The E46 M3, with its high-revving S54 3.2-liter inline six, is undoubtedly an amazing platform, both in stock and modified forms. However, it suffers from major heat issues. So if you want to spend time on the track, both water and oil temperatures need diligent monitoring if you want to keep the motor happy and running lap after lap.

With the additional heat source of our ESS Tuning VT2-525 Supercharger Kit, we were seeing fluid temps skyrocket after only one lap of Streets of Willow Raceway. This was clearly unacceptable; so we contacted our friends at Bimmerworld to seek their expert advise in preparing our M3 for track driving. Along with new fluids from Red Line, we think we've found the perfect formula.

With additional support from Enkei and Falken, we also had dedicated track rubber for the car. And finally, we installed an Awron gauge that told us everything. Once again, european auto source was in our corner and seamlessly installed everything at their Anaheim, CA shop.


The great thing about the partnership between C&R Racing and Bimmerworld is that these parts are meant to fit without requiring any modification. The dimensions are identical to the stock parts they're replacing, but they offer superior cooling.

Fully brazed cores contain no epoxy and are built to spec, maximizing the cooling efficiency. Built for a direct fit, the parts utilize the stock shrouding, clip-on hoses and mounting points, so the C&R Racing radiator is ideal for M3 owners looking for a simple swap. Best of all, it gives 25% better cooling capacity than the stock radiator.

The new oil cooler is also packed with features that enable it to keep the oil cooler than ever. It has double the capacity of the factory unit, and while this helps, there are more variables that affect the temperature. Using a counterflow two-pass design, the oil travels through the back-end, from one side to the other, and to the front. It then travels from one side to the other again, creating a longer cooling path without adding depth or height to the cooler. This maintains the thermal efficiency of the stock unit but increases the cooling ability.

Just like the radiator, there's no epoxy on the furnace brazed core, and the tubes are extruded to withstand higher pressures seen during cold-start. Turbulators are located inside the tubes to agitate the oil as it passes through, while air passes across the top and bottom of the contact surfaces.

With all its technology, the oil cooler is the best for the E46 M3 and that's why we chose it.

Of course, all these cooling enhancements would be pointless without the proper fluid, but we'll get to that later...


As for the installation, first ensure the car is cool, because the last thing you want is to scald yourself with hot coolant. Then start by removing the fan and shroud. The shroud is held four plastic rivets that are extracted with a tack lifter. Following this, you'll need to remove the mechanical-clutch factory fan, which we're replacing with an electric puller fan from SPAL. The mechanical fan is reverse-threaded to the water pump pulley via a 32mm nut but is easily removed. With the car on a lift (or jack stands if you must), remove the undertray.

To install the new radiator, you need to drop the oil cooler anyway, and since we're installing the C&R Racing Oil Cooler at the same time, it couldn't be easier!

There are two 13mm bolts attaching the oil cooler to the car. Once removed, the cooler simply slides back and can either be disconnected from its oil feed and return lines, or left hanging under the car for the time being.

On the passenger's side of the engine bay, you want to pull off the temp sensor from the lower coolant hose. Ensure you have a bucket for the two gallons of coolant about to fall out, though.

With the sensor removed, pry the metal C-clip out of the tube connected to the radiator and pull without getting soaked. Wait until the radiator is empty and you're ready for removal.

Lower the car down and remove the two rubber fittings holding it in place in the top corners. Now, you either pull the radiator up and out or try to do it from the bottom. We chose the latter because we had the lift.

You're ready to install the new C&R unit, but we first installed the SPAL puller fan. At this point we opted to remove both the stock mechanical fan and front auxiliary fan since the car never gets hot in traffic. The SPAL fan can then mount easily to the existing holes on the C&R radiator. EAS wired it to function from the factory thermostat since the auxiliary fan was deleted. This involved a simple, two-wire splice to the thermostat using the brown ground wire and black power wire.

Lower the new radiator down from above and slide it into position. Reinstall the two rubber supports and the upper coolant hose. From underneath, reinstall the lower coolant hose and the radiator is fitted.

After disconnecting the oil lines from our factory oil cooler, we simply placed the new C&R Racing cooler in the factory position. It fit just like stock and EAS completed the installation in less than 10min.


To maintain cooler oil temps, we decided to step up to a heavier oil. It might take slightly longer to reach operating temperatures, but it would hold that temp more consistently, with less fluctuation. So we used Red Line 15W-50 Synthetic Motor Oil.

Commonly used in turbo and supercharger applications, the oil has 25% more viscosity than 20W-50 oil and, in the Southern California climate, the thickness is less of a problem, although it's not recommended for cooler climates, especially in winter.

