Whu? The local Chevy Stealership wants $36 for a new one!

Here's what I am going to do. I am using our CNC lathe to make the pulley, so I can hit the taper on the money, and do some cool profiling. I am going to make the diameter at the root of the V 4" (stock is 5" on the pulley I have). I will run a cooler for the powersteering to make up for the increased output (find a place to put it in a Flatty!) as well as synthetic fluid.

Anyone see anyproblem running the the pump 20% faster with the extra steps I have taken?

Would anyone be interested in a custom 4" Aluminum pulley for their Saginaw Power Steering Pulley?:D

Hey I was thinkin' of doing the same thing!














































:D

Not trying to be a newbie fawker or anything, but the speed change is related to the circumference not diameter.

C=pi*D

Old C = pi*5 = 15.7
New C = pi*4 = 12.57

So the speed change is the ratio of the two:
15.7/12.57=1.25

Or better stated that the new speed will be 125% of the original speed.

Or even better stated, a 25% increase

how would this change any operating temps or create a need for synthetics? Do you run a govenor on your rig? If not, your vehicle always is changing rpm's and the "increase" in pump rpm's would only be noticed at idle, since it'd be similar to reving your motor to 3500 rpm instead of 3k. ANy way a cooler should be used regardless for wheeling with large tires.

Newbie question, but when you place a cooler in the system, would you put it in the return line because the pressure line would have to be custom made? But then would there be enough pressure in the return line to flow through the cooler?

Originally posted by diiulio
Newbie question, but when you place a cooler in the system, would you put it in the return line because the pressure line would have to be custom made? But then would there be enough pressure in the return line to flow through the cooler?

Yes & Yes

My only concern would be at the higher RPM's would the pump stay together?
When your getting it, you could be up at 5K, and what would the pump be with the old diameter and the new diameter (need the ratio for that)?

Originally posted by CP8071
Not trying to be a newbie fawker or anything, but the speed change is related to the circumference not diameter.

C=pi*D

Old C = pi*5 = 15.7
New C = pi*4 = 12.57

So the speed change is the ratio of the two:
15.7/12.57=1.25

Or better stated that the new speed will be 125% of the original speed.

I hate to pick nits, but diameter is directly related to circumfrence... you said it yourself.

Originally posted by CP8071
Not trying to be a newbie fawker or anything, but the speed change is related to the circumference not diameter.

C=pi*D

Old C = pi*5 = 15.7
New C = pi*4 = 12.57

So the speed change is the ratio of the two:
15.7/12.57=1.25

Or better stated that the new speed will be 125% of the original speed.

Uh, diameter and circumference are related :D Circumferance is a function of the diameter and pi. I just divided the little circumference by the big one 4(pi)/5(pi)(pi cancels out)=.80 or 80% But you are correct that the ratio is defined by dividing the intial value by the new value:5(pi)/4(pi)(pi cancels)=1.25 or 125%.

The whole purpose of this excercise is to get more flow in the lower rpm range where I need it. Face it if your into it pretty good, your covering some ground and the steering resistance isn't as great at speed.

As for a govenor, no. I'm not running a rev-limiter but if I hit 6 grand the last thing I am going to be worried about at that moment is my PS pump :D Besides I've seen plenty a wheeler hit 6 grand + and have never heard of any PS pump problems.

I am only running 33s right now, but plan on 35s next year. FWIW I am thinking about making a 1.5 quart resivior in between the cooler and the pump.

Thanks, and keep it coming.

Originally posted by Magoo

As for a govenor, no. I'm not running a rev-limiter but if I hit 6 grand the last thing I am going to be worried about at that moment is my PS pump :D Besides I've seen plenty a wheeler hit 6 grand + and have never heard of any PS pump problems.

6K RPMs, think about drag cars, with solid lifters and cam and roller rockers I have seen a 350 turn 9K but then again the system was under no strain, still no pumps are bitched about alot.

I would think you could find specs for the manufacturer's max RPM though.

Hi Magoo,

I think your idea will work fine to a point, and I applaud your creativity, but I don't think you are going to see a 25% increase in flow over any great portion of the RPM range.

Most P/S Pumps are controlled by their valuing, and all put out maximum pressure and flow somewhere around 1,000 to 1,400 RPM. Beyond that speed, there is not improvement in either pressure (PSI) or flow (GPM).

However, below that speed I would suspect you would indeed pick up on both these values.

I'm not sure I explained that properly.

Once the valving limits are reached, speed has no effect on the pumps performance.

On my TJ, once I hit 1,400 RPM it doesn't matter how fast I turn the engine (or PS pump) all I get is the same PSI and flow rate.

From Idle to about 1,400 RPM the flow in particular , is effected by speed of the pump (or engine.)

If you are interested in increasing either the pressure or the flow you might want to try a search on this board as there were some greats posts that you might find useful.

That said, go for it. You will definitely have an effect at low rpms.

Hope this is helpful.

Frank