Jump to content
SAU Community

Recommended Posts

Wow maybe I have a compression problem. I read it and its still used to drain oil. Or a method of managing blow by. But all my stuff is on the turbo side no fittings are on the intake side. I feel there is no evidence that one side is better than the other. It like saying I took a leek on the back side of a tree. There is no back side. A circle is a circle. Right after the center line it becomes equal again. So I might be wrong here but thats my 2 cents.

I understand that, but its still a circle. The vacuum can be created right after it passes the center line. And to me that a equal effect after all all the engineers at nissan couldnt get it all that wrong. So the a 2jz is was better not cause of 500cc more but because they placed the oil return on the opposite side. I feel the oil return based on side is just hype. The method in getting the motor to breath and manage blow by as well as oil drain is like 95% more valid than what side on the sump should be chosen. Thats all im saying.

Wow maybe I have a compression problem. I read it and its still used to drain oil. Or a method of managing blow by. But all my stuff is on the turbo side no fittings are on the intake side. I feel there is no evidence that one side is better than the other. It like saying I took a leek on the back side of a tree. There is no back side. A circle is a circle. Right after the center line it becomes equal again. So I might be wrong here but thats my 2 cents.

You are wrong but no point repeating all the arguments that are pretty much resolved later in the thread.

Wow that was weak. But its not an argument mate. Its just a discussion. A friend of mines from collage has a software witj liquid dynamics and he does some really good stuff with it. Ill see if I can have him do somtjing to show you my piont. As for reiterating. Things on threads thats a given. Cause from reading this tread which on of the best ive read so far. There is more if I may say off topic discussion around really good points. For exsample way back from page 16 and down someone menstion venting the sump. The difference is he didnt go into details people said no its a supply problem. But as I read on some people just changed the idea and place the vent line in the catch tank and change up the wording just a bit. Here what ill do all the same and use the opposite side for a comparison sake. I appreciate all advise on here. When I help people on here I dont have any problem saying things over agian. I just clean it up better the second time around.

Marcus,

I do CFD (that software stuff that your college mate uses for fluid dynamics modelling). Well, I don't actually do it - I have CFD people to actually do it, but that's not the point. The point is that doing a proper CFD simulation to show that one side of a sump is better than the other for venting, or to demonstrate that there is no difference, is not actually a trivial task. 90% of people who attempt it would do it wrongly. They would make the wrong assumptions going in, and they would interpret the results wrongly too.

Regardless, there is a better side of the sump to vent from, and it is because of crank rotation, and it is because of windage, and it is because the crank flings oil droplets more to one side than the other. And those are all different ways of saying the same thing. And you don't want the oil droplets in the sump gas that you vent, if you can avoid it.

Really, how does the crank spit oil more on one side then the other ?

Does it stop oil from getting pushed out on one side but then lets it go on the other :/

What alot of people dont take into account is the fact the crank case is under pressure at full noise where oil control or more venting control is most needed

Marcus,

I do CFD (that software stuff that your college mate uses for fluid dynamics modelling). Well, I don't actually do it - I have CFD people to actually do it, but that's not the point. The point is that doing a proper CFD simulation to show that one side of a sump is better than the other for venting, or to demonstrate that there is no difference, is not actually a trivial task. 90% of people who attempt it would do it wrongly. They would make the wrong assumptions going in, and they would interpret the results wrongly too.

Regardless, there is a better side of the sump to vent from, and it is because of crank rotation, and it is because of windage, and it is because the crank flings oil droplets more to one side than the other. And those are all different ways of saying the same thing. And you don't want the oil droplets in the sump gas that you vent, if you can avoid it.

