Jump to content
SAU Community

Recommended Posts

So theoretically it would actually be best to have the sump breather go back into the cam covers, which would help push oil down the head drains if it has that external passage.

But by that logic the breathers at the back of the block are pretty massive and there are two... So the oil drains shouldn't have that much trouble draining..... Theoretically.

No it doesn't help in the way you've described because the sump itself is where the blowby goes and where the "high" pressure is. The idea is to reduce the blowby gasses that have to go through the head - either by directing them to the catch can or around the head into the breather system (via the filler cap mod). I favour the former simply because it reduce the velocity of the gasses in the breather system and therefore makes it less likely they will entrain oil. Also you don't want the whole system pressurised as it just costs you horsepowahs.

In a wet sump the only thing returning oil to the sump is gravity and the oil has to pass the blowby gasses going in the opposite direction.

I'm trying to upload a pic of my bay but it won't let me :(

Menthol,

It's not that it will push oil down but reduces how much air is flowing up the returns trapping the oil in the head, people under estimate how much blowby come out of these things under high boost applications,ie 20psi+, next time your car is on the dyno see if you can watch the breather outlet, it will shock you

Simon,

While it will greatly reduce the amount of air pressure is the crankcase, air will flow the path of least resistance and if that is via the two lines running to the catch can then that is where the air will flow and it will take the oil with it, if the catch creates a restriction then it will leave via the oil returns again trapped the oil in the head

I have seen too many times setups running from to low in the crank case ( mine included which come from the block ) where the lines leave without passing through the cam covers and they end up filling up the catch can leaving the sump with out enough oil :(

If the pickup is to low then around a high speed high power corner the oil will cover the pickup and the blowby will pump the oil up the line to the catch can, but if you are not having issues with yours then you obviously have it sorted :thumbsup:, if it aren't broke don't fix it :)

Another way to increase vacuum in the crankcase and rocker breathers is to also run a large diameter line from the catch can to the intake pipe. This will induce a lower then Atmospheric pressure AND it allows you to run a sealed catch can and make it more legal if you choose to do so...

Down side is if you choose to seal the catch can there may get oil in the intake

Another way to increase vacuum in the crankcase and rocker breathers is to also run a large diameter line from the catch can to the intake pipe. This will induce a lower then Atmospheric pressure AND it allows you to run a sealed catch can and make it more legal if you choose to do so...

Down side is if you choose to seal the catch can there may get oil in the intake

What you are describing is the stock setup for the GTR's with a Nismo can fitted.

Another way to increase vacuum in the crankcase and rocker breathers is to also run a large diameter line from the catch can to the intake pipe. This will induce a lower then Atmospheric pressure AND it allows you to run a sealed catch can and make it more legal if you choose to do so...

Down side is if you choose to seal the catch can there may get oil in the intake

In theory that's sounds good but what it does is increase air velocity up the oil returns/catch can lines increasing the amount of oil leaving the engine, and is how my setup is currently done for legal reasons and why so much thought had to go into it and it's proven to work with 22psi boost and 400kws at all 4 on SMSP-s which is a tight twisty track that does a good job of showing a setups short comings

Do you have an oil return line from your catch can to the sump mick?

If it was draining back when the engine is in vacuum that would be a solution?

Yeah, -12 line from bottom back of front catch can to fitting in block next to starter motor with a one way valve on it

It can't until engine is off as the vacuum is running through the catch cans

I'm trying to upload a pic of my bay but it won't let me :(

Menthol,

It's not that it will push oil down but reduces how much air is flowing up the returns trapping the oil in the head, people under estimate how much blowby come out of these things under high boost applications,ie 20psi+, next time your car is on the dyno see if you can watch the breather outlet, it will shock you

Simon,

While it will greatly reduce the amount of air pressure is the crankcase, air will flow the path of least resistance and if that is via the two lines running to the catch can then that is where the air will flow and it will take the oil with it, if the catch creates a restriction then it will leave via the oil returns again trapped the oil in the head

I have seen too many times setups running from to low in the crank case ( mine included which come from the block ) where the lines leave without passing through the cam covers and they end up filling up the catch can leaving the sump with out enough oil :(

If the pickup is to low then around a high speed high power corner the oil will cover the pickup and the blowby will pump the oil up the line to the catch can, but if you are not having issues with yours then you obviously have it sorted :thumbsup:, if it aren't broke don't fix it :)

yeah exactly what happened to me, Did you just bore a hole in your crank and weld -12s into that?

i was thinking about doing this but was worried about the strength in the block walls.

if this can be done it would save me alot of headache

yeah surely not the best :/ I have 2x -12 on the highest point of my sump, and iv only had the issue of puking when I over fill my sump.

seeing as I run e85 I don't drain mine back to sump either

would be interesting to know how else you could get the vents higher.

next time ill just go drysump, LESS HASTLE!!

Hardly less hassle but certainly as better solution if you have money to burn. I have managed without but if I had a 600kw build I would at least look at an accusump If not a full dry sump.

