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I would like to modifly a car from hydrauli power steer to electric power steer to decrease the engine load, but any kits on sale for it?

You need to remove the belt that drives the power steering pump and replace it with an electric motor.
I cannot see the point however, The amount of power sourced from the engine will remain about the same.

An EPAS is only drawing power from the engine when the power assist is active. A hydraulic pump runs all of the time. So with an EPAS you will free up a little power down the straights when you are not using the steering.

Tim

do there any non-hydraulic fully EPAS kit?

Tim.Wright wrote:An EPAS is only drawing power from the engine when the power assist is active. A hydraulic pump runs all of the time. So with an EPAS you will free up a little power down the straights when you are not using the steering.

Tim

Yes but the 'alternator' is charging the battery to ensure sufficient energy is available for the electric power steering when needed, so where is the difference?

As I said, the difference is when you drive straight;
The EPAS doesnt take any energy from the battery because its asleep
An HPAS is still spinning the pump so there are losses there.

Thats the difference.

I do agree, however, that in a cornering situation when the EPAS is active, the the energy required to run it is probably the same as a hydraulic unit.

Anyway, to answer the original posters question, I have seen an ad for an EPAS system in Racecar-Engineering mag, but I cant find it now. I will have another dig tonight, but I'm sure you will find something with a google search.

Tim

I thought the alternator still worked when the car was going strait?

Tim.Wright wrote:As I said, the difference is when you drive straight;
The EPAS doesnt take any energy from the battery because its asleep
An HPAS is still spinning the pump so there are losses there.

Thats the difference.

I do agree, however, that in a cornering situation when the EPAS is active, the the energy required to run it is probably the same as a hydraulic unit.

Anyway, to answer the original posters question, I have seen an ad for an EPAS system in Racecar-Engineering mag, but I cant find it now. I will have another dig tonight, but I'm sure you will find something with a google search.

Tim

did you talking about this?
http://www.racecar-engineering.com/news ... s-ecu.html

almost all modern cars today have electric assist power steering and rack and pinion
steering racks ..
as far as I know most systems feature a separate ecu for the steering ,so you really
only need the hardware and the wiring layout to supply the correct inputs ..be it speed or whatever.

One example quite long in production is the NEW Mini .
EPAS is produced by KAYABA ,but also TRW has a brought protfolio of electrical assit racks ,also Delphi has something wich is built into the steering column.

of course the DC electronics kit is the one stop source to get everything out of one hand ...and realistically you should think twice about your recources available before trying to go your own ways..

maybe you look up this :itis Honda NSX ,i think that was one of the first to use such a system..

http://www.nsxprime.com/FAQ/Technical/eps.htm

autogyro wrote:I thought the alternator still worked when the car was going strait?

Not so... A common misconception.

Ok, Yes the alternator is running but the EPAS is not using any power then.
...Therefore none of the torque at the alternator is from the EPAS
...Therefore the EPAS is not taking any power from the engine.
...It is as though it isnt there.

When you corner, and the power assist is active, the electric motor takes current and puts a load on the alternator. Once the steering straightens out, the epas switches off and there no assist and no load on the alternator.

I really dont know how much clearer I can make this!?

Scania wrote: did you talking about this?
http://www.racecar-engineering.com/news ... s-ecu.html

No I think what I saw was just an advertisement. That is for the ecu, not the complete kit.

Tim

Tim.Wright wrote:

autogyro wrote:I thought the alternator still worked when the car was going strait?

Not so... A common misconception.

Ok, Yes the alternator is running but the EPAS is not using any power then.
...Therefore none of the torque at the alternator is from the EPAS
...Therefore the EPAS is not taking any power from the engine.
...It is as though it isnt there.

When you corner, and the power assist is active, the electric motor takes current and puts a load on the alternator. Once the steering straightens out, the epas switches off and there no assist and no load on the alternator.

I really dont know how much clearer I can make this!?

Scania wrote: did you talking about this?
http://www.racecar-engineering.com/news ... s-ecu.html

No I think what I saw was just an advertisement. That is for the ecu, not the complete kit.

Tim

The battery is still there Tim. If the electric power steering takes current from the battery, the energy needed to drive the alternator when the steering is not in use is still needed because of the steering being used earlier.
Also the pump on a hydraulic power steering unit takes very little energy when it is freewheeling through dump valves with the car in a strait line. In fact probably less than the alternator as it recharges the steering rack current losses in the battery.

I deleted the power steering on my car and it's the greatest thing EVER. The feedback is better, there's SO much more room to work under the hood, and I could probably still over-correct into a Jersey barrier if I felt so inclined. Seriously, the only time you notice it's missing is in the drive-thru or parallel parking and even then it's not much more effort unless you've got really sticky tires or really weak arms (and I'm no gun show myself).

autogyro wrote:
The battery is still there Tim. If the electric power steering takes current from the battery, the energy needed to drive the alternator when the steering is not in use is still needed because of the steering being used earlier.
Also the pump on a hydraulic power steering unit takes very little energy when it is freewheeling through dump valves with the car in a strait line. In fact probably less than the alternator as it recharges the steering rack current losses in the battery.

Well, I think the battery is effectively not there after the car has started. All the electrical systems pretty much run from the alternator and the battery is just there to provide a high current for short durations when required.

So when an EPAS is used, it will use current generated in the alternator rather than the battery, so as soon as the steering is released, the alternator load goes away.

But... even if the EPAS did draw from the battery, conservation of energy says it would still only equal the amount of energy used in the turning event. Whereas the HPAS takes the same energy from the turn plus the residual losses from the pump etc.

The EPAS still comes out using less power. Theoretically.

However, I do accept that the residual pumping losses in the HPAS are probably very low. I really can't put any numbers on it, but I can spin a power steering pump with my hand so the losses cant be that great.

For me, the benefits of an EPAS would be the reduced weight and complexity. I couldnt justify such a system on the power gains alone. But I am convinced they exist

Are you conviced yet?

Tim

Could someone suggest some ESPA system which is suitable for race car to me plz?

Scania wrote:Could someone suggest some ESPA system which is suitable for race car to me plz?

the dc kit seems to be the only available complete kit on the market.

the NSX hardware could be a cheaper alternative see my post above ,I remeber quite a few NSX wrecked in recent years and it was long on the market..maybe worth a look .
checkout my previous post!