12psi but NOT an installation issue
Jun 4, 2011 | 08:08 PM
#16
is there any shaft play on the turbo?? maybe the turbo said f you. thats like the last thing i can think off after everything else you've done/tried. that sucks man deff keep us posted on what happens
Jun 4, 2011 | 08:26 PM
#18
The best way is to run a length of vacuum hose directly from the compressor housing discharge nipple to the nipple on the WGA. Plug off the open ends of the hoses going to the MBC with golf tees and 1/4" hose clamps.
Rotate the turnbuckle on the end of the threaded actuator rod inward clockwise about three complete 360* rotations. Take the car for a WOT run in 4th and check the peak boost level. Has boost gone up or does it remain at 12#?
Jun 4, 2011 | 08:38 PM
#19
Outside Hartford
IX, held 50psi in boost leak test
We added a ton of preload several times. We didn't do the method you said but we disconnected the wastegate line from the MBC and capped it. Should have been able to run max turbo boost like that but still stuck at 12psi, which is weird since it's an 18psi wastegate and we added a good amount of preload.
I might pick up a used 9.8 hotside and try that. Running out of things to replace.
IX, held 50psi in boost leak test
Not so fast. Definitely, you should try adding more preload.
The best way is to run a length of vacuum hose directly from the compressor housing discharge nipple to the nipple on the WGA. Plug off the open ends of the hoses going to the MBC with golf tees and 1/4" hose clamps.
Rotate the turnbuckle on the end of the threaded actuator rod inward clockwise about three complete 360* rotations. Take the car for a WOT run in 4th and check the peak boost level. Has boost gone up or does it remain at 12#?
The best way is to run a length of vacuum hose directly from the compressor housing discharge nipple to the nipple on the WGA. Plug off the open ends of the hoses going to the MBC with golf tees and 1/4" hose clamps.
Rotate the turnbuckle on the end of the threaded actuator rod inward clockwise about three complete 360* rotations. Take the car for a WOT run in 4th and check the peak boost level. Has boost gone up or does it remain at 12#?
I might pick up a used 9.8 hotside and try that. Running out of things to replace.
Jun 4, 2011 | 09:11 PM
#22
The method that I outlined is a standard and accepted method to go about setting wastegate spring pressure once the turbo has been installed on the car. This method eliminates a lot of variables from the equation.
So, you disconnected the line from the WGA to the MBC, but you didn't disconnect the hose from the J-pipe's nipple to the MBC? Hmmm.
However, there is an easier way that doesn't involve disconnecting your existing MBC lines. You can leave all the boost hoses connected the way that they are. Just turn the MBC out all the way counterclockwise to full soft which would be the lowest boost adjustment possible on your MBC.
But, I still want you to crank the turnbuckle in to add preload. But, you might as well crank it in as far as it goes. Take the car for a WOT run and see if the boost level has increased at all.
So, you disconnected the line from the WGA to the MBC, but you didn't disconnect the hose from the J-pipe's nipple to the MBC? Hmmm.
However, there is an easier way that doesn't involve disconnecting your existing MBC lines. You can leave all the boost hoses connected the way that they are. Just turn the MBC out all the way counterclockwise to full soft which would be the lowest boost adjustment possible on your MBC.
But, I still want you to crank the turnbuckle in to add preload. But, you might as well crank it in as far as it goes. Take the car for a WOT run and see if the boost level has increased at all.
Jun 4, 2011 | 09:15 PM
#23
The method that I outlined is a standard and accepted method to go about setting wastegate spring pressure once the turbo has been installed on the car. This method eliminates a lot of variables from the equation.
So, you disconnected the line from the WGA to the MBC, but you didn't disconnect the hose from the J-pipe's nipple to the MBC? Hmmm.
However, there is an easier way that doesn't involve disconnecting your existing MBC lines. You can leave all the boost hoses connected the way that they are. Just turn the MBC out all the way counterclockwise to full soft which would be the lowest boost adjustment possible on your MBC.
But, I still want you to crank the turnbuckle in to add preload. But, you might as well crank it in as far as it goes. Take the car for a WOT run and see if the boost level has increased at all.
So, you disconnected the line from the WGA to the MBC, but you didn't disconnect the hose from the J-pipe's nipple to the MBC? Hmmm.
However, there is an easier way that doesn't involve disconnecting your existing MBC lines. You can leave all the boost hoses connected the way that they are. Just turn the MBC out all the way counterclockwise to full soft which would be the lowest boost adjustment possible on your MBC.
But, I still want you to crank the turnbuckle in to add preload. But, you might as well crank it in as far as it goes. Take the car for a WOT run and see if the boost level has increased at all.
Pulling the boost source to the WG should result in max boost, it was still at 12-14 psi.
Jun 4, 2011 | 09:16 PM
#24
Jun 4, 2011 | 09:17 PM
#25
12 PSI is just about base WG pressure. Is this the max pressure that you see if the MBC is cranked all the way in clockwise to the highest boost setting?
Does it make any difference whether the MBC knob is cranked all the way in as opposed to being turned al the way out? Or, is it the same 12# regardless?
Does it make any difference whether the MBC knob is cranked all the way in as opposed to being turned al the way out? Or, is it the same 12# regardless?
Jun 4, 2011 | 09:25 PM
#26
So, you state it is not an install problem, and that the turbo is in good condition, you've done a boost leak test, the wastegate puck is functioning properly, and I am assuming that the MBC is hooked up properly. Then the problem is in the WGA, or the MBC.
The best way to eliminate the MBC as a possible cause is to do the test which I outlined above which removes the MBC as a variable in the equation. The method I indicated will also let you know if your WGA is functioning properly because you will be setting peak boost directly via the WGA's adjustable actuator rod.
You are assuming that your MBC is working properly and you are assuming that your WGA(s) is/are functioning and is set up properly to work with your particular combination.
Just because you install a new Forge WGA and give it a few turns does not mean that there is enough preload or that it is set up properly.
The best way to eliminate the MBC as a possible cause is to do the test which I outlined above which removes the MBC as a variable in the equation. The method I indicated will also let you know if your WGA is functioning properly because you will be setting peak boost directly via the WGA's adjustable actuator rod.
You are assuming that your MBC is working properly and you are assuming that your WGA(s) is/are functioning and is set up properly to work with your particular combination.
Just because you install a new Forge WGA and give it a few turns does not mean that there is enough preload or that it is set up properly.
Last edited by sparky; Jun 4, 2011 at 09:38 PM.
Jun 4, 2011 | 09:31 PM
#28
I am not trying to be a *****. I have run that Forge Racing VIII WGA myself. I think that the Forced Performance HD 18# actuator is the one that is advertised as being an 18# unit though isn't it. The Forge actuator has a couple of spring options available. The Red spring is the firmest.
Jun 4, 2011 | 09:36 PM
#29
I have run it both on an VIII turbo with a 9.8 housing and on an VIII turbo with a 10.5 housing. Depending on which turbine housing that your VIII turbo is configured with(I am presuming 10.5cm, right?) Then you may have to trim a few threads off the actuator rod to get it to preload properly.
