Engine Oil pressure issues w/ SS turbo feed line

[pickens]

I was wondering... most of us run aftermarket SS feed lines to the turbo off the filter housing. I remember when I replaced mine, the stock line had a small restrictor in-line at the housing. All SS lines I have seen do away w/ this restrictor. I see a potential problem w/ out that restrictor. Mistu engineers most likely sized that restrictor to limit the flow to the turbo and maximize flow to the engine. W/out that restrictor the flow to the turbo must increase significantly which means some flow is taken away from the engine to compensate. Think this would cause bearing faliures or at the least shorten the life? hmmm...

 

[GTM]

...
All SS lines I have seen do away w/ this restrictor. I see a potential problem w/ out that restrictor. Mistu engineers most likely sized that restrictor to limit the flow to the turbo and maximize flow to the engine. W/out that restrictor the flow to the turbo must increase significantly which means some flow is taken away from the engine to compensate. Think this would cause bearing faliures or at the least shorten the life? hmmm...

I can appreciate your concern, yet I have seen no evidence where the increased oil flow has in any way compromised the turbo or the engine. I have read reports where oil pressure dropped at idle and a high RPM but these were already borderline cases which needed repairs such as bearing replacement and worn oil pump. The reading I did suggested that the SS hose diameter acted much like a capillary tube and did not substantially divert excess oil to the turbo. In otherwords the cap tube acted like a restrict or over it's given length and placing a restrict or would have been redundant. While we do see substantial failures I think there are reasons for these such as abuse beyond normal engineering uses anticipated. Extracting 30% or more hp was not factored into the original design thus a greater failure rate is to be expected.

Cheers,
GTM

 

[Defiant]

It's more a concern of oil pressure the turbo oil seal is subjected to than engine oil supply. Check with your turbo manufacturer and see if they recommend a restriction. If not, find one of the hundred other DSM quirks to start worrying about.