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ZS Phil · 04-05-15, 05:46 PM

Since you asked

So previously I had been running 25 psi boost with the WG controlled by an external WG specific controller (the black thing in the diagram) which SHUTS at threshold pressure meaning boost pressure can no longer enter the top chamber of the WG however boost pressure still goes to the bottom chamber which pushes against the diaphragm and the gate opens.

This worked fine however because the wastegate spring is only rated to 10 psi and I wanted 25 psi, I was starting to get creep at 18-19 psi. One of the benefits of the screamer pipe is you can hear exactly when the gate starts to open.

Now to overcome this I have tried something which I haven't seen done before... I have added a mechanical boost controller before the lower chamber of the WG.
I have left the original WG controller at 25 psi so boost stops reaching the top chamber at 25 psi still however no boost will be allowed to reach the bottom chamber until 27psi as dictated by the added mechanical boost controller. Peak boost is now 29 psi.

There is now much less creep, the gate is virtually open or closed with absolutely minimal "in between".
This means spool is much quicker and there is less smoke. The extra few psi have transformed the car and really started to help the extra fuel from the 200 tdis get burnt.

I am currently running the fuel pump maxxed out with the landrover nozzles too so there is some smoke as to be expected. I'm going to tweak fuelling down a bit up top but I'm at the stage now where I'm confident the landrover nozzles are a good choice for the correct turbo.

I couldn't be happier with the 2056 now I've made the negligible changes.

Some results from testing:
EMP @ 70 mph cruising = 4psi
EMP during normal but hardish acceleration= 1:1 ratio with boost.
Peak EMP (4th gear foot to the floor 50-90 mph= 38psi @ 29-30psi boost.

All in all, I think that illusive 200 is on the cards for the "masses" without VNT.

04-05-15, 05:46 PM	#105
ZS Phil Member Join Date: Jul 2007 Location: Lytham St Annes, Lancs Posts: 1,556	Since you asked So previously I had been running 25 psi boost with the WG controlled by an external WG specific controller (the black thing in the diagram) which SHUTS at threshold pressure meaning boost pressure can no longer enter the top chamber of the WG however boost pressure still goes to the bottom chamber which pushes against the diaphragm and the gate opens. This worked fine however because the wastegate spring is only rated to 10 psi and I wanted 25 psi, I was starting to get creep at 18-19 psi. One of the benefits of the screamer pipe is you can hear exactly when the gate starts to open. Now to overcome this I have tried something which I haven't seen done before... I have added a mechanical boost controller before the lower chamber of the WG. I have left the original WG controller at 25 psi so boost stops reaching the top chamber at 25 psi still however no boost will be allowed to reach the bottom chamber until 27psi as dictated by the added mechanical boost controller. Peak boost is now 29 psi. There is now much less creep, the gate is virtually open or closed with absolutely minimal "in between". This means spool is much quicker and there is less smoke. The extra few psi have transformed the car and really started to help the extra fuel from the 200 tdis get burnt. I am currently running the fuel pump maxxed out with the landrover nozzles too so there is some smoke as to be expected. I'm going to tweak fuelling down a bit up top but I'm at the stage now where I'm confident the landrover nozzles are a good choice for the correct turbo. I couldn't be happier with the 2056 now I've made the negligible changes. Some results from testing: EMP @ 70 mph cruising = 4psi EMP during normal but hardish acceleration= 1:1 ratio with boost. Peak EMP (4th gear foot to the floor 50-90 mph= 38psi @ 29-30psi boost. All in all, I think that illusive 200 is on the cards for the "masses" without VNT. __________________ ZS Turbo!!cough (diesel)