Some to look into are off-road applications:
Some to look into are off-road applications:
I think the answer to this lies much more in the implementation than the hardware itself. There are good and bad examples of both.
All the Porsche weenies went crazy when EPAS was implemented in the 981/991 and said how much less feel there was than the hydraulics in the 987/997. I've driven both and strongly prefer the EPAS in my 981.
APEowner said:The current Porsche GT3 has the best feedback I've ever felt in a non-race car and they are equipped with EPS.
Panorama had an article about this when it was introduced: it's the same hardware as the regular 911, with more than a year of specific software development to make it GT3-worthy. Software eating the world, again.
MrFancypants said:californiamilleghia said:For me , I want EPS to park and move at slow speeds on my older cars ,
do some of them "time out" above a certain speed ?
Yup. EPS is basically a manual rack with an electric motor attached to it, so the manufacturer decides how and when the motor engages. If you're really desperate for a manual rack you can just unplug the motor, but with wide tires and quick rack ratios that might not be terribly pleasant even at speed.
I've driven an ND Miata with a dead battery that had been jumpstarted. The alternator was not quite putting out enough power at parking lot speeds to consistently drive the EPAS. When it cut out, it was REALLY heavy. More so than just a hydraulic PS system with the belt removed.
FYI.
Keith, I had read that some Miata drivers were defeating the PS for solo events. Now the cars that I have with PS have the steering go very heavy indeed - to the point where you can hardly turn the wheels. Is that not the case with the Miata or were they doing something else to defeat that situation.
If you simply remove the belt from the pump, you're still pushing fluid around the system using the rack. To properly depower the rack, you need to remove the internal seals that allow this to happen. Then you can remove the plumbing and cap the holes.
It's still heavy because the gear ratio was chosen with the expectation of assist, but it's workable.
For either electric or hydraulic, rack (or box) design and ratio, plus leverage from steering arm length, etc. all factor into effort when the assist goes away. For example, I've got 2 vehicles here with steering boxes and hydraulic assist. Linkage design and box ratios are different, but overall steering ratio is very similar (vehicle A is 2.75 turns lock to lock, B is 3, but B has slightly higher max steering angle at the wheels).
On vehicle A, with the engine off it's extremely hard to turn the wheels while stopped (almost impossible if you're in the driver's seat) and a serious challenge while moving (and there's no way you could turn them fast enough to actually drive the thing). Even with assist, the steering is rather heavy.
On vehicle B, the steering would be pretty heavy to drive with no assist, but you can turn the wheels at a stop without assist, just takes some effort. With assist, the steering is still moderately heavy. Comparison is with the same width tires on both, A's tires are 2 inches taller.
The NA/NB Miatas kept all the same geometry with the manual racks, but the ratio went from 15:1 to 18:1 (from memory). The NA manual rack was a crash development projects because of purists who went waaah waaah waaaah during the car's development, and it was never very good. The NB version was much better and was installed on literally hundreds of cars in the US - 1999 base models and the 50 Club Sport models sold in 2003.
The Mazdaspeed Miata shows fewer turns lock to lock, but that's because it has less travel due to the tall wheel/tire package bolted on that car to make it look cool. It retains the same 15:1 ratio.
So as a guy who races old cars but advocates about new cars I will chime in.
I've driven every model of Porsche road car from 356 to GT-3RS on track and while some models had better steering feel than others...................it's simply not enough to live on in my opinion
None of these cars is devoid of feel like mom's old Dodge Polara or my 30 year old Ford Van.
Also some of the steering feel we gone on about in old cars isn't near as good as we think because it's attached to a flexi-flier chassis.
I think part of the perceived feel is from the levels higher road vibration that is passed back through the steering, this would be totally unacceptable in a new car.
I'll trade feed back for the assist all day long. My old Datsun is more physical to drive than my Formula car.
preach (Forum Supporter) said:Some to look into are off-road applications:
I'm pretty seriously considering installing something like this in my 308 (if I ever get the engine running right) and probably also adding a quickener like this in front of it:
That would yeld about 1.6 turns lock to lock with the goal being to get more autoX friendly steering that doesn't beat me up too badly. The stock manual isn't terrible, fine in motion really but at lower speeds its a lot of effort to where you see the whole steering column moving around. Maybe next winter as part of a suspension rebuild.
I stumble on this unit and they will ship a sample for $250
....so much for waiting until winter.
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