Oil Control In Rb's For Circuit Drag Or Drift

[mickr33couple]

Pressure relief valve crack off is 75psi outta spring only

[mickr33couple]

Narrow it down to ill be setting pressure to 70-65psi

Narrow the restritors to

Leave VCt, 1.3mm in the other two

Or

Leave VCt, 1.5mm and block rear, (or should this be block middle 1.5mm rear)

Abr33 are you running a head drain? Also are you running bigger sump with extended pickup?

[abr33]

Doesnt really matter which oil feed gets blocked, it all runs a common gallery for lifters...

I have a gated and baffled sump that I made with better pickup, holds bit over 7 litres. If you need pics I think I put them up several pages back or can send more.

And have a rear head drain/vent also enlarged oil return channels and drilled return holes to 9mm. Also running front of sump to cam vent but will send it to a can soon.

[brad 110]

Don't block the rear oil feed it does matter, block the centre at 75 to 85 psi max hot oil pressure if you leave the front restrictor std (which if you want the VCt to operate you should) and block the centre then reducing the rear to as little as 0.9mm combined with using a high volume pump so as oil pressure at idle is 30 psi or greater hot the lifters won't rattle.

[mickr33couple]

Don't block the rear oil feed it does matter, block the centre at 75 to 85 psi max hot oil pressure if you leave the front restrictor std (which if you want the VCt to operate you should) and block the centre then reducing the rear to as little as 0.9mm combined with using a high volume pump so as oil pressure at idle is 30 psi or greater hot the lifters won't rattle.

So many mixed story's, this thread has a graph on the first page and that says to block the rear?

[brad 110]

Fine on a gtr head with solid lifters and no VCt. You have VCt and hydraulic lifters yes? Then don't block the rear, your engine builder would know this if they don't be concerned, mention loss over distance and gauge the response , trust me block the rear and the lifters at the rear of the head will define it for you.

[mickr33couple]

Fine on a gtr head with solid lifters and no VCt. You have VCt and hydraulic lifters yes? Then don't block the rear, your engine builder would know this if they don't be concerned, mention loss over distance and gauge the response , trust me block the rear and the lifters at the rear of the head will define it for you.

Yeah running hydraulic lifters and VCt, the engine builder didn't wanna put any in for the fact of noisey lifters...

Nitto website says dual spring crack off is 120psi... Single spring crack off is 75psi??

Should I do the single spring to give me the 75psi if this is max?

[t_revz]

I have new standard pump which is lower flowing than yours. Blocked rear, left front and middle standard.

No noise

[VLSteve]

Hello all.

I've searched but havent found the answer I'm looking for....

My motor is a Stock S2 RB25DET, standard bottom end and oil pump. But has Tomei Poncams and Hi flow OP6 turbo.

Its only street driven but with occasional drags.

What restrictors should I fit.

SK has said Leave VCT, block center and 1.5mm for rear.

From my searching I have found that the standard RB25DET restrictors are already 1.5mm. So all I need to do is block the center one?

Or is there no point in even removing the head to just to block off one restrictor with a stock motor?

Cheers

[KiwiRS4T]

Shouldn't need restrictors at this point with stock oil pump. You may need a properly set up catch can but if you haven't had a problem so far don't worry.

[VLSteve]

I am getting a bit of oil through my cooler piping etc as its running the stock breather hoses off the rocker covers.

Will look at a catch can.

Btw motor is out of the car at the moment, hence why I'm thinking of pulling the head to do the restrictors...

[skylinestx]

Hi everyone my name is stef..I hope someone can offer me some advice as I have read this hole thread from start to finish!

I'm in the middle of a forged rb25det build with an n1 oil pump.. After reading this thread I have come to the conclusion that I need to leave the vvt, block the middle and restrict the rear to 1.5mm. Now upon stripping the engine which I believe has been untouched I have found that all three restrictor a are 1.2mm which has now confused me lol..should I still block the middle supply and drill the rear out to 1.5mm? Thanks for any help

Regards

Stef

[kitto]

Is it an RB25 NEO?

If so, middle and rear feed will be approx 1.2mm factory and the VCT feed should be a 5mm hole.

[skylinestx]

hi no its not a neo as it has spec 1 cams came out of a 1994-5 car..thanks

[VLSteve]

Yeah I just got the head off mine this week. The front vct is 1.5mm and the other 2 are 1.2mm

Motor is a S2 RB25DET from a 95 R33.

So should I just put in 2x 1mm?

[skylinestx]

I'm not sure tbh I think because the others are smaller means I don't need to block the middle? It would be nice to know for a fact though

[skylinestx]

Anyone else found this to be the case? And what restrictors they use? Cheers

[KiwiRS4T]

Yeah I just got the head off mine this week. The front vct is 1.5mm and the other 2 are 1.2mm

Motor is a S2 RB25DET from a 95 R33.

So should I just put in 2x 1mm?

Depends on what pump you are using. I have an N1 pump RB30 block S2 head and I'm successfully using 2 x 1mm restrictors (street. track and to come - drags).

[skylinestx]

I intend to run a n1 pump..should I still block the middle/front gallery and leave the vvt and rear at 1.2mm?

[skylinestx]

anyone?