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Today I basically only took care of removing all the old lines. Tomorrow I will wire the pump. One wire to ground, one wire direct to batttery (with 80 amp fuse) and one wire to switched power on.
Very cool. A lot came off the motor along with those lines. I ended up using the Patrick motorsport plug thingy and shop fabbed a bit of tin to fill in the mount where the gap is in the engine tin for the pump / belt shroud.
I didn't weight but having picked up the box of crap that came off compared to the cup pump, suspect saved a bit of weight, better, moved it up front and got rid of flammable PS fluid in the engine bay.
1. 8ga brown wire goes to ground. I used an existing grounding point but also added a 4ga ground wire direct to battery for good measure.
2. 8ga red wire goes direct to the battery using an 80 amp fuse close to the battery. I have a shut-off switch so I went directly to it so the power is shut off when pulled for safety. On a street car, go straight to battery.
3. 16ga wires. There are three: Black, blue/white and brown white. The brown with a white stripe is not used. The Black goes to switched key on and blue white to alternator. But I wanted my pump to activate with key on so that I can have power steering when rolling the car into the trailer. So, in this case combine black and the blue/white wires and wire to the fuse box. I here tapped slot 28 (sunroof/mirrors) with a 15amp fuse.
This ended up working perfectly as I am wanted it to.
pics below ( I know, wiring will be cleaned up for a more pro-install look which I will do next).
Ground to passenger fender ground point plus a direct proper ground connector direct to battery. Red direct to battery. Thin wires black and blue/white to slot 28 in the fuse box. Brown/white is not used.
Direct to battery inline fuse - I used a fuse holder popular when wiring high output stereo amplifiers.
In my case - wires direct to battery via safety shut-off.
That PS pump sound, I was waiting for the announcement of "Flight crew, prepare for take off" lol.
Nice clean wiring job, interested in your feedback re: steering feel/feedback (as well as weight savings & perhaps a few hp not having to run the old belt driven pump) on our next track day.
Last edited by Meatball964; 07-15-2018 at 09:33 PM.
Here is my A Class PS pump startup and idle sound for those wondering the difference. Once the engine is running the pump is barely noticeable as well. I used soft rubber bushings to isolate it from the mount, having the trunk carpet helps as well.
How do these either pumps sense load? The Benz pump is attractive due to its smaller format allowing it to be used and retain the the spare/luggage space for cars that travel. Andrew what was the solution to the steering stop issue?
Here is my A Class PS pump startup and idle sound for those wondering the difference. Once the engine is running the pump is barely noticeable as well. I used soft rubber bushings to isolate it from the mount, having the trunk carpet helps as well.
Thanks Andrew! This is an excellent idea - comparing various setups, wiring options, kits/fabrications and noise etc. This will certainly help those who are looking to do this mod to their cars.
Peteinjp: The Benz pump uses trigger wire. It can work off of pulse or steady 12v. I have the trigger wired to the ABS circuit (steady 12v) and the pump starts with the engine. Since the initial load is massive I've considered adding a time delay relay, but have not yet had any issues with starting. Positive is wired directly to the battery using 60amp inline maxi fuse and the pump is grounded to the mount I made for it. I've put in the larger steering stops and soon after discovered the ER bump steer kit is too wide and doesn't allow for proper wheel alignment. After some back and forth and consulting with other on this forum we came to a conclusion that the 89 964 had a wider rack than the rest and thus causing the steering stop issues. I had to put the rack off-center to be able to get close to any reasonable alignment and so one of the return passages inside the steering gear is still miss-aligned causing the pump to overload and shut down.
s4magman: This is an excellent resource. I know couple of people who converted to 997 cup pump and are very happy with the result. I don't want to hijack your thread, so here is the link my install (middle of the page): https://rennlist.com/forums/964-foru...inning-13.html
Peteinjp: The Benz pump uses trigger wire. It can work off of pulse or steady 12v. I have the trigger wired to the ABS circuit (steady 12v) and the pump starts with the engine. Since the initial load is massive I've considered adding a time delay relay, but have not yet had any issues with starting. Positive is wired directly to the battery using 60amp inline maxi fuse and the pump is grounded to the mount I made for it. I've put in the larger steering stops and soon after discovered the ER bump steer kit is too wide and doesn't allow for proper wheel alignment. After some back and forth and consulting with other on this forum we came to a conclusion that the 89 964 had a wider rack than the rest and thus causing the steering stop issues. I had to put the rack off-center to be able to get close to any reasonable alignment and so one of the return passages inside the steering gear is still miss-aligned causing the pump to overload and shut down.
s4magman: This is an excellent resource. I know couple of people who converted to 997 cup pump and are very happy with the result. I don't want to hijack your thread, so here is the link my install (middle of the page): https://rennlist.com/forums/964-foru...inning-13.html
Thanks!
Andrew
You are certainly not hijacking since anything related to power steering belongs in this discussion. I am very impressed with your build and can’t believe I haven’t seen your thread before.
Great thread! The cup pump really sounds like a turbine spinning up when started. The Benz pump spins up almost instantly. I used an existing hole in the frunk to route the lines, just removed a rubber plug. My Benz pump has been working perfectly for over a year now. Here's a link to my install and some new notes on trigger wiring- https://rennlist.com/forums/964-foru...es-all-in.html
For the record, the weight/performance benefit is very little. The stock pump/mount/hardware comes to 10lbs. I didn't weigh the stock lines (how can you?!), but they can't be more than 5lbs. The Benz pump weighs 8.4lbs. So you move a relatively small weight from over the rear wheels to over the front wheels, and drop about 5lbs. I wouldn't think that the engine drag is more than 1-2hp, and that's only while the steering wheel is moving.
emailed dawes, they don't make the kit anymore. anyone have the specifics to the fittings to and from the power steering pump to the power steering unit.
That is unfortunate - I actually got my kit a couple of years ago. Why don’t you ask them for the specifics you need? At least on the hoses so you can have them fabbed up.
07-12-2018, 10:53 PM
