Comparing Power Steering Reservoirs

[mikerunt]

I've searched the threads and haven't seen a definitive guide for what track and race specific recommendations are for power steering reservoirs. my first out in a newly built e90m3 ended very short with power steering fluid all over the place.

here are the options i've seen:

Turner

Bimmerworld

Any others (that aren't a sweatband related)?

i also will be doing the CSF power steering cooler.

[roastbeef]

its been a while and i don't want to misspeak and trash the incorrect brand, but there were a few people having trouble with aftermarket power steering reservoirs causing intermittent firm steering.

i run a black sweatband and it works.

some use a brembo motorcycle reservoir, a tube, and a plastic nipple tapped into the vent on the oem cap with good results. while i like the oem look, its unnecessary clutter and weight.

as for my long term goals for this car, i want to do an electric power steering pump, a better ps cooler, and delete the a/c. i have not heard of anyone with an electric power steering pump have overflow issues. i think its been said its due to cavitation or foaming from prolonged hard use at high rpm, but i don't have the knowledge to comment on that.

i don't think you'll find a definitive guide... everyone comes to the table with different experiences and theories, but it doesn't hurt to talk about it.

[amg6975]

There's also a kind of hacky way to rig up a 1M reservoir that doesn't seem to have the overflow issue but a lot of installs I've seen use Home Depot plastic components in a very high temperature, very corrosive, environment.

There was also some scuttlebutt a while back about solutions without filters causing damage to the system but I'm not sure any of it was scientifically proven.

I zip tie a couple squares of paper towel over mine and just top it up and change the paper towel after each track event. No complaints.

The DO88 cooler is probably recommended over the CSF, as most of their stuff is, but I have not seen any data comparing them.

[mikerunt]

Thanks for the feedback. The car being a “race car” in that it never sees the street I want to go for a more permanent solve for the issue.

Has anyone used either the Turner or BW reservoir with success?

[haile90]

Originally Posted by mikerunt

Thanks for the feedback. The car being a “race car” in that it never sees the street I want to go for a more permanent solve for the issue.

Has anyone used either the Turner or BW reservoir with success?

couple of guys i spoke to at Buttonwillow running the Bimmerworld one said they had no complaints. No increased noise or rack stiffness. I was told that since there is no filter that it is reccomended to change fluid out more regularly. I’m planning on doing a lot more track days so I didn’t mind since i was planning on changing PS fluid out every year. Just ordered my BW reservoir last week, gonna get it powdercoated before installing.

[tsk94]

All of the aftermarket options are a waste of money, IMO.
The issue is the factory reservoir cap has a vent hole in it. So on track, when the fluid gets hot and slushes around it comes out of the hole (not a lot, but enough to make a mess).

This is what I did on my old E92 race car. No mess afterward and wayyy cheaper than an aftermarket option. Similar to what roastbeef mentioned above.


I'll be doing the same thing on the new M3 I'm building soon.

[mikerunt]

Originally Posted by tsk94

All of the aftermarket options are a waste of money, IMO.
The issue is the factory reservoir cap has a vent hole in it. So on track, when the fluid gets hot and slushes around it comes out of the hole (not a lot, but enough to make a mess).

This is what I did on my old E92 race car. No mess afterward and wayyy cheaper than an aftermarket option. Similar to what roastbeef mentioned above.


I'll be doing the same thing on the new M3 I'm building soon.

Nice set up - looks like a motorcycle reservoir?

[tsk94]

Originally Posted by mikerunt

Nice set up - looks like a motorcycle reservoir?

I believe it was a fuel tank for a model airplane. But the same idea, just something around that size.

[haile90]

Originally Posted by tsk94

All of the aftermarket options are a waste of money, IMO.
The issue is the factory reservoir cap has a vent hole in it. So on track, when the fluid gets hot and slushes around it comes out of the hole (not a lot, but enough to make a mess).

This is what I did on my old E92 race car. No mess afterward and wayyy cheaper than an aftermarket option. Similar to what roastbeef mentioned above.


I'll be doing the same thing on the new M3 I'm building soon.

this is actually a really clean setup i do understand the simple solution to fix the stock PS reservoir.

waste of money is a bittt of a stretch imo. the main thing that sold me on the Bimmerworld reservoir was simply the bigger sizing of the unit and that they switched the routing of the hoses. so that the feed to the PS pump is on the bottom and return is on the top, so you’re never starving the pump of fluid in aggressive turning instances. at this point, i kinda considered it like a “preventative” maintence item since i don’t want to go through replacing an entire PS pump down the line.