Man. I was and will brake it down. Because all the oil is at the bottom in the sump. Chances are the coming around the crank will hit some oil and splash the oil to the intake side and just as it passes the center line, and that where ever you plan to place your an fitting. Then it becomes a vacuum. On the back end of the crank. Not that it spit it out or sucks it in. All im saying it that its totally even on eather side. Its simple. This reminds me of a f1 engineers can look at an engine block and tell how the layout internally is placed. This gift is priceless. Hence the 6 figure pay cheque. Look. If the carnk is in a 360 degree situation and most of the oil is in the bottom how can the crank coming up from the oil source before the center line not bring oil with the rotation (wet setup here) and after pacing the center line which is 90 degrees in most occasions only after that is there a vacuum. Only after that point of where you place your oil vent or an fitting. Just my two cents mate. But my friend is very very skilled at it but we haven't talked in years but went to school together. His pay has separated use over time. I have sent him an email. I invited him to the bahamas. Im sure if he comes this conversation wouldn't even matter. I just would be happy to have seen him again. But his skill I wouldn't even question in liquid dynamics. Not for one second. This is a great thread guys. Reminds me of why I like this form so much

Edited by MJTru
  • 2 weeks later...

update

from my build/thrashing thread

so have been doing some investigation into my catch can setup following eastern creek happy fun times

on long left hander’s i noticed that oil pressure would drop to 30psi under high load

i can confirm this with the Haltech data logger, plus warning lights and i was going so slow i have time to check guages mid corner at 180km/h

This has only cropped up since going to the hancock rubber ( never had a issue on the r888 which are slower)

so i checked my oil levels as i do and she was at the hump in the dipstick so 10 litres of oil in the slightly larger stock sump

so slapped another 2L in which brought the oil level up to crank level and about 1 inch above the kink in the dipstick (about 3 inches higher than the full line)

next session this resulted in perfect oil pressure on left handers however the downside was the catch can pumping about 1 litre of oil out the drain and under the car

i already had a cunning plan to fix this and was expected considering the thrashing teh car cops/ engine wear

i will be going to version 3 catch can which involves putting it the one way valve to the catch can and activating the external pump that i had installed (have not been using it till required)

i am hoping this will give me a extra year or two of thrashing ( or about 10 gearboxes time) before i have to start backing off the revs to control blowby

will also extend the -20 drain hose to back behind the rear cradle to that the poor bastard behind me cops it and not the under part of my car

It looks like the sump breathers are just pumping the excess oil up to the can and back through the top breathers. You need to be able to raise the breathers up some more by welding a tube bending upward like a little snorkel. Not sure if there would be room to do it though.

Is that breather off the filler cap really dumping to ground?

