Oil Control In Rb's For Circuit Drag Or Drift

[Mr. Untouchable]

heres a interesting catch setup. The car belongs to a tuner here in Tas.

I wont go into all the specs, but its a 25, 8500rpm, nitto pump, 11L sump .85 restrictor in the rear and I think 1.5 in the front enlarged oil returns etc, he does run the rear -12 drain on the rear of the head and said he found it did... not very much. hydraulic lifter still.

anyways just thought I'd put up a pic as I found it pretty interesting (sorry if no one else does!)

[R32 TT]

heres a interesting catch setup. The car belongs to a tuner here in Tas.

I wont go into all the specs, but its a 25, 8500rpm, nitto pump, 11L sump .85 restrictor in the rear and I think 1.5 in the front enlarged oil returns etc, he does run the rear -12 drain on the rear of the head and said he found it did... not very much. hydraulic lifter still.

anyways just thought I'd put up a pic as I found it pretty interesting (sorry if no one else does!)

Ha! I like his 'recirc' idea by putting the little K&N in with the main Airfilter.. haven't seen that before

[R32 TT]

heres a interesting catch setup. The car belongs to a tuner here in Tas.

I wont go into all the specs, but its a 25, 8500rpm, nitto pump, 11L sump .85 restrictor in the rear and I think 1.5 in the front enlarged oil returns etc, he does run the rear -12 drain on the rear of the head and said he found it did... not very much. hydraulic lifter still.

anyways just thought I'd put up a pic as I found it pretty interesting (sorry if no one else does!)

Ha! I like his 'recirc' idea by putting the little K&N in with the main Airfilter.. haven't seen that before

[Swiper the Fox]

heres a interesting catch setup. The car belongs to a tuner here in Tas.

I wont go into all the specs, but its a 25, 8500rpm, nitto pump, 11L sump .85 restrictor in the rear and I think 1.5 in the front enlarged oil returns etc, he does run the rear -12 drain on the rear of the head and said he found it did... not very much. hydraulic lifter still.

anyways just thought I'd put up a pic as I found it pretty interesting (sorry if no one else does!)

the drain back to the passenger side rocker cover needs to be lower...otherwise a good set-up.

bingo on the rear head fitting...it does fu(k all except vent air under boost.

[rad100]

On the circuit race cars we take a 5 step approach in controlling the amount of oil that is trapped in the cylinder head and/or blown into the catch can;

1.Block off one oil feed in the block (RB26’s have this standard)

2.Fit an appropriately sized restrictor to the other feed. The size of the oil pump is one of the determinates for the size of the restrictor, ie; a high flow, high pressure pump needs a smaller restrictor. Constant higher RPM needs a smaller restrictor etc.

3. Fit an external oil return from the rear of the cylinder head to the sump

4. Drill out the oil return galleries in the head and block

5. Machine around the oil return galleries to facilitate access for the oil

i know ppl will say call workshop..

but before i can, just wondering what to budget to do all the above modifications to my rb25det??

if anyone has paid to get it done let me know how much it set u back..

as i had oil coming out of my breather after a grip day..

and i mean 600ml worth of oil...

cheers

[topher_]

First attempt at a table;

Drag ----------------------------------- 1 mm, Block off, ------------------------------ 1.25 mm, Block off, ------------------------------ Leave, Block off, 1.25 mm,

Circuit/Drift ------------------------------ 1 mm, Block off, ------------------------------ 1 mm, Block off, ------------------------------ Leave, Block off, 1 mm,

Is that information for dedicated track / drag cars? Or is it fine for a street car making over 350kw that sees a track / strip every once a while and sometimes a bit of high rpm in other places

[waxracing]

Wow interesting read for sure.

I think something that will clear it up is to remember its not about vacuum its about high and low pressure. Air will always try to go from a high pressure to a lower pressure. Remember this is how the piston is pushed down the cylinder. So at any given moment if the air pressure is higher in the crankcase than in the exhaust then it will flow towards the exhaust. Upside of lowering the crankcase pressure is the pressure differential between the crankcase and the piston just got larger. free power not much but still free

I also read about dipsticks flying out etc mmm sorry the area being worked on in a dipstick tube is tiny and so its hard for it to make the load required to actually blow it out, if you have x amount of psi in the crank cases and then the dipstick equals 1/10th of a square inch then the pressure on the dipstick is x amount of pounds divided by 10.

Here is what I will be trying in my setup. 30/26

A catch can, breather bottle taken from the top of the rocker covers. One from the sump taken from well above the oil level.

I then plan on using a one way vacuum fitting into the exhaust to help pull a low pressure into the breather bottle.

The rocker covers will get an uprated baffling as well as a 1.5 mm restrictor in the front of the block and a total block on the back. normal cleaning up of oil galleries etc

Im always interested on feedback in case I have over looked something

Edited June 23, 2010 by waxracing

[the_tonkau]

Hi Guy's,

Let me start by saying I have read this thread right through and it's been full of great idea's, a lot of which I have already implemented but I'm still having major issues and I think I'm at the stage where I am looking at reverting to a standard oil pump unless I can think of a solution. I will outline my setup and what I've already done in the hope that someone may think of something that I have not tried.

