Kooks headers - Go green or not?

[SkidMark]

All;

I could really use some feedback. I am wanting to get a set of Kooks headers for my 05 Envoy XL. Should I get the one with the green cat or the standard with the race cat? I am in Maryland and have emission checks.

I was planning to get the regular set and have my brother put a tune on it with EFI Live, but I am concerned that the race cat will throw a code and "tuning" it out will not pass inspection.

I've read some threads on other forums where the green cats still throw codes, so I don't particularly want to spend the extra $200 for the green and still have to tune it.

What are your thoughts?


Please let me know if you need any further information.

Thank you!


Regards,

Mark

 

[dmanns67]

Just my opinion, but I do not think the juice is worth the squeeze for the Kook header until the price drops significantly.

From the dyno results I have seen, a $900 header is not worth the money for the gain. Add in another $150 for a tune plus another $200 for labor (unless you do the work yourself) your at $1250. If you are installing a header you will need to upgrade the exhaust. Thats another $250-$500. Probably another couple hundred for a performance CAT or just gut your current CAT. Then if you have trouble passing the emissions test, all of the work and money spent is for nothing.

Too expensive for my blood for the minimal gains. I am happy with just a PCM tune. If you have deep pockets, then I say go for it.

Do you have any other performance mods done or are you stock? Is this going on your daily driver?

 

[Mounce]

 

[stickypoop]

... and also the possibility of busting off studs removing the old manifold. Unless it has to be replaced anyway, I'd leave it be

 

[SkidMark]

Thanks for the replies thus far. I completely agree with you all that the gains are not likely worth it.

However, I have a cracked manifold and really don't relish doing this job more than once. I talked to the wife (her DD at the moment) and she believes we will have the Envoy for the foreseeable future, so I am hedging my bets.

Since I have to change it anyway, does that change your opinion?


Thanks again.


Regards,

Mark

 

[BlazingTrails]

This is the one I purchased about 10 months ago and it has been great.

http://pages.ebay.com/link/?nav=item.view&id=130931138117&alt=web

 

[Midnyteryder196]

This is the one I purchased about 10 months ago and it has been great.

http://pages.ebay.com/link/?nav=item.view&id=130931138117&alt=web

Hell the 10 year warranty n for under 100 bucks... I would deff go this route if and when mine ever cracks...

 

[dmanns67]

$100 sure beats $1000 plus dollars, especially if you are only looking for a replacement part and not performance.

 

[BlazingTrails]

It sure does and the stock style manifold flows very well. I port matched my manifold and gasket which also ads a little more flow. The kooks header really won't flow much better than this one, although it looks hella cool

 

[Playsinsnow]

To answer your question, no.

I was just browsing MANY exhaust threads here and on the OS.
I've had my TB for 125+k over seven and a half years. For the price of an OEM manifold on GMpartsdirect and how long my original lasted, I am having a hard time choosing a different one because this is only the second complaint I have had on my exhaust. The first being the resonator in back. The crack I can hear now goes away once it warms up.

 

[BlazingTrails]

FYI the stock manifolds are notorious for cracking. One thing that does sometimes push them over the edge is a clogged catalytic converter. Just food for thought.

 

[SkidMark]

Wow! Thank you, all, for the responses.

I really appreciate it!

It looks like I'll be going the ebay route. Thanks for the link, BlazingTrails!

I have to admit, I was not expecting a complete shying away from the Kooks. It was an eye-opener. I was all set to buy the headers. I did something similar back in the day for my 95 Z28. The performance increase was much welcomed and the fact that the engine bay was so tight you couldn't really get to the spark plugs from the top side was further justification.


Just one more thing for my own edification.

The reason I ask is that the ramifications of this would apply to applications in the future.

So, does tuning out the CEL still pass emissions inspections? I guess I don't understand what that type of "tuning" means. Is the PCM being tricked to just not throw the code even if the conditions exist or is a situation where the conditions are tuned to take into account possible lower O2 sensor temps or something similar?

I guess I was concerned that under the former, the VEIP stations in Maryland could tell if I was messing with it. The latter would possibly be less obvious.

Just curious.