[mikerunt]

Originally Posted by haile90

this is actually a really clean setup i do understand the simple solution to fix the stock PS reservoir.

waste of money is a bittt of a stretch imo. the main thing that sold me on the Bimmerworld reservoir was simply the bigger sizing of the unit and that they switched the routing of the hoses. so that the feed to the PS pump is on the bottom and return is on the top, so you’re never starving the pump of fluid in aggressive turning instances. at this point, i kinda considered it like a “preventative” maintence item since i don’t want to go through replacing an entire PS pump down the line.

Sold me on it - thanks.

[haile90]

just showed up from UPS lol. size comparison to the OEM reservoir. it’s CONSIDERABLY larger. Welds look great, i’m almost considering not powdercoating it for a bit of bling lol. i love the interior baffling, looks like it’ll hold a lot more fluid compared to the stock filtered one. the only complaint would be with the cap. idk maybe me being picky but it just looks a bit janky and cheap compared to the rest of the unit. not a big deal to me, i think it’ll still look sweet in the engine bay!

[mikerunt]

Wow - I’m stoked on my purchase!

I’m going to leave mine raw and match it to another Moroso coolant overflow because #racecar

Do you have any idea what he capacity is?

[DRLane]

Do yourselves a favor and clean or rinse the hell out of those BW reserviors. An inline filter would be a a requirement personally.

They do look pretty, but also just more weight on the wrong side of the axle.

[haile90]

Originally Posted by mikerunt

Wow - I’m stoked on my purchase!

I’m going to leave mine raw and match it to another Moroso coolant overflow because #racecar

Do you have any idea what he capacity is?

hahaha this would probably tie in perfect then! I can’t find any info on the capacity of the unit, hopefully someone else here knows??

[bosstjm3]

I have a EAE upgraded PS resevoir. I have tracked multiple days and not ran into the overflow issue and recommend it as a solve. The fitment is solid and i like how it retains OEM like look. It is used in tandem with my DO88 upgraded PS cooler and don't have any issues . I linked the product below to their website and I did not have any issues with and recommend.

https://europowermotorsports.com/pro...ing-reservoir/

[okusa]

Originally Posted by bosstjm3

I have a EAE upgraded PS resevoir. I have tracked multiple days and not ran into the overflow issue and recommend it as a solve. The fitment is solid and i like how it retains OEM like look. It is used in tandem with my DO88 upgraded PS cooler and don't have any issues . I linked the product below to their website and I did not have any issues with and recommend.

https://europowermotorsports.com/pro...ing-reservoir/

I'm running the same and love the look. I've tried everything, including the 1M reservoir and this is the first thing that seems to work (as long as you follow their fill procedure and don't overfill). I've now run 3 days with no spillage.

[roastbeef]

Steal his look- $9

https://amzn.to/4bkPWKI

[P1zzaboy]

Originally Posted by amg6975

There's also a kind of hacky way to rig up a 1M reservoir that doesn't seem to have the overflow issue but a lot of installs I've seen use Home Depot plastic components in a very high temperature, very corrosive, environment.

There was also some scuttlebutt a while back about solutions without filters causing damage to the system but I'm not sure any of it was scientifically proven.

I zip tie a couple squares of paper towel over mine and just top it up and change the paper towel after each track event. No complaints.

The DO88 cooler is probably recommended over the CSF, as most of their stuff is, but I have not seen any data comparing them.

Tried the 1 series reservoir and it’s a waste of time and money. Also hose had to be cut so I’ll have to change it to revert back to another solution

[Bimmer Barney]

I’ve run a few track days and about 20k miles with the BW reservoir. Steering isn’t broken and no spillage. I have an in line filter sitting on the shelf. I figure I’ll install it probably maybe.

[mikerunt]

Was out a Buttonwillow yesterday and tried the “sweat band” method - no luck. Still had leak / spray everywhere from it unfortunately.

I ordered the Bimmerworld one and should be here this week.

[bigjae1976]

The overflow issue is not a heat issue. The system has an extremely high pressure. So when the fluid returns to the reservoir, the pressure drops but the velocity of the fluid speeds up. The white disc at the bottom of the reservoir is a diffuser.

The foaming is aeration of the fluid which will quickly destroy your pump.

The pump is a positive displacement gear pump. Sending foamy fluid will cause pump cavitation - cavitation is caused by a pressure drop which lowered the boiling point of the fluid and creates air pockets.

Undersrive pulleys can cause a loss of power assist at low RPMs and still achieves the same pressures thus the same spillage.

A positive displacement pump has a pressure relief to protect the pump and regulate pressure. The only way to prevent spillage is to lower the system pressure thus the regulator has to be modified.

If someone wants to send me a PS pump, I can have the regulator modified.

The benefit of the modified regulator is slightly more steering effort, lower pressures will extend the life of system components, less heat in the PS fluid.

Downside is more steering effort. Might not be the best idea for an endurance car with a team of drivers with weak or bad shoulders.

[mikerunt]

Has anyone used or heard of the “Volvo PS Conversion”?