My setup- R33 Gtst, engine is about 4000Klm's old (half that on the bloody dyno it seems) 25/30 VVT 340RWKW @ 15 PSI with GT35Riw, hydraulic lifters, rebuilt with the standard Nissan bearing clearances, dash 10 rear head mod going to sump on inlet side, VVT oil feed untouched, front oil feed blocked, rear oil feed fitted with 1.5mm restrictor. It also runs Castrol edge 10/60W and has a high volume gated sump. The oil return galleries are untouched (unfortunately) and worst of all its seems, an N1 oil pump is installed.

On the street cruising around is fine, the thing runs great and pulls like a steam train but every time I go near a race track it tries to push all of the oil out of it, in a real hurry too! In my last diagnostic testing I removed the catch can setup and have the three breathers from the rocker covers running into a huge open bottle to try and take any breathing restrictions out of the equation. It STILL wants to push oil out after a bit of sustained high rpm high gear runs. Two laps of Sandown saw about 2 litres come out...don't ask where

Lets talk oil pressure. From memory the factory manual for an RB30 tells me it should have about 65psi @ 4000 rpm. I always thought about 10 PSI for every 1000rpm plus base pressure of 20ish PSI was about right. This should mean I should have about 30psi @ idle and roughly 85psi @ 6500rpm. What I see is about 85psi @ idle and then it quickly gets to 110psi @ around 3000rpm and then slowly creeps to over 120psi @ 6500rpm........seems way too high!

What else can I do taking in account the above mods already completed? Am I right in thinking a pump change is next? Maybe I have a dud oil pump and the pressure relief valve is not working correctly? Is my next move to change the pump back to standard? Should I take the N1 pump out and mod it for better pressure relief? It looks like I need to take the engine out to do a oil pump swap, is this correct or can it be done with the engine still in?

AHHHHHHHHHHH!!!! ............to say this is frustrating is an understatement. I hope someone can help.

Cheers

[the_tonkau]

Tumble weeds..

[bubba]

Hi Guy's,

Let me start by saying I have read this thread right through and it's been full of great idea's, a lot of which I have already implemented but I'm still having major issues and I think I'm at the stage where I am looking at reverting to a standard oil pump unless I can think of a solution. I will outline my setup and what I've already done in the hope that someone may think of something that I have not tried.

My setup- R33 Gtst, engine is about 4000Klm's old (half that on the bloody dyno it seems) 25/30 VVT 340RWKW @ 15 PSI with GT35Riw, hydraulic lifters, rebuilt with the standard Nissan bearing clearances, dash 10 rear head mod going to sump on inlet side, VVT oil feed untouched, front oil feed blocked, rear oil feed fitted with 1.5mm restrictor. It also runs Castrol edge 10/60W and has a high volume gated sump. The oil return galleries are untouched (unfortunately) and worst of all its seems, an N1 oil pump is installed.

On the street cruising around is fine, the thing runs great and pulls like a steam train but every time I go near a race track it tries to push all of the oil out of it, in a real hurry too! In my last diagnostic testing I removed the catch can setup and have the three breathers from the rocker covers running into a huge open bottle to try and take any breathing restrictions out of the equation. It STILL wants to push oil out after a bit of sustained high rpm high gear runs. Two laps of Sandown saw about 2 litres come out...don't ask where

Lets talk oil pressure. From memory the factory manual for an RB30 tells me it should have about 65psi @ 4000 rpm. I always thought about 10 PSI for every 1000rpm plus base pressure of 20ish PSI was about right. This should mean I should have about 30psi @ idle and roughly 85psi @ 6500rpm. What I see is about 85psi @ idle and then it quickly gets to 110psi @ around 3000rpm and then slowly creeps to over 120psi @ 6500rpm........seems way too high!

What else can I do taking in account the above mods already completed? Am I right in thinking a pump change is next? Maybe I have a dud oil pump and the pressure relief valve is not working correctly? Is my next move to change the pump back to standard? Should I take the N1 pump out and mod it for better pressure relief? It looks like I need to take the engine out to do a oil pump swap, is this correct or can it be done with the engine still in?

AHHHHHHHHHHH!!!! ............to say this is frustrating is an understatement. I hope someone can help.

Cheers

Why did you block the front oil feed?

With my N1 pump I saw 100psi by 5000rpm but that's as high as my gauge went.

I would be wondering what restriction is causing the high pressures.. someone knowledgable engine builder needs to come in here and have a read but could blocking the front oil feed increase the pressure abnormally?

