Well update on waste gate testing. I made an adapter to see how much pressure it takes for the gate to start opening. The pressure was applied to the exhaust in side of the gate. First the adapter shown in the first pic is not going to work I had an explosive pop out of the tube before the gate opened (very exciting ) J. So the second picture shows the adapter with the hose bolted down. As an aside before I get to the actual numbers, the waste gate was very dirty with a lot of soot caked in to it. (the car is a 1986) so 20 years of it. This prevented the gate from ever closing all the way. So I cleaned the gate lip and the valve ( simple green, tooth brush and steel wool se next pic). After it was seating well, I took my readings and here they are:
1) stock 20 year old gate. The gate leaks a little around the valve, but it holds till 20 psi then a rush of air comes out.
2) With 3 mm of shims installed the gate holds till 30 + psi and then there is a rush of air. (the small leak at any pressure remains).
3) The diaphragm starts to open at 5 psi and full open at 8 psi (stock old gate).
4) The diaphragm starts to open 7 psi and full open at 9 to 10 psi (with shims) I did not expect that much difference in the diaphragm numbers as the aperture and the chamber in the diaphragm housing is quite small and the pressure difference is comparatively large ??

That was from my testing in 2007....

So my current numbers are quite a bit worse.
Sox

I applied vacuum with a hand vacuum pump to the WG control line and boost did reach 2 bar on the stock gauge. Which I guess should have told me that the WG is not working properly :eek:


That would suck!

Thanks
Mike G.

I am going to test mine with the vacuum on the WG and also test if the WG is still letting go at the same time.
Sox

Mike have looked through this thread ?
http://forums.pelicanparts.com/porsche-944-turbo-turbo-s/343134-boost-problem-again.html

Well what are you waiting for? SmileWavy

Thanks
Mike G.

Xmas ??

Ran the vacuum on WG and pressure monitor on the turbo inlet (header side) test.
-With no CV to WG hose had 11psi boost and approximately 25psi on the turbo.
-With 10 inches of vacuum to WG had 15psi boost and 31 to 33 psi on the turbo.
-With 20 inches of vacuum to the WG had 17 psi and 44 to 47 ish psi on the turbo. Chickened out as the boost was headed north at a very fast clip...don't want to do head gaskets at the moment :).
Sox

Was the top of the WG open to atmospheric pressure or was the line blocked off?

Thanks
Mike G.

P.S. Thanks for getting that done before xmas;)!

Top was connected to my vacuum source...
Sox

So after further pondering helped along with a little tequila...
I have devised a way to help the spring in the WG that does not require surgery of the OEM WG, or loosing the protection of the KLR.
Before y'all pile in and tell me my mechanical skills are lacking..:) this is just a proof of concept.
It does increase the the pressure needed to start opening the valve by 3 psi for my out of the junk box spring.
I will neaten it up so it fits in the WG outlet to the exhaust.
Sox

http://forums.pelicanparts.com/uploa...1580085910.jpg

That there spring on that there position in that there exhaust flow is gonna gets purdy dang hot!

Thanks
Mike G.

Yah, but it only gets heat during boost bypass. Normally the valve is closed. Secondarily a stainless steel spring meant for exhaust valve should be able to handle it.
If not "such is life". :)
Sox
Ps. I did say the idea was born out of a shot or 10 of tequila....

as that spring gets hot and the metal expands and gets softer the spring pressure will change, and then change even more when the wg opens and temperature rapidly rises. it might be unpredictable.

Nize, yah...true. Need to use pressure/vac combo.
Was trying to think outside the gate (pun intended).
I am going to test with this version of the spring. WG starts to open at 9 psi and fully open at 14psi.
Sox

http://forums.pelicanparts.com/uploa...1580151542.jpg

Put it in the normal spot like a beer drinker would not a tequila drinker.

Thanks
Mike G.

Mike, too boring....no tequila no excitement :)
Sox

Nize, if you are reading my other concurrent thread KLR part2, I am going to use the KLR to control the boost. So if the spring changes, the sensor along with the control loop in the KLR should handle it and keep my boost in the range I want. I am planing on setting it to 10 to 13 psi at this point.
Sox

This question isn't exactly pertaining to WG testing but what are you doing for fuel/ign mapping with the added boost?

Thanks
Mike G.

Mike at this time I am not planning to go past 14 psi, so I will have plenty of margin with existing fuel/air. As you see at 13.32 psi I am still well below 12 AFR (I would not want to go leaner than 12).
Sox

http://forums.pelicanparts.com/uploa...1580231998.JPG

Geez that's still super rich! Stock ECU/Chip FPR and all?

Thanks
Mike G.