Originally Posted by tank the ek
So I recently purchased a catless downpipe for my 2011 subaru wrx. The catless downpipe I purchased uses a divided design in contrast to the bell mouth design. From what I have studied and understood, the divided design is utilized to help separate the main stream of exhaust gases, from the gases used to bleed of from the internal waste gate.
It is common knowledge that the catless downpipe design can, and usually does create a boost creep situation, that cannot be remedied through tuning solutions. Due to this flaw, the use of an external waste gate must be installed to accurately regulate boost levels.
This all leads me to the question of why would companies design a product with a design the is aimed towards one setup (internal wastegates) while the product itself almost always requires a different setup (external wastegate)?
Am I looking at this the wrong way while there are other solutions to this issue(and if I am, please advise me on my best direction to go into) or are these products truly counteracting their purpose? I understand that companies like the one who created the product I purchased have years of research and development with their design, but this just seems crazy to me. Please, no flaming, and no pissing contest on which product is better/ bashing reputable companies. Just looking for someone with maybe a little more experience or just complete knowledge on why these products were created this way. Thanks in advance.
Because it doesn't happen on every car. And on most internally gated aftermarket turbos it is not an issue either. You can have the wastegate ramp ported/polished on the stock turbo help reduce the boost creep issue.