Understanding the Civic Type R Cooling System and Overheating
The FK8 Civic Type R was released nearly 10 years ago now and in this period Honda has released the current FL5 to improve upon the FK8 in some ways but one question that has been asked time and time again for both generations: how can I keep this darn Type R from overheating on track?
So much about the Type R is great right from the factory, the chassis and suspension is stiff yet compliant, the interior is utilitarian yet stylish, the drivetrain is mostly robust yet for some reason the engine just can't seem to keep temps down on track. So we put together this article to break down some of the large contributors to this issue and what YOU can do to overcome it and enjoy your Type R on track the way it should be.
Thermal load. That's it. That's why these cars overheat. Mystery over.
Okay now that the smart ass answer is out of the way; the reason these cars overheat is because the heat input into the cooling system is greater than its ability to shed heat into the environment. Honda asked the Type R's cooling system to cool A LOT of things, that list consists of: the engine, the engine oil, the transmission oil, and the turbo. All of these things are hotter than the engine coolant when you're on track. This is not a normal system and many cars do not tax the cooling system this heavily. To make it easier to understand we made the following visual below.
Random tangent related to the image: I left the throttle body heater circuit out because it doesn't play much of a factor in this but for the guys looking for every last morsel that circuit is worth capping off. We also show the heater core here because the heater core is a heat exchanger that can be used to lower coolant temps if you're in a pinch so long as you're will to deal with sweltering heat being blown at you while you drive, I don't consider this a solution but it's a last ditch effort to gain some slight extra heat capacity if your Type R can't keep temps in check at the track and you're hell bent on driving.
Starting with the factory engine oil heater. The K20C1 engine used in the Type R has what Honda calls an oil heater bolted to the bottom of the water pump. This heater block has interwoven passages for both coolant and engine oil to transfer heat from one system to the other. On the street the coolant is usually a higher temp than the oil so this causes it to heat the oil, but on track the oil gets to a higher temp than the coolant which results in the oil dumping heat into the cooling system. Strike 1.
Next is the transmission "cooler". This has a similar form factor as the engine oil heater, except this time instead of transferring heat between the engine coolant and engine oil it's between the engine coolant and transmission oil. And like the engine oil on track, the transmission oil gets hotter than the engine coolant, which leads to the cooling system being left to absorb more heat. Strike 2.
Last and least controversial is the turbocharger. Honda, like every other manufacturer, uses engine coolant to cool the bearing system of the turbocharger, this has been done for decades and is a very well proven way to make a turbo live a long life and avoid coking oil inside the turbo. The coolant that goes through the turbo is less than the other two systems outlined above, but the turbo is much hotter and it does add some amount of extra thermal strain on the cooling system. The smallest strike, but still strike 3.
To make matters worse, all of these circuits share one thing in common; they all bypass the radiator, so not only is the coolant coming out of these systems hotter than it went in, but it's also not getting cooled off in the radiator and going straight back into the engine! So how do we overcome this uphill battle? We reduce the amount of things taxing the cooling system. Lucky for you we've developed 3 distinct products for this exact purpose!
The Wunderladen Racing Oil Cooler
First up is our oil cooler. The foundation for our oil cooler is our billet oil cooler housing, this replaces the factory oil heater and bolts to the bottom of the water pump. It blocks off the coolant passages so coolant is NOT circulated through the cooler housing and more coolant is forced to go through the radiator. It also sends oil to a dedicated air to oil heat exchanger so the oil receives superior cooling and isn't dumping heat into the coolant system. There are a load of other great things about our oil cooler as well, you can read about those HERE on the product page. The end result is lower engine oil and coolant temps.
The Wunderladen Racing Transmission Cooler
Next up, we've got our transmission cooler. This takes the same approach as our oil cooler kit, it eliminates the factory coolant to oil heat exchanger, forces more coolant through the radiator by blocking off a coolant circuit that would otherwise bypass the radiator, and routes the transmission oil to a dedicated air to oil heat exchanger. Transmission oil temp plays a large part in how gears fare and overheated oil will drastically decrease the fatigue life of gears, so the cooler also helps to increase gear life in the transmission. This is not available as a separate product yet but keep your eyes peeled, it's releasing very soon and we'll update this post when it is released. The end result is lower transmission and coolant temps.
The Wunderladen Racing Tri Cooler
Finally, our Type R cooling piece de resistance, our tri cooler. This combines both the oil cooler and transmission cooler and takes things one step further by also adding in an auxiliary radiator. This is accomplished by utilizing the coolant lines that were used for the factory trans cooler and routing them to a dedicated heat exchanger. This creates a secondary heat sink to not only increase the heat rejection capacity of the cooling system, but also means that there is less coolant going around the radiator without being cooled off before going into the engine. All of the details about the tri cooler can be read HERE on the product page. The end result is a combined effort to reduce engine coolant, engine oil, and transmission oil temps!
We hope that this article was helpful in demonstrating just how overburdened the cooling system is on the Type R and explaining how our cooling system products help to climb the mountain of thermal load that these cars must face to live a fair life on track. At the moment we only have these systems available for the FK8 but we are working on FL5 solutions as well!
If you have any questions about any of this feel free to leave a comment or reach us via email at support@wunderladenracing.com. Thanks for taking the time to read and checking out our site!