The Honda FL5 Civic Type R is a pretty amazing car, but like its predecessor, the FK8, it tends to run hot on the track. The oil temperature can easily exceed 275 degrees F, which is more than the 250 degrees maximum temperature that we recommend an engine sees under continuous hard use. CSF Racing has come to the rescue with a comprehensive oil cooler kit, which has been shown in testing to control the oil temperature even under demanding track conditions with modified engines. We were involved in the early prototype testing of the kit to help validate it as a third party as well.
Since bearings are made of soft, low-melting-point metals, they lose a lot of strength and load-bearing capacity once you get much past 250 degrees. This is why we like to keep our oil temps below that.
For our video on the cooler, check this out!
The CSF oil cooler kit uses two of its dual-pass heat exchangers to cool the oil; the FL5 really gets the oil hot, and it was found that two coolers packaged best in the tight confines of the car’s front end. The coolers use bar and plate construction, which is sturdy and has built-in mounting pads that are strong enough to take the strain and vibration of being mounted directly to the chassis. The dual pass means that the oil flow dubles back through the heat exchangers, which makes them about 15% more effeicent that elements of the same size but single pass.
CSF worked with Dyme PSI for the plumbing and fittings for the cooler kit. Dyme PSI components are of the highest quality. The Dyme PSI hose is carbon-reinforced PTFE with a Twaron aramid fiber braid cover. Twaron is similar to Kevlar and tends to perform slightly better than it. especially in cut resistance. Dyme PSI hose is much lighter than traditional braided steel and is stronger with an amazing 9500 psi burst strength.
CSF’s thermostatic adaptor housing uses an OEM-style wax element valve, which is more stable and higher flowing than your typical leaky and restrictive bimetallic flap that most housings of this type have.
Dyme PSI custom-made these large internal diameter, high-flow banjo fittings for the cooler end of the hose. This is because of the tight clearances in this area.
Dyme PSI quick-connect fittings were used at the thermostat housing for easy tool-free removal and quick maintenance. The fittings have a large internal diameter for good flow and chemical-resistant Fluorok o-rings to ensure leak-free operation.
CSF supplies this compact windshield washer reservoir as the cooler intrudes on the space of the OEM reservoir. This bolts right in place of the stock part and is compatable with the factory hose attachments.
To feed air to the coolers, CSF supplies these beautiful carbon fiber air inlets. The carbon is flawless, and the inlets have a mesh grill to protect the coolers from road debris. You have to cut the bumper cover for these to snap in place, but CSF supplies full-size templates and thorough instructions to make this less intimidating.
These grills provide an air exit on the back side of the coolers to improve their efficiency. As a note in our testing these grills were not yet ready and our test car did not have them. We would have had even better results if we did have them at the time of testing.
The cooler heat exchangers bolt, one to each side of the car, using the CSF supplied brackets and factory existing holes.
The filter adaptor goes on the oil filter boss. The additional cooling that the CSF cooler provides in addition to the factory water to oil cooler, takes a lot of the oil cooling load off of the radiator and leads to lower coolant temps.
Here are the air inlets installed on the bumper. We think they look pretty cool!
The exit grills are installed in the wheelwell liners.
The air inlets blend with the FL5’s styling perfectly.
To test the oil coolers’ effectiveness, we ran repeated back-to-back dyno pulls as fast as the dyno could manage until the oil temperatures stabilized. We saw a 9-degree reduction in oil temperature. We also saw less of a variation in temperatures between pulls. We were not able to achieve track-like 250-degree-plus oil temperatures on the dyno like the stock car can easily, but we were able to show that the CSF cooler did make a substantial reduction in oil temperatures. We also did not have the rear flow-through grills in place as they had not been developed yet. This would have also made a significant improvement in the cooler’s performance.
We did see an almost 11-degree reduction in coolant temp during testing due to the removal of the factory water to oil cooler.
In track testing, we typically see oil temperature reductions of around 30 degrees and coolant temps of at least 20 degrees, even on modified cars with over 500 whp. By keeping the oil temps under control, the ECU does not pull power out on hot days as well, which is important for competition and track day fun.
There is a slight hot oil pressure drop from the coolers and additional plumbing. The drop is very slight and is easily rectified by switching from the factory fill of 0W20 to 0/5W 30 oil. In our opinion, no car, much less a turbo one, should be driven with 0W20 period, and we get rid of that oil in all of our cars, factory fill or not, as soon as we get them! In our opinion, 0W20 is one of the reasons why so many manufacturers are currently experiencing a rash of engine failures. For instance, our project GR Corolla got 5W40 in it within days of us taking it home.
So if you have a track-driven FL5, you need this, even if it is stock! The CSF cooler is not only functional but stylish. Not only will your power stay consistent, but your engine’s bearings will thank you as well!
5 comments
What’s with 0W20? Or will there be a whole article about it? *nudge nudge*
A video
whats “data point”? is it a minute? a second? different on each chart? as temp is still trending up on both, its an important metric
Love the Dyme PSI quick-connect system. Man… the FL5 runs hot.
The 30-degree oil temp drop on track is the number that matters – the FL5 heat-soaks so fast that a stock car can be down on power before the second session. I liked that you measured the hot oil pressure drop too, since that is the trade-off people worry about with any cooler kit. The thermostatic wax valve and the quick-connect fittings are smart details for a car that still gets driven on the street. Good test, and the back-to-back dyno method is the right way to show it works rather than just quoting a parts list.