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Discussion Starter · #1 ·
Just got my new setup in the mail. Went with OBX 1 7/8 headers with 3" X-pipe. After reading several threads about these I decided to go for it. After initial inspection, I'm very pleased. Used a level to check the flange and everything is straight and perfect there. All the welds look very good too. They were packaged very well but I did notice they have quite a few nicks and small scratches... Probably from the way they were stored at the warehouse I guess. NO big deal though because they will be under the car and get more.

I would like to get the headers and x pipe section ceramic coated but I really want to install them asap not sure I want to wait for the coating... You think its worth it? probably will be about $350.

CALLING ALL OBX AND KOOKS OWNERS!! QUESTIONS...

1. I looked inside the X-pipe and the hole that ties the two pipes together seems rather small. I've never owned or seen this inside of another X pipe, but I just figured that merge or hole would have been larger.

2. The X pipe section after the actual "X" there is a slight bend in pipe giving it a slight arch. Is this normal? My guess is this "arch" is to help provide clearance over the tunnel brace?
 

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They look like a nice piece overall. If you're that concerned about the X you could get a new one welded in once it is on the car. Up to you, drive it for awhile and if you like it I say leave it.

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Discussion Starter · #4 ·
Interesting opinion on ceramic coating headers. Quote from "ChucksTuning" on houstonperformancetrucks.com

"This is just my experience from what I've seen in making headers. Another thing we could go into is coatings, and how much I dislike them on headers Ceramic coated headers always seem to cause detonation. Why? Well everybody jumps on this bandwagon of wanting to keep underhood temps down. Which is great, I love it, whatever you can do to keep underhood temps down is going to help make the motor produce more power. But what we're doing by ceramic coating the headers is we are locking that heat inside the exhaust... Not allowing it to dissipate... This heat now acts as an agent in producing detonation. Almost every car I've ever tuned that had ceramic coated headers, was not able to take as much ignition timing as a car with uncoated stainless steel headers. So the power was greatly reduced because instead of tuning for all out power, I had to tune for detonation. Extra fuel, and less timing... Things that have a great effect on what kinds numbers your car will put down on the dyno, and at the track".

Opinions.......?
 

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Discussion Starter · #5 ·
They look like a nice piece overall. If you're that concerned about the X you could get a new one welded in once it is on the car. Up to you, drive it for awhile and if you like it I say leave it.

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Definitely will not be doing any cutting and welding to this but just curious about the size of the cutout hole is all. Maybe someone would chime in and say "most look the same as that", or "Yes that does look to be on the small side".

Not worried about it, just wanted to look into comparisons.
 

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Interesting opinion on ceramic coating headers. Quote from "ChucksTuning" on houstonperformancetrucks.com

"This is just my experience from what I've seen in making headers. Another thing we could go into is coatings, and how much I dislike them on headers Ceramic coated headers always seem to cause detonation. Why? Well everybody jumps on this bandwagon of wanting to keep underhood temps down. Which is great, I love it, whatever you can do to keep underhood temps down is going to help make the motor produce more power. But what we're doing by ceramic coating the headers is we are locking that heat inside the exhaust... Not allowing it to dissipate... This heat now acts as an agent in producing detonation. Almost every car I've ever tuned that had ceramic coated headers, was not able to take as much ignition timing as a car with uncoated stainless steel headers. So the power was greatly reduced because instead of tuning for all out power, I had to tune for detonation. Extra fuel, and less timing... Things that have a great effect on what kinds numbers your car will put down on the dyno, and at the track".

Opinions.......?
A proper tune should take care of any detonation (unsure as to why he says this, detonation is a GOOD thing, as this is what makes power. PRE-DETONATION is the bad thing...) issues that may arise.
 

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The heat stays in the pipe, not the engine. Now if the exhaust is a restriction, the now hotter exhaust might have some reversion back into the cylinders. That could cause some added heat and detonation.
 

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heat in exhaust piping speeds up the exhaust flow which results in faster evacuation of spent exhaust gasses. Plus, as the engine is driving (airflow from forward movement) the headers that are exposed under the car (weather coated or uncoated) are cooled by the relative cooler air that is in contact with them at speed. When idling, uncoated headers will increase underhood temps more than when idling with coated headers, from my understanding.

