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Oil Pressure, Head Restrictor, Big Pump = Too Much Oil

BoostdR

By BoostdR,
in Engines & Forced Induction

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BoostdR Mentor

BoostdR

Posted
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I am trying to sort my oil controll issues but have had no luck. I have some questions

What oil pressure should a GTR run at max warm? Mine sits on 7.5bar-7.75 warm, cold at idle is 7 and warm idle is 4.5-5

What oil restrictor would should I use. Currently has 1.5mm. Car is used on the track mostly but also a streeter. Making in excess of 550kw

I have seen plenty of GTRs on te track with similar power without a rear head drain without the associated issues.

I am using 5w30 oil atm

The engine also has Mines baffles.

Reinmax Oil Pump

I have run out of ideas to fix it so the next step is pulling the motor and reducing oil pressure and changing the restrictor size. Would like to confirm if I am on the right track.

Regards,

Matt

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R31Nismoid Grand Master

R31Nismoid

Posted
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Well from your last thread we worked out that your pump doesnt flow anymore than a N1 pump yes?

My oil pressure is higher than yours with a N1 pump cold and driving around, im using Edge 10/60 however.

I've not seen many people post using 30w oil with built motors, usually at least 40 IIRC?

BoostdR Mentor

BoostdR

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Well from your last thread we worked out that your pump doesnt flow anymore than a N1 pump yes?

My oil pressure is higher than yours with a N1 pump cold and driving around, im using Edge 10/60 however.

I've not seen many people post using 30w oil with built motors, usually at least 40 IIRC?

I tried to replicate the same spring seat pressure as an N1. My gears are much bigger than N1 in width and dimension. The pump flows double a std unit according to the specs.

I have trouble working out why it would flow more than any other pump when it is governed by a pressure reg. It should flow the same as any pump if the target pressure is the same....since pressure is a measurement to restriction of flow. Sure more would come out the bypass....

What are your oil pressures?

cold idle

warm idle

warm max rpm

mine get to max pressure very quick not long after 3000rpm

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
I tried to replicate the same spring seat pressure as an N1. My gears are much bigger than N1 in width and dimension. The pump flows double a std unit according to the specs.

I have trouble working out why it would flow more than any other pump when it is governed by a pressure reg. It should flow the same as any pump if the target pressure is the same....since pressure is a measurement to restriction of flow. Sure more would come out the bypass....

What are your oil pressures?

cold idle

warm idle

warm max rpm

mine get to max pressure very quick not long after 3000rpm

My cold temp is off the gauge :)

Running around pretty sure it sits on 7-8 depending. It's been like that across two motors and most other Racepace motors have similar gauge action.

Im running thicker oil though don't forget /60w

R32 TT Mentor

R32 TT

Posted
Posted (edited)
Larger gears = more volume ..even if its the same pressure.

Huh??

Same engine (ie same restrictions, clearances etc) means same pressure = same flow. The only way you could have more volume AND same pressure is if you had less restriction.

Is it likely its blowby pressurising the sump perhaps? If you've got bucket loads of flow out of your rocker covers its going to take oil with it..

Edited by R32 TT
BoostdR Mentor

BoostdR

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Huh??

Same engine (ie same restrictions, clearances etc) means same pressure = same flow. The only way you could have more volume AND same pressure is if you had less restriction.

Is it likely its blowby pressurising the sump perhaps? If you've got bucket loads of flow out of your rocker covers its going to take oil with it..

motor is tight... leak down is 4.5%

What head restrictors are people running?

Thicker oil should flow less at the same pressure but will also return to the sump slower

Its an RB26/30

DVS JEZ Grand Master

DVS JEZ

Posted
Posted
I would hope his car doesn't have oil pressure problems over the 8 or 9 seconds it runs!

Haha yeah its a little different to circuit thats for sure.

What catch can and breather setup do u run. Do u have stock baffles in the cam covers?

