Performance and Safety:
Now that we’ve discussed proper cornering and car control, we can go a little more in depth about improving your car’s acceleration, in both directions. Confusing? Technically in physics when you bring a body in motion to a stop you are simply accelerating it in the opposite direction to its motion, so when you are braking in your car you are technically accelerating in reverse. Just a fun fact, not really important. What is important is making sure your car can slow down properly before you try to make it go any faster. This can be achieved by two things, better brakes, or weight reduction.
Brakes are one of the most important systems on your vehicle. If you’re going hard on the track you are frequently going to be braking late and aggressively. This results in heat, lots of it. Some heat is good (promotes proper friction between pad and rotor), but too much of it is very very bad. Heat can do all sorts of fun stuff to your brakes, most notable of which is hampering their ability to stop the car. As many of you will probably know, that is the brakes’ only job, so you can see why this would be a bit of an issue.
First and foremost, as we covered in the maintenance subsection you should be changing out your brake fluid asap after buying your M3. It’s relatively inexpensive and will give you much more peace of mind when braking. The reason you want new fluid in there is because over time glycol based liquids (like brake fluid) absorb moisture from the air, which can lead to an effect called Vapor Lock. Vapor Lock is the result of accumulated water in the brake system boiling, leading to vapor pockets within the system under hard braking. This causes increased pedal travel and a loss in braking force, which is both scary and dangerous. Put simply: fluids don’t compress, gasses do, and hydraulic systems work on the principal of pedal gets pushed -> fluid gets pushed -> caliper pistons get pushed. If there is gas in the system (vapor) then you’re going to get a spongy pedal, because science. Unlike the show section, here we are going to insist that you do a full fluid flush, it’s not that much more work that bleeding the system and you don’t want any old fluid in your lines if you’re putting the brake system through the rigors of a track day.
Another problem heat can cause is a loss of proper friction between the pads and rotors. As the pads and rotors heat up (super hot, not normal hot) the resin in the friction material begins to break down (essentially boiling), creating a gas layer between the pad and rotor that reduces contact between the surfaces. This effect is what you’ll hear referred to as “brake fade”, you’ll feel like you’re braking normally, but you car won’t slow down like you’re used to. Scary stuff.
To battle this effect you would want to equip your car with brake pads that have a higher heat rating and rotors which have better cooling fins. Some popular pad choices among track enthusiasts include the Carbotech XP series, the G-LOC R series, Endless “Sprint Race” Pads, or Performance Carbon (PFC) Racing Pads. However, we don’t recommend upgrading to racing pads immediately. As with our suspension recommendation, we suggest keeping the factory pads until you’ve become familiar with it (still replace the fluid), learning what the pads feel like at their limit and how to preserve them over the course of a session. That way when you finally do upgrade you’ll be able to feel the difference the new pads are making and will appreciate their heat resistance and pedal feel.
We recommend not upgrading your brake fluid to a super high boiling temp race fluid until you have upgraded your brake pads. While boiling brake fluid can be bad, boiling brake pads are even worse. A high temp racing fluid will be able to withstand heats that a street pad will not, therefore your brakes could fail suddenly and without warning. Sticking with factory BMW DOT4 brake fluid (or equivalent) while on street pads will give you an early warning of a lightly squishy pedal, letting you know to maybe take it easy on the brakes until they cool down so you can avoid vapor locking them.
You have an M3, you have plenty of power already. That being said, if you really want your car to be faster (and you’ve already improved your tires, wheels, suspension, and brakes) everything in this category will give you some improvement in horsepower/torque. This will help with your straightaway speed and post-corner acceleration. Brakes are especially important to tend to before modding for power because the faster you are going the more braking force is required to slow you down. Keep in mind that more power means harder braking, and finer modulation of the throttle during and after corners. Just something to remember before you throw on a lot of power mods, it will affect a lot of things you might not think about. That being said, here is our small list of suggested power mods that you can use to give your car that bit of extra power you crave.
An intake will give you small increases in both your horsepower and torque, giving you more power at your disposal. This will translate to small gains in speed on the straights and a slight increase in acceleration coming out of corners. While this will not be a mind-blowing difference in itself an intake will not set you back much in the long run and when combined with other small upgrades can make a decent difference. If you just want something better than the stock air-box something like an Injen intake or a K&N intake is a good basic option. If you are after every marginal increase in performance you can get, the Eventuri intake has some of the most impressive airflow and intake air velocity we’ve seen out of an intake. However just be aware that with the inverted filter design it acts as a sort of dust shovel so you’ll be cleaning it quite a bit more often than you would a normal cone filter.
Surprisingly exhausts are not just about making your car sound good (although that is an added bonus for a track car), they have real benefits for your performance. You’ll hear a lot of claimed horsepower numbers but in terms of power gains your mileage may vary, generally 5-10hp give or take unless you’re doing the full headers to muffler. However one definite area that an exhaust can benefit you is weight savings. The stock muffler weighs around 54 pounds, so with an aftermarket exhaust you’re saving anywhere from 10-40 lbs (40lbs would be a full titanium muffler).
Note: We unfortunately do not offer headers on our website as modifying E46 headers involves removal or replacement of the factory catalytic converters. Modification or removal of the factory catalytic converters is against California Air Resources Board and Environmental Protection Agency regulations.
