Thread: OBX EL header
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Old 06-02-2006, 07:19 PM   #52
Patrick Olsen
NASIOC Supporter
Member#: 120
Join Date: Jul 1999
Chapter/Region: AKIC
Location: Where the Navy sends me...
1997 Legacy 2.5GT
1996 Impreza coupe


Got my header at the end of last week and took some pics this evening before I go about installing it. I'm generally pretty impressed by the quality of construction, the welds look good, flanges are pretty thick, and it's got a nice shine to it so my neon should reflect of it really well. That's just the visual impression - they look nice - but I wanted to do a little more detailed inspection before I put them on.

The one thing I particularly wanted to check on was how straight/flat the flanges are. As soon as I took the header out of the box and laid it on the floor I could see that the forward flange on the little mini mid-pipe was not straight. Here it is loosely assembled:

And here it is by itself with a straight edge held flush against one side:

That's a pretty significant amount of misalignment, way more than a gasket will be able to make up, so that'll need to be fixed/replaced.
Edit: I put the two parts together and tightened the bolts down and the flange misalignment closes up nicely. So, disregard the above statement, I just underestimated how much the flanges would deflect when actually bolted together.

The other thing I noticed pretty quickly is that the piping necks down significantly where it joins the OEM mid-pipe. You can see it's smaller just before the flange here:

I put a vernier caliper on the opening at each end of the mini mid-pipe and found it's 2.25" at the inlet, but only 1.75" at the outlet. It's not a huge deal, but since I've got an aftermarket mid-pipe already (from my current MRT setup) I'll be chopping off that necked down section of piping so I can have 2.25" all the way through.

Last but not least, I checked the flangers where the header will mate up to the heads. I've had some issues blowing out the gaskets on my MRT header, but have never bothered to check the flanges to see if they're "square" or not - I guess they must not be. Anyway, I put the straight edge front-to-rear on each flange and they seem pretty good...


... and passenger:

Neither of them is flat (the PS picture was taken a little low, so you really can't see that it's not quite flush all the way across), but the variation is pretty small.

I then laid the straight edge across the two flanges side-to-side. It laid flat on the passenger side flange, but it appears the driver side flange is canted inward a bit:

Again, I think that's more than a gasket can make up, but torquing the flange onto the head might pull that into alignment.

The last thing to do is measure across the front of the header to see how the flanges will line up with the heads, as it seems some people have gotten headers that were a little off in that dimension.

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Last edited by Patrick Olsen; 06-03-2006 at 08:41 PM.
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