Duncan Grand Master

Duncan

Posted
Posted

no special challenge in my motor either....it runs 12psi not 30 or 40! And built with quite tight clearances (less power but more time between rebuilds). It really doesn't breathe at all.

But FWIW...I have nitto pump, oil return at the rear of the head, enlarged block oil returns, restrictor in head oil feed, standard cam cover baffles with fuel cell foam behind, small oil/air seperator above motor, and catch can in the engine bay.

9krpm Mentor

9krpm

Posted
Posted
I would hope his car doesn't have oil pressure problems over the 8 or 9 seconds it runs!

It has been doing 1.15 on slick around Mallala without any oil problem so far.

I've his drag car engine with same specs, well almost Greddy pump instead of Jun which has been known to be the same pump origninally, and had no problem on the circuit either but converting it to dry sump atm .....just for peace of mind.

BoostdR Mentor

BoostdR

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When i was talking to Kier about RH9 he was saying he doesnt use a rear drain but a 1mm restrictor with Jun pump im sure.

Interesting. Any other specs guys on head oil restrictor size?

BoostdR Mentor

BoostdR

Posted
  • Author
Posted
It has been doing 1.15 on slick around Mallala without any oil problem so far.

I've his drag car engine with same specs, well almost Greddy pump instead of Jun which has been known to be the same pump origninally, and had no problem on the circuit either but converting it to dry sump atm .....just for peace of mind.

Would like to know what oil pressure it is running also.. Anyone Know?

BoostdR Mentor

BoostdR

Posted
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Interesting. Any other specs guys on head oil restrictor size?

Found some info on The lewis Engine web site

RB oil restrictors

p115_05_lube.jpgWe manufacture many different combinations of oil restrictors for the RB, CA and SR engines. The benefit of them is to restrict the oil flow to the top end ensuring the sump has as much oil in it as possible to prevent oil starvation to the bottom end. Our restrictor sizes and combinations are a decision made up of hundreds of hours testing on track and street cars. Use these combos below and please state when ordering what engine etc you have.

1. RB20 RB25 HYDRAULIC HEAD 2x 1.3mm restrictors

2. RB30/25 head HYDRAULIC 2X 1.3mm restrictors

3. RB30/25 NEO solid lifter head 1x 1.3mm 1x blockoff

4. GTR RB26 ALL solid lifter 1x 1.3mm 1x blockoff

5. CA 18 hydraulic 1x 1.5mm restrictor

6. SR 20 hydraulic 1x 1.5 mm restrictor

7. CA and SR solid lifter conversion 1x 1.3mm restrictor

8. RB25 NEO 1x 1.3mm 1x blockoff

9. RB30 single cam 2x 1.3mm restrictors

I calculated the difference in area between 1.5mm and 1.3mm and 1.3mm comes to 75% of what I have(as I currently have 1.5mm)

Going from 1.5mm to 1mm is a reduction in to 44% from what I have now.

The fact my pump very happily pumps 4bar at idle I feel I can go smaller than I have without a noisy head at idle. the question is...how small?

Edited by BoostdR
HoWiE_Au Collaborator

HoWiE_Au

Posted
Posted

Just a thought when this engine was built was the clearance between the sump and pickup measured ???. Also is it running the same Valve stem seals ? if so what type are the positive pressure type ?. Yeah maybe even to much volume trying to be delivered. Think of a hose squirting oil into a hole the size of 10 cents and then think about the same size hole but a 1 inch hose feeding oil into it theres a few ideas to make of it . But eliminating other varibles is the way to go. Start by removing your restrictor it sounds stupid but try it, its not going to kill anyone or anything.

Cheers Rob

HoWiE_Au Collaborator

HoWiE_Au

Posted
Posted

Also empty the catch can and drive around at 2500rpm for say 10 mins , then drive around at 3000rpm + for 10mins and check the catch can . Obviously its going to higher at 3000+ but at least you know its being delivered into the catch can by excess pressure

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