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4.2L Headers

74K views 170 replies 45 participants last post by  The Neens 
#1 ·
Here at Kooks custom headers we are striving to bring the absolute best products to the market. As part of that process we are always looking for what the next product should be.I would like to gauge the interest in a Stainless header for the 4.2L I6. I would like as much input from you as possible.

(Mods please add a poll interested Yes No)
 
#73 ·
That is what we talked about yesterday, and I was told that was the plan. The begining of next week the TB should be back to PCM of NC. They will use the information they collect to make the great tunes they are already known for. So if you have the headers on order you may want to give them a call so you can get the new tune and take full advantage of the headers. I will keep you up to dateas I get more information. I am very excited to see what PCM of NC can do with this set up. I may also have to get their electric fan conversion while they have it at the shop.

Quick video of the TB at PCM of NC.

http://s246.beta.photobucket.com/user/novajoe1966/media/Trail Blazer/100_3123_zpsa5ee9b79.mp4.html
 
#74 · (Edited)
Joe,

The VVT table has 0 retard at higher load (rpm/map) - most of the overlap is down low for EGR purposes. Taking that out will help low end torque, and adding it in up higher should result in HP increase.

You might want to mention this to them.

If you can consider getting a spare head and re-working the exhaust ports - there is 25+ HP bottled up. The 06 up exhaust valves are 1mm bigger and will help.

With the head reworked this becomes a 300+ HP engine - take out the TM and enjoy the ride. GM tuned this for socer moms not the race horse it really is.
 
#76 ·
Maybe after getting the head reworked it might be better, but I noticed when futtsing around with the retard down low it felt like a Honda trying to hit VTEC. Lost a little low end for some reason. Almost a hiccup/hesitation. Advancing it in the higher RPM range though to 25* as you said a while back made it a lot more fun to drive.

I'm excited to see the results of the header though.
 
#78 ·
My Envoy finally got the Crack.

I was reading a bunch of threads on the manifold crack (after my Envoy just got really loud over the weekend) and found this thread on a header for the Envoy.

I'd rather put on a header for some more money then replace it with the same. + extra HP, is always needed.

How long till one is available for purchase and a final price on it? Will it come with bolts, gaskets and everything needed for direct install? I probably will not be doing the repair till spring, so I have some time. How does PCM of NC go about the "new tune".

Thanks for any answers you have.:thx
 
#81 ·
I was reading a bunch of threads on the manifold crack (after my Envoy just got really loud over the weekend) and found this thread on a header for the Envoy.

I'd rather put on a header for some more money then replace it with the same. + extra HP, is always needed.

How long till one is available for purchase and a final price on it? Will it come with bolts, gaskets and everything needed for direct install? I probably will not be doing the repair till spring, so I have some time. How does PCM of NC go about the "new tune".

Thanks for any answers you have.:thx
When I talked to Chris he said he will get me more info shortly.
 
#83 · (Edited)
We are very busy in R&D with work, our engineers did not like the flange design and made a change the new ones are now here. We are also building 2 sets of headers one that we keep here for reference and to build the fixture, the other final set so Joe's truck. the tune and Dyno time will be up to PCM of NC as to when they can get it on their Dyno.

I was reading a bunch of threads on the manifold crack (after my Envoy just got really loud over the weekend) and found this thread on a header for the Envoy.
I'd rather put on a header for some more money then replace it with the same. + extra HP, is always needed.

How long till one is available for purchase and a final price on it? Will it come with bolts, gaskets and everything needed for direct install? I probably will not be doing the repair till spring, so I have some time. How does PCM of NC go about the "new tune".

Thanks for any answers you have.:thx
They are designed to be a factory manifold replacement. If you get the Ultra Performance Cat you will not get an engine light for catalyst low efficiency. you can contact PCM of NCfor the information on the tune.
 
#85 ·
We are very busy in R&D with work, our engineers did not like the flange design and made a change the new ones are now here. We are also building 2 sets of headers one that we keep here for reference and to build the fixture, the other final set so Joe's truck. the tune and Dyno time will be up to PCM of NC as to when they can get it on their Dyno.


They are designed to be a factory manifold replacement. If you get the Ultra Performance Cat you will not get an engine light for catalyst low efficiency. you can contact PCM of NCfor the information on the tune.
The 2006 up head has a different exhaust port shape...
 
#88 ·
Some new pictures of the Connection pipe being Finished.


Drew Amitrano
Sales & Tech Representative
Kook's Custom Headers
141 Advantage Place
Statesville, NC 28677
Phone - (704) 768-2288 x218
Fax - (704) 768-2266
Email - drew@kookscustomheaders.com
Web - www.kookscustomheaders.com
 

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#89 ·
Fitment looks good, but what is it made of? Will this pass an emissions test? Is there a full exhaust system? And what kind of numbers did it make? You say this is a bolt on kit so everything that is needed is included Correct.
 
