AVO "Stage 2" Build

[qtwre]

Presumably to have the headers refaced you would have to remove the turbo from them, right? Would that require a new turbo gasket to put back together? Maybe it doesn't even need to be disassembled. I don't know how the surfacing process works.

I haven't installed mine yet but I'd hate to have to buy a new turbo gasket before I even knew if there was a problem.

[gdrider77]

Originally Posted by qtwre

Presumably to have the headers refaced you would have to remove the turbo from them, right? Would that require a new turbo gasket to put back together? Maybe it doesn't even need to be disassembled. I don't know how the surfacing process works.

I haven't installed mine yet but I'd hate to have to buy a new turbo gasket before I even knew if there was a problem.

yes, you are correct. Will need to pull off most of the assembly, then remove the manifold. T25 gasket needed to replace

[King Tut]

Originally Posted by gdrider77

Latest update on my car.......failed welds on manifold.....

So noticed a significant amount of noise from below the car taht sounded like an exhaust leak. Lifted the car, and did an oil change and decided to pinpoint the exhaust leak as well. Like many others experienced, leaking at the mainfold-head flanges....well, i had the upgraded forester gaskets but those did not seem to hold, as there were clear visual build up/leaks, and also a very audible leak. Upon further inspection i saw that the header itself had broke a weld. So unfortunately, had to pull this all apart to get that part off.

I know I am late, but I couldn't resist, and I can't believe I haven't seen anyone use this meme yet for the AVO manifold issues:

[Swift]

getting them refaced isn't that simple. You need them to be on the same plane I presume, therefore when you bolt it up..it is not "bending" to meet the head causing it to be under more stress to break a weld.


So it would be a pita to do.

[AVOturboworld]

Originally Posted by Swift

getting them refaced isn't that simple. You need them to be on the same plane I presume, therefore when you bolt it up..it is not "bending" to meet the head causing it to be under more stress to break a weld.

There is a certain amount of flex in the Subaru header design, it's fairly unique in that it's two separate flanges that are connected up. Inline 4's, 6s, and even the V6's and V8's don't have to deal with that.

So the two flanges not being on a absolutely flat plain is not uncommon unless you went to a cast exhaust manifold. Even then, the Subaru cast manifold has a flex in it. Which has had cracking issues. And that's also what we've discovered over two decades of making and fitting Subaru exhaust manifolds, flex joints will fail.

Furthermore, once the exhaust manifold heat cycles, the pipes are naturally going to start moving. That's inherent to the Subaru design.

We know what the issue is with the leaking gaskets. The issue is that people are re-using their stock standard used gasket, which should be thrown out and replaced with new gaskets. There are many different aftermarket gasket thicknesses out there, and if they are too thick, they'll cause a height distance between the flanges at the exhaust manifold and at the bracket at the turbo that mounts to the block, which can pull the exhaust manifold up to 4mm. As a consequence, we will be supplying future kits with new exhaust manifold gaskets to make sure this won't happen.

Current customers of our kits, if they've fit a Grimmspeed or similar extra-thick gasket, they will need to put a washer between the turbo-side bracket and the block to space it out correctly so that it's not pulling down on the exhaust manifold.

[SkAsphalt]

Originally Posted by AVOturboworld

There is a certain amount of flex in the Subaru header design, it's fairly unique in that it's two separate flanges that are connected up. Inline 4's, 6s, and even the V6's and V8's don't have to deal with that.

So the two flanges not being on a absolutely flat plain is not uncommon unless you went to a cast exhaust manifold. Even then, the Subaru cast manifold has a flex in it. Which has had cracking issues. And that's also what we've discovered over two decades of making and fitting Subaru exhaust manifolds, flex joints will fail.

Furthermore, once the exhaust manifold heat cycles, the pipes are naturally going to start moving. That's inherent to the Subaru design.

We know what the issue is with the leaking gaskets. The issue is that people are re-using their stock standard used gasket, which should be thrown out and replaced with new gaskets. There are many different aftermarket gasket thicknesses out there, and if they are too thick, they'll cause a height distance between the flanges at the exhaust manifold and at the bracket at the turbo that mounts to the block, which can pull the exhaust manifold up to 4mm. As a consequence, we will be supplying future kits with new exhaust manifold gaskets to make sure this won't happen.

Current customers of our kits, if they've fit a Grimmspeed or similar extra-thick gasket, they will need to put a washer between the turbo-side bracket and the block to space it out correctly so that it's not pulling down on the exhaust manifold.

Well crap... (grimmspeed gaskets here)

[AVOturboworld]

It's not the end of the world - check if there is tension on that bracket next to the turbo, if there is, unbolt and use a washer or two to take the tension out of it. It's to take the load off the manifold at the exhaust port end, not to hold it down tight.

[SkAsphalt]

Originally Posted by AVOturboworld

It's not the end of the world - check if there is tension on that bracket next to the turbo, if there is, unbolt and use a washer or two to take the tension out of it. It's to take the load off the manifold at the exhaust port end, not to hold it down tight.

Will do! thanks

[gdrider77]

yeah, as paul suggested, i put in a couple washers. Mine had about a 3mm gap due to the larger grimmspeed gaskets.

[SkAsphalt]

Sounds like a very easy fix (cause who does not have a million washers laying around) so I wrote this down on my install guide and will do it once the weather here is not abysmal

[tiny41]

grimmspeed gasket here and it is definately leaking...
Will most likely change it again when I change the oil soon

[gdrider77]

So just pulled off my old exhaust and having a new custom 3" one done. One issue i had with spacing out the manifold with the thicker gaskets is that now the overpipe wouldnt fit without banging on the crossmember. So rather than keep fighting that, i decided to have a custom 3" overpipe back made.

It was really tight before with only a few mm gap, and so just spacing out the manifold by that 3-4mm really made it off. I see this as an issue for others that use thick gaskets, and then decide to put a larger overpipe in there. There is room for a larger overpipe, but getting it to line up with the discharge pipe might be an issue for some.

Will post pictures once done.

[Pitman]

Originally Posted by gdrider77

So just pulled off my old exhaust and having a new custom 3" one done. One issue i had with spacing out the manifold with the thicker gaskets is that now the overpipe wouldnt fit without banging on the crossmember. So rather than keep fighting that, i decided to have a custom 3" overpipe back made.

It was really tight before with only a few mm gap, and so just spacing out the manifold by that 3-4mm really made it off. I see this as an issue for others that use thick gaskets, and then decide to put a larger overpipe in there. There is room for a larger overpipe, but getting it to line up with the discharge pipe might be an issue for some.

Will post pictures once done.

I am looking forward to seeing you pictures - my car is booked in mid March to have a custom 3" overpipe / HFC pipe made (as well as sorting out the Ultimate Racing catback where it goes under the rear crossmember).

[gdrider77]

Originally Posted by Pitman

(as well as sorting out the Ultimate Racing catback where it goes under the rear crossmember).

What is the issue you currently have with this?