# Using a hydraulic power steering pump with a double shaft warp 9



## EV-propulsion.com (Jun 1, 2009)

There is a thread about this, but we have done numerous p/s setups this way-and it works surprisingly well-without an idle system-pretty much as soon as the motor starts moving the car there is power assist-yes you can parallel park no problem. As far as efficiency, there is not much load when going straight- the pump is basically bypassing the pressure until you turn. Electric power steering creates other issues like-should it be run at all times and if not, how and when will you turn it on. I don't have power draw figures for with or without p/s, but I can say the motor's coast down time is pretty long-proving it can't be taking much power away. I always suggest p/s this way and without an idle circuit.( unless for a/c in high traffic areas.)


----------



## dimitri (May 16, 2008)

For what its worth I did both EPS and belt driven PS in 2 different EVs and if you already plan on the belt for air conditioner, you might as well drive PS pump with the same belt. Like Mike said, PS pump poses virtually no drag until you turn the steering wheel.


----------



## frk2 (Jan 2, 2009)

So its done then. Hydraulic PS Pump it is. Thanks for the input guys. Makes the job a LOT easier for me


----------



## kittydog42 (Sep 18, 2007)

Just as belt-driven pumps offer little drag at idle, electric hydraulic pumps don't consume much current (under 2A) at idle.


----------



## DIGGER11 (Mar 16, 2010)

What is the preferred engineering solution to connect the power steering / air con pumps to the Warp 9 ?

Do you build a backing plate (1/2" aluminium ?) that bolts to the back of the motor and then fit a pulley (possibly the original crankshaft pully from the ICE) to the rear output shaft ? Then you mount all of the accessories to this backing plate ?


I assume you also need an additional pulley for tension ?


----------



## EV-propulsion.com (Jun 1, 2009)

Well it really depends on how your original parts mount, but here's a couple of pictures showing two made of 1/4" aluminum, bolted to the front of the motor and a right angled piece gusseted (and attached to a wraparound motor mount further back on the motor) running parallel to the motor case, where the accesories are bolted to. Generally the original pulley can be used, but sometimes they are way to large and an aftermarket pulley can be welded to a hub with a 7/8' keyed hole through it as a substitute. An idler does need to be added for adjustment, unless the original setup has an adjustment that can be used. These pictures show an idler pulley from aftermarket timing belt parts. Of course, keep in mind the length of belt needed, because there aren't alot of choices in serpentines when you get under 30 inches. Oh, the upper picture hides the idler behind the black plastic hanging down...bad photo to show ...also the upper picture shows the front accesory plate acting as the front motor hanger too.
Mike
www.EV-propulsion.com


----------



## frk2 (Jan 2, 2009)

I was planning on using the exact same setup as on the ICE with the crank pulley bolted to the motor by some magic. If you use smaller pulleys dont you offset the gearing and possibly the RPM on the aircon and PS pump? is there some downside to that? I'm guessing the auto engineers had worked in the maximum safe RPM on these pumps and making the engine pulley smaller would speed them up significantly. Any thoughts?


----------



## EV-propulsion.com (Jun 1, 2009)

Actually a smaller motor pulley will slow down the accessories. But pulleys come in a large variety of sizes and offsets, it will take a while to sort them out and find the one that works for you.
mike
wwwEV-propulsion.com


----------



## frk2 (Jan 2, 2009)

Hmm now that i think about it - yes indeed! So i guess its safe to go small, given the fact that the motor will most likely be spinning higher than an ICE most of the time. Guess I can use another A/C or alternator pulley instead of the gigantic crank pulley.


----------



## lonestarrpm (Aug 18, 2011)

frk2 said:


> Hmm now that i think about it - yes indeed! So i guess its safe to go small, given the fact that the motor will most likely be spinning higher than an ICE most of the time. Guess I can use another A/C or alternator pulley instead of the gigantic crank pulley.


My first search missed these posts.

So I created another topic -- which I will try to kill 

However, now that I've to PS and AC, what about using the ALTERNATOR
instead of a DC to DC?

I'd basically mimic the ICE setup and I had planned on using the ICE engine harness so this just makes a lot of sense.

thanks,

Mike


----------

