Motorsport Plumbing Systems: Materials
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Materials
12.37
| 00:00 | - For each plumbing system, we'll be covering all the different materials that are commonly used from the factory configurations, to aftermarket and custom executions for performance and motorsport applications. |
| 00:12 | When it comes to the intake track, the core components themself such as intercoolers, turbos and throttle bodies will be left out of this module and we'll be primarily discussing the sections of piping connecting the components that we defined as the plumbing in the previous system overview module. |
| 00:30 | In any engineering case, the materials used need to be considered alongside the requirements for the application. |
| 00:37 | This could be in regards to the strength and integrity, ensuring that the parts don't fail, or if the parts need to be replaced or maintained often. |
| 00:45 | In regards to the intake and charge air systems, the plumbing needs to withstand the pressure of the air that it's carrying which will be the greatest after the compressor in a forced induction application. |
| 00:57 | This doesn't just involve the material choice and thickness but also the quality of the fabrication work like any welds for example. |
| 01:04 | It goes without saying that welded areas as well as sharp corners that concentrate internal stresses in the material will be the weak areas and the first point of failure. |
| 01:15 | The chemical and corrosion resistance is an extension of this. |
| 01:18 | The fluids flowing through our plumbing systems are often corrosive so naturally the material exposed to these needs to be resistant. |
| 01:27 | But even if there are no chemicals present, for example the intake air plumbing, it's still a harsh environment that's used outside and exposed to the elements. |
| 01:36 | So at the very least, it's important to avoid materials that will rust easily unless they're well protected in some other way. |
| 01:43 | Weight is also a big factor when it comes to performance and in almost every case we want to minimise it which can come at the expense of strength and reliability, depending on the material chosen. |
| 01:55 | Careful consideration of the routing of this plumbing however can often reduce its length and hence weight. |
| 02:02 | Heat resistance is another important factor in motorsport and something we'll dive into in more detail in the next module but from a material perspective, it's clearly important than the material holds up to the heat structurally. |
| 02:15 | This again is going to be the most severe for charge air plumbing of forced induction applications. |
| 02:22 | In some cases, it's also beneficial for the material to insulate the charge air from the radiant heat in the engine bay. |
| 02:30 | For example, keeping the intake air as cool as possible. |
| 02:33 | The final requirement is something we haven't discussed yet and that's flexibility. |
| 02:38 | Some parts of the system such as the air box or intercooler for our intake and charge air system, will usually be hard mounted to the chassis. |
| 02:47 | Whereas the other parts like the turbo and throttle body and intake manifold will be mounted to the engine. |
| 02:54 | The point being, the engine and drive train move to some degree relative to the chassis so there'll need to be some fleixbility between these parts of the system to avoid cracking or breaking the plumbing connecting them. |
| 03:06 | The degree of flexibility required will depend on the rigidity of the engine mounts. |
| 03:10 | The considerations we've just discussed apply to most of the plumbing systems we'll cover in this course. |
| 03:17 | With the requirements out of the way, let's move on to discuss the different types of materials that might be used for the intake plumbing. |
| 03:25 | While factory vehicles commonly use injection moulded plastics and cast aluminium parts, the nature of the manufacturing processes and associated cost means they're not suitable for our lower volume, mostly custom use. |
| 03:38 | Rubber hose or other elastomer piping can also be used by OEMs in certain areas to provide flexibility and decoupling between the engine and chassis. |
| 03:49 | So let's look at materials more commonly used in performance aftermarket and motorsport applications that we can use to build our plumbing systems while keeping in mind that some factory parts can be retained and used in conjunction with these to some extent. |
| 04:05 | Aluminium piping is really the standard here as it's plenty strong enough for even the most extreme pressures we might see. |
| 04:12 | It also offers good corrosion resistance and it's very light. |
| 04:16 | It's also very easy to form and work with for flaring or bead rolling which we'll cover in the practical skills section of this course. |
| 04:25 | Aluminium is also weldable with an AC TIG welder, making it suitable for most automotive fabrication jobs, while being relatively cheap compared to the other materials we'll be looking at. |
| 04:38 | Besides this, aluminium has high thermal conductivity, meaning it cools quickly but it also heats quickly. |
| 04:45 | We'll come back to this in a moment. |
| 04:47 | Next we have stainless steel which is also commonly used for intake and intercooler piping and naturally offers great corrosion resistance. |
| 04:56 | It's about 3-4 times more dense than aluminium but a lot stronger, making it possible to use thinner wall tube to help reduce the extra weight. |
| 05:06 | For comparison, even with thin wall stainless, the weight is likely to be around double that of the weight compared to aluminium tube. |
| 05:15 | Stainless steel is also a lot harder to work with compared to aluminium in terms of cutting and forming but it could be argued that it's easier to weld. |
| 05:23 | A consideration here being that the inside of the stainless piping needs to be purged with the welding gas as well to displace oxygen on both sides of the weld to ensure a strong weld with a smooth internal surface. |
| 05:37 | Cost wise, it can be cheaper or more expensive than aluminium, depending on your location. |
| 05:43 | Less commonly used is titanium which sits between aluminium and stainless steel in terms of weight and strength. |
| 05:51 | Specifically its density is roughly double that of aluminium, however due to its strength, we can use a much thinner wall tube so the finished product isn't significantly heavier than aluminium. |
| 06:04 | In New Zealand for example, our aluminium piping is commonly available in 1.6 and 2mm wall thicknesses. |
