Nameless Downpipe: Official 5th Gen GT Install Thread

Heck, you could probably just throw a second gasket in there, unless they're a lot thinner than I'm thinking they are. Seems like an easier way to test than finding someone to burn you out a custom spacer, unless the inner rings in those multi-layer steel gaskets need to sit inside something to seal.

Stock gaskets are probably about 1mm. There is no recess for sealing, just flat plate.

My truck's turbo has a similar overboost issue where a high flow exhaust cause over boost spike and/or boost creep. Porting the turbo helps, but it get worst with larger diameter downpipe (3" vs the stock 2.5") The enlarged downpipe opening (removing the wall in the turbo exhaust housing but that doesn't apply to LGT's) is the solution that fixes the problem. It isn't the most elegant solution. The factory down pipe is centered off the turbine housing and the wastegate air flow has to make a two 90 degree bends, one because the flange is in the way and 2nd to mix with the turbine gases. Anyway here is a picture, I wonder if something like this would help the LGT.

http://www.syty.net/forums/showpost.php?p=984664&postcount=2

http://www.syty.net/forums/showpost.php?p=984664&postcount=2

Side note: I just realized I think that is my picture. I had sold my downpipe to user and that looks like my garage floor and how I would have taken the picture.

So I got my housing ported by Boost Labs. Here are my takeaways.

First they are an awesome local shop. I couldn't ask for anything better. They ported and media blasted my housing very quickly.

#2 they know of nameless performance and were surprised at this situation.

#3 they said on their own accord that this is a poorly designed housing.

#4 they suggested if there are still overboost problems after this, cut off the circular protruding piece on the DP because in their opinion it interferes with savaging of the exhaust.

#5 they wouldn't recommend changing the flapper and opening the hole further because they've seen situations where changing the lever can cause the mechanism to seize once things heat up.

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So I got my housing ported by Boost Labs. Here are my takeaways...

 

#3 they said on their own accord that this is a poorly designed housing.

 

#4 they suggested if there are still overboost problems after this, cut off the circular protruding piece on the DP because in their opinion it interferes with savaging of the exhaust.

That's the second shop that's said this in the last 30 days.

I don't see much porting in there.

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I don't see much porting in there.

 

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I think they did a fine job. They ported what needed to be ported. They knocked out that large lump, made a straight path, and made a tapered edge to the waste gate.

I believe I'm going to also take their advice and cut some out of the DP. I can feel the flapper interfering with the dp.

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I'm going to end with this. IMO there is a design flaw with the dp.

If your were to pick this up with no knowledge of this issue you have a high chance of overboost. The reason I believe is because of their directional separator. The waste gate will jam against it if you don't mount it perfectly. And that's completely dumb. The waste gate won't open fully and you'll be over boosting or it will scrape past eventually and be stuck open. This is what nameless was attempting to say when they mentioned move it in some direction. That 1 or 2 mm adjustment could mean the difference between a new engine. And if you're just doing an install that should be as straightforward as it looks and sounds who's really checking to see if their waste gate has proper room for travel? Look at my vid and see how much difference that 2mm makes.

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That's interesting, but even with clearance they made for the wastegate travel the actuator doesn't move the arm that much. Are you planning to find a longer throw actuator.

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The one I tested showed about half that movement. The arm stopped a few mm from coming into contact with the housing.

Fully open.

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I'm going to end with this. IMO there is a design flaw with the dp.

 

If your were to pick this up with no knowledge of this issue you have a high chance of overboost. The reason I believe is because of their directional separator. The waste gate will jam against it if you don't mount it perfectly. And that's completely dumb. The waste gate won't open fully and you'll be over boosting or it will scrape past eventually and be stuck open.

And if you remedy the interference by chopping off the part of the main dump pipe that extends into the exhaust housing, you lose the effect that Nameless was going for, namely having the flow from the turbine pass through the cat and the wastegate flow bypass it. Chop it down and as much gas as can flow through the bypass pipe will, until that's choked and the rest will go through the cat. So the cat then becomes kind of useless with so much gas bypassing it, and there's so much of the turbine flow going through the bypass pipe that wastegate flow will have to compete with it for flow capacity.

The one I tested showed about half that movement. The arm stopped a few mm from coming into contact with the housing.

That looks like about 20*, which I agree is not a whole hell of a lot.

...that video was actually pretty helpful. Also just double checking, the AVO cbe should be

Just bolt up to the Nameless dp right?

