Here is the final core design

**Dawings33** · 07-29-2009

you really should have seperated the BBV and the core from one another. This design will allow boost to bypass the core. It is not much but I would consider a small change when you start producing them.

**whitelightnin04MC** · 07-29-2009

Originally Posted by Dawings33

you really should have seperated the BBV and the core from one another. This design will allow boost to bypass the core. It is not much but I would consider a small change when you start producing them.

I don't really see what you're getting at? When the BBV is open, the boost is going past the core, through that little hole. The BBV is closed in most circumstances. It only opens when you're in reverse, in decel, when the engine temp gets too high, and when drivetrain abuse is detected.

Is it that beneficial to have the BBV hole part covered by the core? Is ZZP's core like that? It wouldn't keep me from buying this setup over ZZP's.

Maybe I'm just not understanding what you are talking about. Hopefully you can explain it a little further so that I can get a better grasp on it.

**thomasj** · 07-30-2009

Just to keep people from being misinformed .

I think Boost will not bypass the core. The circle around your bypass hole in the blower will seal against the intercooler plate and seal any air from entering through here under boost. ZZP removes the H bar and does not use a bypass hole in their intercooler because they say it allows the use of a longer core and lets the boost pressure flow over more of the core area. I can tell you 90% of the heat is concentrated in the front half of the core so I really think its not needed. This design is just fine and that part of the core sticking into the bypass hole will not hurt a thing.

The bypass valve is closed only when you do not have vacuum. This greatly depends on throttle position and engine speed. If your at wot you have NO vacuum and thats what lets the bypass valve close. There is a spring inside the valve that closes it by default. When you idle or are at light throttle, driving down the hiway ect, manifold vacuum holds the valve open. Its open while cruising, Idling, or anytime there is manifold vacuum. When you open the throttle and lose vacuum it closes to keep boost pressure in the LIM where it belongs.

**Dawings33** · 07-30-2009

I never said it would leak boost out of the BBV. Anytime you flow through a core, expecialy one with a fin count this high there is some restriction placed on the system. Fluids will take the path that is most open. meaning air will be able to bypass the core and travel down the BBV tube. This is not a huge deal but as i said to the OP it is something to consider if he does any sort of redesign. Just for the record im not just nit picking I have actually made a few cores just never sold them for profit. Most were local sales for club members.
Full Phenolic with 2 inch core gen V

**explokid** · 08-07-2009

Originally Posted by Dawings33

I never said it would leak boost out of the BBV. Anytime you flow through a core, expecialy one with a fin count this high there is some restriction placed on the system. Fluids will take the path that is most open. meaning air will be able to bypass the core and travel down the BBV tube. This is not a huge deal but as i said to the OP it is something to consider if he does any sort of redesign. Just for the record im not just nit picking I have actually made a few cores just never sold them for profit. Most were local sales for club members.
Full Phenolic with 2 inch core gen V

looking at your post, then:

I see your point. A little more R&D is needed around the BBV.
A functional PCV would also be awesome, but one step at a time.