or better yet, pssssst psssst whoosh

 

unless you have proof (measurements) that it does delay the closing.

The turbo will not make boost when the bpv is open, so there is no pressure to push the BPV piston back against the spring while the BPV is closing. If the BPV is leaking, the overall boost drops rendering the spring more effective against the sum of the boost on the diaphram and inlet side.

I do see the point of having the lower pressure differential at the manifold area compared to the turbo outlet, plus the fact the pressure build up on the manifold will be delayed even more (with larger IC), but I think a well matched spring will take care of all.

The question is, with a 13-14psi "spring", will there be 13-14psi diffential from the turbo outlet to the manifold nipple, and for how long.

 

I am going by what I got with the valve on my car while running the TurboXS and a EVO fmic. When I switched out the valve for a bosch valve the delay was gone and when I put it back in again it was there.


You cant change spring rates in the stock bosch valves and I was using 5-6 washers in the turboXS and the delay did not go away and would just cause a honking noise since the valve would open and close 3 times, which would just cause a back lash of boost onto the turbo blade.

BTW how do you get that a turbo is not making boost while the BPV is open or leaking, do you for some reason think the bpv is a N75 valve or boost controller. The # 1 and only job of a BPV is to release boost pressure from the IC and to keep it from coming back at the turbo while you get off the throttle, it does not in any way control the output of the turbo. That is the job of the wastegate.

As for the side inlet for the bosch valves there is a very good reason for it. If you put pressure on the vacume nipple side of it and pressure going into the bottom tube which is on the other side of the diaphram and spring, you end up putting pressure against each other and the rubber diaphram cant take that pressure so it rips. But if you put the release/vacume of the turbo on the bottom side you will just be using the turbo to help keep the valve shut during high boost and the valve will also shut faster.

 

Other then that you pretty much cant make a NA car make that noise using air from the motor since it is always in vacume.

 

The function and sole job of the dv is to maintain an air-tight seal during acceleration, and remain open at all other intervals. It's as simple as that.

xr4tic is on the money about no matter which way you install it, there is pressure that's going to open up the spring and release air.

<img src="http://home.attbi.com/~mistertam33/spring.jpg">


<b>During accelerationg (installed in reverse):</b>
spring tension (13-14psi)
+
Manifold pressure (15-16psi)
-
turbo pressure (15-16psi)
---------------------------
Total pressure against port #1 (13-14psi)

<b>During acceleration (installed normally):</b>
spring tension (13-14psi)
+
manifold pressure (15-16psi)
-
turbo pressure (15-16psi)
---------------------------
Total pressure against port #2 (13-14psi)


Proof of this is given in the experiment that was done with the bike pump. If there were no pressure pushing the spring open, then I would
have been able to EASILY pump more than 10psi of air into port#2 before it started leaking.

Now that being said, one can argue about the surface area that's pushing on it and so forth.
(look at example below)

Now that we have determined that at each port,
there's the same amount of pressure keeping the
DV shut, We go back to my original wording of

"if the spring end can hold more pressure WITHOUT
the assistance of boost pressure [than the other end],
then it should be installed in reverse."

It's hard to understand the above unless you visualize it. I had to read it three times to myself, and I wrote it!!!

The question is why? and prove it!

Firstly, proof is that I simply blew air into each port.
The winner (side that held more psi) gets to point
down into the IC piping.
(In the Forge's case, the port that held more
pressure was the one with the spring)

Why? Well I'm sure someone can explain it better than me, but I'll take a gander at this...
Let's use a balloon as an example.
1. You have a water balloon (small) symbolizing the port end with the spring (less volume)
2. You have a regular balloon (normal) symbolizing
the other end (more volume)

Which one is easier to blow bigger? (normal balloon)
The Boost pressure from the turbo is doing the exact same thing your mouth is to the balloon.

In the end though, does it REALLY REALLY matter which way the aftermarket forge is installed? As long as you don't leak and the DV does it's simple job of opening and closing, then
you're aok. That's how good the forge and bailey are.
Remember that not all springs are the same, and that springs do become weaker over time.

My question is how many people had my issue of the
stock braided hose to the manifold drying out and
cracking?!!?! This causes the DV NOT to open, and
thus TURBO SHOCK! eesh. Since, I now have silicone
hoses, but before that, I bought new braided hoses and
drowned them in a nice coat of ArmorAll.<ul><li><a href="http://dv.mistertam.com">The Great DV Face Off</a></li></ul>

 

great link!

 

more potential issue with bosch bpv's, where spring load was only 5-6 psi.

 

what do you recommend? what size hose? silicon?

on DBW, the hose TO the BPV actually goes under the intake manifold to a box, then to the BPV from there...

I noticed mine was leaking at the nipple, but then I noticed it was actually dried out and cracked and hence leaking all over... Since I MAY have to remove the intake manifold to get to the box, I only want to do it once...

what would you suggest for new lines? I found silicon hoses at the local ricer shop, albeit only in red, blue or yellow, but it is only rated to 350degrees...

I am planning on doing this today... any help on sourcing and whatnot would be great!

 

You can buy it at hosetechniques.com or your local riceshop should do fine since.

I think mine measured out to be 3.5mm thick, so it was a perfectly snug fit for me.

others have used 3mm which is a tight fit.

 

5/32 (stock size).... goodyear braided... I will run those for a bit, then perhaps swap ALL the lines for silicone later... but I need to fix the leak NOW...