Originally Posted by SonicVQ

Here is some interesting info on the cause of overheating power steering with the engine at high RPM:



Pump Chart From Turn One's Jeff Roethlisberger:
This graph represents pump flow (y axis) vs. pump rpm (x axis) of a stock production pump and a Turn One pump. Analyzing the solid line graph of the stock pump at approximately 900 rpm, the pump achieves flow control mode, which means the pump will deliver one constant flow to the steering box/rack at any rpm above 900.

The 2.6-gpm flow control value is used here as an example. Depending on application, the actual flow control may vary.

Following the dashed line of the stock pump at 5,000 rpm, the pump delivery is 15 gpm. This is the total volume at 5,000 rpm, with 2.6 gpm being delivered to the box/rack. The other 12.4 gpm is being recirculated internal of the pump. This excess flow is what creates high fluid temperatures and robs horsepower.

Analyzing the Turn One pump graph, it achieves 2.6-gpm flow control at 1,300 rpm. At 5,000 rpm, it's pumping a total of 10 gpm, recirculating only 7.4 gpm.

That's 5 gpm less, resulting in lower fluid temperatures and less parasitic horsepower consumption. You may ask why the production pump is designed this way. The reason is to have more than adequate flow at low engine rpm. So, due to production variation, higher-than-average steering effort wouldn't be experienced during low-speed maneuvers.

Great power steering FAQ here: Turn One

Originally Posted by SonicVQ

I wonder what the 370z guys do to prevent boiling the fluid?