Porsche Enthusiasts Club Forum

Too much of the stuff! Heard a little pink flat in 5th the other night, looked down, 25psi ffs. Turned MBC down a bit. Same. Turned way down. Same. What do we think? Waste gate stuck shut or MBC failure or a line disconnected? Not had a proper look yet. Using a Lindsay DPW. Worth noting exhaust was disturbed to change gearbox last week.

Thoughts please chaps. Also posted on PCGB.

Stuart

Did it feel quick?

Did the wastegate get disturbed with the exhaust? Plumbed the dual port the wrong way round?

If you have an air regulator type MBC then once it’s turned down, no boost signal should be getting to the top port to stop the wastegate opening and managing the boost.

No experience of Lindsey WG to add further. But for some old WG, when the diaphragm fails it keeps the wastegate closed and keeps boosting

Hi Steve. Yes very quick! The wastegate doesn't look like it was disturbed, just seems a coincidence that part of the exhaust was removed and there is now a problem. I think I need to get the wastegate off and investigate. Turning the MBC up or down makes no difference and the re-circ valve is a fairly new Forge item and seems to be good. I get about 19psi in 3rd, about 23psi in 4th and in 5th it goes post 25psi (all WOT), it just seems like the wastegate is jammed shut. I've managed to get hold of a standard shimmed wastegate with an 18psi spring in it, so once the Lindsay item is off, if I can't fix it, I'll pop the other one on for the time being.

Stuart

Update. All fixed. Failed WG diaphragm caused by combination of old age and corrosion on metal plates that sandwich diaphragm. Diaphragm was only available from Lindsay. $80 plus $35 delivery and £23 import tax. Ouch. Metal plates blasted and painted and new diaphragm installed. Everything all back to normal now!

Stuart

Excellent news!

Indeed! Hopefully some progress on the gearbox rebuild this week.......