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In the spirit of learning with the OP, maybe the best question to ask is why? Why install a .060" restrictor? What is the configuration that may need it? What is the benefit? What are the concerns? It's safe to say, we've all made mistakes (learning opportunities) by trying stuff without good insight/info. Without some testing and results, we may try stuff, usually as best guess, based on someone elses results that are usually provided with limited info to make a well informed decision. With a $200 turbo, all these details are likely less important for most folks.
OP, a turbo journal bearing uses the oil very similar to your engine main bearing. Turbo journal tolerance/clearance (are the restriction within the CHRA), oil weight, oil temp, pressure all dictate the amount of oil flow that will go through the turbo. Besides lubrication, cooling is a key byproduct of the oil flow. Without flow and temp measurements, ideal oil flow to/through a turbo is just a guess. Didn't mean to go all Kingtalon on ya, just pointing out there is lots of info to wrap our mind around to make an informed decision.
Last edited by tblentrprz; Jun 27, 2020 at 08:40 AM.
Like everything, it's a trade off. In an idea world, you'd run a fire hose for a return line and not have any restriction on the inlet side. Unfortunately, some setups (particularly those that are DD'd with all accessories that limit the turbo location) can't run a massive return for a multiple of reasons. This is where a slight restriction on the feed can be of benefit. When you run a restriction you need to check flow like Forcefed86 said. You want the LEAST restriction on the feed line that keeps oil from getting past the seal rings. Sometimes this is trial and error, but in most instances a .060 to .080 isn't going to make or break the setup.
In the spirit of learning with the OP, maybe the best question to ask is why? Why install a .060" restrictor? What is the configuration that may need it? What is the benefit? What are the concerns? It's safe to say, we've all made mistakes (learning opportunities) by trying stuff without good insight/info. Without some testing and results, we may try stuff, usually as best guess, based on someone elses results that are usually provided with limited info to make a well informed decision. With a $200 turbo, all these details are likely less important for most folks.
OP, a turbo journal bearing uses the oil very similar to your engine main bearing. Turbo journal tolerance/clearance (are the restriction within the CHRA), oil weight, oil temp, pressure all dictate the amount of oil flow that will go through the turbo. Besides lubrication, cooling is a key byproduct of the oil flow. Without flow and temp measurements, ideal oil flow to/through a turbo is just a guess. Didn't mean to go all Kingtalon on ya, just pointing out there is lots of info to wrap our mind around to make an informed decision.
but one must think. You have this tiny shaft, just rotating and really not much thrust except on the thrust surface.....especially compared to an engine. In my mind, why do you need the same amount of oil? Let’s do this. HOW MANY PEOPLE on here have had premature turbo failure of journal bearings and had a restrictor? Post up. I’m interested in knowing. Not due to a motor failure, just a worn out or locked up turbo. Post details too. Dont just say “me”. Post up the combo, miles, boost, the name brand of the turbo, oil pressure etc.
then how many people have had smoking issues with no restrictor?
I swapped from a 7875 on my huron kit, never had smoke. Went to the VSR T4 80mm and I get some smoke. This turbo is bigger so I get less fall on my drain which dumps as high in the Moroso pan via an AN10 as I could get. I put in an .060 restrictor and it helped but didn't eliminate. I have a scavenge pump on order as I don't want to restrict it any further and that should address the issue..
All that to say outside of the pump i had 2 choices, restrict it further or rework my huron piping to raise the turbo.. Would rather buy a new $800 turbo in a year or 2 than start trying to cut/rearrange all my piping amongst all the accessories.
In the old days it was not uncommon to put oil restrictors in big block and small block chevys for cam bearings which are probably a better analogy than main and rod bearings. I think (yea I know not worth 2 cents) the journal bearing will get plenty of oil with a .060 restrictor at the pressure we are putting through it.
