restricting oil to turbo?
04-05-2007, 07:37 PM
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restricting oil to turbo? I have a STS kit that was originally for a late model Silverado but I adapted it to fit my 93 S10 Blazer which has a 6 liter/4l80e.
Anyways, ever since I got it running it has smoked out the tailpipe and loaded the intake piping with oil anytime I try to boost at all. I have talked to STS multiple times and they faxed me some good info on diagnosing oil control issues, but nothing I have tried has seemed to help until I started restricting the oil supply to the turbo.
About the setup......I have a -4an line running from the external oil filter adapter to the turbo. The return from the turbo is a 5/8 hose running downhill to the STS electric pump. The pump is wired properly and is running in high speed mode all the time (on purpose) I have a -8an running from the outlet of the pump to a fitting on the side of the oil pan. If I unhook this and stick it into a pan with the motor running, oil squirts and dribbles out like it is supposed to. The turbo is clocked with the the oil inlet at 12 oclock and the drain at 6 oclock.
STS uses a 3psi pressure switch in the return line at the inlet of the pump. They want the pump to pull a vacuum on this port under most cicumstances but it should never get over 1 or 2 psi from what I understand, or oil will back up in the turbo and flood the seals and do what its doing on my setup. I get 6 to 7 psi in this oil return line under full boost and the weird thing is that the pressure in that line seems directly linked to engine boost.....it comes up from a vacuum situation to pressure pretty much like the boost gage does.
Ok, anyways, I decided that maybe I am just getting too much oil to the turbo and that the return system cant pump that much oil back to the motor so I made a fitting so I can use a N20 jet in the -4an supply line. I started off big and went down to a 93 jet today. The most pressure I saw in the return line today was 3 or 3 1/2 psi but the intake piping blew loose so I dont know if it was finished rising or not.
I guess my question is, how small is too small on the oil restriction? I don't want to burn up my turbo trying to chase down this problem.
Thanks for any advice or suggestions.....
Anyways, ever since I got it running it has smoked out the tailpipe and loaded the intake piping with oil anytime I try to boost at all. I have talked to STS multiple times and they faxed me some good info on diagnosing oil control issues, but nothing I have tried has seemed to help until I started restricting the oil supply to the turbo.
About the setup......I have a -4an line running from the external oil filter adapter to the turbo. The return from the turbo is a 5/8 hose running downhill to the STS electric pump. The pump is wired properly and is running in high speed mode all the time (on purpose) I have a -8an running from the outlet of the pump to a fitting on the side of the oil pan. If I unhook this and stick it into a pan with the motor running, oil squirts and dribbles out like it is supposed to. The turbo is clocked with the the oil inlet at 12 oclock and the drain at 6 oclock.
STS uses a 3psi pressure switch in the return line at the inlet of the pump. They want the pump to pull a vacuum on this port under most cicumstances but it should never get over 1 or 2 psi from what I understand, or oil will back up in the turbo and flood the seals and do what its doing on my setup. I get 6 to 7 psi in this oil return line under full boost and the weird thing is that the pressure in that line seems directly linked to engine boost.....it comes up from a vacuum situation to pressure pretty much like the boost gage does.
Ok, anyways, I decided that maybe I am just getting too much oil to the turbo and that the return system cant pump that much oil back to the motor so I made a fitting so I can use a N20 jet in the -4an supply line. I started off big and went down to a 93 jet today. The most pressure I saw in the return line today was 3 or 3 1/2 psi but the intake piping blew loose so I dont know if it was finished rising or not.
I guess my question is, how small is too small on the oil restriction? I don't want to burn up my turbo trying to chase down this problem.
Thanks for any advice or suggestions.....
