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-   -   Oil drain tube sizes..what r u using? (https://www.miataturbo.net/diy-turbo-discussion-14/oil-drain-tube-sizes-what-r-u-using-27215/)

thirdgen 10-16-2008 09:38 AM

Oil drain tube sizes..what r u using?
 
Just wondering what size lines you guys are using for your oil drain lines. I assume nothing is too big, just overkill, but what size is too small? My oil feed line to my SR20 turbo is -4 and I am using a 1/8" I think pop rivet for my restrictor, so what size I.D. drain hose should I be using?

Braineack 10-16-2008 09:47 AM

5/8" should be sufficient.

mikef85 10-16-2008 10:02 AM


Originally Posted by Braineack (Post 320424)
5/8" should be sufficient.

Agree, I'd run -10 or -12

photoeye0 10-16-2008 10:15 AM

I'm using a -4 feed line with no restrictor and a -10 drain line. Now I less than 10 miles on my new set up so I'll let you know how it turns out, but with the -4 feel line and no restrictor the turbo see a max of 30psi of oil.

Braineack 10-16-2008 11:14 AM


Originally Posted by photoeye0 (Post 320438)
but with the -4 feel line and no restrictor the turbo see a max of 30psi of oil.

Is this at idle?


With no restrictor and a -4an line I don't see how it wouldn't see over +90psi of oil pressure when you near 7000RPM.

I personally have to run a .040" restrictor with my -4an line; even a .065" orifice is too large.

Saml01 10-16-2008 11:28 AM

-4 feed. 5/8 drain, no restrictor.

Braineack 10-16-2008 11:44 AM


Originally Posted by Saml01 (Post 320470)
-4 feed. 5/8 drain, no restrictor.


T25G? that a Ball Bearing turbo? Those tend to have a built in .035" restrictor.

tilt 10-16-2008 11:58 AM

-3AN feed, -10AN drain hose

Saml01 10-16-2008 12:10 PM


Originally Posted by Braineack (Post 320481)
T25G? that a Ball Bearing turbo? Those tend to have a built in .035" restrictor.

Journal bearing off an SR20.

m2cupcar 10-16-2008 01:14 PM

I'm using some of that water pump tubing that runs to the heater core (5/8" I think). Here's some oil flow using a -3 feed line (no restrictor) t3 center and a shimmed oil pump at ~1000 rpm idle. I've run about 500 miles since the install and haven't had any issues w/o a restrictor. YMMV


Stephanie Turner 10-16-2008 01:15 PM

On a T25 turbo a -8, -10, or 5/8" is sufficient.
Stephanie

kenzo42 10-16-2008 04:20 PM


Originally Posted by m2cupcar (Post 320515)
I'm using some of that water pump tubing that runs to the heater core (5/8" I think). Here's some oil flow using a -3 feed line (no restrictor) t3 center and a shimmed oil pump at ~1000 rpm idle. I've run about 500 miles since the install and haven't had any issues w/o a restrictor. YMMV



I've been looking for this video forever.

Anyway, -8 = 3/8", right?

boileralum 10-16-2008 04:42 PM

-8 ~ 1/2"

patsmx5 10-16-2008 05:30 PM

just a minute....

Joe Perez 10-16-2008 05:58 PM

Nominally, the AN sizes go in increments of 1/16". So -8AN should, in theory, be 1/2" ID.

That said, these is tremendous variance in actual sizing from one hose to the next, which is one reason why, when assembling AN lines, you have to be sure that the hose ends you have selected are rated as being compatible with the particular hose you are using. (variances in OD, even for a common ID, are another)

As an example, Earl's Auto-Flex has an actual ID of .438, whereas Earl's SuperStock had an ID of .5, and Earl's Speed-Flex has an ID of .563.


That said, +1 on -10. (that's looks weird to write)

dynokiller90 10-16-2008 06:31 PM

-4 supply no restrictor, -12 drain . that's on a big 16g. went for the way overkill setup. no issues and it looks bitchen'.

photoeye0 10-16-2008 07:30 PM


Originally Posted by Braineack (Post 320461)
Is this at idle?


With no restrictor and a -4an line I don't see how it wouldn't see over +90psi of oil pressure when you near 7000RPM.

I personally have to run a .040" restrictor with my -4an line; even a .065" orifice is too large.

Hot idle is right around 7psi if I recall correctly I'll take an other look at it. I'm using a GM brake banjo bolt (found in the "help" section of most parts stores), with a banjo to -4 adapter, and -4 into the turbo and oil psi gauge.

thirdgen 10-16-2008 07:35 PM

So my feed line is a -4 and I am running a 1/8" pop rivet for restrictor. My drain line is 3/8". My question is, will this drain line in time be insufficient and cause my seals in the turbo to blow and leak oil?

kenzo42 10-16-2008 10:17 PM

1 Attachment(s)
So if 3/8 :ne: -8, am I looking at this chart wrong?

Attachment 210510
http://www.anplumbing.com/thread_npt.html

NPT 3/8 closest AN Ftg. Size is 8?

boileralum 10-16-2008 10:44 PM

http://en.wikipedia.org/wiki/AN_thread

The AN size is based on OD, apparently.


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