Thanks again, everyone!


Regards,

Mark

 

[BlazingTrails]

All that emissions testing looks for in the pcm is that the systems have completed diagnostics. Tuning out the rear 02 sensor will not affect that. The pcm just doesn't look for it. They usually do a visual inspection to look for the catalytic converter so I wouldn't remove it, but you could gut it like I did. Noticeable power gains there.

 

[The Neens]

There is absolutely no way that the $100 Dorman manifold is anywhere near as efficient as the Kooks header...How do I know? My Ass-O-Meter tells me Is it worth $1,000? Probably not to the "normal" user, fortunately I found a used header & cat...I don't own a chassis dyno or flow bench to back up my efficiency claims, but it wasn't too difficult for me to see the improvements once I got into varying driving conditions...Am I happy with my decision? Yes, because I didn't pay retail and I'm not "normal"...If cast iron exhaust manifolds were the best choice, Erica Enders and Jeg Coughlin would be using them...Not apples to apples, but you get the point...Thank you, speech over

 

[dmanns67]

There is absolutely no way that the $100 Dorman manifold is anywhere near as efficient as the Kooks header...How do I know? My Ass-O-Meter tells me [emoji2] Is it worth $1,000? Probably not to the "normal" user, fortunately I found a used header & cat...I don't own a chassis dyno or flow bench to back up my efficiency claims, but it wasn't too difficult for me to see the improvements once I got into varying driving conditions...Am I happy with my decision? Yes, because I didn't pay retail and I'm not "normal"...If cast iron exhaust manifolds were the best choice, Erica Enders and Jeg Coughlin would be using them...Not apples to apples, but you get the point...Thank you, speech over [emoji3]

Butt dynos are great, but here we like to use facts. The facts are that you will see an increase of roughly 16 hp and 19 ftlb torque (header and PCM tune numbers). Skip out on the PCM tune, we are talking about less gains. http://pcmofnc.com/images/tbdyno.jpg

To the average person, $1000 is not worth the minimal gains. Like we mentioned, if the price dropped significantly, then one might be able to justify buying the header.

The fact is the OP has a cracked manifold and the vehicle is the wife's DD. So not looking for performance.

Not going to lie, if I had a bunch of disposable income, I most likely would get this header. How much did you pay for your used header?

 

[limequat]

FYI the stock manifolds are notorious for cracking. One thing that does sometimes push them over the edge is a clogged catalytic converter. Just food for thought.

This. There are a few boosted 4200s with the stock manifolds. None of them have cracked. None of them have cats.

For my money, get the dorman replacement, gut the cats, and get a tune. You'll get more performance than from the header alone and save a lot of cash.

 

[lint]

sorry out of my head there wrong subject i deleted

 

[The Neens]

Butt dynos are great, but here we like to use facts. The facts are that you will see an increase of roughly 16 hp and 19 ftlb torque (header and PCM tune numbers). Skip out on the PCM tune, we are talking about less gains. http://pcmofnc.com/images/tbdyno.jpg

I like facts too and I've viewed the dyno reports, which don't always tell the whole story...

To the average person, $1000 is not worth the minimal gains. Like we mentioned, if the price dropped significantly, then one might be able to justify buying the header.

I completely agree, as I already stated...

The fact is the OP has a cracked manifold and the vehicle is the wife's DD. So not looking for performance.

The fact is he asked about a Kooks header, unless I misread something in post #1...

Not going to lie, if I had a bunch of disposable income, I most likely would get this header. How much did you pay for your used header?

I've got $400 in it, that's with having a muffler shop modify the muffler connection because the header is from a 06-09...I bought it from a member on the "OTHER" forum...Hopefully I won't get banned now ;-)

 

[HARDTRAILZ]

Anyone ever see a tuned dyno vs a tuned w header dyno?

All I have seen is stock vs tuned and header. My butt dyno says the tune was a solid 20 HP...

