I am getting full boost, and am wondering if I got my vaccums wrong on the 46mm Tial. The side port on the Tial goes to the in port of the MBC, and the top goes to the out port of the MBC and to the IC pipe for pressure correct?

 

Manifold to side, MBC to top port! MBC input connects to a T to the side, or to the manifold...

 

If you're using a MBC it's a lot easier just to set it up single port as dual port is normally only used for electronic boost controllers. So if you have a mechanical boost controller, single port makes a lot more sense and less hoses.

 

saw a peak of 30psi momentarily....yikes! Good thing I had 110 in the tank huh?

 

Correct me if I'm wrong but I don't think that's right. It's late and I can't think straight but do yourself a favor, put it in single port. Pressure to MBC to side port on the WG. Leave the top port venting.

 

It could also be if the WG is installed backwards....

 

I second this.

 

IF it is a LR dual port yes I would agree, but the ports on the TiAL WG are the opposite!

Lindsey:

"The wastegate in this picture is a Lindsey Racing Dual Port Wastegate. If this was a TIAL brand wastegate, the lines at the wastegate would be reversed. Side is now top, and top is now side. This is done because the valve travels in the opposite direction."

FROM the TiAL WS:


Boost control valve to the TOP port on the TiAL, but to the side port of the Lindsey Dual Port!

 

Yeah it was reversed..... now seeing a cool 12psi with the boost turned all the way down. Time to turn it back up. Thanks guys.

 

Yeah it is reversed, meaning that you have to do single port to the top of the lindsey racing, and side port to the TiAL.
The side port of the LR is pressure that helps the spring in keeping the valve closed. The top port is the pressure trying to open up the valve and prevent the turbo from spooling any further. Since the TiAL is reversed you would do single port to the side and vent the top

The reason it is confusing is because the unrestricted airflow on the TiAL is going to the side port, and to the top port of the LR one. This is the air that opens the wastegate. The MBC is restricting air flow, meaning it will always be less then what is going to the port that opens the valve. So, in a dual port set up, if you want to run 16 psi the following would occur. 16 psi will go to the side port on the TiAL and to the top of the LR, the MBC will be restricting that same 16 psi (as it comes from the same initial source in the intake tract) down to say maybe 5 psi that will reach the top of the TiAL or side of the LR unit. Now, in conjunction with the, let's say, 9 pound spring keeping the valve shut you have a total of 16 psi pressure on both the opening of the valve and closing of the valve. If the pressure rises to greater then 16 psi on the opening, it will open and prevent further spooling of the turbo. If the pressure drops then the 16 psi on the back of the valve keeping it closed will keep it closed.

So when going to single port all you do is apply zero pressure to the spring side so there is never more than the assumed 9 pounds for the spring keeping the valve closed. Instead the pressure line leading to the side of the Tial or top of the LR unit goes through the MBC which restricts the pressure the wastegate sees and allows higher boost. The only difference is that you twist the MBC in the opposite direction to increase boost in the single port configuration.