Stock Wastegate
12-14-2009, 12:00 AM
#1
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Stock Wastegate
I have the stock wastegate still. How much boost does it take for the weak spring to start opening by itself and is it ok to put a shim inside or is the only way getting a whole new unit.
12-14-2009, 12:34 AM
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so exactly what happens when you say lazy, i take it you mean no consistent, sticking, not very accurate to control. is this correct? and how much is a tial
12-14-2009, 12:37 AM
#4
The stock wastegate is a vering shade of gray due to age and miles.
I was lossing 3psi in 4th gear a 6k rpm on a heavly tracked wastegate.
It was an OEM waste gate shimed to run 15psi
All was solved by a tial 38. I now hold 17psi to 6k rpm no problem.
(kkk26/8 and Manual boost contoler)
I bought mine from Pauer Tunning and was VERY impressed with the quality of the kit!!
Just my 2 cents...
I was lossing 3psi in 4th gear a 6k rpm on a heavly tracked wastegate.
It was an OEM waste gate shimed to run 15psi
All was solved by a tial 38. I now hold 17psi to 6k rpm no problem.
(kkk26/8 and Manual boost contoler)
I bought mine from Pauer Tunning and was VERY impressed with the quality of the kit!!
Just my 2 cents...
12-14-2009, 12:45 AM
#5
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It starts to open at about 4 psi if not interfered with by a boost controller. Each mm of shim will increase that by roughly .5 psi and double that at full boost.
Of course, achievable full boost is more than that, because of the stock cycling valve or an aftermarket boost controller.
Of course, achievable full boost is more than that, because of the stock cycling valve or an aftermarket boost controller.
12-14-2009, 12:52 AM
#6
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Nicholas, the stock wastegate does bleed boost, you might want to read the next thread, it shows a dyno before and after a stock wastegate was replaced.
https://rennlist.com/forums/944-turb...yno-chart.html
https://rennlist.com/forums/944-turb...yno-chart.html
12-14-2009, 01:14 AM
#7
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To start, it was designed with 12psi in mind, give or take. Then add years of service, and the valve stops sealing as well -- in part because the valve and seat get old and in part because the spring and diaphram just can't hold it closed as tight as when new.
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12-14-2009, 02:27 AM
#8
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get the Lindsey dual port conversion done.A KKK waste gate with adjustable can is good enough for a 1000hp 935 so its good enough for your car.
if you must have a a Mugatu sticker ... get a sticker ... Mugatu??? oh sorry i mean Tial ...whatever
if you must have a a Mugatu sticker ... get a sticker ... Mugatu??? oh sorry i mean Tial ...whatever
12-14-2009, 09:01 AM
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Shimming and a little pneumatic trickery (inline check ) helps a bit.
i think Sid explained how to do a very cheap and easy dual port conversion with 20$ worth of home depo bits ...
with a dual port you send a regulated(or capped ) signal to the close side of the valve and this holds the valve shut until a higher boost pressure ..
so lets say the valve opens at 7psi you set up a regulated 6psi into the close chamber so it now takes 13psi to open the waste gate .
i think Sid explained how to do a very cheap and easy dual port conversion with 20$ worth of home depo bits ...
with a dual port you send a regulated(or capped ) signal to the close side of the valve and this holds the valve shut until a higher boost pressure ..
so lets say the valve opens at 7psi you set up a regulated 6psi into the close chamber so it now takes 13psi to open the waste gate .
