Power steering system

[Hollowpockets]

Hi guys,

I'm finding that with prolonged track time on the slicks, my car is trying to empty the contents of the power steering bottle onto the inside of the clam. I don't just mean a wee splash like what we all see at some point, the whole inner arch at the right side is soaked and down the side of the engine, so the level is right down and the steering rack was whining when I came into the pits.

I since topped up, pushed a bit of cloth into the breather hole with a self tapping screw to block it up to stop it pissing out everywhere, does anyone with decent knowledge of the system know if this is ok or if I'll cause damage by perhaps pressurising the system??

Cheers

Graham

[Hollowpockets]

Also would a bigger cooler at the front help? That would be easy to change.

[951]

Do you actually need the power steering? Or is that another diet opportunity?

[Adrian W]

Talk to Wayne at Pro-ally, over the years we have had several conversations about this, he has not produced a tank yet as its quite tricky, the gauze in the bottom of the ZF tank does more than you think. The oil expands as it heats up, which doesn't do any favors.

[andygtt]

The older white version is better than the later black one that you have and I have one on the shelf you can try.

I had on designed and made and despite revving to 8k mine hasn't leaked a drop (unlike original white one).... as adrian said the tank needs careful design to make sure the air separates from the oil and has room to expand and breath.

Cant remember exactly but pretty sure cost was under £200.

[anonymous-user]

The problem with conventional PAS systems is that the pump MUST be designed to provide full flow at, or very close to, engine idle speed. This is because for most people, they do a lot of "arm twirling" at low engine speeds when parking etc. This means that as engine speed increased, more and more fluid is being pumped around the (open spool) system. As such, the oil heats rapidly, and can easily cavitate and aerate. For track driving, when you are racing round at high rpm, this can overheat the system, leading to oil expansion, aeration and overflowing, something the std cars PAS header tank really isn't designed to prevent.

Two options exist:

1) make a bigger header tank, with more expansion volume and better baffling/sperators/oil mist catchers etc
2) Ditch the engine driven PAS pump and go ElectroHydraulic.

[andygtt]

Hi Max... the noble has a power steering oil cooler at the front and we have had some new belt pulleys made to gear them down for track work... the header tank Graham has is too small imo and is known to leak at high rpm, hence I made my own.

BTW Graham, don't block the hole, its needed to allow for the oil expansion and you will pressurise the system and possibly blow a gasket in your rack...

[RobP]

I lose PS fluid on fast right hand bends when pulling ~1.3g or thereabouts. I have rigged up a little catch tank that keeps the system at atmospheric and keeps the alt belt and clam nice and clean. Still have to top up with fresh occasionally, but less frequently if you keep it topped to minimum rather than maximum! This is fine for my track day purposes with a standard car, but with a race car on slicks you may need a meatier solution! I'm convinced that in my case at least, PS fluid loss is g related and not over heating the system - anyone whos been round a track with me knows that I barely move the steering wheel!

[chuntington101]

How about fitting an electric rack in-stead?

[Hollowpockets]

As RobP says, not much steering involved but the constant high G's will push out the oil, then the remaining oil heats up too much and air is then in the system. I think a bigger capacity tank and cooler would benefit but just need to find one that fits.

I don't want to start messing with electic or removing the PAS as the car is great as it is. It's not a development project any more, it needs to be on the track and I don't have the time/money to mess around in-between

[anonymous-user]

chuntington101 said:

How about fitting an electric rack in-stead?

The problem is finding a suitably "high ratio" electric rack, and then integrating that, as it will be calibrated for the car it was taken from. You could fit one of the electric column assist systems, but these are relatively low power, have a poor response and tend to struggle to assist with very high speed arm twirling (which on a track car you might find yourself doing, intended or not..... ;-) Better is to fit one of the electrohydraulic power packs, allowing you to keep all your existing steering gear in place. If you can find space for it at the front, loosing the long PAS hoses and cooler would probably give a weight saving too........

[andygtt]

Max_Torque said:

Better is to fit one of the electrohydraulic power packs, allowing you to keep all your existing steering gear in place. If you can find space for it at the front, loosing the long PAS hoses and cooler would probably give a weight saving too........

now that is a very interesting idea... I definately have space at the front now... do they need controlling by an edu or do they just provide a static pressure?... as we use a ford mondeo power steering pump we should be able to get an equivalent?

[anonymous-user]

I use a TRW Gen3 EHPAS pump on my car, it's used on things like Focus ST/RS and has a decent amount of power (~1kW) so is man enough to cope with rapid inputs into a high ratio rack, unlike a lot of the smaller hydropower units people use from smaller/older cars.




Unfortunately, it needs CAN to command it if you want to run it at variable speed (ie with road/handwheel rate proportional assistance)

TRW EHPAS CAN Control on YouTube

[Hollowpockets]

Well, here's what I'm doing with this -
7 row power steering cooler will be removed and kept as a spare,
10 row gearbox cooler will be drained and moved onto the power steering system,
New 13 row cooler will be used for the gearbox cooling.

So both power steering and gearbox will get an increased capacity and more cooling area, which should help on the longer races as it seems any more than 30 minutes things are starting to get hot, I anticipate even hotter on a hot day so this will give me more piece of mind

The engine oil cooler is still 16 row but the engine oil seems to stay around 105-110C just now which is fine.

I am also looking around for an overflow tank for the power steering fluid to spill into when it does start to blow some out.

[andygtt]

also try the older white reservoir as that is much less prone to leaking than the black thing... i have a spare you can try!

[CaptainJp]

I brought an alloy PAS tank.
I think it was designed to go on a cosworth engine, it's much larger capacity which might help you, but I have no idea what the baffles are inside, but if your new coolers lower the temp it might be enough to stop it boiling.

The one I have is too large to fit, where I want it to so I'm sticking with the standard black one for now.

Jp

[Hollowpockets]

Just an update on this,

PAS cooler increased from 7 to 10 row, new O-ring on pump feed pipe, and my overflow plumbed with vacuum hose into an 'iron bru' bottle all fitted, after testing, practice, quali and 2 races, not a drop of PAS fluid found its way out the tank, as I had made the changes I also ran the system with more fluid than I usually do and it also ran much smoother at low speeds without pushing a drop out. A result I'd say!