Motorsport Plumbing Systems: Materials
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Materials
09.21
| 00:00 | In this module we'll dive deeper into the fuel lines themselves and discuss all the different materials that are commonly used from factory configurations to aftermarket and custom setups for performance and motorsport application. |
| 00:14 | As always, the core components themselves such as the tanks, pumps, filters and pressure regulators are not the focus of this section. |
| 00:23 | What we're most interested in is the plumbing between the components that conveys the fuel around the vehicles. |
| 00:30 | Similar to our other systems, chemical, corrosion and heat resistance are important while conveying the fuel, especially in regards to safety. |
| 00:40 | Of course, weight, strength and structural integrity are also key considerations. |
| 00:45 | Since the tank will usually be mounted to the chassis and the fuel needs to be supplied to the engine, some flexibility in the plumbing will also be required to avoid damage to the lines due to the engine moving. |
| 00:58 | From factory, we commonly see a mixture of hard lines and flexible hose to accomplish this task. |
| 01:04 | The hard lines, which can be a variety of materials like zinc coated steel, stainless steel, aluminium and copper nickel, typically run the majority of the distance under the vehicle in the transmission tunnel or next to the chassis rails from the tank towards the engine and of course the return. |
| 01:23 | The hard lines are strong and resistant to corrosion, heat and abrasion. |
| 01:28 | In relatively modern factory vehicles we might also see hard nylon tubing, sometimes referred to as rigid lines rather than hard lines. |
| 01:37 | But just like hard lines, these don't provide any flexibility. |
| 01:41 | So, hard or rigid lines are usually attached to the tank and fuel rails with flexible hose. |
| 01:48 | The hose is almost always reinforced rubber, but again since it's conveying fuels, it's important that it's resistant to whatever that fuel might be. |
| 01:57 | Standard rubber vacuum or coolant hoses for example shouldn't be used with fuel. |
| 02:02 | Quality fuel hose is usually marked with a number that can help us figure out from what material that hose is made from. |
| 02:09 | This is an SAE standard so the label will have SAE followed by J30 or 30 for fuel or oil hose and then the letter R and a number, which differentiates the specification of the hose such as the construction, chemical resistance and temperature range. |
| 02:27 | SAE, J30, R6 and R7 were the industry standard for a long time. |
| 02:34 | Designed for fuel systems working on 50 psi or less like carburetted engines. |
| 02:40 | These feature a nitrile rubber inner core reinforced with a braid and a neoprene outer layer cover. |
| 02:47 | The key problem other than the pressure rating is these hoses aren't suitable for use with ethanol and many other fuel blends or additives. |
| 02:55 | Ethanol will dry out neoprene, making it very brittle and susceptible to splitting. |
| 03:01 | R9 hose on the other hand has a fluoroelastomer inner liner that can generally handle all types of fuel and up to 100 psi, with hose clamps on either end. |
| 03:13 | It's also more resistant to permeation so the fumes can't escape from the hose as easily. |
| 03:19 | Permeation is something that needs to be considered seriously if you're plumbing fuel lines through the cabin and you'll want to cut down on fumes as much as possible. |
| 03:29 | It's of course also something unique to consider if you don't want your garage to always stink of fuel. |
| 03:35 | This is a worthwhile upgrade over R6 and 7 for carburetted cars, as even modern pump gasoline can be blended with ethanol and other additives. |
| 03:45 | For total permeation resistance, some OEMs have made the move to PTFE hose in an effort to lower emissions. |
| 03:53 | PTFE, as we covered when discussing coolant lines, has great chemical resistance and will last when exposed to all common automotive fuels. |
| 04:03 | SAE J30 R10 is what's known as submersible hose and as the name suggests, it's designed to be used in a fuel tank for in tank fuel pumps where it will be submerged in fuel. |
| 04:16 | It is designed with extra layers that prevent it from becoming saturated but shouldn't be used unsubmerged as high temperatures will cause it to degrade quickly. |
| 04:26 | While these materials are commonly used in high performance and motorsport applications, we'll move on and discuss some special considerations. |
