HIS4

It appears that the have machined an adapter to allow the stock inlet piping to be used for the Garrett turbos. Now, isn't the Garrett turbo inlet larger than stock? So by reducing the inlet size, does this limit the flow of air into the turbo and affectively limit the power output such that you would never be able to use the full potential of the turbo?

I'm no expert but it seems like that's what I was reading. Hopefully someone with a little more knowledge than myself will chime in here and clarify this.

Todeshandler

Yes you are correct. Inlet size does "limit the flow of air" "affectively limiting the power output"

davenew

Most people simplify and consider the pressure ratio as the boost you're running compared to atmospheric pressure. It's actually what you would measure between the output and inlet, right at the compressor. If you have vacuum at the inlet, you're really running a higher pressure ratio than you think. All that means is the turbo is running slightly faster rpms and the efficiency is slightly lower.

If the garrett turbos can handle the higher pressure ratio to generate the same outlet boost, I doubt it's very noticeable. I wonder how high the vacuum gets at the turbo inlet with the K03 pipes?? With K04 turbo inlet pipes, I only measured a max of around 5-6 inches of water. For reference, 1 psi is around 27-28 inches of water.

It sounds to me like they realized the turbos can handle it and the gain isn't worth raising the cost of the kit to include custom inlet pipes.