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Yeah, was thinking of cutting them and having them remade so they run above the fitting but it isnt exactly a cost effective solution and I assumed that they were metal for a reason (heat, preassure).

Was thinking about the hose diameter for a while but with a standard flow rate pump (NISMO), sucking from a trust extended sump and a tomei oil restrictor, how much oil that the factory returns cant cope with is there realy going to be?

We tapped and threaded a large 90° brass elbow intothe back of my RB26 head and then fitted braided hose down to a -12 fitting on the RHS of the sump, just below the dipstick hole.

  • 3 weeks later...
  • 2 weeks later...

Is a restrictor still needed for a dry sump setup?

Depends on the Dry sump setup. If the dry sump doesn't have a pickup from the cylinder head then i would definitely recommend a restrictor. On the kits i make they are a 4 stage and don't require a restrictor as they create a vacuum which draws the oil from the rear of the cylinder head. So controlling top end oil flow isn't such an issue.

Another notable point is one of the main reasons people put the restrictor in place is to reduce the oil flow so as to not trap all the oil in the cylinder head and pump the sump dry. This is not an issue with a dry sump setup obviously.

  • 3 weeks later...

just got a few questions..

what size do i drill the oil galleries in the head and block..?

only facilitate it at the head with die grinder. and approx how much...?

and i am running slightly bigger clearences for the bigend bearings will that effect what restrictors i should use if i go by your table...?

and if i am running an n1 oil pump. is it still a good idea to run the oil return in the back of the head..?

thanks

what size do i drill the oil galleries in the head and block..?

1mm larger than they are now

only facilitate it at the head with die grinder. and approx how much...?

It's a funnel, so 8 to 12 degrees taper is fine

and i am running slightly bigger clearences for the bigend bearings will that effect what restrictors i should use if i go by your table...?

Yes

and if i am running an n1 oil pump. is it still a good idea to run the oil return in the back of the head..?

Yes

oh and one more question... is it safe to have all this done to ya motor while trying to run it in.. while using a running in oil

Yes

Cheers

Gary

thanks for your help...

the oil clearences i am running are of the higher tolerence a standard rb25 should have.. or just a fraction over..

what ones should i block off and what restrictors should i use and where...?

im keen on doing all the mods you have suggested as i have my motor partially build with forgies ect.. and i dont wanna blow up another motor lol

Here are some pix of what we have done with my gtr with the oil return, the blue line runs down to the sump on the intake sump into a off the shelf fitting that was tapped in and will be secured with two stainless hose clamps each end. Not fully finished yet but gives you guys an idea

I havent seen the rear of a gtr for a while but my car doesnt have a heater or anything like that so ive removed all those hoses and am routing the turbo return into below the front of the plenum. I did this so if i did spring a leak, it could be easily seen and fixed.

Tapping and running a 90 fitting in there would work nicely without being 2 obtrusive

hasn't that been covered ahead? gravity return should be a minimum of 1/2" internal diameter as the standard turbo returns are. And where you return it is up to you, another effective place is adding a Y to the rear turbo drain

I am using basically the same setup as described by Gary. One minor modification I did to expediate things down the track was to put a an extra join in the drain back line close to the head but accessible enough to get at.

Reason being The first time i lifted the head for a valve upgrade it was a total pain in the arse trying to lift the head off the arp studs as the hose wasnt long enough and it is nigh impossible to get to the back of the head to disconnect it.

Doing a cam upgrade atm and it sure bore fruit. A couple of clamps and off she comes. Great thread this. :(

I am using basically the same setup as described by Gary. One minor modification I did to expediate things down the track was to put a an extra join in the drain back line close to the head but accessible enough to get at.

Reason being The first time i lifted the head for a valve upgrade it was a total pain in the arse trying to lift the head off the arp studs as the hose wasnt long enough and it is nigh impossible to get to the back of the head to disconnect it.

Doing a cam upgrade atm and it sure bore fruit. A couple of clamps and off she comes. Great thread this. :D

I disconnect at the sump, no joins.

I am not in favour of plumbing the head oil return into the turbo oil return. The turbo rotation thrashes the oil into a foam and it fills up the hose pretty well. It might be OK on a twin turbo (as per Duncan's application) as there is only half the oil flow in the rear turbo oil retrun. But I wouldn't do it on a single turbo application.

Cheers

Gary

  • 4 weeks later...

Very odd, I have a virgin RB25 S1, has 1.25mm restrictors in all 3 oil feeds... anyone ever had one like this? the last 2 RB25's I did were not like this.

Also if you block the VVT feed off on this it will have no oil going to the front cam journal at all, obviously you have the feed from the block to the oiling ring, then the port that runs off via the solonoid back to the head to drain, it is totaly independant of the main galleys...

Would any one like some pictures of drilling out the returns and matching the rear returns? I have taken some pics along the way.

cheers

  • 2 weeks later...

Sorry to bring this old thread up again,i just want to make sure i have this correct.

I have an RB25 with VCT:

Ill be running an N1 oil pump aswell.

So i leave the front oil feed,block the middle feed and put the 1.5mm restrictor in the rear feed?

What do i use to block the oil feed? And how will i know it wont come out and destroy my motor?

Also i have bought a fitting that replaces the top welsh plug in the head for the external drain,but was wondering were on the sump do i tap into?

Do i tap into it near the top or the bottom of the sump?

you can block the oil feed with any fitting tight enough that it needs to be hammered in. we used a screwdriver body (pretty high tech) but the right way to do it would be to machine it on a lathe.

re the return - above oil level on the drivers side of the sump is perfect. just tap a tapered thread and put a fitting in.

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