Why is PS system vented?

[VictorH]

I am one of many who had had the stock PS reservoir spray fluid during track days. During my last service I decided to add a Bimmerworld PS fluid reservoir. I have not been to a track day event yet but I've noticed some odd items. Firstly, the cap and consequently the system is not vented. Now, I'm one to think the factory engineers probably know better than the aftermarket why certain things are done, i.e. venting.

What I've noted is if I've been running the car for extended periods at higher rpm (not consistently redline) but in the 5,000+ range, when I get home the front of the motor has a loud almost gear whine type of noise and I've had two episodes of PS fluid being pushed out of the hoses to the reservoir (the clamps are pretty darn tight already). I'm thinking that at high rpm the system is somehow getting pressurized, causing strain on the pump (probably the source of the noise) and then pushing fluid out of what is normally a low pressure system. I'm going to add a vent to the cap with perhaps some small weedwacker fuel line tubing and see if this addresses the problem.

I don't think the fluid is getting hot enough to boil in my street use, but something is possibly pressurizing the system and with no vent, it doesn't escape. Anyone know why these systems need to be vented? I'll keep you posted on the outcome. I have 3 day track event in March, hope to find that this is the solution and it will be the ultimate test.

[okusa]

This is exactly why I've stayed away from that unit and will be switching over to the 1M unit instead.

[Hujan]

All German Auto makes a nice billet aluminum PS reservoir with extra fluid capacity and greater head space as well. It is vented like OEM. I have it on my car.

http://www.agatools.com/part/bmw-pow...servoir/angled

I still believe the best solution to the PS fluid spills is the threaded backup reservoir offered by 3D Design. I'm not sure they still sell it anymore and it was WAY overpriced, but it is a very slick piece. JEllis has one on his car and having seen it in person, it looks great. I wish a company would manufacturer them at a lower price point. I would buy it if it were $200-300.

http://www.m3post.com/forums/showthread.php?t=913679

[dparm]

Originally Posted by okusa

This is exactly why I've stayed away from that unit and will be switching over to the 1M unit instead.

Can you clarify what's different on that unit?

[SYT_Shadow]

I also have the BW reservoir. I did not think it was 'sealed'. It's closed but I don't think sealed

Anyway, i also noticed an annoying ps steering sound that more or less coincides with when I installed it

I guess i'll go with the kaiv solution!

[cenix]

I really like that 3D Design overflow piece. In my opinion the pricing doesn't seem way over the top for the quality (by the looks of it since I've never seen it in person). I would buy it if I tracked regularly, otherwise I think a ziptied sweatband/rag is the most economical for most people. I like the idea of keeping the "vented" feature.

[Hujan]

Originally Posted by cenix

I really like that 3D Design overflow piece. In my opinion the pricing doesn't seem way over the top for the quality (by the looks of it since I've never seen it in person). I would buy it if I tracked regularly, otherwise I think a ziptied sweatband/rag is the most economical for most people. I like the idea of keeping the "vented" feature.

Yeah, it is definitely a high quality piece. But $600 for a small piece of billet aluminum is a lot.

[okusa]

Originally Posted by dparm

Can you clarify what's different on that unit?

It has an improved venting system.

[Redd]

Just put a sock on it. Low tech solution to a high tech problem. Lol

[dparm]

Originally Posted by okusa

It has an improved venting system.

And it's a direct swap with ours? Is the capacity the same?