Zeff

I can't wait, the car should be putting down something in a similar range to yours.

rluciano

+1 here

toddk911

Which is why a lot of other forums I have read run the the WG line tapped AFTER the IC. That way if your boost is set to 15 psi, then 15 psi is when the wg is actually opening and 15psi is therefore in the intake.

Where as if the WG line is before the IC and it opens at 15psi, only 14 or 13 or less boost is actually getting into the motor due to the pressure drop.

Reimu

Anyone used one of the intake ports for wastegate vacuum and plugged up the port on the IC pipe?

User 52121

Well now THERE is an incredibly simple idea that I hadn't thought of.

Hmmm.

So is the theory that the pressure pre-IC climbs as RPMs do, and at a different (faster) rate than the pressure in the intake manifold, thus pushing the WG open further as revs climb?

mclarenno9

Yes, basically. Pressure drop through the IC goes up with flow (i.e. RPM).

You would be moving the sensing line further away from the compressor outlet but I suspect the delay wouldn't be noticable.

Edit: I'm thinking with an MBC that spikes may become more prelevant with this setup, however.

User 52121

Well once the weather brightens up a bit, this is something I'll for sure experiment with unless someone out there in a warmer climate is game to try it. I'll mount my GoPro to the window to record the gauges @ 60fps so I can review after the fact and see if things improve (poor man's data logger!)

refresh951

Great point. See the Tial install guide below (before the TB):



Also note that Tial recommends a 6mm ID supply line to the wastegate. Currently I am using LR vacuum line (3.5mm ID) as the supply line.

zerMATT951

So how do 951 owners typically tap boost pressure after the IC but before the TB? Drill and weld another bung onto the IC pipe going to the TB? Or tee into the idle air control valve hose?

refresh951

I bought a spare set of stock IC pipes a while back and had a buddy weld bungs in each near the IC for temp sensors. I think I will use these to test this.

toddk911

Yes, my WG is tapped into the IC out tube right in the middle before the TB.

User 52121

Well as an experiment, just to test the idea of whether or not it's the tap location that causes boost to fall off in high RPMs, couldn't you just pick it up at the manifold, after the TB?

From looking at it, I think the only difference of before TB vs. after TB would be spool up times between shifts. Shut the throttle, and you instantly get vacuum before the TB (closing the WG), whereas you might still have some pressure in the intake after the TB (holding the WG open for an instant or two.)

Or am I missing something else here?

mclarenno9

You will actually have the highest vacuum in the manifold once the throttle plate closes, which you would not want to subject the WG diaphragm to.

Darud35

Shawn, great results! Thanks for sharing. I'll be following to see if you can manage the boost to redline

blown 944

I've had my wg signal lines tapped off of the manifold for years. Seems to give a more consistent control. I hardly think the vacuum from the manifold is going to cause any issues with the wg diaphragm in comparison to the pressure differences it sees already vacuum would be the leafy of my worries.

With that said, in either config I have seen small "spike and settle" boost pressures with MBC and non solenoid ebc's.