| 04:35 | Fundamentally, the hard lines are much the same in that aluminium, stainless steel and copper nickel are used, although mild steel tends to be avoided due to its lack of corrosion resistance. |
| 04:46 | We're going to take a deep dive into these hard lines in a coming module, but the main differences come down to strength, formability, weight, corrosion resistance, aesthetics and cost. |
| 04:58 | Similar to what we discussed earlier around intake air plumbing, since the fuel lines are relatively thin wall piping, they're going to reach the same temperature when exposed to heat regardless of how conductive the material is. |
| 05:11 | All of these materials will be able to handle the heat well, what's more important is trying to keep the fluid in the lines as cool as possible but we'll discuss this more in the next module. |
| 05:22 | Cost of course is another important factor to consider with hard line materials, with aluminium generally being the cheapest, followed by copper nickel, then stainless steel, but this can vary depending on where you live. |
| 05:36 | Let's move on to discuss our flexible lines, which provide our movement in isolation between the chassis and engine. |
| 05:43 | Again the same reinforced rubber hose that's used in factory applications can be a good option here as it's cheap, easy to work with and readily available. |
| 05:53 | The main drawback of using this type of hose in motorsport applications is the lack of abrasion resistance, especially when we consider how much more regular the servicing on components is, these hoses just don't last as long when constantly taken on and off, or when there's unintentional contact with other moving components or chemicals. |
| 06:14 | We'll also need to use hose clamps for security, which is a much more fiddly and time consuming process compared to using the AN hose end fittings we'll be covering in much more detail later in the course. |
| 06:26 | The exposure to higher temperatures also causes the rubber to break down a lot faster and this tends to be accelerated in lower grades or lower quality hose. |
| 06:37 | As with our coolant line, the next step forward is braided lines. |
| 06:41 | However, the CPE commonly used for coolant lines will break down with different fuel blends so we definitely want to avoid using it for this application. |
| 06:50 | PTFE braided hose is really the ultimate here, although it's relatively expensive, it's resistance to chemicals, heat and abrasion means it can last a lifetime of the vehicle. |
| 07:02 | We've already covered this but to reiterate, the hose features a PTFE inner tube with an abrasion resistant outer braid, usually made from stainless steel. |
| 07:12 | Some suppliers also include an additional inner braid reinforcement and another outer hose layer like silicon. |
| 07:21 | Specifically for hose that needs to be run inside the cabin, PTFE is required as the vapour barrier means fumes won't permeate through the walls. |
| 07:30 | We just need to be careful with routing as although it can form relatively tight bends, it can also kink, preventing fuel flow. |
| 07:38 | The other issue to note is that if our fuel plumbing only consists of hard lines and PTFE hose, we can end up with a knocking sound from what is essentially a water hammer inside the lines from the injectors opening and closing. |
| 07:54 | Due to the rigidity of the lines, this effect is audible and can be an annoyance to say the least, especially in a street car. |
| 08:01 | Replacing a section of the line with some rubber hose, even if braided, will help diminish the issue by dampening the water hammer effect. |
| 08:10 | Let's summarise our fuel system materials before moving on. |
| 08:14 | Similar to our other plumbing systems, strength and weight are important considerations as well as abrasion, heat and corrosion resistance and flexibility between the engine and the chassis. |
| 08:25 | But specific to the fuel system, we need to consider the internal pressure and resistance to the chemicals we're conveying, while always keeping safety in mind. |
| 08:35 | Aluminium, copper nickel and stainless steel hard lines are typical in factory and motorsport arrangements while flexible lines allow for relative movement between the engine and chassis. |
| 08:47 | The flexible lines are commonly rubber hose with a variety of ratings, but it's important that they're suitable for use with the fuels we intend to use. |
| 08:57 | If you plan on using rubber hose for anything performance related, then SAE J30 R9 is your best bet before moving on to PTFE braided hose, which is really the ideal flexible fuel hose. |
| 09:12 | Submersible hose must be used for in tank plumbing, but shouldn't be used for anything out in the open. |
