Venting Diff

[Riceburner]

I've been putting quite a few miles on the ricey lately, but everytime I do highway miles I find diff oil all over the rear of the suspension and the car. I have fitted a "perrin' diff cover and I also fitted a copper vent pipe with catch can. I have caught approx 350mls so far, The diff has not been over filled but is consistantly pumping oil out at highway speeds.

 

I have noticed the later factory breathers are metal and have horizontal holes where as my copper pipe has a hole at the bottom going up vertically. Could the DIY breather be the problem? The 'perrin' cover has nowhere near the amount of baffles/webbing as the oem cover. Is this allowing the oil to go up and out of the diff?

 

What setup do you race guys have?

 

I have removed the diff, inspected, refitted the standard breather. So far after 2hrs of hwy driving it's not pumping oil out.

 

Good news is the Diff still looks in great condition  lucky I checked it or there could of been a disaster at the nats!!

[dat2kman]

What oil you using?

Some are known to foam /aerate quite a lot, and bubble out, due to increae in volume due to aeration.

 

Once the oil has been "slung" by the rotating assembly inside, it is like a tall wall of oil pushing upwards against the diff cover inside.

The stock cover webbing, and position of breather helps to deflect some of this wall.

 

Not sure what a Perrin is, ( a bird of flight??) but i use a 5/16"  barbed bsp straight fitting, a short bit of 5/16 hose and an old plastic fuel filter, held vertical, and yes, in race situation the pladtic filter does fill, but drains out.

10 hard laps at PI does see some slight oil film on bottom of tank and up taillights rear panel.

[Riceburner]

I've switched from penrite LSD oil cause that was foaming up, now running Motul 75/90 gear oil as that was recommended as the oil for a torsen centre. My setup sounds pretty close to yours, perhaps it's the lack of baffles/webbing on the aftermarket diff cover not helping? 350ml seems like a lot of oil.