I wouldn't think too much about it, figure out if you want coated or not, and go for it. After the insides of the pipes have a few thousand miles of carbon built up on the INSIDE of the pipes, then it's probably a wash anyways.

My headers (kooks) are coated and I have had no problems. Mine look nearly as new as when I bought them, and I drive year round through salt, snow, rain, you name it... so I am glad that I got mine coated.

Good luck in your decision.
 

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While I have no experience at all with X-Pipes, I do know that this is a "kissing" type X-Pipe.

The theory of any type of crossover is to balance exhaust pulses and often times create a scavenging effect. The exhaust in the left bank will push through the 3" section and create a suction as it passes the "kissing" area, thus creating a vacuum in the right bank. I really don't think you want a full 3" opening in this area unless your going with a true X pipe.

There are a lot of articles on X and H pipes and each claim theirs are better.
 

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Definitely will not be doing any cutting and welding to this but just curious about the size of the cutout hole is all. Maybe someone would chime in and say "most look the same as that", or "Yes that does look to be on the small side".

Not worried about it, just wanted to look into comparisons.
You might not realize the function of the x-pipe... which simply "Excites" the two otherwise-disjoint banks of exhaust gasses when they merge. It somewhat effects sound (more even sound) but it mostly "balances" the exhaust pulses from side to side as the firing order is rolled through. Do you need a bigger hole? Most likely not...

the function of the hole inside the x-pipe is to release kinetic pressure built up between the banks.

If you have a straight exhaust, at certain times during the firing order, one side will have high pressure (due to combustion exiting the chambers on that side of the engine) whereas the "other side" of the straight exhaust would be low pressure as it prepares for the combustion event. Without the x-pipe in place, these two disjoint "pathways" cannot ever merge, and sound and pattern is noticable.

WITH the x-pipe, the pressure differential is able to normalize from the "high pressure side" to the low pressure side (via your xpipe's hole) which smooths out the pressure differential, effects sound output, and makes the car "purr" just a little smoother.

I'd say throw on that x-pipe and run like that for a while, you'll like it. Anything above stock mousemode is an improvement, and an Xpipe design seems to work well for GM LS engines.

--zep

EDIT: TLS beat me to it, ah well
 

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Discussion Starter · #11 ·
Thanks everyone for the info and replies. Thing is I know plenty about x pipes, h pipes, difference, benefits, and the difference between sound on straight pipes verse the balancing from the x pipe.

All I was asking is if anyone thought the hole was on the small side lol.

It's hard to see in the pics but on one side u can see the pipe was cut more oval and a little larger, then the other side it's more circular and smaller. So therefore why you "see" and will result in the small size hole. I'm sure it's fine but looks like it could be trimmed a bit, if I had a way to get in there. I need a dremel with a 1.5' extension haha
 

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That might be simply the afterproduct of merging the two pipes at a wierd angle, maybe they don't have a jig and were just "eyein it up".

Sorry for the lessons if they weren't wanted. lol

I'd say it's good as it is; leave it and install it and enjoy the results.
 

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ya that looks like that pipe they welded together didnt get cleaned up well. Most probabaly is not a big issue if you are in a hurry to get the exhaust on. Otherwise contact OBX and verify that other x-pipes are the same and request a replacement.

Some small issues you have to deal with for a slightly "cheaper" exhaust option.

Can you point out in pictures exactly where the OBX pipes go from 3" to 2.5" ?

Thanks for sharing!!
 

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Discussion Starter · #15 ·
I would LOVE to see the same pics I took but of the KOOKS x pipe! (marylandspeed please)

sure I can take a picture of the 3" to 2.5" pieces.
 

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Can you point out in pictures exactly where the OBX pipes go from 3" to 2.5" ?
Same place the Kooks do...

First post, third picture (the one with the whole system on the living room carpet), the very bottom is where the next section bolts on. From that connection rearward, they drop to 2.5"
 

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Same place the Kooks do...
First post, third picture (the one with the whole system on the living room carpet), the very bottom is where the next section bolts on. From that connection rearward, they drop to 2.5"
Thanks for the info. Anyone know off hand what the stock GXP pipe sizing is in that area ? 2.25" I believe?
 

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Discussion Starter · #20 ·
SRG,

Do you know about the bend in rear section of the x pipe? I took a pic of it. should the bend face upwards like ^ or downward like v. just thinking logically it looks like I have it correct in the picture with the bend facing upward.
 
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