[TiTAN]

my 25/30 is running 2x 1.5mm oil feeds + the vct feed, standard drains with an N1 pump.

oil pressure once warm is using 10w-40 (also does the same with a peak of 6.5kg using 10w-60)

2kg @ idle

4kg @ 2000

6kg @ 3000+ and holds 6kg to 7500

that works out to be ~90psi from 3000-7500. i know when cold my engine does breathe a fair bit (just air no real oil to it) but it gets much better once its all warmed up and with the catch can on for ~3 months of driving (inc some decent thrashing) i got about 200-300ml of oil in there.

[Roy]

heres a interesting catch setup. The car belongs to a tuner here in Tas.

I wont go into all the specs, but its a 25, 8500rpm, nitto pump, 11L sump .85 restrictor in the rear and I think 1.5 in the front enlarged oil returns etc, he does run the rear -12 drain on the rear of the head and said he found it did... not very much. hydraulic lifter still.

anyways just thought I'd put up a pic as I found it pretty interesting (sorry if no one else does!)

Any more info on that R32. Seems well sorted with a pokey engine, MCA suspension etc. Interested to read more

[Shane_954]

Any more info on that R32. Seems well sorted with a pokey engine, MCA suspension etc. Interested to read more

A well set up car, lots of goodies. Hollinger box etc.

Spends most of its time racing at symmons plains, has done a low 57 so far and expected to go quicker soon.

[bubba]

heres a interesting catch setup. The car belongs to a tuner here in Tas.

I wont go into all the specs, but its a 25, 8500rpm, nitto pump, 11L sump .85 restrictor in the rear and I think 1.5 in the front enlarged oil returns etc, he does run the rear -12 drain on the rear of the head and said he found it did... not very much. hydraulic lifter still.

anyways just thought I'd put up a pic as I found it pretty interesting (sorry if no one else does!)

Is that a drain from the first (horizontal) can, through a filter and back to the sump?? I say drain as opposed to breather as it's on the bottom of the can..

[the_tonkau]

my 25/30 is running 2x 1.5mm oil feeds + the vct feed, standard drains with an N1 pump.

oil pressure once warm is using 10w-40 (also does the same with a peak of 6.5kg using 10w-60)

2kg @ idle

4kg @ 2000

6kg @ 3000+ and holds 6kg to 7500

that works out to be ~90psi from 3000-7500. i know when cold my engine does breathe a fair bit (just air no real oil to it) but it gets much better once its all warmed up and with the catch can on for ~3 months of driving (inc some decent thrashing) i got about 200-300ml of oil in there.

Thanks for the feedback Titan. Looks like your setup with an N1 works great. You would think that with more restriction in my engine (front feed blocked as per SK's matrix) that it would be better at beating the problem........So far the cause is a mystery...a real shit one

[kyle785]

Thanks for the feedback Titan. Looks like your setup with an N1 works great. You would think that with more restriction in my engine (front feed blocked as per SK's matrix) that it would be better at beating the problem........So far the cause is a mystery...a real shit one

ive got a N1 in my 25 and had the same high oil pressure (peak pressure 116psi at 7000 and above 90-105psi 4500-7000) that was with std restrictors pulled the head off and installed 1x1.5mm restictor rear and blocked the middle, vct feed left untouched found no difference in oil pressure hope that helps answer that question

to fix my high oil pressure i bought a peterson external inline oil pressure relief valve and plumb it inline with my remote oil filter and oil cooler lines now i can adjust my pressure as i see fit

[the_tonkau]

ive got a N1 in my 25 and had the same high oil pressure (peak pressure 116psi at 7000 and above 90-105psi 4500-7000) that was with std restrictors pulled the head off and installed 1x1.5mm restictor rear and blocked the middle, vct feed left untouched found no difference in oil pressure hope that helps answer that question

to fix my high oil pressure i bought a peterson external inline oil pressure relief valve and plumb it inline with my remote oil filter and oil cooler lines now i can adjust my pressure as i see fit

Hi Kyle, thanks for the feedback. This thing is doing my head in. Awesome fix! Did you have to mod your internal oil pump as well as fitting the external pressure relief valve?

[kyle785]

i didnt need to mod the oil pump at all becuase im running a lower relief pressure via the external one, main reason i went this way was becuase it was easyer for me to do the external relief valve set up then to pull the sump off to get the oil pumps relief valve to alter the spring tension and that would of been a trial and error till i got the right pressure

[the_tonkau]

Yeah, after thinking about it, it makes sense that if you want to lower the pressure you don't need to mod the oil pump as you are just adding to the negative if you know what I mean. How does the relief valve "bypass" the pressure? Does it need a return fitting on the sump?

i didnt need to mod the oil pump at all becuase im running a lower relief pressure via the external one, main reason i went this way was becuase it was easyer for me to do the external relief valve set up then to pull the sump off to get the oil pumps relief valve to alter the spring tension and that would of been a trial and error till i got the right pressure

[kyle785]

yes you will need to plumb a return into the sump i just happen to weld a extra fitting on the sump just incase i needed it in the future just so happened the future wasnt so far down the road lol