Randy V

Easy and relatively inexpensive upgrade is to have the hoses rebuilt using a larger inside diameter hose and deleting the restrictor valve from the high pressure hose.

Made a huge difference on my previous '79.

hacker-pschorr

A manual steering rack option would be nice for the 928, already available for the 944 crowd.

I've driven my 81 with the belt removed, wasn't terrible, just took longer to park

blown 87

Damn, There you go busting my visions of you, I had suspected that you just picked a spot and slid it in using nothing but the parking brake, skill and bravery.

AO

Of course the PS assist improved. It's hard to develop hydraulic pressure without hydraulic fluid.

blown 87

dr bob

Power assist decreases with car speed --because the effort required to steer decreases--. There's also a consideration for generally not using nearly as much steering lock at higher speeds, so less assist is required. Think back to the discussion on how the spool valve works, where assist is added based on torque on the steering wheel against torque required to get the rack to move.

The pumps are very simple devices, with internal bypass-type relief valves. Faster pump RPM's, once the pump achieves bypass pressure, generally does not translate into significantly increased flow since excess flow just gets bypassed. The pump operation has no connection to car speed.

axis of evil

This isn't made by the Lucas,"Prince of darkness" company ,is it?

F451

Just this weekend I spotted an ad in Grassroots Motorsports for a manual rack for the 944 and I was thinking the same thing, I'd love to have one.

No more hydralic issues to deal with.

I drove my S4 for a while with the belt removed too, it was no biggie. Felt the same once I got up to speed. But sipping my beer while trying to get a toke off of my j while talking on my cell phone while shifting while going around low speed corners, well that was a bit trickier.

Auskartdyno

Reading through some old posts on how to lighten steering I see questions about how power assist is speed sensitive. I believe the answer is that unassisted steering effort has always been speed sensitive and as the little torque shaft in the spool valve on the 928 rack twists more the heavier the steering and gives more assist the reverse is true so at higher speeds when less steering force is required then less assist is given. ie speed sensitive power assist!

Mike

Tom in Austin

Correct, yes, sensitive to the speed the pump is turning. Not the speed a car is traveling, at least not on hydraulic systems

NelaK

Does anyone know if the 100bar steering pumps are still available? No more reference to them on the Griffiths website.

dr bob

You can call him.

Griffiths is no longer a site sponsor, so you are unlikely to get a direct response from him here. Meanwhile he does have some good info and solutions to common 928 refrigeration problems. And like many of our specialty partners, websites are not their primary activities. A phone call or e-mail will get you the true scoop.

Meanwhile... You've read through the thread and discovered that the 100 bar pump alone won't do much for low-speed steering assist. You'll want to install new hoses (needed wit the new pump anyway) without the restrictor in the pressure side. To reap the full benefit, you'll want the later '91+ rack. Better rebuilders are becoming sensitive to the differences in the racks, so you may forfeit the core value if you try and return your lower-assist rack. The ones who don't know the difference will sell you what they have, so it's the luck of their pick for what you get to actually install.

icsamerica

I'm updating this old thread, becasue I did successfully lighten my steering using a modified rack, Porsche 944 100 bar pump and pressure hose with no restrictor.

Details here.
https://rennlist.com/forums/928-foru...l#post16654765

Chuck Schreiber

I did this many years ago on the 79. My steering was very heavy at parking lot speeds. I also had a scraping noise when i turned the wheel.
I installed the 100bar pump from Griffith's and it made a difference at parking lot speeds. When i took the pod apart to do LED upgrade, I replaced the steering column bushings, the scraping stopped (steering wheel to pod) and the steering got even easier/lighter at both parking lot speeds and highway. In fact, I think it's a little too light at highway speeds. I'd rather have the old pump back and may do it some day. When i did all this, I put ALL new hoses on as well, but they were stock part numbers to the 79. (Can't remember if the later models have totally different part numbers for the to and from rack hoses. ( i know the reservoir to pump is different in the later models, but that would have NOTHING to do with pressure as it just feeds the pump)

So, If you want lighter steering, the 100bar pump definitely works, you just may not like the "lighter" feeling at speed.