[TheElementalCashew]

Originally Posted by Zl1steve

I was shocked how loud the car is now with headers and no cats even with stock mufflers. when you hammer on the car it thunders.

Yessssss!!! But it is nice that it isn't overbearing when light on the throttle.

[Evolvedx27]

Originally Posted by Johnnysflooring

Do you have a video or a sound clip on how this set up sounds? Any drone with the exhaust?

No videos yet. With the fuse in it shouldn't drone too much. It's a muscle car don't forget.

[Evolvedx27]

Originally Posted by 7WSM

Cause spending the extra grand or whatever it is for the NPP mufflers that makes 0 hp isn't worth it. I do hate the suitcase factory axle back look though.

I wouldn't say 0 hp. It's gonna bottleneck at the oem muffler. Plus why hack up your oem exhaust.

[Zl1steve]

Originally Posted by TheElementalCashew

Yessssss!!! But it is nice that it isn't overbearing when light on the throttle.

Your mods match mine except for the cats. What a difference eh? I was stunned how much harder the car pulls now and how snappy it is.

[TheElementalCashew]

Originally Posted by Zl1steve

Your mods match mine except for the cats. What a difference eh? I was stunned how much harder the car pulls now and how snappy it is.

Oh yes, it was fast before, but now it pulls like an animal. Really need the new wheels to show up for some better traction.

[Zl1steve]

Originally Posted by TheElementalCashew

Oh yes, it was fast before, but now it pulls like an animal. Really need the new wheels to show up for some better traction.

And the cars are the same color!! lol

[TheElementalCashew]

Originally Posted by Zl1steve

And the cars are the same color!! lol

Great minds think alike, lol

[Cmyskill]

Since you removed the cats, do you have a issue with the car smelling like it is running rich? I know in some of my older cars when I remove the CAT it changed the smell to a strong gas smell ... just wondering

[nicktechla]

Originally Posted by Cmyskill

Since you removed the cats, do you have a issue with the car smelling like it is running rich? I know in some of my older cars when I remove the CAT it changed the smell to a strong gas smell ... just wondering

that's because the cat isn't burning off the exhaust

[BMWM.D.]

Originally Posted by Can'tHave2MuchHP

So is everyone saying that Kooks SS headers BOLT up to the factory exhaust after secondary cats or do they have to be welded or a reducer used to clamp them up?

I haven't seen a 2017 ZL1 underside but usually the secondary cat is pretty far back, much further back than most Long tubes and non-catted pipes/Highflow/green cats go.

Every header system for the ZL1 requires cutting the stock exhaust; unless of course you get a complete system with mufflers like Kooks, SW, and ARH sell.

I personally like the idea of a simple cut after the secondary cats, which means only one extra set of clamped connections in the exhaust. After having a number of full length header systems that go to the stock muffler, I've learned that I'm not a fan of those slip-fit connections. Mine have always seemed to leak, and they make the exhaust a PIA to disassemble. At least with the Kooks flanges, dropping the exhaust should be pretty easy, and there are less places for potential leaks.

[Evolvedx27]

Originally Posted by BMWM.D.

Every header system for the ZL1 requires cutting the stock exhaust; unless of course you get a complete system with mufflers like Kooks, SW, and ARH sell.

I personally like the idea of a simple cut after the secondary cats, which means only one extra set of clamped connections in the exhaust. After having a number of full length header systems that go to the stock muffler, I've learned that I'm not a fan of those slip-fit connections. Mine have always seemed to leak, and they make the exhaust a PIA to disassemble. At least with the Kooks flanges, dropping the exhaust should be pretty easy, and there are less places for potential leaks.

Slip fit is like the best connection to prevent leaks as long as theirs enough overlap and quality clamps (quality system) you can also disassemble the exhaust as many times as you like. No worries about replacing gaskets. You install an exhaust with the intention of it not coming on and off anyway...