Motorsport Plumbing Systems: Routing & Heat Management
Watch This Course
$129 USD $64.50 USD
-OR-
Or
8 easy payments of only $8.06
Instant access. Easy checkout. No fees.
Routing & Heat Management
06.52
| 00:00 | - The cooling system is all about regulating the heat of the engine so naturally heat management is a big factor in our plumbing considerations and the routing of the plumbing has an impact on the heat management and performance of the system. |
| 00:14 | Heat transfer is the main consideration, with our 3 heat transfer mechanisms; conduction, radiation and convection all contributing to the effect commonly referred to as heat soak where the temperature of all components rises as a result of the primary heat sources affecting their performance and ability to function. |
| 00:34 | We want some heat in the system of course as the engine and other components are designed to work within a certain temperature range which is most often higher than the local temperature. |
| 00:45 | More often than not though as we make more power and we drive faster and more aggressively, the main challenge is preventing damage to components from too much heat. |
| 00:55 | With our coolant plumbing system there are really 2 ways to prevent this, the first we'll discuss is related to the system's performance. |
| 01:03 | This is a matter of the internal fluid temperature, meaning the temperature of the coolant itself, flowing through the plumbing system and therefore its ability to cool the engine. |
| 01:14 | Although the components in the system aren't the focus of our plumbing discussions, the radiator plays such an important role in this case that it needs to be discussed. |
| 01:23 | The first place to look is the airflow through the radiator which although is technically an external fluid flow, the main effect is reducing the coolant temperature. |
| 01:33 | It's very common for the airflow into, through and out of the radiator to be too restrictive and prevent efficient heat transfer, far less than what the system is capable of. |
| 01:44 | One of the primary ways of increasing this airflow is using ducting to force fresh air through the radiator and over the fins, preventing it from simply following the path of least resistance and flowing around the outside. |
| 01:58 | Thicker radiator cores, although able to increase the cooling capacity of the radiator tend to make the airflow through the radiator more restrictive so although it can seem counter intuitive, in some cases using a thinner core can increase the cooling simply by getting more airflow through the radiator. |
| 02:17 | Better fin design can also help here which is different between manufacturers and also a point of price difference. |
| 02:24 | Out the other side is just as important. |
| 02:26 | To increase the flow through the radiator, the air must be able to flow easily out the back without creating a high pressure pocket that would further restrict flow. |
| 02:35 | Some more ducting can help here, providing a path for the heated air out of the vehicle and back into the air stream. |
| 02:42 | The last thing we want is hot air from the radiator being trapped in the engine bay and adding to the heat issue. |
| 02:49 | The other thing to consider is increasing the coolant flow through the system, as generally speaking, and all other things equal, the faster the fluid is flowing, the more convective heat transfer we'll see, given that the flow is laminar. |
| 03:03 | But if the flow is too fast, resulting in turbulence, the cooling ability is somewhat reduced. |
| 03:10 | Without getting too deep into fluid dynamics, we essentially want the coolant to be moving well but not excessively. |
| 03:17 | The water pump has an effect on this as well as restrictions in the system and these need to be considered to avoid cavitation. |
| 03:25 | The trick here is that as the coolant gets hotter, we need more cooling efficiency from our radiator and more coolant to increase the thermal mass. |
| 03:34 | At this point we can start to consider a bigger radiator with more surface area or a thicker core or even one with more passes as long as we can maintain good airflow. |
| 03:44 | It should be noted that if the coolant temperature is too low, which can also be damaging to components and performance in general, the opposite needs to happen. |
| 03:53 | The airflow through the radiator could intentionally be reduced, the coolant flow through the system could be restricted, potentially by the thermostat, a smaller radiator could also be used with less area for airflow and also less coolant capacity. |
| 04:09 | Both of which can also help to reduce the weight of the system. |
| 04:13 | That covers the internal temperature of the coolant itself but there is another method of controlling heat, reducing the external temperature of the plumbing. |
| 04:22 | The same methods we discussed in our intake air system apply here. |
| 04:26 | THis can involve routing the plumbing system and positioning components to avoid heat sources, or preventing radiant heat from escaping from these heat sources in the first place and getting to the plumbing with the likes of turbo blankets, heat shielding or exhaust wraps. |
| 04:42 | We can also use insulation over the plumbing such as fibreglass sleeving to cut down on the effect of radiant heat and heat transfer by convection from the hot engine bay air. |
| 04:52 | Or, we can duct cold fresh air into the engine bay and vent hot air. |
| 04:57 | We can use convectional heat transfer to transfer heat from the coolant system as we discussed with the radiator. |
| 05:05 | While we covered routing around heat, there are some other considerations not directly related to heat. |
| 05:10 | As we discussed in the earlier system overview module, we need to consider routing our coolant plumbing in order to prevent air pockets as these make it difficult to bleed the coolant effectively, reducing the system's ability to cool the engine. |
| 05:25 | We'll be covering the bleeding of the coolant system later in the course in the practical skills section but this primarily means keeping the filling point at the highest point of the system, ideally higher than the top of the engine while avoiding locallised high points where the air could be trapped in a bubble. |
| 05:43 | Finally as with routing any plumbing system we discuss and more critical for systems like this, conveying large volumes of fluid is weight. |
| 05:52 | If we can minimise the length of the plumbing required, this can help save weight though this shouldn't be done at the expense of the system's ability to perform its task of cooling the engine. |
| 06:03 | Let's wrap up this module with a summary of what we've just covered. |
| 06:07 | The core function of the system is to manage heat but too much heat comes at a risk of damaging components so the performance of the system and preventing damage are closely linked. |
| 06:19 | Within the system we want to control the temperature of the coolant by way of airflow through the radiator, coolant flow through the system and radiator efficiency. |
| 06:28 | While outside the system the same considerations as usual apply with avoiding heat sources and minimising radiant and convective heat transfer to the plumbing with the use of heat shield, insulation and routing considerations which can also have an affect on our ability to bleed the system as well as the weight. |
