EVO power steering pump vs regular (possible cheap upgrade)

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EVO power steering pump vs regular (possible cheap upgrade)

Postby uhlhazard » Thu Apr 09, 2015 9:26 pm

So my donor suburban for my v8 swap has evo power steering. Thats fancy talk for kickass power steering assist at idle. You can turn lock to lock with your pinkeye.

Well the donors 2wd so I just listed the power steering setup on craigslist and thats that. About a month later I started to pull listings and fill up my scrap truck to hit the scales and I thought: "Man that would be badass if it worked on my wifes GMT400 4x4 2 door tahoe".

Well it was. But not as badass as it was on the suburban. The assist seemed great initially but after I started driving the truck myself I noticed that as the truck was warned and rpm's low the assist was reduced and "bouncy" like it would go full on assist then stumble then full on etc. After some thinking, I decided that the evo system needed to be swapped in as a whole. I pulled my wifes brand new oreilly reman pump and installed the suburbans probably leaky evo pump. (old parts make my cynical)

Fast forward 2 hours and the tahoes steering with full assist at idle like nobodies business. Even with her 33" tires compared to the suburbans 29"ers.

SO I wonder if the evo pump unit itself just has much better flow at idle compared to a regular unit? If so will you get better assist backing in trailers or axle deep in mud with the EVO pump vs the factory one? Now I understand that there are 2 parts that make the donor suburbans power steering awesome: 1: softer torsion bar in the gearbox that controls when assist is applied 2: higher volume/pressure of fluid at low rpm's from the pump. Now theres a 2 wire pwm contraption on the pump that most people unplug when it starts to wig out (which is what I have done since the tahoe was not equipped) and I'm wondering if the contraption is responsible for the better pump power or is it a different pump altogether. If it's just the contraption you can just grab the adapter off of the back of any EVO pump, grab the EVO pressure hose (cause thay different) and upgrade that way.

Hell of a lot easier than pulling that stupid pressed pump pulley off.

Anyways thats just my observation. For the 4x4 community more power steering is awesome!
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Re: EVO power steering pump vs regular (possible cheap upgra

Postby Rickracer » Fri Apr 10, 2015 7:48 am

If it's like GM, and/or Chevy usually does things, (and probably is), it's probably just the flow control valve that makes the difference. 8)
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