The 15W-50 is great for wear protection and friction reduction across a wide range of operating conditions, and since our S54 likes to hang out at its 8200rpm redline, this was music to our ears!

To see the full benefit of the C&R radiator, we added Red Line WaterWetter to our coolant. This is claimed to reduce or eliminate bubbles and vapor barriers that form on hot metal surfaces, which can otherwise increase coolant temps by up to 20°.

By improving heat transfer and reducing head pressure, we can run more spark advance, resulting in more power and greater efficiency. Add one bottle to 3-5 gallons of coolant and you'll be amazed at the difference on the track.

Since installing the radiators and fluids, both the coolant and oil temps are far more consistent with the C&R units. We now rarely see the gauge pass 210° in either oil or water temp, which is great news. What's more, the car can run more laps without an issue, and we couldn't be happier.

Wheels & Tires

While our Volk TE-37 wheels were an aggressive, lightweight, track-proven wheel, we always wanted a square setup, with the same size rubber at each corner. So we looked around for an affordable, light, strong wheel and came up with the Enkei NT03+M.

Its strength is in large part due to the perimeter bracing ring, which is said to enable the wheel to resist deformation or distortion from outside forces. This gives you some leeway on the track or hitting a pothole on the street, where the NT03+M shouldn't simply bend. We also love how the wheel looks with its aggressive size on the M3.

We chose 18x10" at all four corners, with a low +25mm offset, resulting in a deep concaved face and healthy outer lips. In F1 Silver powdercoat, the Enkei's added some attractive contrast to our grey paintwork and truly gave it the racecar feel we wanted.

Paired with a set of massive 275/35 R18 Falken Azenis RT-615K tires, our wheel and tire combo looks certifiably insane. In order to squeeze these into the front fenders, we're running -3.8? camber. So now the car turns-in with the sharpness of a straight blade, and looks like an angry pitbull from the front.

We continue to run Falken tires because they've performed flawlessly on both road and track since we started the project last year. The beautiful asymmetrical tread design, good wear characteristics and high level of grip mean we're always ready to take turns or put the power down. And they do this with little road noise, which is even better since our M3 is a daily driven monster.


The Awron DGA Gauge is an all-in-one display that presents a wide array of real-time data for the E46 M3. It fits in the center vent and features a color OLED display. It comes pre-installed in a factory vent and its mostly orange lights match the M3's instruments.

The gauge can display oil, water and exhaust temp, throttle angle, air/fuel ratio, voltage, g-force, 0-60 and 0-120mph acceleration and maximum recorded values.

We also have the Kompressor Option, which monitors boost pressure and intake temp to cover every aspect of our turbo M3.

With all these options, controlling and scrolling through menus might have been a pain, but the Awron gauge uses a touchscreen, so you simply tap to select the next menu.

While the seamless installation and integration within the cabin is appreciated, we feel the device could be improved. Since it's tapping into the OB2 port, it would be quite useful if it could scan and clear simple engine codes like the P3 Cars gauges can offer. Furthermore, while it does display a form of air/fuel ratio, it might be best if there was a wideband option for those who take tuning more seriously. Finally, we'd like to see customizable screen layouts that would let us choose perhaps four parameters and have them read on one screen.


The installation is straightforward since the gauge taps into the stock ECU with a plug-n-play harness.

Start by removing two Phillips screws from the instrument cluster. Then adjust the steering wheel to give more clearance to remove the dials. Next, remove the trim by popping it out with a soft plastic pry tool - avoid snapping the plastic tabs.

With the trim removed, pull out the center AC vents. You'll replace them with the Awron unit, routing the wiring harness behind the console and instrument cluster, where you'll tap into the dash illumination wire. This wire is behind the dimmer switch and it's easier to push it from behind to pop it out.

Next is the tapped connection to the OBD2 port below the dimmer switch, where you'll tap the two supplied wires into it. Finally, tap power and ground from the harness and you're done. The installation took EAS less than an hour!

Supplier Part Price
C&R Racing/BimmerWorld aluminum radiator $900
C&R Racing/BimmerWorld oil cooler $880
Red Line WaterWetter $10.95
Red Line 15W-50 motor oil $11.49 per quart
Enkei Wheels 18x10" NT03+M $1500
Falken Tire 275/35 R18 Azenis RT-615K $1428
Awron DGA gauge $1249
SPAL Electric Fans 16" fan $149.99

4085 Pepperell Way
VA  24084
Red Line Synthetic Oil
6100 Egret Ct.
CA  94510
Enkei Wheels
5001 Henrietta Creek Road
TX  76262
European Auto Source
4015 E. Leaverton Court
CA  92807
By Alex Bernstein
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