| 06:12 | The stainless steel is readily available in 1.5mm and titanium at 1mm. |
| 06:18 | It's possible to go hunting for different offerings but that's what's easiest to get. |
| 06:23 | 1.6mm aluminium would be the lightest in this case with 1mm titanium being about the same weight, only slightly heavier. |
| 06:32 | 2mm aluminium is a little bit more while 1.5 stainless is around twice as heavy. |
| 06:38 | Even at 1.6mm, aluminum will still be safe for any boost pressures we're likely to see. |
| 06:45 | So generally speaking, this or titanium will be the best option weight wise given what's readily available. |
| 06:52 | The key benefit of titanium over aluminium in this case is usually the increased corrosion resistance and aesthetics. |
| 07:00 | The downsides are that titanium is significantly more expensive and takes some experience and special knowledge to weld correctly. |
| 07:08 | With aluminium, stainless and titanium, it's possible to buy straight sections of pipe in all different sizes, mandrill bends in various radii and angles and a myriad of collectors, reducers and so on. |
| 07:22 | On that note, it's always best to use mandrill bends as this means the tube will retain a circular cross section through the bend, making it stronger and better flowing than the alternative simple press bent tube where the material is somewhat flattened at the bend. |
| 07:39 | Carbon fibre on the other hand is generally much stronger and lighter than the three materials we just discussed, depending on its construction which is mostly down to the fabric used and the ratio of resin to fibre. |
| 07:52 | The key difference though lies within the form of the parts, the manufacturing process used to make them and how they can be modified for the application. |
| 08:01 | Carbon fibre parts for intake plumbing are laid up in a mould, so compared to aluminium, stainless or titanium tubing we've just discussed, the carbon fibre parts can take on much more irregular forms to aid in airflow and packaging. |
| 08:16 | The downside here being that if we need to modify the parts, it's usually more difficult and time consuming. |
| 08:23 | Carbon fibre is also relatively expensive and this is mostly a result of the manufacturing process and the time this takes. |
| 08:31 | Coming back to the thermal properties of these materials, as we discussed, aluminium has a very high thermal conductivity compared to stainless steel and titanium has less again, while carbon fibre conducts the least heat out of all of these options. |
| 08:46 | We'll dive a bit deeper into heat transfer mechanisms in the next module but in basic terms, the higher the thermal conductivity, the quicker the material will heat up and also cool down. |
| 08:58 | Intercoolers are aluminium for this reason, to help with heat transfer but also in the interest of keeping weight minimised. |
| 09:06 | One of the key arguments we see when people are comparing the materials for intake plumbing is the thermal conductivity of the material and what this does to the intake air temperature. |
| 09:17 | The fact is, the thermal mass or ability of the material to absorb, store and release heat for the piping itself is so low compared to that of the surface area that once the engine has been running for a reasonable amount of time, the temperature of the plumbing will be more or less the same, regardless of the material. |
| 09:37 | The difference in heat transfer to the intake air via convection will also be negligible as this is more dependent on the fluid and the speed of the flow rather than the surface material. |
| 09:48 | So the considerations around heat which we'll discuss more in the next module, aren't significantly influenced by the material of the plumbing pipeline. |
| 09:57 | With all this in mind for the materials we've discussed, the truth is, they can all be strong enough to withstand the temperatures and pressures they'll be exposed to. |
| 10:06 | Your decision really comes down to the weight, cost and availability to you as well as your preference in terms of the aesthetics of the finished plumbing and the ability to work with the materials for your application. |
| 10:19 | The only exception lies with some plastic parts made using additive manufacturing or 3D printing techniques which is becoming more and more common in the motorsport space for lower volume items. |
| 10:32 | In these cases, the strength of the design and manufacturing process needs to be considered as well as the thermal properties of the materials themselves. |
| 10:41 | Although the technology to print parts capable of withstanding the high engine bay temperatures of motorsport is relatively young and expensive compared to traditional fabrication techniques, it's only becoming more and more accessible and allows much more flexibility in the designs and forms of the parts to optimise them for their applications. |
| 11:02 | With that covered, let's now summarise the key points we've gone over in this module. |
| 11:07 | First our intake and charge air plumbing needs to be corrosion and heat resistant to offer a good service life in the demanding conditions of a race car engine bay. |
| 11:17 | It also needs to be strong enough to withstand the high internal pressures that could be experienced especially in forced induction applications. |
| 11:25 | It's also important the plumbing is lightweight, as the length required can be substantial and result in a significant weight penalty. |
| 11:33 | On top of this, some flexibility will be required between components hard mounted to the chassis and the engine to avoid breaking or cracking the plumbing. |
| 11:43 | Factory intake plumbing, commonly involve plastic moulded or cast aluminium parts which although they can be effective, aren't something we'll generally work with in the aftermarket due to the manufacturing constraints as well as the plastic parts being difficult to modify if required. |
| 12:01 | In performance aftermarket and motorsport applications we'll mostly be working with aluminium piping due to its lightweight nature, structural integrity, corrosion resistance and being easy to work with. |
| 12:13 | Stainless steel is an alternative but generally comes with a weight penalty and titanium, although it's relatively lightweight, comes at an extra cost. |
| 12:22 | Carbon fibre and 3D printed parts are also viable options and present some advantages around the forms that are achievable to aid airflow but come with their own manufacturing challenges. |
