Motorsport Plumbing Systems: Common Issues & Troubleshooting
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Common Issues & Troubleshooting
12.28
| 00:00 | To wrap things up, we're going to be discussing some of the common issues we can find with plumbing systems. |
| 00:05 | As always, we'll be talking specifically about the issues with the plumbing, not the performance of individual components that the plumbing connects. |
| 00:13 | But with that said, the system still needs to be considered as a whole. |
| 00:17 | As with all the systems we discuss, we need to make sure the components involved are functioning properly as well, to be able to identify the root cause of the issues. |
| 00:26 | Of course it's all very well knowing how to identify and diagnose issues, but we also need to know how to fix them. |
| 00:33 | This won't be an exhaustive list of every issue possible, nor is it an in depth guide of how to fix them all, but rather the key issues we commonly see, and again, are related to the plumbing specifically. |
| 00:46 | We'll start by discussing the issues seen in all systems, and then cover a few system specific ones before wrapping up. |
| 00:53 | The effects of heat are one of the most common trends throughout all our plumbing systems as it's one of the key challenges in motorsport. |
| 01:00 | Besides the damage to the plumbing materials themselves, like rubber hoses degrading, leading to cracks and leaks, excessive heat transferred to the fluids also has a negative effect on the function of all our systems. |
| 01:13 | For example, brake fluid boiling and forming air bubbles, leading to compliance issues, or intake air temperatures rising, and our engine's power potential dropping as a result, among other issues like detonation. |
| 01:25 | Reviewing data or viewing gauges from sensors like intake air, engine coolant and oil temperature sensors, is the ideal way of identifying these heat issues. |
| 01:36 | If these sensors or others aren't already in place, they can of course be added for monitoring purposes. |
| 01:42 | Just something to note here, the factory gauges aren't a reliable source of information. |
| 01:47 | For example, the coolant temperature gauge will typically sit at the midway point from around 60 to 105 degrees Celsius, and then shoot up quickly with anything over this. |
| 01:59 | This essentially means it's relatively useless except for letting us know when our engine's about to overheat. |
| 02:05 | Regardless, while the aim is to minimise the temperature, there are many factors that determine what's too high, such as the ambient temperature, engine configuration, fuel and tuning. |
| 02:16 | What this means is it's best to consider the value with reference to the ambient temperature, and how this changes over time. |
| 02:23 | For example, if the intake air temperature is significantly higher than ambient, and continues to increase over time, this would suggest that we may have an issue. |
| 02:33 | The methods of dealing with high temperatures are detailed in the earlier fundamental knowledge section, so I'd recommend revisiting this if you need a refresher. |
| 02:43 | In short, for all our systems, the main areas to focus on in regards to our plumbing are routing to avoid heat sources, using heat shielding and insulation, and lowering the engine bay temperature with ducting and ventilation. |
| 02:56 | But in some cases, like the coolant system, ensuring it's sufficiently bled is also critical. |
| 03:03 | Aside from this, components like turbos, intercoolers, radiators, and radiator caps will have a significant impact on temperature generation and cooling. |
| 03:12 | Internal heat generation is also a factor, for example, from the power steering or fuel pump heating the respective fluid. |
| 03:20 | Still, as far as the plumbing goes, routing and heat shielding are your best bet. |
| 03:25 | On the topic of routing, there are two more issues common to all our plumbing systems, and they both have to do with unwanted contact. |
| 03:33 | The first is interference between our plumbing and other moving parts. |
| 03:37 | Viscous fans, for example, will quickly destroy a plumbing line and likely themselves in the process. |
| 03:43 | Likewise, while unwanted contact between an oil line and the engine might not seem as dire as contact between our flexible brake hoses with the wheel, it can still lead to some serious problems, even if it happens at a slower rate. |
| 03:58 | On this note, the other common issue is where the damage happens in the opposite direction. |
| 04:03 | With the amazingly abrasive stainless steel braided lines rubbing through anything and everything that they come in contact with, in either case, to avoid this, we really want to route our lines well clear of any other components and make sure that they're well supported. |
| 04:19 | Unsurprisingly, incorrect sizing of plumbing lines is another common issue, which is why we dedicated modules to this in the earlier fundamental knowledge section, along with heat management and routing. |
| 04:31 | This tends to be mostly around the fuel and oil lines, where the plumbing is too small and therefore restrictive, leading to pressure issues which can have nasty consequences for these systems. |
| 04:43 | Again, tools like fuel pressure and oil pressure sensors will allow us to determine if these are in fact issues. |
| 04:50 | In the previous module, we covered a practical test to determine if our fuel system is able to support our power goals. |
| 04:57 | And while this won't pinpoint the exact issue, it's still a powerful technique. |
| 05:01 | For our intake air plumbing, reviewing the data from a map sensor can highlight issues with overly restrictive plumbing, robbing our power making potential, although this can be a bit more tricky to accurately find the culprit. |
| 05:14 | For naturally aspirated engines, if there is no restrictions, we should be seeing atmospheric pressure or thereabouts throughout the entire rev range. |
| 05:23 | However, if our manifold pressure is dropping at higher RPM, this shows that we have some form of intake restriction. |
| 05:30 | Unfortunately, this doesn't highlight where exactly our restriction is. |
| 05:35 | So from here, we need to do some testing to determine what makes a change in the right direction. |
| 05:40 | This also doesn't help us with turbocharged applications as the manifold pressure, although still influenced by the restrictions, is really just a function of how hard we're driving the turbo. |
| 05:52 | We can't easily tell if there are restrictions or not. |
| 05:56 | A method that solves both of these difficulties is using an extra pressure sensor. |
| 06:01 | Essentially, this allows us to measure the difference or pressure across components and sections of plumbing in our intake system. |
