Are you taking your E46 M3 to the track more? Well good because it’s a great out of the box platform to take to the track. Even bone stock, it’s a very well balanced car. It doesn’t have a ton of horsepower but the car is very forgiving to drive with just enough oversteer to control. Now when you start upgrading, the E46 M3 becomes incredibly capable of producing very fast lap times. And if you haven’t taken it out on the track or autocross course just yet, you should! I’ll go through my experiences from my first time out to where I’m at now competing in a small time attack series.
Whether you are building a serious E46 M3 track car or first time going out, we’ve compiled a track day guide to get you acclimated to the wonderful sport of Motorsports. Check out below for the list of essential E46 M3 track day mods.
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First Track Day
1. Maintenance
The first thing for any BMW owner is to make sure the overall health of the vehicle is in good status. And this isn’t just a thing for first timers, but for anyone who is taking their car to the track. We wrote the Ultimate E46 M3 Maintenance Guide which covers the Inspection I and Inspection II protocols. It’s a good starting point to go through this list and make sure all your basic maintenance items are covered. The most important part of track day is safety. All track day organizations have some sort of track day tech inspection sheet which you must fill out and sign in order to participate.
2. Alignment
A good alignment can dramatically change the handling characteristics of your car. We made an E46 M3 Alignment Specs Guide to list setups depending on the driving type e.g. autocross, track, etc. Once you start exploring different tracks you’ll want to change your alignment to dial in for that specific track, but this is a good baseline to start.
3. Tow Hook
It’s pretty much mandatory to run at least one tow hook point on the front or rear and both are highly recommended.
4. Build Track Awareness
The primary goal of your first track day is not to go fast, but to learn how a track day works. You’re going to learn things like spotting the flag towers, memorizing all the different flags, knowing where to enter pits, learning to exit pits, signs for passing other vehicles, learning track lines, learn to hit the apexes, etc.
2-5 Track Days
1. Brake Pads
Now you want to start building confidence mods. Not fast mods. The confidence will make you faster. Brake pads can help you stop when you need to.
2. Stainless Steel Brake Lines
Again, another confidence mod. Stainless steel lines won’t expand as you apply more brake pressure on your pedal. Your stock rubber lines will. SS lines will make the pedal feel more firm and better response.
3. Coilovers
This is a big one. Suspension is very important and changes the entire behavior of your car on-track performance. The more grip you have with the tire and road, the more G’s you can pull. The more G’s you can pull, the better your car will be around corners. This concept is called mechanical grip.
4. Brake Fluid
Brake fluid can boil and add air in your lines. Air is not good because it is compressible meaning if you step on your pedal and pass through air, your pedal will go down, but the pressure won’t be applied to the brakes. We wrote an article on the best racing brake fluids.
5. Tires
Similar to suspension, tires will help increase mechanical grip. Different tires have different compounds. The idea is that the lower the treadwear rating, the sticker it is. Grip vs life is a direct trade off.
6. Wheels
You want the strongest and lightest wheel possible to reduce unsprung weight. Rotating mass requires more momentum to move, meaning there is an exponential effect for every extra pound added on to unsprung weight. Also you might need to get a wider wheel to fit a larger tire for maximum grip.
7. Data Acquisition
If you want to improve as a driver, you need to study your data and results. A proper data acquisition system like the AIM Solo will give you at the minimum – lap time, g-force, MPH. Through graphing and visualizations, you can see where you are fast and where you need to improve.
6-10 Track Days
1. Radiator
You’ve probably done a few super hot days already and realized your cooling isn’t good enough. The OEM radiator has plastic end tanks and are prone to crack. It’s probably a good idea now to replace with an all aluminum tank.
2. Steering Rack
The stock E46 M3 (non ZCP) steering is pretty numb because of the low ratio. You can upgrade your rack with a “yellow tag” E46 ZHP rack found on the 330 and some regular 330’s. The BMW part number is 7852974712. The faster steering ratio feels great on track.
3. Exhaust
Now that you’re becoming familiar with your car, you can start upgrading power. Just be mindful. Driver mod can still shave you more time than what a 5-10 hp increase an exhaust can get you. Learn the car as much as you can and once you feel confident with your driving abilities, get power.
4. Short Shifter
If you’re driving a manual, an upgraded shifter can change your gears faster. Meaning you can increase speed faster resulting in faster lap times. I recommend a good trans mounted shifter like an RTD or CAE.
5. Subframe Bushings
You should know the E46 M3 subframe is prone to cracks. Strengthen up your diff bushings while you take care of the subframe reinforcement by adding in some race poly or solid bushings. Solid bushings will be loud, but removes 99% of the deflection. Race poly is still good if you’re doing street/track duty.
6. Transmission Bushings
Why do you need transmission bushings? The powertrain will see a lot of force on track causing movement which can affect your shifting especially for manual cars. Ever try shifting in high G corners and the selector rod just doesn’t seem to want to get in to gear? You may have bad transmission bushings.
7. Differential Bushings
Soft OEM bushings are designed for comfort, but it’s not the best for track performance. If you get rid of deflection, you can put more of the power and grip down to the ground. Same logic goes for all your bushings.
