz28]

Any other mods besides headers. Since you’ll need a tune with that anyway might as well add an intake.

[Liquidstone]

Originally Posted by Markoz28

Any other mods besides headers. Since you’ll need a tune with that anyway might as well add an intake.

Totally aware. Currently i have the Roto-Fab cai, LT5 95mm throttle body installed. My e85 flex fuel sensor kit, and elite x2 catch can sitting in my garage will be installed once i get my custom tune done

[SilverZl1]

You’ll be good with the Kooks LT, high flo cats and NPP set up you described. You’ll get rid of 90% of the rasp with the high flo’s and still have the volume and tone without it being crazy. I have kooks LT’s, no cats into NPP but added bullet resonators at the “crimp” to kill the rasp/tinny sound. To me it’s just right, the deep sound and loudness are spot on. I ran it without the resonators first and hated it (had a crazy big cam in it at the time) Yours should sound very similar to my current set up, even though I’m (now reasonably) cammed and have more mods.

[Markoz28]

Originally Posted by SilverZl1

You’ll be good with the Kooks LT, high flo cats and NPP set up you described. You’ll get rid of 90% of the rasp with the high flo’s and still have the volume and tone without it being crazy. I have kooks LT’s, no cats into NPP but added bullet resonators at the “crimp” to kill the rasp/tinny sound. To me it’s just right, the deep sound and loudness are spot on. I ran it without the resonators first and hated it (had a crazy big cam in it at the time) Yours should sound very similar to my current set up, even though I’m (now reasonably) cammed and have more mods.

Not to high Jack the thread but was your Z done tuned by Matt? If so is it the same one on his FB?

[Liquidstone]

Originally Posted by SilverZl1

You’ll be good with the Kooks LT, high flo cats and NPP set up you described. You’ll get rid of 90% of the rasp with the high flo’s and still have the volume and tone without it being crazy. I have kooks LT’s, no cats into NPP but added bullet resonators at the “crimp” to kill the rasp/tinny sound. To me it’s just right, the deep sound and loudness are spot on. I ran it without the resonators first and hated it (had a crazy big cam in it at the time) Yours should sound very similar to my current set up, even though I’m (now reasonably) cammed and have more mods.

Sound clips pleeeeeease....