3 AN or 4 AN line for turbo feed line?
 

With all the talk of oil pressure being to high would a 4 AN line be good enough?

I think either will work but make sure you use a stout drain line where the lowest point is at the front cover -> -10AN or -12AN is my recommendation.

B

I use -4 in and -12 out

I used -4 in, and 3/4'' heater hose out :)

I'm back in the graveyard digging things up.

Has anybody used a -4an with a -10an return? Based on what I've read in the archive -10 fits better than -12 over the stock return. The banjo bolt on the feed line I am going to use has a -4an out. Therefore the -4/-10 combo would be the simplest solution, but I don't want any excess oil smoke. Meaning, if -4an is acceptable but -3an is ideal I would rather add an extra adaptor and go with -3an.

I think you'll be fine with the -10. FYI I'm using a -12 return and had no problem fitting and sealing it on the stock return. You could always just buy a foot of each and use whatever works best. You could possibly even find some scrap at a shop to use. :)

I used 10 AN

Thanks for the replies guys, but what feed size is the 10 being used with, -3AN or -4AN. I have two concerns:

(1) that -4AN may be too big of a feed, even with a simple gravity drop on the return

(2) increasing the feed from a -3AN to a -4AN while at the same time decreasing the return from a -12 to a -10 mayl create backpressure causing some oil to be pushed out through the turbo seals.

3 AN feed, 10 AN return, and there is no smoke or backpressure

I'm using 3an inlet and 10an return.

My S5 Turbo was rebuilt and the turbo guys removed the internal oil restrictor.

If you still have the internal restrictor(special thing hitachi's have) then 4an would be fine.

If it's removed you run the chance of too much oil in the turbo.

Normally, with people that run the -4 feed, they run the larger (-12) return to aid in the flow of oil, but I'm pretty sure a -10 will be enough.

As said above though, some people have experienced excess oil with the larger feeds..

Justin

oops..

when i bought my turgbo i was told 3 an feed 10 return or 4 an feed and 12 return. but they recomended a 3 feed with the rotaries high oil presure

Well Stock FC's have 4an inlet and 10 return.....

The restrictor inside the Hitachi's probably has a big job in this setup working.

:beerchug: Same here

What shop did you buy your turbo from and do you have a 3rd gen or 2nd gen?

I spoke to Demetrios today. He runs a -4AN feed with a -10 return and no restrictors.

My friend called Turbonetics and they suggested either a 3/10 or 4/12.

It sounds like a 3 or 4 feed will work with either a 10 OR 12 return.

i bought it from cheapturbo.com i got a 2nd gen. what i was saying is if you wanna go with a 4 feed then use a 12 return or if your gonna use a 3 feen then u can use a 10 return. 3/10 is a -3 an and 4/12 is -4 an, i am pretty sure.

anyone got pictures of the return going to the stock oil return line? What did you use to get it to seal?

not exactly sure of what your asking but here is my SS oil return going to and from stock locations.

http://images.cardomain.com/member_i...07_26_full.jpg

Here is what is in the Garrett book.

Recommended min ID for oil feed is 9.53 mm= -6
Recommended min ID for drain is 19mm = -12

Oil pressure at turbo inlet to be 2.11kg/sq cm minimum at peak torque speed and above, and no lower than .70kg/sq cm at low idle.

oil outlet should be angled no worse than 35* when installed.

That's per Garrett, My opinion is -4 feed and -12 return minimum.

Run no restrictor due to the fact the bearing housing is it own restrictor. The "seal" on the turbine end of the shaft is a piston ring, there is no positive oil seal, therefore the drain tube must be free of "goosenecks" or elbows due drain flow is not under pressure. The drain tube must return the oil and vent back up the same tube, that is why the size needs to be so much larger than the inlet. The compressor end seal may also be a piston ring seal or a carbon seal. If it is a carbon seal, then its more of a positive seal than the piston ring, but we still have the piston ring on the turbine end.

Hope that was helpful


-Sean

yes it was.

thank you.

yes it was.

thank you.

Sean,

I see you got my email.
Very interesting.
Great response as usual.
Thanks again.

Digi,

Did you make or buy your oil return line? If you made where did you get the fittings. If you paid cash, where did you get it. I need a return for a 3rd gen.

Thanks
Chris

I made it myself.
You can get those turbo and side plate adapters from apt turbo online. like 16bux each.

I got the SS hose and fittings from a local hotrod shop called Lopers here.

It cost me about 40bux.