Restrictor in turbo oil line? - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Reply
 
 
 
LinkBack Thread Tools
Old 01-22-2007, 05:04 PM   #1
Newb
Thread Starter
 
Join Date: Jan 2007
Location: Cornwall - UK
Posts: 11
Total Cats: 0
Default Restrictor in turbo oil line?

I'm putting a turbo kit together - home made manifold and Garrett T25 from a Nissan 200sx 1.8.

The donor for the turbo has a 1mm about 40thou restrictor in the oil feed fitting coming off the block. I know a number of folks have used this turbo in their Miatas do you also restrict the oil flow or do you just let it rip?? It is a plain bearing type tubo not BB. On the same theme whatever turbo kit you have fitted do they have retrictors? The Garrett site makes reference to restricting flow to BB turbos but don't make mention of restrictions for plain bearing units.

I'd be glad of any comments.

Malcolm
malcpw is offline   Reply With Quote
Old 01-22-2007, 05:06 PM   #2
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,904
Total Cats: 1,793
Default

Typically you want around .060". Although, turbos need very little oil. But what I'd do it put it together without it and see if you dont have problems with oil blowing past seals. If so then install it.

Tons of members here need them, tons don't.
Braineack is offline   Reply With Quote
Old 01-22-2007, 06:35 PM   #3
Senior Member
 
Join Date: Dec 2005
Posts: 865
Total Cats: 0
Default

i not running 1 and its scares me but has been good so far,ive got a gt2560.
turbopezz is offline   Reply With Quote
Old 01-22-2007, 07:21 PM   #4
Senior Member
 
Join Date: Dec 2004
Posts: 1,450
Total Cats: -1
Default

It would be smart to take a look at the stock Nissan 200SX oil feed line (diameter? restrictor? etc.).
bripab007 is offline   Reply With Quote
Old 01-22-2007, 10:29 PM   #5
Elite Member
iTrader: (7)
 
samnavy's Avatar
 
Join Date: Apr 2006
Location: VIRGINIA BEACH, VA
Posts: 6,020
Total Cats: 175
Default

If you're going to look at a stock Nissan application, be sure to also check what kind of oil pressure they run. I see about 30psi at idle and aroun 70psi at WOT running Mobil1 20w-50synth. Less pressure, smaller line, restrictor, larger oil drain all contribute to getting less in and more out so you don't overpressurize the CHRA and blow seals.

A cheaper solution and one that has worked fine for me is to purchase a 1/8" aluminum pop-rivet and sandwich it between your feed-line and fitting at the turbo.

By the way, I asked this question about a month ago:
https://www.miataturbo.net/forums/sh...ighlight=rivet

Bottom line. Start with a 4an feed line and 10an drain. After a couple days driving if you're not smoking, you probably don't need one. Don't forget to check the compressor side to see if your blowing oil in to the IC. If there are no problems, relax. If you are having a problem. I'd start with the pop-rivet. If still problems, swap down to an actual .035 restrictor. If still problems, it's probably blown seals in your turbo.
samnavy is offline   Reply With Quote
Old 01-23-2007, 05:25 PM   #6
Newb
Thread Starter
 
Join Date: Jan 2007
Location: Cornwall - UK
Posts: 11
Total Cats: 0
Default

Thanks for all your input guys.

I'm going with a 1/16" restrictor and we'll see what happens.

Having read all your info I figure that should be safe bet.

Thanks again

Malcolm
malcpw is offline   Reply With Quote
Old 01-25-2007, 06:51 PM   #7
Junior Member
iTrader: (1)
 
Join Date: Sep 2006
Posts: 464
Total Cats: 0
Default

From Garretts site, not to informative except for actually giving a concrete number for the BB CHRAs.

Oil requirements depend on the turbo's bearing system type. Garrett has two types of bearing systems; traditional journal bearing; and ball bearing.

The journal bearing system in a turbo functions very similarly to the rod or crank bearings in an engine. These bearings require enough oil pressure to keep the components separated by a hydrodynamic film. If the oil pressure is too low, the metal components will come in contact causing premature wear and ultimately failure. If the oil pressure is too high, leakage may occur from the turbocharger seals. With that as background, an oil restrictor is generally not needed for a journal-bearing turbocharger except for those applications with oil-pressure-induced seal leakage. Remember to address all other potential causes of leakage first (e.g., inadequate/improper oil drain out of the turbocharger, excessive crankcase pressure, turbocharger past its useful service life, etc.) and use a restrictor as a last resort. Garrett distributors can tell you the recommended range of acceptable oil pressures for your particular turbo. Restrictor size will always depend on how much oil pressure your engine is generating-there is no single restrictor size suited for all engines.

Ball-bearing turbochargers can benefit from the addition of an oil restrictor, as most engines deliver more pressure than a ball bearing turbo requires. The benefit is seen in improved boost response due to less windage of oil in the bearing. In addition, lower oil flow further reduces the risk of oil leakage compared to journal-bearing turbochargers. Oil pressure entering a ball-bearing turbocharger needs to be between 40 psi and 45 psi at the maximum engine operating speed. For many common passenger vehicle engines, this generally translates into a restrictor with a minimum of 0.040" diameter orifice upstream of the oil inlet on the turbocharger center section. Again, it is imperative that the restrictor be sized according to the oil pressure characteristics of the engine to which the turbo is attached. Always verify that the appropriate oil pressure is reaching the turbo.

The use of an oil restrictor can (but not always) help ensure that you have the proper oil flow/pressure entering the turbocharger, as well as extract the maximum performance.
PAT! is offline   Reply With Quote
Old 01-25-2007, 06:56 PM   #8
Supporting Vendor
iTrader: (6)
 
Join Date: Mar 2005
Location: Broken Arrow,Ok
Posts: 1,061
Total Cats: 40
Default

I believe that everyone should use one just to be safe. Puttin in 1 more fitting is easier than replacing a seal. If anyone wants them I carry a -4 male to -4fem with a 1/16 rest.
-Michael-
TheBandit is offline   Reply With Quote
Old 01-25-2007, 07:35 PM   #9
Senior Member
 
Join Date: Dec 2004
Posts: 1,450
Total Cats: -1
Default

Quote:
Originally Posted by PAT! View Post
Remember to address all other potential causes of leakage first (e.g., inadequate/improper oil drain out of the turbocharger, excessive crankcase pressure, turbocharger past its useful service life, etc.) and use a restrictor as a last resort.
Couldn't have said it better myself...wait, I think I have said that very thing myself!

Quote:
Originally Posted by TheBandit
I believe that everyone should use one just to be safe. Puttin in 1 more fitting is easier than replacing a seal. If anyone wants them I carry a -4 male to -4fem with a 1/16 rest.
Only if by "safe," you mean running the risk of under-oiling your turbo and ruining it. I think it'd be far easier to just run the turbo w/o an oil restrictor for a short period of time while looking for smoke, oil in the charge pipes and other tell-tale signs of problems, rather than just installing the restrictor sight-unseen.
bripab007 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Garrett Turbo, 1.8 Oil Pan, & Misc. Stuff nbdooey Miata parts for sale/trade 9 08-30-2017 10:50 PM
1994 Spec Miata Race Car SM/SM2/SSM For Sale Quinn Cars for sale/trade 6 10-23-2016 08:58 AM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
3rd Time's a Charm...hopefully. zephyrusaurai Meet and Greet 2 09-28-2015 11:59 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 11:03 AM.