Oil Control In Rb's For Circuit Drag Or Drift

[Swiper the Fox]

PLENTY of people do but not with RB's.

Your onto something there

have a look at how mine is set-up

[DCIEVE]

PLENTY of people do but not with RB's.

Your onto something there

I spent plenty of time looking into it some time ago but couldnt decide on an optimal way to set it up. Most people seem to run the pump of one cam cover vent (with a catch can in-line) and run a vacuum relief valve on the second cam cover. But then this gets back to the problem of drawing gases through the oil drain ports in the head. I was leaning towards drawing vacuum from the sump (maybe the second turbo oil drain seeing as I run a single), blocking one cam cover vent and running a vac relief valve on the second. Problem then is finding a pump capable of running continuously, most are designed for drag engines.

Edited June 28, 2009 by DCIEVE

[Chris Wilson]

So why does this engine produce so much ring blow by anyway? Are the bores deforming, the pistons deforming, or are the ring packs incapable of sealing at a particular boost or RPM? To me addressing the ROOT problem would be key. Poor ring sealing = less than optimum power.

[Ramius83]

And to add to this in regards to the rear head welsh plug drain mod. Where is the best place to locate the drain on the oil pan? I have seen some add the fitting on the rear of the oil pan, while others do it near the pick up (sump side) of the oil pan. What's best?

[leeroy_25]

I would like to know this also.. So are we saying that oil will not normally pass down the pipe? Or it might but generally it will be an air passage? It read to me in the earlier post that the pipe should be below oil level in the sump? However surely it would then not allow passing air or fluid? I have seen a few people with the pipe fittings in the front r/h side of the sump around where the dipstick is above the baffle? That's where I intended to put mine.

Another point is if this is not an oil drain then why the hell are we all struggling to fit a fitting in the tight space at the back of the motor? Could you not have a fitting out of one of the rocker covers down to the sump or there is plug in the exhaust side of the head that you could take out and possibly get a ftting in. that would equire grinding a bit off the manifold though and it possibly is not a good place for oil to be passing by in the event of a leak!

[PSI Parts]

Tee it into the line going from the rear of head to sump

I'm not running a line from the head to the sump.

[Cjmartz2k]

More messages from the same engine builder..................

Ask them three questions.

1. If it's a problem, why after three generations, did Nissan never do it?

2. If it's a problem, why does Nissan not do it on any of their 500hp race cars?

3. Ask them to explain how oil runs forward from the back of the head to the front of the oil pan at approximately 60-70 degrees (yea, it's flatter than 45 degrees) in a 1,000hp car accelerating at over 1G, when the oil in the pan will stand up at 45 degrees under the same g load?

It should be an interesting read to see how some people grasp the concept of simple physics.

Ask them to grab a ride in a 500-600hp GT-R and pour out a glass of water under acceleration and observe where the water goes. Then ask them how the oil in the back of the head somehow is able to defy the laws of physics because they read it on the Internet somewhere...

Another cool test is to fill a hose with water and hold the thumbs over both ends. At 1g down and 1g back in a tube at 45*, it's equivalent to holding it horizontal. Release the ends and see what happens to the water. Out both ends... Oil in the hose returns to the head and to the block... no new oil enters the hose assuming constant acceleration like that in a drag car.

Now, because the hose is at about 60*, tilt the end that's the head end towards the ground approximately 15* and release the thumbs... Not only does all the oil return to the head, if the inlet to the pan is in the wrong place, oil from the pan can leave the pan, heading towards the rear of the head :lol:

Fun with physics.

Still waiting for arguments to the contrary by the supporters of this mod. Trying to get an honest discussion going here.

[r33_racer]

I was under the impression the oil/vent return from the back of the head to the sump pan, or block should be on the exhaust side so it gets pulled in to the sump/engine by the crank vaccum. Same reason why the oil returns from the head through the block are on that side....thats my reasoning behind it

[Fishpaste~]

1. If it's a problem, why after three generations, did Nissan never do it?

2. If it's a problem, why does Nissan not do it on any of their 500hp race cars?

3. Ask them to explain how oil runs forward from the back of the head to the front of the oil pan at approximately 60-70 degrees (yea, it's flatter than 45 degrees) in a 1,000hp car accelerating at over 1G, when the oil in the pan will stand up at 45 degrees under the same g load?

These are just random thoughts on the topic

1. risk/cost vs reward? doing it for your average street car isn't worth it risk/cost wise for nissan? how many non-track GTRs actually blow and engine because of this?

