Only give this setup a try if you have the Synchronic BOV recirculated, or if you are running a standalone and VTA. Make sure that Port C does have boost-only connected to it.

As you know, there are 2 ports on the back, which can produce 3 different combos of vac setups.

I want you guys to try all 3, and please post what your impressions are.

1) Port A&B to boost/vac
2) Port B only to boost/vac, Port A open to atmosphere
3) Port A only to boost/vac, Port A open to atmosphere



I'm most interested in seeing your impressions with running Port A only.

 

Currently running port A to vacuum, port B to atmosphere, port C to boost, and small preload spring removed. Quite nice in this orientation with only issues coming on during 5th gear highway passing scenarios where minute throttle modulation during slow build up of boost is required.

 

How is steady state throttle modulation in say third or fourth, in a condition like a long turn on a track where you use throttle modulation to maintain a line?

 

Are you describing jerkiness in part throttle, low boost situations? Are you running the stock turbo?

 

I'm tinkering myself on a stock turbo VIII MR. Part throttle DV flutter is much more muted in my opinion. Instead of a fast oscillation of the BOV, it is either fully closed or a small soft leak depending on how you have it setup.

I want to get actual users input on the Port A config before explaining what exactly is going on.

 

I'm running the first setup. I get a lot of jerkiness at low boost. I will try just running setup 3 today and see what it does. I really can't stand the first setup because it will not hold steady on a slow de-acceleration. It jerks pretty bad and its scary when going into a turn jerking.

I will post setup three hopefully today if not tomorrow.

 

I on a standalone and vernting to the atmosphere am running A and B Y'ed into one vacuum to intake manifold and C open to the atmosphere and the car has been excellent. Should C be to the atmosphere or should I close it up?

 

No ports should ever be plugged. Port C should be to boost-only.

 

I have ran it each way so far. I think that set up 3 seems to work the best. With all 3 connected its a lil jerky nothing serious. then just a + b it would just flutter extra long. With only a connected now it seems more crisp and less flutter.

 

What is a good boost only source? The turbo nipple? I thought every port would always see vacuum at some point in time.

 

Evo8 do you have port c connected?

Turbo nipple is perfect for boost-only

 

do people run it with C open to the air? I was told to hook it up like I did (A+B Vacuum. C open to the air) Also its in your video set up like that.

S

 

I was running C open to air and I was getting bad compressor surge. The instructions it came with said to leave it like that.
I just hooked port C to a boost only source and it fixed that problem. The valve sounds like its working a lot faster and moving a lot more air.
Part throttle is good as it always was.
For reference I have A to vacuum, and C to boost only. B is open to air.

 

when we first wrapped up the design, many of the test cars were aftermarket turbo with a later spooled unlike the Evo. So Port C being mandatory wasn't necessary at the time.

More testing told us that port c to boost-only is a must for anything over 6 psi of boost.

But bear in mind that every car is different. I have a guy in Australia running 2 bar without port c.

More and more testing and specific to the Evo is this config we're looking to get feedback on. You don't have to spend more money, just a hose swap.

 

Im running 35psi without port C and the car hasnt skipped a beat at least I dont think. I havent put her on the dyno but if you think I should hook up port C to a Boost source I will try that. I will be running about 44 psi all said and done with this BOV.


Suman