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Nameless Downpipe: Official 5th Gen GT Install Thread


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It'll be interesting to see what, if any, differences there are between the GB DP and the one Swannee was using.

 

Swannee's DP is coming my way in a few weeks. I plan to install the GB DP and see if I have any issues. If so, I will install Swannee's. If there is no issue with that one, then we have some ammo to go back to Nameless with to show that their change in design for the GB DP caused issues.

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So can these ARP bolts be used in some other location (bolt on turbo, headers) or are they pretty much 40 bucks in the garbage?

 

The Totally Stainless bolts actually give just a hair more clearance than the stock studs IIRC.

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Didn't get a chance to pull a log for you guys last night. I did monitor target and actual boost this morning on my drive to work. Target is set to 18.5 psi and I was actually underboosting a bit, it was 50 degrees outside and I think the highest I saw was about 16.9 that wasn't a nice long pull but I remember when it was first tuned it could easily hit 20+ by about 5k. I'll keep watching it on my way home and try to see if I can get it to overboost again.

 

What gear did you do the pull in? Your best chance of overboosting will be in higher gears. I wouldn't personally go WOT in 6th or probably even 5th at low RPM, but a 4th gear pull might get you to spike a little bit if you were doing your previous pull in a lower gear.

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The Totally Stainless bolts actually give just a hair more clearance than the stock studs IIRC.

 

I was under the impression that the TS bolts could have been the source of my problems initially. The OEM studs have the shoulder area to help locate the whole DP assembly to the turbine housing and that shoulder area is just a tiny bit smaller than the TS bolts.

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What gear did you do the pull in? Your best chance of overboosting will be in higher gears. I wouldn't personally go WOT in 6th or probably even 5th at low RPM, but a 4th gear pull might get you to spike a little bit if you were doing your previous pull in a lower gear.

 

Usually I do 3rd gear pulls when I'm trying to monitor. I think its creeps more when I get into boost quickly as oppose to rolling into it. I'll try 4th gear on the way home.

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I was under the impression that the TS bolts could have been the source of my problems initially. The OEM studs have the shoulder area to help locate the whole DP assembly to the turbine housing and that shoulder area is just a tiny bit smaller than the TS bolts.

 

I think you're right. Couldn't remember for sure.

 

Maybe jojorios can sell them to someone with another brand of DP.

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Found out I accidently unsubscribed from this post. When I installed the Dp for the first time I did not have any issues whatsoever. That was with McDowell stg 2 tuned. No over boost issues then. After my engine rebuild and BNR 20G with ported wastegate. I was having over boost issues. But they were not related to the Downpipe at all. The issue with mine was the actuator arm after the wastgate was hitting the heat shield on top of the turbo. I was concerned about the wastegate not opening due to clearance with the DP but that was not the case, as I took off the down pipe and hooked up an air compressor to the wastgate and physically saw the flap stay closed but the whole heatshield shifted when the air was applied. I marked where it needed to be cut and removed about a 2-3 inch section from the heatshield. After I installed it again. My overboost issues were gone.... I have the Original design for the downpipe. Not the Group buy one. And I'm also at elevation. About 3500ft.
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.... After my engine rebuild and BNR 20G with ported wastegate. I was having over boost issues. But they were not related to the Downpipe at all. The issue with mine was the actuator arm after the wastgate was hitting the heat shield on top of the turbo....

I marked where it needed to be cut and removed about a 2-3 inch section from the heatshield. After I installed it again. My overboost issues were gone....

 

SMOOVE this could be your fix

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Considering the size of the wastegate I wouldn't think a different bend in the tube would cause any issues especially with the size relative to the wastegate.

 

If the flow from the main pipe is diverting into the wastegate dump pipe it could be causing back pressure on the flapper. I could see that happening on the GB DP, not on the original design the Swannee has.

 

On the other hand, the Nameless DP might just flow so much better than any other DP on the market (being that it completely separates turbine flow from WG dump) that it's just superior, and causing problems as a result.

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That's what I was thinking. The size of the tube is much larger than the waste gate and it's pretty short. I just don't see it being the limiting factor.

Besides, isn't the turbo spun mostly off of thermal expansion? That would mean you wouldn't need a real big leak to relieve it.

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If the flow from the main pipe is diverting into the wastegate dump pipe it could be causing back pressure on the flapper. I could see that happening on the GB DP, not on the original design the Swannee has.

 

On the other hand, the Nameless DP might just flow so much better than any other DP on the market (being that it completely separates turbine flow from WG dump) that it's just superior, and causing problems as a result.

 

If that were the case the more free flowing systems would have less of an issue because there would be less pressure in the main pipe to back feed the wastegate pipe. It is more likely the wastegate itself is not sufficiently sized to release the pressure.

 

More back-pressure would cause greater over-boosting if that were the case. It would be nice to hear from Nameless on this thread, to see what their thoughts may be.

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As much as it sucks to say it I think that this may be a flaw in our turbos. Sounds like as soon as we get exhaust that can flow freely enough the WG just is not able to slow down the turbine. Even in some cases it sounds like with a ported WG. Could be just a problem with the WG flow design. All I know is that it sounds like we just need to have a restriction in the exhaust somewhere to inhibit flow through the turbo a bit.
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