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Vee Dub Nut.....two questions.....I always thought the BOV should be as close to the TB as possible ? And what was the reason and/or engineering behind running a 'Y' intake as opposed to a 'T' style intake manifold.

Having the BOV close to the TB is "supposed" to improve boost response between gears. From my research it ultimately doesn't matter. If you look at modern turbocharged cars, most of them have the BOV or bypass valve integrated with the compressor housing like the VW 2.0T does.

-Nick-

panel wrote: ↑Sun Dec 10, 2023 3:56 pm Vee Dub Nut.....two questions.....I always thought the BOV should be as close to the TB as possible ? And what was the reason and/or engineering behind running a 'Y' intake as opposed to a 'T' style intake manifold.

Hey Panel

RE: BOV location:

I picked pre-intercooler primarily because I intend to still add some provision for water/meth injection downstream of the intercooler (if/when i really lean on the car), and I simply wanted to the BOV to be sufficiently away from that point as to not vent any water/meth out of the intake during shifts/blow off events.

I did a bunch of reading about ideal BOV location, and it seems to be pretty split into two camps: 1) as close to the throttle body as possible, and 2) as close to the turbo as possible. Both have their arguments as to why. In practicality, even OEM's have them in a wide range of locations/configurations, and I just don't think it matters as much as we tend to think it does, so long as you have one in there.

RE: Y vs T

In general a fabricated Y should have a lot better flow coefficient than a hard 90/tee. Since I'm injecting fuel at the plenums out at the heads, I opted for the Y to make that transition behind the throttle body to be a smooth as possible for the air flow. I've read that for draw through setups (or other setups that inject fuel before that part of the intake), that the T is preferred to introduce more turbulence to help with fuel mixing. No first hand experience with that though. I've used a hard tee on my old port injected EFI turbo setup in the past, and just opted to fab up a nice smooth Y this go around. Another one of those things that I think matters less in actuality than we tend to think, but technically the Y should flow better.

nbuscemi wrote: ↑Sun Dec 10, 2023 7:24 pm Having the BOV close to the TB is "supposed" to improve boost response between gears. From my research it ultimately doesn't matter. If you look at modern turbocharged cars, most of them have the BOV or bypass valve integrated with the compressor housing like the VW 2.0T does.

-Nick-

Yea, that is the same justification I saw for BOV close to the TB when I researched it.

I just noticed your signature... are you located in Texas?

nbuscemi wrote: ↑Mon Dec 11, 2023 6:29 pm I just noticed your signature... are you located in Texas?

Was.. Born and raised there, went to A&M, and the wife and I lived in San Antonio after school up until 2018. Now in the greater Atlanta GA area (where the wifey is from).

Vee Dub Nut wrote: ↑Mon Dec 11, 2023 9:03 am
RE: Y vs T

In general a fabricated Y should have a lot better flow coefficient than a hard 90/tee. Since I'm injecting fuel at the plenums out at the heads, I opted for the Y to make that transition behind the throttle body to be a smooth as possible for the air flow. I've read that for draw through setups (or other setups that inject fuel before that part of the intake), that the T is preferred to introduce more turbulence to help with fuel mixing. No first hand experience with that though. I've used a hard tee on my old port injected EFI turbo setup in the past, and just opted to fab up a nice smooth Y this go around. Another one of those things that I think matters less in actuality than we tend to think, but technically the Y should flow better.

I think the reason a T works so well in reality might just be that flow in the manifold (and headers) is not one-way all of the time.

Only recently fully understood the impact of turbo exhaust manifold back pressure vs intake pressure and how it affects camshaft selection. Definitely an “ah!” moment.

Although maybe that’s not relevant to your point