| 06:09 | And if we measure the pressure drop, we know we have a restriction. |
| 06:12 | Normally, we'd measure the pressure at the turbo outlet and then compare this to the manifold pressure. |
| 06:18 | The result shows the total pressure drop due to restrictions in the whole system. |
| 06:23 | We do need to consider that some amount of pressure drop across an intercooler is actually normal and to be expected though. |
| 06:30 | Ideally, we'd like to see this drop to be no more than one to one and a half psi. |
| 06:36 | If the pressure drop is reaching three to four psi or more, the flow restriction could be considered excessive. |
| 06:43 | An alternative method here is to use a water manometer, which we could make ourselves or purchase. |
| 06:49 | This is basically a thin tube filled with water and usually coloured to make it easier to read. |
| 06:55 | We can attach each end to points in our intake plumbing, which then allows us to measure the pressure differential between the points and find restrictions. |
| 07:04 | Again, components like filters, intercoolers, airflow meters, throttle bodies, and the intake manifold itself are usually the main culprits of these pressure drops and this should be expected. |
| 07:15 | But our plumbing can also make a significant difference as well. |
| 07:19 | To avoid restrictions in our plumbing, there are a few main areas to focus on. |
| 07:23 | Essentially, we want to keep the plumbing as short as possible and avoid tight radius bends. |
| 07:29 | The straighter and shorter we can make it, the less restrictive it'll be. |
| 07:33 | In saying that, intake plumbing length can have a significant impact on the power and power band of naturally aspirated vehicles, where in some cases, even though a shorter intake will be less restrictive, due to the harmonics of the air pressure in the intake, a longer intake can be beneficial. |
| 07:51 | But this is a case by case basis and really requires its own research and testing. |
| 07:56 | Naturally, there are also going to be packages and considerations and compromises here. |
| 08:01 | For example, we don't want to remove a restriction if the alternative will be a significant increase in the intake air temperature that will do more harm than good. |
| 08:11 | It's also common for older factory vehicles to come with corrugated intake tubing for a range of reasons, including cost, noise, manufacturability, and flexibility. |
| 08:21 | The airflow over the irregular internal surface is restrictive, so it's usually an easy win to replace these with something with a smooth internal bore. |
| 08:31 | But we still need to retain enough flexibility for our plumbing between the chassis and drivetrain. |
| 08:37 | Moving on, the final issue common to all our plumbing systems we'll discuss is unsurprisingly leaks caused by incorrect hose-in installation. |
| 08:46 | Naturally, pressure testing these before installation will help us spot potential leaks before we fit them and fill the system with fluid. |
| 08:55 | Otherwise, leaks will be fairly easy to find when our fluids are flowing from the fittings and making a mess. |
| 09:01 | We've covered pressure testing in its own dedicated module, so be sure to check back if you need a refresher. |
| 09:07 | While it's possible for crimped hose-ins to leak, simply as a result of a poor quality crimp process, it's more common for issues with reusable hose-ins, as assembly for them is much more of a manual process. |
| 09:20 | Failing to cut the hose square and clean in the shears, getting the insertion depth into the socket wrong, having the hose-end push out of the socket when the fitting is threaded in, or simply not doing the threads up enough can all result in leaks to the hose-end. |
| 09:36 | If we are getting leaks, then we need to remove the hose-ins and reassemble them, potentially replacing any damaged components. |
| 09:43 | Clearly, we can also get leaks on the flare of AN fittings, but this will be caused by a damaged fitting rather than incorrect assembly. |
| 09:52 | On the topic of leaks and moving on to some system-specific issues, boost leak testing has also already be covered in a dedicated module, and one of the most common culprits in aftermarket performance applications is silicon couplers popping off. |
| 10:07 | This can often be prevented by the use of a bead on the end of the piping and the use of a suitable hose clamp. |
| 10:14 | We just need to be careful not to over-tighten the hose clamp and damage the coupler or pipe. |
| 10:19 | It's important to ensure the coupler isn't stressed by misaligned pipes, or as is sometimes the case, the coupler hasn't allowed enough flexibility between the chassis-mounted intercooler and components mounted to the engine. |
| 10:31 | This extra stress will only make matters worse. |
| 10:35 | For higher boost pressures, we can also reach a limit for silicon couplers when it comes to security. |
| 10:40 | This can prompt the move to a high-pressure solution like a Wiggins clamp, capable of holding greater pressures with more security. |
| 10:48 | Another system-specific issue is excessive compliance, and although this is most common for the brake system, it's also undesirable for our power steering. |
| 10:57 | While damaged fluid from excessive heat resulting in air bubbles is a primary cause of this, among many other things, in terms of our plumbing, this is most often the result of swelling of factory-style rubber brake hoses. |
| 11:10 | The result is a soft or spongy brake pedal or steering feel that's difficult to modulate and not ideal for driver control or confidence. |
| 11:19 | Besides reducing the amount of flexible hose, the go-to fix is using stainless steel braided lines that are less prone to swelling while also benefiting from more heat, corrosion, chemical, and abrasion resistance. |
| 11:32 | If you've had any involvement with brake system design, modification, or maintenance, then you're probably aware that there's a long list of potential issues, some of which are specifically related to plumbing of the brake fluid. |
| 11:45 | The HPA Brake System Design and Optimization Course covers all these issues in much finer detail, so if you're interested in diving further into the subject, I'd recommend checking that out. |
| 11:56 | Let's summarise our final discussion to round out the course. |
| 12:00 | The most common issues seen with all our plumbing systems include excessive heat and unwanted interference from poor routing, as well as incorrect size lines leading to restrictions and pressure drops, and incorrect hose end assembly resulting in leaks. |
| 12:16 | More system specific issues that are also very common include boost leaks in our charge air plumbing and excessive compliance with brake and power steering systems. |