 

[BlazingTrails]

There is absolutely no way that the $100 Dorman manifold is anywhere near as efficient as the Kooks header...How do I know? My Ass-O-Meter tells me Is it worth $1,000? Probably not to the "normal" user, fortunately I found a used header & cat...I don't own a chassis dyno or flow bench to back up my efficiency claims, but it wasn't too difficult for me to see the improvements once I got into varying driving conditions...Am I happy with my decision? Yes, because I didn't pay retail and I'm not "normal"...If cast iron exhaust manifolds were the best choice, Erica Enders and Jeg Coughlin would be using them...Not apples to apples, but you get the point...Thank you, speech over

Sorry but I stand behind my statement about flow, the oem style manifolds are very very made. Too bad you don't live around here, we could line em up and see which one does better. My money's on my truck. But I guess I'm just a "normal" guy right?

This. There are a few boosted 4200s with the stock manifolds. None of them have cracked. None of them have cats.

For my money, get the dorman replacement, gut the cats, and get a tune. You'll get more performance than from the header alone and save a lot of cash.

That is exactly what I did, along with a lot of other things. Thanks for the tune btw, it was good
(I did finally get around to street tuning it, your timing maps were great, just adjusted fuel mostly)

Anyone ever see a tuned dyno vs a tuned w header dyno?

All I have seen is stock vs tuned and header. My butt dyno says the tune was a solid 20 HP...

 

[dmanns67]

Butt dynos are great, but here we like to use facts. The facts are that you will see an increase of roughly 16 hp and 19 ftlb torque (header and PCM tune numbers). Skip out on the PCM tune, we are talking about less gains. http://pcmofnc.com/images/tbdyno.jpg

I like facts too and I've viewed the dyno reports, which don't always tell the whole story...

To the average person, $1000 is not worth the minimal gains. Like we mentioned, if the price dropped significantly, then one might be able to justify buying the header.

I completely agree, as I already stated...

The fact is the OP has a cracked manifold and the vehicle is the wife's DD. So not looking for performance.

The fact is he asked about a Kooks header, unless I misread something in post #1...

Not going to lie, if I had a bunch of disposable income, I most likely would get this header. How much did you pay for your used header?

I've got $400 in it, that's with having a muffler shop modify the muffler connection because the header is from a 06-09...I bought it from a member on the "OTHER" forum...Hopefully I won't get banned now ;-)

I guess your butt dyno filled in the rest of the story.

Now if the header was sold for $400, I and most likely other members would be all over that. Much more reasonable.

What company sells the 06-09 Kooks header? I see PCMofNC only sells the 02-05 header.

 

[HARDTRAILZ]

Kooks sells it.

 

[BlazingTrails]

I guess your butt dyno filled in the rest of the story.

Now if the header was sold for $400, I and most likely other members would be all over that. Much more reasonable.

What company sells the 06-09 Kooks header? I see PCMofNC only sells the 02-05 header.

I would absolutely buy it for $400 all day long. If nothing else then for the looks

I could probably squeeze another 10 hp out of the old girl

 

[HARDTRAILZ]

I can assure you for $400 I would have been in first 10 sold.

 

[The Neens]

Sorry but I stand behind my statement about flow, the oem style manifolds are very very made. Too bad you don't live around here, we could line em up and see which one does better. My money's on my truck. But I guess I'm just a "normal" guy right?

Not sure what you mean about that??? Well made??? I would love to line em up with you, I have a pretty good record with that...And no, you're not "normal" either, anyone who spends money modifying a straight 6 instead of getting a V8 isn't "normal"

I guess your butt dyno filled in the rest of the story.

Not sure about that either, but I'm sure it was hysterical

Now if the header was sold for $400, I and most likely other members would be all over that. Much more reasonable.

What company sells the 06-09 Kooks header? I see PCMofNC only sells the 02-05 header.

 

[BlazingTrails]

Yeah lol that was supposed to be "very well made" lol

It does sound as though we would have a good time

 

[The Neens]

Yeah lol that was supposed to be "very well made" lol

It does sound as though we would have a good time

Absolutely...What part of the country do you live?

 

[BlazingTrails]

Newnan Ga, all the way on the opposite side of the country

 

[SkidMark]

Again, I thank you all for the continued commentary. This is great stuff.

