First up - I am a C5 guy and just chasing a rabbit hole question from someone on that side of the forum. I don't have any C7 experience so please forgive my ignorance of any common topics on the platform.

How does the power assist work on these cars? I have read that it is the same power assist as some Porsche cars. Does that make it a TRW product? Or who is the base manufacturer?

What inputs does the motor receive, if any, from the car? Is there a modulator for speed to affect assist such that it provides more assist at 0 to 10, mid assist 15 to 60, less assist 60 to 200? Is it in plateaus like that or linear if it scales?

What plug goes into it. Simple power and ground, or is there a signal, high, low involved? If any signal wire were unplugged, would it go into a limp mode where it defaults to a set psi level?

I had looked into using TRW and FoMoCo electric pumps for C5s in the past. They will work easily on NA cars with an idler pulley in place of the PS pump. More complicated if you run a secondary drive blower belt kit like my own.

So I thought I'd ask a bunch of these dumb questions in hopes of gaining better understanding. For the drift community this might be a decent option - though I've not sought bolt spacing for the cradle or spline compatibility with the steering box.

 

Here is the limited info the FSM has on the steering:



I believe steering assist is calculated by the Software in the Power Steering Module and the PS Motor is driven by the module to provide the desired assist.

Bill

 

Yes, the p/s is completely electronically controlled. I learned firsthand that if the p/s control module goes out (and it can instantly) any and ALL power steering goes away with it.

In 2017 I bought a new M7 St'ray from Kerbeck's, flying in to get it and drive it home. Just minutes before leaving the p/s died completely without any warning! At that time it wasn't generally known that GM got some back electronic modules which were fitted to several different GM vehicles, not just Vettes. When the "fix" proved impossible in the short term by Kerbeck's main wrench who was called in specifically to fix it, I was given an identical '18 and sent on my way. Fortunately, by introduction of the '18s all had been cleared up. Only the following year was it generally reported what had happened.

 

Ok, so it requires input from a 9-wire connector and is modulated by unknown software/parameters.

So if it were ever to be used sans OE steering programming.... someone would need to figure out signal input to motor rpm / psi output. With that in hand, a pwm box can be made which either allows rheostat input control of the pump or an automated GPS providing the box with vehicle speed and then inputting the correct signal.

Totally doable. Just not by me. The man has more things on his mind right now, such as a new addition to his family by now hopefully, but I'll tag @MetalMan2 who I know at least would be curious about such a thing. But anyone going to that step would want to first ensure than the rack can be used or easily adapted to a C5/C6 front cradle and C5/C6 steering input shaft.

GM... always keeping things quiet. The multiple LS7 valvetrain and dry sump failures. Roof panels coming off. Early C8 engine failures. Ongoing C8 transmission fluid / track use failures. C7 steering. C5 can "never" have the column lock engage and have the car be in motion. Early C5 drive and passenger seats pin sheering and collapsing full back while presumably driving aggressively. Such is big business. And such is the nature of drivers/owners who make it a point of abusing the vehicles for fun. These aren't exactly mini-vans I suppose.

 

The electric power steering system is engineered by Bosch (Germany) partnered with ZF (Germany), and the units used in the C7 Corvette are manufactured either in the USA or China.
Electric Power Steering Belt Drive Servo Unit (bosch-mobility.com)

Some Porsche models use similar units made by Bosch/ZF, but those are made in Germany.

 

You refer to a pump. The C7 steering rack is not at all hydraulic; there is no pump. C7 steering power assist is accomplished entirely by an electric motor mounted to the rack itself. This actually may make it a better candidate for a swap, as you do not need to deal with hydraulic lines or translating signals to a pump to alter pressure.