I've been stripping some of the last few things off my donor and I've found that the power steering pump is also the hydraulic assistance on
the brakes.
I wasn't planning on using the power steering box as it sits behind the engine but I want to keep the big brakes on the beemer so I may be stuck
with it.
id say you dont want power assist on a kitcar, but then id also say ditch the servo for the brakes. Assuming you're building a heavy and powerful car, you could well want to keep both.
you could just join the in and out unions on the pump to let the fluid circulate ,on the beemers i have worked on the brakes use an electric motor to
pressurize an accumulator (green sphere) to provide assistance
Id junk it and put a different vac pump on it if u need one. Ps is only good for parking.
There's no real need for power steering on a seven, unless your car will be very heavy. Nor servoed brakes.
I could be wrong but I think Aerosam is using a BMW 5 series as a donor, complete with the V8.
Having had a 540i as a daily driver, I'd say keep the power steering! Assuming you won't be using little 13" wheels on it.
When you are finished you can try it without it, but to retro fit it may be a right pita.
Mike
Good quality power sterring is very pleasant, and I don't think it would be detrimental to a kit car, especially one with a large engine close to the front wheels
In my BEC the steering (non powered) is perfectly usable. no need for any more assistance.
Can't comment on a CEC, though.
I considered fitting the power stearing on my car, but as it wouldnt fit didn't bother. Would be nice at low speed 10 to 15 mph or less, but above that not needed. One thing I would say DON'T fit a quick rack, it makes the stearing far too heavy. Cheers Ray
Guniess is quite right, I'm using a BMW 530 V8 as my donor.
I'm hoping to keep the ABS, so I really want to use the brakes as a complete system. It does have an electric motor and an accumulator, but the
hydraulic assist is also plumbed into the power steering circuit. (perhaps this is just to run it through the oil cooler?) TBH I'm not very
familiar with the system.
I'm trying to use as much of the donor as possible, but the steering is just completely unsuitable. I think conrodkid might be on to something
with just plumbing the hydraulics through the brakes alone. Will take some serious thinking to work out how to do it though.
I would have thought the Beemer rack is quite difficult to design into a Locost and the stock brakes will probably be ott with the servo on such a
relatively light car. Also you might find the steering will be too twitchy at speed, although a big V8 over the wheels might require some good biceps
when parking
[Edited on 27-5-08 by RazMan]
quote:
Originally posted by RazMan
Also you might find the steering will be too twitchy at speed,
[Edited on 27-5-08 by RazMan]
Yeah but ... no but ... yeah but on a car under half the design weight it will behave rather differrently 
A couple of things.
(I have a 740i which uses the same setup as far as I know)
1) the hydraulic system (filled with that bloody pentosin expensive fluid) provides the power steering assist AND the brake assist BUT it acts like a
servo on the brakes - there is a conventional abs brake system, then there is a hydraulic assist cylinder on the master cylinder, which is fed from
the main hydraulics.
The ecu that controls everything also monitors the pressures in this system.
2) Surely the bmw uses the same power steering BOX as mine (recirculating ball ZF system), not a rack at all............which will be fun fitting to a
locost!!
ok, see you mention not using the steering box, and I agree, whatever you do don't!! it weighs nearly as much as a bike engine on its own!!
quote:
Originally posted by RazMan
Yeah but ... no but ... yeah but on a car under half the design weight it will behave rather differrently
quote:
Originally posted by RazMan
Yeah but ... no but ... yeah but on a car under half the design weight it will behave rather differrently
Chris Gibbs brother Mick has successfully transplanted the BMW ABS (from a 525) into his mega-wide roadster, I'll have to get in touch and see
how it performs.
Just a thought, would it bepossible to use the power steering rack from another car (probably E30 or E36 BMW) and plumb it into the PAS system I have,
or would that just completely not work?
quote:
Originally posted by mr henderson
If it was my project I would definitely use the power steering. I think the chances of it being a problem are very low (not zero) but very low, and certainly well worth the try.
John