Motorsport Plumbing Systems: Sizing
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Sizing
04.00
| 00:00 | The size of the oil lines we use for different applications will depend on the system's requirements, the components we're using and the fittings they're integrated with. |
| 00:09 | Hopefully these components have been designed and spec'd to the engine's oil pressure and flow requirements but we still need to ensure the size of the plumbing connecting them is suitable. |
| 00:20 | As you'd have probably guessed by now, lines that are too small will be overly restrictive to the oil flow and result in pressure drops. |
| 00:28 | Low oil pressure and flow is of course extremely dangerous for our engine. |
| 00:33 | Just like the coolant system, if the line is too small, the higher velocity of the fluid can promote cavitation, something we want to avoid as this can lead to vapour lock where the pumping ability is essentially lost. |
| 00:46 | This is particularly important on the pump inlet line of a dry sump system as this will be subject to significant vacuum. |
| 00:54 | Plumbing that is too small will result in excessive vacuum potentially collapsing the line and cutting off the oil supply altogether. At the other end of the spectrum, there's not particularly an issue with oil lines being too large other than unnecessary weight and bulk to fit around the engine bay. |
| 01:12 | However, the increase in oil capacity and ability to support more flow is generally a positive thing. |
| 01:18 | The reality is that with a wet sump system, the external plumbing will be limited anyway. |
| 01:24 | With oil coolers, filter relocations, turbos and superchargers, the components will most likely have fitting ports that dictate the size of the fitting and therefore the size of the line that connects to it. |
| 01:36 | While these can be changed, it's typically something we don't need to second guess on a quality component and the supplier's instructions should lead us in the right direction. |
| 01:45 | With that said, turbo feed lines tend to be dash three or dash four with the return lines being larger at dash 10. |
| 01:53 | Dash 10 lines are also commonly used for oil filter relocation kits, oil cooler plumbing and crankcase ventilation. |
| 02:01 | Dry sump systems are also always supplied with plumbing instructions that specify the size of the line to be used for each part of the system. |
| 02:10 | For example, these dry sump plumbing instructions from Peterson Fluid Systems clearly show the minimum plumbing requirements for the scavenge and pressure lines. |
| 02:19 | Note that the length of the line is also important. |
| 02:23 | The longer it is, the more restrictive it'll be. |
| 02:26 | So, if the line is relatively long, which is common when the tank and the engine are at opposite ends of the vehicle, then it may need to be stepped up a size. |
| 02:34 | Naturally the supplier's instructions should be followed first and foremost if we want to ensure the best performance and reliability. |
| 02:42 | In that sense, the reality becomes like our cooler plumbing system, where there's no easy rule to apply to sizing the plumbing lines and the size of the plumbing is mostly dictated by the components we use and the instructions of the suppliers. |
| 02:55 | There are of course going to be certain applications that could require custom setups. |
| 03:01 | Again, there's no hard and fast rule here, especially with the variations of engines and pumps. |
| 03:07 | So, trying to find a proven system of a similar application could be the best bet. |
| 03:11 | But in general terms, dash 12 is the standard for scavenge and pressure lines between the pump and engine, whereas dash 16 is the standard for the pressure inlet from the tank to the pump and the scavenge return from the pump to the tank. |
| 03:27 | These sizes are fairly universally used and should provide a safe starting point for most applications that aren't too far out of the ordinary. |
| 03:36 | To recap the main points here, oil lines that are too small can cause significant oil pressure and flow issues in our oil system and risk damage to our engine. |
| 03:47 | The best approach is always to follow the supplier's instructions for what they have found to be suitable, but for custom applications, we've covered some possible starting points. |
