Gutted manifolds vs headers
Lexus Champion
Joined: Mar 2006
Posts: 1,841
Likes: 74
From: FL
Two car lengths sounds about right... but you're taking advantage of the tuned intake since you've headers, whereas your friend is getting nil from it, according to RR Racing. Regardless, smarter money is in making her lighter. You'll see the same effect for a third the dough for lighter wheels, plus "adding lightness" does wonders on all points of the traction circle. No wonder it's one of EE's very first videos... because it matters! Headers will benefit one vector, but lightness improves all four: https://www.youtube.com/watch?v=JjCcFsGLpaM
Or as Mike Kojima wisely stated to open his series on race car dynamics, "Horsepower is sexy and chicks dig it, at least a lot of meatheads think that way."
Or as Mike Kojima wisely stated to open his series on race car dynamics, "Horsepower is sexy and chicks dig it, at least a lot of meatheads think that way."
Even my 17lb track day 18's were only $1k all in, and I found the new NT01's to match for $109 ea locally. Gently used R7's and Pirelli slicks aren't much more - I'd probably gone that route had I known they were widely available.
Pole Position
Joined: Apr 2016
Posts: 212
Likes: 34
From: CA
You don't need to cut the cat shell out, just stuff a tube inside to prevent the volume change. As much as I am a big fan of properly designed headers for ultimate power, I'd bet the OEM manifolds with a proper diameter tube stuffed in them would be painfully close to header performance for very little money.
That’s a good idea. I wonder if anybody has tried this yet and how much work is involved to get a tube to fit properly inside the gutted cat. I also wonder if this could be done without having to remove the stock headers to save on the time and costs associated with that.
Lexus Champion
Joined: Mar 2006
Posts: 1,841
Likes: 74
From: FL
Not even close... The Advanti Hybris 19's I referenced were $934 shipped to my door and 19.6lbs ea. If you buy them when you need new tires, wheels are your "only" added cost. Plus, I got $1200 for my stock '11 wheels, so I actually made money on the deal!
Even my 17lb track day 18's were only $1k all in, and I found the new NT01's to match for $109 ea locally. Gently used R7's and Pirelli slicks aren't much more - I'd probably gone that route had I known they were widely available.
Even my 17lb track day 18's were only $1k all in, and I found the new NT01's to match for $109 ea locally. Gently used R7's and Pirelli slicks aren't much more - I'd probably gone that route had I known they were widely available.
Driver School Candidate
Joined: Aug 2018
Posts: 1
Likes: 4
From: Fl
Gutted Cat straight Pipe
You don't need to cut the cat shell out, just stuff a tube inside to prevent the volume change. As much as I am a big fan of properly designed headers for ultimate power, I'd bet the OEM manifolds with a proper diameter tube stuffed in them would be painfully close to header performance for very little money.
Hey guys resurrecting this thread, so just did a thing.. got my exhaust guy to work miracles and he manged to get a straight pipe welded in the gutted header cats to get rid of that hollow chamber. Wanted to share the results with you guys.
Driver School Candidate
Joined: Nov 2016
Posts: 33
Likes: 3
From: CA
That's awesome! Make sure to update us if you decide to dyno. 
how's the smell in the cabin and outside? Same as with headers or worse with this upgrade?
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If I take this route, I will definitely put GESI cats on it. Can't stand the smell of the exhaust without something to clean it up. When I was a kid, it smelled awesome. Now, it smells disgusting. Probably the TE lead from the old days...
Pit Crew
Joined: Feb 2015
Posts: 136
Likes: 11
From: CO
a lot more sweet smelling aromatics in gasoline back then as well before they put limits on it (especially benzene).
Please do share with us on it performs. I am very interested in the outcome.
Thread Starter
Driver School Candidate
Joined: Sep 2014
Posts: 47
Likes: 4
From: arizona
any noticeable performance gains?