8. Intake
Probably one of the easiest way to increase horsepower to your car. More air in the engine means more power. Although there is a lot of debate about aftermarket performance intakes, the right one will produce more power over OEM. We recommend Turner CSL or Eventuri.
9. Tune
In addition to an intake, a tune will maximize performance by re-calibrating engine parameters to produce more horsepower. We can help you tune your S54 with our B-Spec Tune.
11-15 Track Days
1. Front Control Arm Bushings (FCAB)
OEM FCABs provide comfort for driving, but allows a lot of deflection in the front wheels. Upgrading to a harder bushing allows for increased “steering precision, turn-in response, and direct braking feedback” which makes the car feel very direct on track. We recommend the Turner Monoball FCAB for heavy track use and there is essentially no increased noise, vibration or harshness (NVH).
2. Rear Trail Arm Bushings (RTAB)
While you’re doing the FCAB upgrade, match the bushings with a similar rear trail arm bushings. RTABs can help with “maintaining alignment settings and minimizing wheel hop” by removing deflection. On RWD platforms, it’s important to get the power down to the ground by getting all the grip you can.
3. Roll Cage
You’re getting faster now and safety is still #1. At the minimum, you want to add in a half cage roll bar to protect incase of a roll over on track. There are a few easy bolt-in solutions e.g. Kirk, Auto Power. Better to be safe.
4. Race Seat
If you’re running a roll bar or cage, it’s very important you run a proper harness/seat belt because in case of an accident, you may hit your head on the roll bar/cage. From time to time, I see drivers running a roll bar in their street car with a street seat. That is not safe. You should be properly strapped into a bucket seat with shoulder straps.
5. Race Harness
We recommend at least a 5-point racing harness. A 5-point includes 2 shoulder straps, 2 side belts and an anti-submarine belt which prevents you from sliding underneath your belts in high G situations. Also another thing to consider is if you’re running a HANS device (neck restraint) there are 2″ to 3″ belts since HANS recommends using a 2″ belt.
6. Steering Wheel
You should not get an aftermarket steering wheel without getting a cage, race seat and and harness. Not a good idea to remove OEM airbags without proper supporting safety equipment. An aftermarket steering wheel can provide weight reduction benefits, quick-release for ease of access and improved ergonomics with a change in diameter.
7. Fire Suppression
Incase of a fire situation, you want to be prepared with a fire suppression system. The easiest thing to do is get a handheld extinguisher with a quick release mount. There are plenty of quick release mounting options on eBay as well.
16-20 Track Days
1. Oil Diverter Valve
Are you seeing high oil temps? You can reduce oil temps by about 30+ degrees with a simple oil diverter kit. The OEM oil filter housing limits the amount of oil flow to warm up the car faster so this kit allows a “full-flow” to cool the oil temps. This is not recommend for street cars unless you add a performance inline thermostat as you won’t each safe operating temps.
2. Big Brake Kit
Are you experiencing brake fade? The stock brake system utilizes a 325mm (345mm for ZCP/CSL) rotor in the front which may overheat on track. A big brake kit can help with cooling and overall braking performance.
3. VANOS High Pressure Oil Line
The factory VANOS high pressure line has a high failure rate for track cars. The metal gets brittle over time and cracks. Failure to the VANOS line can be catastrophic so replacing it with a stainless steel line is the best way to go. This is a mandatory item per our Ultimate Maintenance Guide.
4. Brake Ducts
If you’re still overheating your BBK, then it is time for some brake ducts. Brake ducts will allow air to feed into a backing plate, provided in most kits, which then feeds to the back of the rotors.
20+ Track Days
1. Differential
It’s all about getting the power down to the wheels. The factory M Variable limited slip differential is good, but it doesn’t perform as well as say a 3-clutch diff. The OEM also wears out fast. According to Diffs Online you need to refresh the diff in about 80k miles. If you don’t have a ton of money to shell out on a new diff, a great alternative is to change the R&P to a 3.91 or 4.1 – poor man’s supercharger.
2. Aero
Want more grip? A proper wing, diffuser and front splitter setup can increase downforce significantly providing more grip at speeds. We’ve created our own splitter brackets for the E46 M3 featuring a quick-release to install/remove in seconds. Check out our store for more aero products.
3. Lexan/Poly Windows
Polycarbonate windows can save you some unwanted weight and can also provide some aero/cooling benefits with the use of NACA ducts.
4. Full Cage
Safety is the #1 reason why you should get a full cage, but there are added benefits of going full e.g. tie-in the cage to the front/rear struts for additional chassis rigidity. Also with proper side/door protection, you can remove the OEM doors for a lightweight one. TC Design in Northern California is one of the best fabricators in the USA.
5. Carbon Fiber Trunk
The OEM trunk weighs in at about 45 lbs. A carbon fiber or even fiberglass can save 30+ pounds of weight. You can pickup a CSL style carbon fiber trunk for improved styling as well.
6. ZF 5-Speed Transmission
If you want to save even more weight, you can swap in a ZF 5-speed transmission from an E36 M3. Some drivers say it provides better shifting points on track, but that largely depends on the track itself. The weight difference from a stock E46 M3 transmissions vs the ZF 5-Speed is about 5-10 pounds, but if you’re scraping for weight, it all adds up.
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great write up. quick note: zcp/csl rotor size should be 345mm and standard is 328mm.