2. probably because lots of race gtr's would get stripped and rebuilt regularly? cost and longevity aren't one of their concerns? getting threw a race as quick as they can are... hence probably why they also didn't have catch cans?!? less weight, less complexity and the greater risk but greater reward?? =P where as if you track your GTR you want to do everything possible with regards to preventing something from exploding on you (that normally costs less) than rebuilding your whole engine!!

3. So what about when you are running 24psi, holding it at over 7,000 rpm constantly for (insert random number of seconds here) seconds? your not accelerating right? therefor the oil will have the same momentum/inertia as the car and flow with gravity towards your pickup... but if there is no oil getting back down to your bottom end (for pressure/flow reasons) what will it pick up?? its fine to say under conditions where you accelerate at over 1g things might happen? but for how long will you be accelerating that hard??? long enough to drain all the oil thats in your sump baffels etc??

all of his arguments cited acceleration... how many of the broken track GTRs you know about died because of oil starvation under acceleration ?? i know mine didn't, it was continuous high revs (and a failed nissan part )...

i dont know if its just me, but his acceleration logic just doesnt privide a compelling enough argument for me to not do these mods! (of course my head drain wont feed into the back of the sump but the side)

[leeroy_25]

Good come back! I am a little behind on this thread but get the general gist.. I agree with the physics bit for cars under acceleration but on the same note the most recent post points to constant throttle which is what causes the problem in the first place. max acceleration is probably not going to be held for a long period of time.. Where as your car on the track is very likely to be seeing high rpm for long periods.. Acceleration and main g forces on a track are also less likely to be in a straight line.. i.e front to back. mostly the car/oil wil be seeing side ways loads. that throws another different spin on things..

Main point being your higher rpm will more likely be a lower g's as you have done the bulk of your accelerating already.

I would still like to know the agruements as to where in the sump the drain should go? i.e above or below oil level?

Lee

[Swiper the Fox]

I was under the impression the oil/vent return from the back of the head to the sump pan, or block should be on the exhaust side so it gets pulled in to the sump/engine by the crank vaccum. Same reason why the oil returns from the head through the block are on that side....thats my reasoning behind it

Because it was never designed to be an oil drain...its a vent for crankcase pressure...it goes on the right hand side of the engine. Performance Metalcraft designed their 9 litre race sumps with this in mind and have placed the vent on the right hand side of the engine.

Ive always said one ill instal a clear tube and a camera under the bonnet to do a mythbusters on this one. Might be time to pull the camera out and prove it once and for all.

finally someone on here who agrees with the oil rear tubo drain...its a crock of shit. The Japs actually only do it to ventilate the crankcase it was never designed to be an oil drain. If you have ever looked at the large oil galleries at the rear of any RB engine you will see that the chance of any oil to actually make its way through a small hole on the centre of a dash 8 or dash 10 fitting is being optimistic in the extreme. It will return to the sump via the large oil galleries that already exist there. Ill get the 'mythbusters' to make some clear hose and mount an uder bonnet camera to prove this myth is just that...a myth. The only thing you may see going on is a constant stream of crankcase pressure being expelled up the pipe and out through the rockers. This mod can be done without having to massage the firewall and running a fitting on the rear. Enlarging the oil returns along the block is a much better option.

Edited June 29, 2009 by DiRTgarage

[Fishpaste~]

Because it was never designed to be an oil drain...its a vent for crankcase pressure...it goes on the right hand side of the engine. Performance Metalcraft designed their 9 litre race sumps with this in mind and have placed the vent on the right hand side of the engine.

Ive always said one ill instal a clear tube and a camera under the bonnet to do a mythbusters on this one. Might be time to pull the camera out and prove it once and for all.

+1

if you think about it logicaly... if you

1) put in a restrictor to the head... less oil getting there

2) open up the galleries ... more oil flowing back down

why would you need ANOTHER drain at the rear of the head? surely nissan designed their head for the oil to flow back along the galleries not pool at the rear of the head?

the issue of high constant revs means lots of pressure in crankcase... so much so it'll push pressure up the galleries and restrict oil flow to an extent, now if you vent this preassure with the "rear head oil drain" it means the galleries can do their job properly and everything is happy

but hey, whats logic when we have the internet!! =)

[r33_racer]

My understanding was to plumb the external return from the back of the head to the exhaust side on your block/sump entry point....for the reasons i was saying.

