Motorsport Plumbing Systems: Materials
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Materials
05.31
| 00:00 | Anything mission critical on a vehicle, and by that I mean anything primarily involved in the direction of the vehicle, be it the suspension, steering or braking, clearly needs to be approached with care. |
| 00:12 | While most power steering systems retain a direct mechanical connection from the steering wheel all the way to the tyres, loss of power steering will result in an abrupt and overwhelming increase in steering torque requirement to control the direction of the car. |
| 00:28 | Power steering racks without hydraulic assistance aren't the equivalent of manual steering racks. |
| 00:33 | They're a lot harder to move due to the drag of the piston seal and hydraulic fluid, as well as often having quicker ratios. |
| 00:41 | Add to the mix wide front tyres with sticky compounds and some downforce and it can be a workout just driving the car back to the pits. |
| 00:49 | Leaks in our system need to be prevented for this reason and there's also some fire risks as although the fluid isn't flammable, it is combustible, meaning it'll burn when exposed to sufficient heat or an open flame. |
| 01:02 | For clarity here, small leaks won't result in complete loss of power steering straight away, maybe just reduced performance that eventually degrades further. |
| 01:11 | We're more concerned about the plumbing lines rupturing, resulting in a loss of a significant amount of fluid and an inability to transmit pressure. |
| 01:20 | To avoid this we need to ensure the abrasion resistance, strength and integrity of all the lines and fittings are up to the task. |
| 01:28 | In standard configurations it's common to see high internal fluid pressures between 800 and 1600 psi in the pressure lines and this will often increase for more demanding motorsport applications, so it's important our plumbing is capable of handling this. |
| 01:44 | As usual, chemical resistance to the fluid being conveyed internally is required but also this plumbing is commonly routed through engine bays where it can be exposed to various externally corrosive conditions. |
| 01:56 | Heat resistance to external sources is obviously also required with the plumbing in the engine bay, as this will cause the plumbing and the fluid to degrade quickly and while we'll cover this in more detail in the next module, just understand that we generally want to minimise the temperature of the internal fluid as much as possible. |
| 02:16 | The steering rack or box will be mounted to the chassis; however, the pump will most often be mounted to the engine as this is what powers it. |
| 02:24 | This requires some level of flexibility in the plumbing connecting these components as the engine will vibrate and twist relative to the chassis. |
| 02:32 | For this reason and those we just mentioned, reinforced rubber hose is the standard from factory, but moving to a PTFE hose with a stainless outer braid is a worthwhile upgrade in the hunt for increased corrosion, heat, chemical and abrasion resistance. |
| 02:48 | It's also common to see another PVC outer layer used here for extra protection and to prevent the abrasive line itself rubbing through other components. |
| 02:58 | We'll be covering fittings in a later section of the course but it's important to understand that while push lock fittings and hose clamps can be used for the return lines between the control valve, reservoir and pump, these fittings are not suitable for pressure lines. |
| 03:13 | This is why in factory power steering lines we see crimped fittings and this is also the best option for security with aftermarket or custom lines. |
| 03:22 | It is possible however to use reusable hose ends with a socket for a secure connection. |
| 03:28 | Where flexibility isn't required, like the lines between parts of the steering rack, hard lines are the preferred method as they can handle the internal pressures better. |
| 03:36 | As with our brake system, aluminium lines aren't recommended for use with power steering systems since the pressures are so high, although with bigger lines it's possible to use greater wall thickness to regain some strength. |
| 03:50 | While factory hard lines tend to be zinc plated steel with relatively thin walls, these will rust over time and be prone to cracking. |
| 03:58 | Moving to copper nickel or ideally stainless steel lines is another worthwhile upgrade to prolong the lifespan of the parts. |
| 04:05 | Although it should be noted here that hard lines tend to be easier to damage with the increased servicing associated with motorsport, especially when removing and reinstalling engines which in some cases can easily contact the steering rack. |
| 04:20 | Flexible hoses can offer some advantages here as they will flex out of the way easily without cracking. |
| 04:27 | In factory hard lines we often see banjo fittings used at the connections to the steering racks. |
| 04:32 | However, in aftermarket applications, the fittings for power steering hard lines are more comparable to brake lines utilising flared mating surfaces and tube nuts. |
| 04:42 | Again, we'll be coming back to discuss fittings in much more detail later in the course, so let's round out this discussion here and summarise what we've covered. |
| 04:51 | Our usual requirements for plumbing apply to our power steering system with strength and abrasion resistance as well as heat, corrosion and chemical resistance, being critical to ensure our power steering system remains effective. |
| 05:05 | Some flexibility between the pump and steering box or rack is almost always required, and we need to keep in mind the high internal fluid pressures in some of the lines. |
| 05:15 | For performance in motorsport applications, it's recommended to upgrade from reinforced rubber hose and steel hard lines to PTFE hose with a stainless steel outer braid and stainless hard lines if the budget allows. |
