S5 stock maniold, external dump

[sen2two]

Here's a sneak peak at this for now. I have been seeing here, and other places, where people want to fix the whole boost creep, and boost dropping off before peak RPM. One way is to get an upgraded Garrett internal gate that is very similar to our stock wastegates, and port the wastegate areas on the turbine housing. This works well for a lightly modded car, but some still need more. Especially if the motor is ported, running higher compression, or runnning a hybrid turbo.

Now it has been done a few times on the much larger S4 manifold. But with the very small compact S5 manifold, and divided runners, making an external dump far more complicated. A few people have also kept the stock wastegate area but separated the down pipe area and wastegate area for an external dump. This still poses a problem with releasing enough exhaust pressure through the holes in the turbine housing. Making creep and drop off less noticeable, but not getting rid of it.

Here is what i am going to do to fix the problem. A one inch hole in each runner, meeting at one point with a 38mm external wastegate.

Pics do much better than words.

(I'll update after it's all welded up and finished, I got side tracked with another project and didn't get t finish)


Holes were done with a bridgeport mill. Now I know not many people here will have access to a machine like that. but its not hard to drill a hole with a hand drill and port it out with a die grinder.









Got some pipe and turned it down slightly in a lathe to fit very snuggly in the holes. I'm all about tight fits,














Cut some pipe and mocked it up. A little trimming and grinding, and this will all fit nicely. There's actually a pretty good amount of room below the manifold to come up with your own design. Just take some measurements and get to cutting!