Whilst running a wetsump system in our circuit car, we had this oil issue bigtime, catch cans were overflowing, and that was with the 1.5mm restrictor in the head. After that, we ran a even smaller restrictor, and the rear return to the exhaust side of the block/sump. We stopped overfilling catch cans, thank god. But when pulling the motor out on many occasions, everytime the rear return has been holding oil and had leaked out on me when removing that line from under the car. If it were just a vent, then it shouldnt have been able to fill with oil right? Unless in a circuit situation only, it can from holding high revs constantly for 15-20mins straight?

However, i can see the point of venting pressure by running it on the inlet side of the motor instead. If I were still running a wetsump system i would try that out and see how well it works, I can see the theory behind the idea. Especially since the motor is out, it wouldnt be an issue to add a -12 fitting to the sump to plumb it to the inlet side.

hahaha...ok i just read what the jap guy was saying on the other page and see what he said is exactly what i proposed....Only difference is i never considered it being a pressure vent....ahh i should have gone through the previous page...lol

Edited June 29, 2009 by r33_racer

[Swiper the Fox]

My understanding was to plumb the external return from the back of the head to the exhaust side on your block/sump entry point....for the reasons i was saying.

Whilst running a wetsump system in our circuit car, we had this oil issue bigtime, catch cans were overflowing, and that was with the 1.5mm restrictor in the head. After that, we ran a even smaller restrictor, and the rear return to the exhaust side of the block/sump. We stopped overfilling catch cans, thank god. But when pulling the motor out on many occasions, everytime the rear return has been holding oil and had leaked out on me when removing that line from under the car. If it were just a vent, then it shouldnt have been able to fill with oil right? Unless in a circuit situation only, it can from holding high revs constantly for 15-20mins straight?

However, i can see the point of venting pressure by running it on the inlet side of the motor instead. If I were still running a wetsump system i would try that out and see how well it works, I can see the theory behind the idea. Especially since the motor is out, it wouldnt be an issue to add a -12 fitting to the sump to plumb it to the inlet side.

hahaha...ok i just read what the jap guy was saying on the other page and see what he said is exactly what i proposed....Only difference is i never considered it being a pressure vent....ahh i should have gone through the previous page...lol

I did a test with our car using a long line from the rear turbo drain running it up higher than the rocker covers to see what would happen under boost. This was on the dyno with no G force effect on the car. The rear turbo drain is not used as i have a single turbo on the car now.

Can anyone guess what happened?

Edited June 29, 2009 by DiRTgarage

[r33_racer]

did it pump pressurised oil/crankcase gases out of it?

[Guilt-Toy]

I did a test with our car using a long line from the rear turbo drain running it up higher than the rocker covers to see what would happen under boost. This was on the dyno with no G force effect on the car. The rear turbo drain is not used as i have a single turbo on the car now.

Can anyone guess what happened?

Oil came out and messed up your sexy engine bay near the catch can.

[Swiper the Fox]

Oil came out and messed up your sexy engine bay near the catch can.

Yes...you gave the game away...bastard!

Guilt's was there to witness this and it was with no added help from G forces on launch.

People have taken this as gospel on a "sydneykid" said so it must be right basis. lol. There is a few things in this thread that he recommends to do that i certanly wouldn't. Ive never used a drain on any of my own engines and only installed it once on an engine i was building for someone after he insisted to be done. If used it must be plumbed to the right side of the engine to have any positive effect. Ive never lost any of my engines or any that ive ever built due to oil starvation. They have all been wet sump engines...dry sump's are a different matter altogether.

Edited June 29, 2009 by DiRTgarage

[phat_man]

Hi,

on this topic im quite confused. i have a very mildly modded rb20 making around 170rwkw.

attached is how i got the crank case pressure release set up. now after reading abit of this thread i realise that the vacuum should actually go through the head, via the stock vacuum line on the intake plenum.

long story short, where the red lines are, its bunged up. the blue lines, is where i just got some heater hose on, and it just vents to the atmosphere.

is this right? or what should be changed?

thanks.

[r33_racer]

Interesting stuff!

Good work for actually proving your point.

So on a slightly different note, would running say total seal rings, help reduce the extra blow-by that pressurises the crankcase? If anyone has run engines with and without?

[jonn]

Because it was never designed to be an oil drain...its a vent for crankcase pressure...it goes on the right hand side of the engine. Performance Metalcraft designed their 9 litre race sumps with this in mind and have placed the vent on the right hand side of the engine.

Are you saying that the fitting on the rhs of performance metalcraft sump is for good for catch can drain back or not?