I drilled and tapped 3 holes in the block ( 2 x -12 and 1x -16 ), placement of these holes is very important for block strength, get it wrong and shit can turn bad pretty quick

I also have the water jackets half full of grout and a platinum racing adaptor plate which ties the girdle and block together

The Accusump is a really really good band aid, but and ounce of prevention is worth a pound of cure, set your oiling system up right from the get go and it shouldn't be necessary

  • Like 1

I have a 600hp 25/30 driftcar, about to turn it up a bit for racewars next yr, hoping to go 800rwhp, but on current set up its running 6.5L trapdoor extended sump, 2L accusump, 2 sump breathers. 2x1.2mm restrictors, blocked vct feed, enlarged oil drains, decent vented catch can. tomei oil pump. all up with the oil cooler and accusump it holds around 9.5L. the only time ive ever had quite an oil puke was when I over filled the sump, other than that, its usually pretty clean apart from the ethanol. has quite a high oil pressure too, sits around 80psi once warm at 2000rpm hits relief spring pressure (110psi) around 4000rpm. haven't had any issues.

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

    • Thought I would get some advice from others on this situation.    Relevant info: R33 GTS25t Link G4x ECU Walbro 255LPH w/ OEM FP Relay (No relay mod) Scenario: I accidentally messed up my old AVS S5 (rev.1) at the start of the year and the cars been immobilised. Also the siren BBU has completely failed; so I decided to upgrade it.  I got a newer AVS S5 (rev.2?) installed on Friday. The guy removed the old one and its immobilisers. Tried to start it; the car cranks but doesnt start.  The new one was installed and all the alarm functions seem to be working as they should; still wouldn't start Went to bed; got up on Friday morning and decided to have a look into the no start problem. Found the car completely dead.  Charged the battery; plugged it back in and found the brake lights were stuck on.  Unplugging the brake pedal switch the lights turn off. Plug it back in and theyre stuck on again. I tested the switch (continuity test and resistance); all looks good (0-1kohm).  On talking to AVS; found its because of the rubber stopper on the brake pedal; sure enough the middle of it is missing so have ordered a new one. One of those wear items; which was confusing what was going on However when I try unplugging the STOP Light fuses (under the dash and under the hood) the brake light still stays on. Should those fuses not cut the brake light circuit?  I then checked the ECU; FP Speed Error.  Testing the pump again; I can hear the relay clicking every time I switch it to ON. I unplugged the pump and put the multimeter across the plug. No continuity; im seeing 0.6V (ECU signal?) and when it switches the relay I think its like 20mA or 200mA). Not seeing 12.4V / 7-9A. As far as I know; the Fuel Pump was wired through one of the immobiliser relays on the old alarm.  He pulled some thick gauged harness out with the old alarm wiring; which looks to me like it was to bridge connections into the immobilisers? Before it got immobilised it was running just fine.  Im at a loss to why the FP is getting no voltage; I thought maybe the FP was faulty (even though I havent even done 50km on the new pump) but no voltage at the harness plug.  Questions: Could it be he didnt reconnect the fuel pump when testing it after the old alarm removal (before installing the new alarm)?  Is this a case of bridging to the brake lights instead of the fuel pump circuit? It's a bit beyond me as I dont do a lot with electrical; so have tried my best to diagnose what I think seems to make sense.  Seeking advice if theres for sure an issue with the alarm install to get him back here; or if I do infact, need an auto electrician to diagnose it. 
    • Then, shorten them by 1cm, drop the car back down and have a visual look (or even better, use a spirit level across the wheel to see if you have less camber than before. You still want something like 1.5 for road use. Alternatively, if you have adjustable rear ride height (I assume you do if you have extreme camber wear), raise the suspension back to standard height until you can get it all aligned properly. Finally, keep in mind that wear on the inside of the tyre can be for incorrect toe, not just camber
    • I know I have to get a wheel alignment but until then I just need to bring the rear tyres in a bit they're wearing to the belt on the inside and brand new on the outside edge. I did shorten the arms a bit but got it wrong now after a few klms the Slip and VDC lights come on. I'd just like to get it to a point where I can drive for another week or two before getting an alignment. I've had to pay a lot of other stuff recently so doing it myself is my only option 
    • You just need a wheel alignment after, so just set them to the same as current and drive to the shop. As there are 2 upper links it may also be worth adding adjustable upper front links at the same time; these reduce bump steer when you move the camber (note that setting those correctly takes a lot longer as you have to recheck the camber at each length of the toe arm, through a range of movement, so you could just ignore that unless the handling becomes unpredictable)
    • I got adjustable after market rear camber arm to replace the stock one's because got sick of having to buy new rear tyres every few months. Can anyone please let me know what the best adjustment length would be. I don't have the old ones anymore to get measurements. I'm guessing the stock measurement minus a few mm would do it. Please any help on replacing them would be fantastic I've watched the YouTube clips but no-one talks about how long to set the camber arm to.
×
×
  • Create New...