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Review: Coated Kooks 1 7/8 headers with Green Cats

Performance nut

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First, I want to say thanks to [MENTION=17009]marylandspeed[/MENTION] for the awesome deal on the headers. Not only was the price very good, to add the coating on top of that was just phenomenal.

I kept the stock resonator and mufflers since headers are notorious for adding grunt to the exhaust note. So please bear that in mind for this review.

First, the great stuff. The note on the car has been dramatically enhanced at the upper RPM range and kept it neighborhood friendly down low. In fact, I can hardly hear the difference at idle (start is a bit more grumble) and doesn't really start getting loud until around 3k RPM. Inside the car is also great. Nothing noticeable at idle or low RPM but it gets progressively louder as RPM's increase. In my opinion, it sounds great. Nothing obnoxious, no drone, just muscle car sound that doesn't compete with my radio. Also, no codes!!! 100% stock tune, no codes and nothing but improvements as far as how the engine runs. I realize a tune will wake the car up but it is good to run these without having to tune and not have to retune when I do my next upgrade.

The good is several things. Low end power seems unaffected but you can feel it at the top. Can't quantify it since I did not do a dyno but its there. Temperatures seem to be affected too. Usually when I'm at a light with the window down, I can feel heat radiate around the car if my arm is on my door. Now, I can put my head at the bottom of my car after driving 30 miles and not feel much as far as heat. In the engine bay, all the heat is coming up front from the radiator, back of the bay seems quite cool in comparison. IAT's didn't really seem to improve though when I was idling but I'm not all that concerned with IAT's.

Now the bad. I was hoping the green cats would be better than performance cats in regards to smell and I was right. Though definitely not as good as the stock cats. They do good at idle but once you start revving the engine, you get a good ol' whiff but nothing really strong (in comparison to cars without cats, this is like smelling roses). Not a big deal for me as I was expecting this and it was better than what I expected. These are also a major pain due to clearance issues. Fortunately, I was smart enough to have these professionally installed but my mechanic told me what it takes to get these in, definitely not in my wheel house to do.

As soon as I upload the video, I'll add it to the exhaust sound sticky on the forum and post a link on this thread. Overall, I'm extremely impressed and very happy with my headers. Highly, highly recommend them.

Edit: Video added.
Edit (11/4): Got my first code Tuesday. Not sure when it happened, just noticed it when I was driving to work. Cleared it out and hasn't returned yet.

[ame="[MEDIA=youtube]LQnnu4OcFZo[/MEDIA]"]Video of idle and revving the engine[/ame]
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Road Dog

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stang77

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Good review. I will definitely have to do something about my current exhaust when I add headers. Don't want to upset my neighbors.
 

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Jeff_oddo

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Trust me... the codes for no cats will come. Mine came on after 300 miles.
 

tsloms

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My CEL came on as well nearly right away but after adding in the Big Daddies angled connectors it has cleared up and not returned in the past 1000 miles.
 

toplesstripcruiser

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You shouldn't get any CEL. The green cats are from a company called GESI, Global Emission Systems Inc. Their cats actually reduce smog and are EPA certified. They are sold exclusively through Vibrant Performance, but I guess Kooks has a deal with them.
I know for a fact they work really well. For a long time I had the stock cat on my Evo because I know they are notorious for getting a CEL even with high flow cats. I really wanted a 3 inch cat I could get with a 3 inch downpipe to mate with the cat back I already had. Then I cam upon GESI. I bought from Vibrant which are expensive. But now seems places like Kooks, Jegs, Amazon CarID have them for cheaper. I was looking for a legit converter that would pass emission testing without any "tricks". I had it welded on a test pipe and put on the car August of last year and no CEL. So over a year, no CEL. So this is most likely a real cat whose main focus is to reduce emissions while still making good power. Not like other high flows that don't really do much do reduce hydrocarbons, hence the higher cost of GESI/green cats.
I just don't know though if the ones sold by Kooks are altered for better flow, or have their on design, which is why some have gotten the CEL.
It's like how the Ford Racing by Borla are different from the actual Borla.
 

Dragster

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And yet most still do.........
Most, huh? Care to elaborate with any stats there? Anecdotally, there are plenty of people on here running with them (including myself) that have never had any CELs. I believe the most common number that I've seen referenced is 90% don't get a CEL. I don't remember where I saw that, but I suppose it doesn't matter because we're not likely to get anything official anyway.

I would like to know if there's a correlation between size and CEL, though. I have 1 3/4 on mine and haven't had any issues (knock on phone).
 

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Performance nut

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Most, huh? Care to elaborate with any stats there? Anecdotally, there are plenty of people on here running with them (including myself) that have never had any CELs. I believe the most common number that I've seen referenced is 90% don't get a CEL. I don't remember where I saw that, but I suppose it doesn't matter because we're not likely to get anything official anyway.

I would like to know if there's a correlation between size and CEL, though. I have 1 3/4 on mine and haven't had any issues (knock on phone).
So are you saying size matters?:lol:

Mine are 1 7/8 so I guess we will see. I'm wondering if people using them will chime in, good or bad.
 

WhiteyDog

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I have the Kook's catted 1-7/8" headers, but not with the green cats. No codes, no nothing.
 
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Performance nut

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I have the Kook's catted 1-7/8" headers, but not with the green cats. No codes, no nothing.
Did you run a stock tune on your headers? Your signature says you have a Lund tune, curious if that is why you have no codes.
 

WhiteyDog

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No, never ran it with the stock tune with headers. When I got the headers and 350IM, I switched to a Lund tune.
 

SVT Wylde

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Sounds good!! I wish I had gone with headers and the stock catback. You can remove the stock resonator if you want a little more sound or try the GT500 axlebacks.
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