I'd have to go look through the group buy thread to figure out who, but I thought someone did exactly that. The AVO midpipe is long enough to where you wouldn't need the "intermediate pipe" section of the Nameless DP, and the split on both is in the same location as where the stock parts split. Only thing I'm not sure on is pipe diameter at that split- something sticks out in my mind about the AVO being 2.5" at the interface to the stock downpipe section, which would require a 3" to 2.5" adapter, but I could very well be wrong about that.

edit: looks like that would be eckseleven.

That's interesting, but even with clearance they made for the wastegate travel the actuator doesn't move the arm that much. Are you planning to find a longer throw actuator.

 

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Idk, I made that clearance. As far as a different actuator, I'm not going to go that far unless the boost situation stays out of control. Last resort.

http://www.forgemotorsport.com/?p=Actuators&page=1

https://www.maperformance.com/collections/wastegates-actuators/products/grimmspeed-adjustable-iwg-mounting-bracket-subaru

And if you remedy the interference by chopping off the part of the main dump pipe that extends into the exhaust housing, you lose the effect that Nameless was going for, namely having the flow from the turbine pass through the cat and the wastegate flow bypass it. Chop it down and as much gas as can flow through the bypass pipe will, until that's choked and the rest will go through the cat. So the cat then becomes kind of useless with so much gas bypassing it, and there's so much of the turbine flow going through the bypass pipe that wastegate flow will have to compete with it for flow capacity.

 

That looks like about 20*, which I agree is not a whole hell of a lot.

Yeah...Idk man. This whole thing is aggravating. For this dp to work were literally doing precautions to make things compatible. Modifying the turbo, then maybe modifying the DP, then my thought of altering the WGA.

Since I know there's an installation issue I'll mount it pushed and pulled or whatever nameless said. Manually operate the arm to check for clearance. Then if OB happens I'll get to cutting.

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...that video was actually pretty helpful. Also just double checking, the AVO cbe should be

Just bolt up to the Nameless dp right?

I'd have to go look through the group buy thread to figure out who, but I thought someone did exactly that. The AVO midpipe is long enough to where you wouldn't need the "intermediate pipe" section of the Nameless DP, and the split on both is in the same location as where the stock parts split. Only thing I'm not sure on is pipe diameter at that split- something sticks out in my mind about the AVO being 2.5" at the interface to the stock downpipe section, which would require a 3" to 2.5" adapter, but I could very well be wrong about that.

 

edit: looks like that would be eckseleven.

Nameless DP will bolt right up to the AVO CBE. cww516 is right about the intermediate pipe that comes with the DP. You won't need it. I purchased just the DP from Nameless for this reason.

No adapter needed. AVO CBE is 3" from the Y at the mufflers all the way forward.

Nameless DP will bolt right up to the AVO CBE. cww516 is right about the intermediate pipe that comes with the DP. You won't need it. I purchased just the DP from Nameless for this reason.

 

No adapter needed. AVO CBE is 3" from the Y at the mufflers all the way forward.

Does this mean that we could just swap out the Nameless downpipe for an AVO one?

....not that I'm considering doing that or anything.

^Yep. I don't see why the AVO DP wouldn't bolt right up to the Nameless intermediate pipe since it works in reverse.

Who would do that though???

In all seriousness though, the AVO DP is pricey unless you can find a used one for cheap. For the cost of purchasing and swapping, you could get your wastegate ported and have a lot of cash to spare.

^Yep. I don't see why the AVO DP wouldn't bolt right up to the Nameless intermediate pipe since it works in reverse.

 

Who would do that though???

 

In all seriousness though, the AVO DP is pricey unless you can find a used one for cheap. For the cost of purchasing and swapping, you could get your wastegate ported and have a lot of cash to spare.

I'm not completely convinced that properly porting the turbo will let you run an aftermarket BPV with this downpipe. I'd also like to think getting just an AVO downpipe is cheaper than some other options for where I am at.

I'm just considering things.

I'm not completely convinced that properly porting the turbo will let you run an aftermarket BPV with this downpipe. I'd also like to think getting just an AVO downpipe is cheaper than some other options for where I am at.

 

I'm just considering things.

I looked into getting an AVO dp at some point. I may have posted about it but I don't remember. That pipe could be a great option but when I was looking it was impossible to find, one website I ordered from listed it in stock and charged me right when I purchased it, then proceed to call me later that day to tell me they actually didn't have it in stock

The worst part about this is that since the part is so troublesome we cant even sell it to anyone else in order to get some money back. So its either build the car around the DP or count the loss.

Maybe I'll make the most expensive mantle ornament I've ever owned, or cap the ends and make a really cool urn. Cause at this point both of those options are less of a headache than putting it on my car.