Kooks Headers 3" to 2.5" size drop

[Jmeo]

Will make almost zero difference until 1,000 ish rwhp and even then it's neglidgable so don't even waste your time worrying about it. I have them with green cats into Borla 2.5" touring exhaust and put down 765 rwhp.

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[daniel_94kg]

I had a shop near my house cut off the step down and weld on the new connections when I had BBK long tubes and Gibson exhaust. It only cost me $80 and I picked the car up before lunch.

Since then I've switched my setup and now have SP headers with cats and it steps down to 2.5" to connect to the 2.5" Solo performance exhaust which opens back up to 3". Zero issues.

From my experience, I recommend if you have a factory connect catback, just bolt it up and rock on. If not, cut off the 2.5" from the end of the lead pipes and weld the appropriate 3" connection on. I searched high and low last year for "bolt on versions" that were budget friendly and came up empty. Good luck man.

 

[5ohh_kenny]

Something to consider besides the power loss with the bottleneck is the sound. One can only assume with removing the turbulence the exhaust tone would become clearer.

 

[whatsup62]

I had a shop near my house cut off the step down and weld on the new connections

Did the same thing. I have MRBP that tapered down as well. Cut of cat-back side and header side, welded a 18" piece in both sides, cost me a $100. Looks great and 3" all the way now.

 

[davidryan1987]

Yea I wonder if taking the bottle neck out will take out the raspiness when letting off the gas at high rpm? I also wonder if going from the magniflow x pipe to a h pipe will give it a deeper tone?

 

[16pandagt]

That's a factory connect set up. You need a perf version. Problem is you'll have to buy new leads which with green cats aren't cheap

So how do I buy the perf version instead of the oem connect so that I don't make this mistake in the future? I don't see the perf version listed on any website that sells the Kooks 1 7/8 headers. I have a Borla S Type 3in catback and don't want headers that taper off to 2.5in.

 

[Evilwill]

This might help you

https://www.kooksheaders.com/2015-ford-mustang-gt-5-0l-full-3-adapter-pipe.html

 

[16pandagt]

This might help you

https://www.kooksheaders.com/2015-ford-mustang-gt-5-0l-full-3-adapter-pipe.html

Excellent! Thank you!

 

[ob1]

I have the Kooks with the perfomance cats coupled to the Solo Mach XV exhaust.
Yes it necks down to the solo exhaust but the sound and perfomance is awesome as I plan to stay NA.

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