#90 ·
They are made of 304 Stainless Steel. Obviously this is the prototype truck so to confirm it will pass emissions is hard to say at this point. With the success of our Ultra High Performance EPA Certified Cat, on other vehicles there should be no issues with passing emissions. The truck is still here getting finished up now those pictures were from late Friday afternoon. One of the manifold bolts had broken upon removal and had to be drilled before the header went on permanently. I will try to get the finished pics up ASAP.


Drew Amitrano
Sales & Tech Representative
Kook's Custom Headers
141 Advantage Place
Statesville, NC 28677
Phone - (704) 768-2288 x218
Fax - (704) 768-2266
Email - drew@kookscustomheaders.com
Web - www.kookscustomheaders.com
 
#94 ·
I don't recall these headers being marketed as emisions headers. Although I do belive that there will be an increase in performance and efficency. You must also keep in mind that this is a new product filling a gap that no other company filled so if Kooks did get them certified it would not be overnight. I am sure that eather way that Kooks has spent a lot of time and money to produce an exceptional product. I was in R&D this morning and the look of the headers was simply awsome. I have appointment on thur. To have the test and tune done on the trailblazer. I am optimistic that the esaults will excead my expitations.
 
#96 ·
System is complete Joe's truck was running today.

Drew Amitrano
Sales & Tech Representative
Kook's Custom Headers
141 Advantage Place
Statesville, NC 28677
Phone - (704) 768-2288 x218
Fax - (704) 768-2266
Email - drew@kookscustomheaders.com
Web - www.kookscustomheaders.com
 

Attachments

#107 ·
So is the system your selling going to replace my original Catalytic converter also? or do I still need a new catalytic converter since I believe mine is plugged.

I called and was quoted a price of $700 and guarenteed 20+ hp gain without retune. Will the price remain the same with only a 10 HP gain without retune.
 
#100 ·
The red line in the graphs are the STOCK pulls. The blue line in the graphs are the STOCK tune and HEADER pulls. And finally the green pulls are the PCM of NC tune and the header pulls. At peak power, the header alone netted a gain of 10hp, and with the tune, 15hp. At peak torque, the header alone netted a gain of 16 ft/lbs tq, and the header and tune netted 19 ft/lbs. Note the enormous tuning gains in the mid-range, almost FORTY horsepower and THIRTY ft/lbs tq!

 
#105 ·
After the tune there is no light and I asked about inspections as we have testing here in NC and i was told that after the relearn it will pass.


novajoe, you probably have mentioned what you have done before, but could you recap any and all mods you have on the truck as it sits now? It would be nice to reference what you have on the truck in a post close to the dyno chart so people don't spend much time looking for the info.

Thanks!

And again, well done Kooks!

The mods list is very simple. NONE! This trail blazer was bone stock. This was the first mod. This is my wifes daily driver, but I can tell you after she drove it with the headers she now has the mod bug. I now have a to do list for her truck! LOL
 
#102 ·
Very nice increase! Well done Kooks!

novajoe, you probably have mentioned what you have done before, but could you recap any and all mods you have on the truck as it sits now? It would be nice to reference what you have on the truck in a post close to the dyno chart so people don't spend much time looking for the info.

Thanks!

And again, well done Kooks!
 
#104 ·
I would like to thank everyone who has helped out with this project. This would include the staff at Kooks and PCM of NC. I got the truck back from Kooks Tuesday night and you could tell right away that the motor was breathing better. If you floored it it came to life and had no hesitation, and the sound real didn't change that much (a little deeper). The first day it took a little bit for the computer to learn the headers but after 100 miles it was getting happy. Then this morning I dropped it off at PCM of NC and they worked their magic. The numbers are great but the seat of the pants meter put a smile on my face. I now have just over 250 miles on the new headers and even with being aggressive and having some fun (higher than normal rear tread wear) I still average 16.9 MPG. I expect it to be much higher once I return to normal driving and repeat a couple month average. I will say that this system is worth the investment. You will never have a cracked manifold, better looks and performance too. I anyone in the Charlotte area want to see it in person please let me know.

I will also be adding the E-fan setup from PCM of NC in the near future ( I got a look at it today and I think it would be a shame not to add it to the mods on the TB)
 
#111 ·
I will also be adding the E-fan setup from PCM of NC in the near future ( I got a look at it today and I think it would be a shame not to add it to the mods on the TB)
I recently installed the latest PCMforLess efan kit. Its been cold, but so far I'm very happy with it. I also have their big 3 wire kit, their tune, and an Airaid intake.

I really like this header and lately the exhaust sounds louder, seems like it is coming from under the hood. So the header would be a nice replacement for a cracked exhaust manifold.

If you add the efan and a cold air kit, I'd be interested in hearing your thoughts once the parts are installed and combined with the header.
 
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