Leaderboard

Bought another one, oops Sent from my SM-A530F using Tapatalk

You trade off making your car slower and kinda raping your turbo in exchange for a bit of "sututututu" noise. Each to their own, but IMO there's a pretty good reason Mr Subaru put a BOV on the car in the first place.

Various links to Subaru FSM’s i’ve come across that may help some of you who haven't yet found one relevant to you. Note there are manuals from multiple regions present which are useful for general tasks but specifics such as wiring/engines/transmissions vary so use with caution in those cases. https://sl-i.net/FORUM/showthread.php?18087-Subaru-Factory-Service-Manuals-(FSM)-Every-Model-USDM-EU http://jdmfsm.info/Auto/Japan/Subaru/ http://people.csail.mit.edu/ilh/vacation/

Any reason why you want compressor surge?

See Prestige Tuning & Motorsport's post on facebook today? Additional front mount lag looks like 100rpm or so. Factory location turbo and manifold, basically longest routing and large volume to fill. Given those results I'd be trying to get as little pressure drop and not really be concerned with volume to fill (with in reason), so 2.75" all round shouldn't hurt.

Read all that and got this as well. tight bends are bad intercooler core design is the biggest factor for real world. Which makes sense as there are some terrible designs with nasty bends at the entry and tiny passages through them. pipe size makes little difference compared to those two if like @A_J_T said you stay about the outlet size. other than that's is complex physics interactions wizardry no one really can explain well that makes little difference.

I've read many threads on this before, these two are good value. https://forums.nasioc.com/forums/showthread.php?t=2399163 https://forums.nasioc.com/forums/showthread.php?t=2648685 My 2c, I think at lower power levels like we are all dealing with 400kw- then its not a massive contestant in the game. As long as you are not going smaller than your turbo outlet things should be good. Smaller pipe is easier to work with and route through the engine bay. I went 2 hotside and 2.5 cold into a 2.75TB

That is the theory, I did write that poorly, meant area to expand into to drop the speed. But to have increased velocity won't you have more pressure and therefore heat since it is a confined space? Also wouldn't it be ideal to have matched to throttle size for when the throttle opens then the pressure wouldn't drop from the expansion of going through the larger throttle area. Like using it as a storage tank for the already pressurized and cooled air. it may be a balance between less ideal in the pipe and more ideal in the cylinder. maybe that also gets balanced with throttle response. Ok at this point it does my head in as too many factors. Need someone with flow modeling software to try it. Someone must have somewhere on the Internet.

Hmmm. Pressure, density & velocity. Higher pressure would increase response (thought test this using extremes of density). Velocity is where we lack understanding, right? From Murch's old post, thin headers are the win. Was this due to velocity or pressure, and as you state @Not_Sean, due to the interaction with another part of the system in regards to either temperature or a bottleneck/step change? Almost need a napkin and a mech engineer who understands fluid dynamics 101