Since The Neens asked, here is my research on companies that sell the 06-09, though they list it as 02-09 in most cases.

http://shop.brutespeed.com/Kooks-6322-04-09-Trailblazer-42L-Inline-6-Complete-To-Factory-Kooks-6322.htm?categoryId=-1
http://www.coloradospeed.com/kooks-long-tube-header-connection-pipe-w-catalytic-converter-158-20022009-trailblazer-42l-p-34698.html
http://www.roushyatesparts.com/kooks-headers-p/kch-6320.htm
http://www.amazon.com/Kooks-Connection-Chevrolet-Trailblazer-Compliant/dp/B00N3MUD36/ref=sr_1_1?ie=UTF8&qid=1420038848&sr=8-1&keywords=kooks+headers+6320

It is my understanding that the only difference between the two year sets is where the header connects to the existing pipe. Since no one has any stock and they must be ordered (I was told that the lead-time pushes receipt of a header til the end of January), as long as you give them the proper year, you should be good to go.

Hope this helps.


Regards,

Mark

 

[redmaro42]

Couldn't you upgrade an 02-05 by buying a newer exhaust manifold with the better designed runners? I heard they bolt up fine to the earlier heads and they might net us a few extra HP because of the design change. Anyone upgraded to a newer exhaust manifold and had any problems or seen gains? Might be a cheaper route than the kooks header but still be an upgrade

 

[limequat]

Couldn't you upgrade an 02-05 by buying a newer exhaust manifold with the better designed runners? I heard they bolt up fine to the earlier heads and they might net us a few extra HP because of the design change. Anyone upgraded to a newer exhaust manifold and had any problems or seen gains? Might be a cheaper route than the kooks header but still be an upgrade

The only difference is they changed the port to match the revised head. I wouldn't expect any gains, but out of the 2, I'd definitely take the 06 design!

 

[redmaro42]

Here are the three different designs:

02-05

06-07

08-09

The 08-09 is what I was thinking as a possible upgrade for earlier years as you can see the runners are built better and look larger at least in the pics. The 02-07 both have o2 bungs in them, I don't see one in the 08-09 one. Maybe it is in the piping just passed the flange or something instead of the manifold.

 

[SkidMark]

Redmaro42,

I see what you mean. Assuming that the actual part is represented here, it does look cleaner.

Thanks for bringing this up.

Can anyone out there address the O2 sensor location question?


Thanks!


Regards,

Mark

 

[redmaro42]

I might order up a couple here at the shop just to see what they look like. 08-09 might be a good remedy for those that run into cracked manifolds and are replacing anyways

 

[BlazingTrails]

Here are the three different designs:



08-09

The 08-09 is what I was thinking as a possible upgrade for earlier years as you can see the runners are built better and look larger at least in the pics. The 02-07 both have o2 bungs in them, I don't see one in the 08-09 one. Maybe it is in the piping just passed the flange or something instead of the manifold.

Mine is the 08-09 version, it fits just like the old one but is an "updated" version that is not supposed to crack like the old manifolds.

 

[redmaro42]

awesome, so fitment is good then, now to find out if they actually flow better and show power gains, anyone have a flow bench? lol

 

[SkidMark]

What about the Bank #1 O2 sensor?

I assume the 02-07 model years will need the pipe in between the manifold and the cat as well. Is that accurate?


Thanks!


Regards,

Mark

 

[BlazingTrails]

What about the Bank #1 O2 sensor?

I assume the 02-07 model years will need the pipe in between the manifold and the cat as well. Is that accurate?


Thanks!


Regards,

Mark

I'm not 100% sure if I understand your question, all years have a mid pipe containing the catalytic converter between the manifold and the rear pipe. You have 2 O2 sensors one in the manifold itself and one just behind the catalytic converter.

 

[coolasice]

Mine is the 08-09 version, it fits just like the old one but is an "updated" version that is not supposed to crack like the old manifolds.

My 08 had the manifold replaced under warranty just before I bought it because it was cracked. I believe gm extended the warranty on the manifolds due to cracking.

 

[Texan]

For future reference, can it be confirmed that the 08 - 09 exhaust manifold has the
02 bung (fitting), and will inter change with all I6's. Thanks.