Hmm. Intresting. This oil issue is still hunting people out there. I have found oil control in the motor itself works with all the additional mods mentioned. I do drag racing and never put the car through a circuit racing. Im doing an experiment right now on a rb25. Im not thinking about this no more. Ive scrap up all my old parts greddy oil pumps that are still good and all different size resistors. Along wit some off the wall things like machining the block head and add a vent hole higher in this old block as high as I can go. We will see what happens. Hopfully I dont crash cause I have no circuits here. Im sick of hearing that skylines have this problem. :angry:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Back again. I returned to Japan in Jul/Aug to spend time with the car on my birthday and remind myself what all the sacrifice and compromise is for. It happened to line up with the monthly morning meet in Okutama, which I have been wanting to go to for a long time. It's a unique event at a unique spot with really rare, interesting, and quirky cars. It's where all the oldheads and OGs gather. The nighttime scene at DKF certainly has its place and should be experienced if you're into cars, but there's too much bad attention and negativity around it now. IMO the better time is Sunday morning at DKF or Okutama; it's more chill and relaxed. I'm glad I was finally able to go, but not sure it's worth the drive from all the way from Nagoya immediately the day before, unless I was already staying in Tokyo for the days right before the meet, because you have to wake up quite early to make it in time. Funnily enough though I didn't drive the car all that much this trip because it was just too damn hot. While there were zero issues and running temps were nominal and the A/C was strong, RBs already run crazy hot as it is. Sure, it took it all like a champ but something about driving these cars in the ridiculous heat/humidity bothers me and makes me feel like I'm asking too much of it. I'm just me being weird and treating the car like a living thing with feelings; I'm mechanically sympathetic to a fault. Instead I was mainly driving something else around - a KX4(silver) 2001 X-Trail GT, that I acquired in May. There's a few different flavors to choose from with Xs, but visually it's the Nissan version of the Honda CR-V. Mechanically it's a whole different story as this, being the top-trim GT, has an SR20VET mated to a four-speed auto and full-time AWD! It was a very affordable buy in exceptional condition inside and out, with very low mileage...only 48k kms. Most likely it was owned by an older person who kept it garaged and well-maintained, so I'm really happy with how it all worked out. It literally needs zero attention at the moment, albeit except for some minor visual touch-ups. I wanted something quirky, interesting, and practical and for sure it handily delivers on all three of those aspects. I was immediately able to utilize the cargo and passenger capacity to its full extent. It's a lot of fun to drive and is quite punchy through 1st and 2nd. It's very unassuming -in the twisty bits it's a lot more composed than one would think at a glance- and it'll be even better once I get better tires on it(yes, it's an SUV but still a little boat-y for my liking). So...now I have two golden-era Nissans in silver. One sports car and one that does everything else; the perfect two-car solution I think👍 The rest of the trip...I was able to turn my stressed brain off and enjoy it, although I didn't quite get to do as much as I thought. I did some interesting things, met some interesting people, and happened into some interesting situations however, that's all for another post though only if people really want to know. Project-wise, I went back to Mine's again to discuss more plans and am hoping to wrap that up real soon; keep watching this space if that interests you. Additionally, while working in the tormenting sweatbox that is the warehouse, I was able to organize most of the myriad of parts that my friend is storing for me along with the cars, and the 34 has a nice little spot carved out for it: And since it can get so stupid hot in there, that made it all the more easy -after I was standing there looking at the car and said 'f**k it'- to finally remove all the damn gauges that have mostly been an eyesore all this time. Huzzah. The heat basically makes the adhesive backing on the gauge mounts more pliable to work with, so it was far less stressful getting this done. I didn't fully clean it up or chase the wiring though; that will happen once I have the car in closer possession. Another major reason to remove all that stuff is to give people less reasons to get in my car and steal s**t while it's being exported/imported when/if the time comes, which leads us to my next point... ...and that is even though it's time in Japan is technically almost up since it's a November car and the X would be coming in March, I'm still not entirely sure where my life and career is headed; I don't really know what the future looks like and where I'm going to end up. I feel there's a great deal of uncertainty with me and as a result of that, it feels like I'm at a crossroads moreso now than any point in my life thus far and there are some choices I need to make. Yes, I've had some years to consider things and prepare myself, however too much has happened in that time to maintain confidence and everything feels so up in the air; tenuous one might say. Simply put, there's just too much nonsense going on right now from multiple vectors. Admittedly, I'm struggling to stay in the game and keep my eyes on the prize. So much so in fact, that very recently I came the closest I ever have before to calling it quits outright; selling everything and moving on and not looking back. The astute among you will pick up on key subtext within this paragraph. In the meantime I've still managed to slowly acquire some final bits for the car, but it feels nice knowing there's not much left to get and I'm almost across that finish line; I have almost everything I'll ever want for my interpretation and expression on what it is I think an R34 should be. 'til later.
    • Thanks for that, hadn’t used my brain enough to think about that. 
    • Also playing with fire if they start to flow more air down low than what the stock twins can. It's not even up top you need to worry, it can be at 3000rpm and part throttle and it's getting way more flow than it should.
    • Any G40/1000 or G40/1250 results out there?  
    • You still want a proper tune on the stock ECU though. Stock tune + stock ECU with GT-SS/-9s is probably playing with fire if you're running more than stock airflow/power.
×
×
  • Create New...