If you were a high dollar turbo company and someone asked you about a restrictor the obvious answer is no, what do they have to lose they point you to a better drain, that sewer hose mentioned. At the end of the day they have no idea what type of oil pressure, weight of oil, etc. you will be running. And I am no rocket scientist so even if they told me I need X gph at Y psi, I would skip even attempting that measurement. Some of us like to drive our cars as much as we work on them so spending countless hours for the PERFECT fix ain't happening. Sometimes you don't have to kill the ant with a sledgehammer.
but one must think. You have this tiny shaft, just rotating and really not much thrust except on the thrust surface.....especially compared to an engine. In my mind, why do you need the same amount of oil? Let’s do this. HOW MANY PEOPLE on here have had premature turbo failure of journal bearings and had a restrictor? Post up. I’m interested in knowing. Not due to a motor failure, just a worn out or locked up turbo. Post details too. Dont just say “me”. Post up the combo, miles, boost, the name brand of the turbo, oil pressure etc.
then how many people have had smoking issues with no restrictor?
When the turbo was designed by engineers, they calculated the supply/flow needed for the turbo to operate its best and live it's longest healthy life. Not to mention... most turbos have the calculated orifice past the supply fitting that regulates the oil to the correct flow anyway. So what happens when you restrict the flow that's already being restricted? If a smaller supply would net a healthier turbo, it would have been used. For the same reason you don't limit the oil supply to your main bearings, you generally don't limit it to your turbo. sure special circumstances exist. If you are doubling the oil pressure and/OR flow of the factory oiling system, you may need to regulate the flow down a bit. this is why the factory repair manuals give a liter per hour min/max figure of some sort. In the OP's case, no restrictor should be used IMO.
I've seen TONS of turbo failures from inadequate lubrication. If you look at Precision or Garrett its listed as one of the #1 reason a turbo fails. As I said... the manufacturers know best. Not the guy selling china remans... If it stops a customers smoking turbo, that doesn't mean it will live it's longest healthiest life.In many cases, It's a band aid for a poor drain. Because the turbo hasn't locked up in a 2 year period and a few thousand miles... doesn't mean its healthy. And if you are still getting the factory minimum flow through the turbo with a restrictor in place, then of course there's no problem running one.
Last edited by Forcefed86; Jun 29, 2020 at 08:04 AM.
When the turbo was designed by engineers, they calculated the supply/flow needed for the turbo to operate its best and live it's longest healthy life. Not to mention... most turbos have the calculated orifice past the supply fitting that regulates the oil to the correct flow anyway. So what happens when you restrict the flow that's already being restricted? If a smaller supply would net a healthier turbo, it would have been used. For the same reason you don't limit the oil supply to your main bearings, you generally don't limit it to your turbo. sure special circumstances exist. If you are doubling the oil pressure and/OR flow of the factory oiling system, you may need to regulate the flow down a bit. this is why the factory repair manuals give a liter per hour min/max figure of some sort. In the OP's case, no restrictor should be used IMO.
I've seen TONS of turbo failures from inadequate lubrication. If you look at Precision or Garrett its listed as one of the #1 reason a turbo fails. As I said... the manufacturers know best. Not the guy selling china remans... If it stops a customers smoking turbo, that doesn't mean it will live it's longest healthiest life. It's a band aid for a poor drain. Because the turbo hasn't locked up in a 2 year period and a few thousand miles... doesn't mean its healthy. And if you are still getting the factory minimum flow through the turbo with a restrictor in place, then of course there's no problem running one.
ok. Cool. Thanks. I’m just gonna keep it as is because it’s working fine. I’ve listened to very convincing internet professionals before and fucked **** up listening to them. I have friends that “know” how to do all kinds of stuff to a vehicle but can’t actually do the work. And they have to pay other people to work on their cars. I’m not one of those. Thanks for the advice tho.
Suuure, but i'm not claiming ownership and this isn't a personal theory. This is basic reading comprehension from the people that designed the part. All I'm doing is trying to point the OP or anyone else at the words. Look them up yourself, don't ever take someone else's word for it. I'm not an engineer, and the amount of "home depot" parts on my car is mind blowing! lol. It's just a hobby for me.... not claiming to be a professional in any way.
Suuure, but i'm not claiming ownership and this isn't a personal theory. This is basic reading comprehension from the people that designed the part. All I'm doing is trying to point the OP or anyone else at the words. Look them up yourself, don't ever take someone else's word for it. I'm not an engineer, and the amount of "home depot" parts on my car is mind blowing! lol. It's just a hobby for me.... not claiming to be a professional in any way.
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