If you’re looking to change out your entire exhaust and want parts that are all made by the same company then you’ll want to check out Supersprint’s lineup of E46 M3 exhaust parts. They have front pipes, connecting pipes, and both street and race mufflers. The race muffler section alone can save you over 20lbs versus the stock muffler. Of course that’s a lot of money to spend for 20lbs of weight and a few horsepower, you just have to decide if it’s worth it to you. And don’t worry, it’s ok to say “yes because I want my track car to sound awesome!” That is 100% a valid reason to get an exhaust. Just don’t get too weighed down (hehe) with the little details like saving a pound here or there or 5 extra horsepower, you’ll make more improvements to your lap times by practicing.
If you’re looking for a little bit of a cheaper option that will still give you a bit of power and weight reduction, we always highly recommend a Remus exhaust. Remus is one of the most respected exhaust manufacturers in the world, we can always safely recommend their products because of the insane level of design and testing that goes into every single piece they manufacture. Remus’s production is so refined that they are trusted by several car manufacturers to produce their OEM exhausts. If you’re interested in knowing a little more about the company we recently posted a blog article about the Remus manufacturing and testing facility. There’s also a video at the top of each page (episode 1 and 2) if you’re not in the mood to read. In the case of the E46 M3 the Remus axle-back exhaust is one of the most affordable options available backed by one of the biggest names in the industry.
Gut it like a fish. The car will not be comfortable, it will not be quiet, and you might hate your life, but all that interior junk weighs a significant amount. You will be recouping a respectable amount of engine power that would otherwise be used to cart around your leather interior and electronically adjustable heated seats. Obviously seats cannot just be removed, you have to replace them with something. Companies such as Sparco make a wide range of seats to fit your needs. Something like the EVO QRT is great if you’re on the smaller side, the EVO II US for if you have wider hips, or the EVO II QRT if you’re a bit too tall and wide for a normal EVO QRT. See sizing charts to check dimensions and determine what would fit you best.
If you’re really hardcore you can even remove your air conditioning to save the weight of the condenser, lines, refrigerant, and compressor. However, if you’re going to be driving the car off the track consider just leaving it in. It doesn’t make that big of a difference and the benefits of not dying of heat stroke in the desert are rather enticing. If you live in a colder climate substitute that with the ability to defog your windshield in the winter, again avoiding possible death.
Speaking of possible death, do not remove your airbags without first installing a full harness and roll bar to anchor said harness to. Just because you’ll be wearing a helmet while you track doesn’t mean you’re suddenly invincible. Consider also purchasing a HANS Device to further protect yourself in the event of a crash, your safety is worth it. For those unaware, a HANS Device is a safety device that anchors your helmet to your shoulders and racing harness (pictured above). In the event of a crash it keeps your neck from being thrown forward while your shoulders are being held back by the harness. Similar safety devices are also available such as the Schroth SHR FLEX or the Simpson Racing Neck Collar, just make sure you’re using something to protect your neck. Before running any of these safety devices make sure your harness and seat properly accommodate them (HANS for instance calls for a HANS compliant seat and specifically a 2″ harness).
Things like weighted shift knobs and/or short shifters are entirely to taste. Whatever makes you most comfortable while driving is what’s best for you. A lightweight bucket seat is preferred by most drivers for the weight savings and superior bolstering, but definitely shop around and see if you can demo seats in people’s cars before committing to one. If you buy a seat sight unseen you may get annoyed 6 months later when you’re struggling to extract yourself from it after thanksgiving. Make sure it’s something you can live with. Otherwise things like bigger floor pedals or bigger paddle shifters (if you own an SMG model) to make driving more comfortable for you are entirely at your own discretion. Your interior is the part of your car you see the most on the track so make it somewhere you want to be.
Gauges are great, they provide you with important information about your car’s vitals that you otherwise would be unaware of. Important gauges to consider installing on your track car are: oil pressure, oil temperature, and maybe water temperature. These three gauges give you a great idea of the health of your motor at a given moment. If you’re full throttle on the track and your oil pressure starts to drop, or your oil temperatures spike, or all of a sudden your coolant is boiling, you’ll want to know right away.
Normal front lips, side skirts, trim pieces, and dinky little trunk wings are completely useless, you’re just adding weight to your car. If you’re building a dedicated track car the only exterior mods you should consider are functional versions of: canards, a splitter, a wing, and a diffuser. Keyword: functional. These things are gonna be big and may look a little dumb to some (and freaking awesome to others), but they will do what they’re supposed to. Canards and a front splitter help with front end stability by reducing drag and adding downforce. A big wing will provide rear downforce for added traction on the driven wheels. A diffuser will reduce drag by channeling air behind the car. With the added downforce you will also need more aggressive spring rates on your coilovers so keep that in mind as well before . This will not be cheap, but it is kind of the last thing you can do if you want to go beyond the realm of normal track car modification.
So, to quickly recap our list:
- Your own driving skills
- Performance (Power/Weight Savings)
- Vehicle Monitoring Equipment (Gauges)
After Maintenance and Driver skills there is no particular order in which you have to address each area of the vehicle, but we strongly suggest wheels and tires first as they have such a direct impact on your car’s performance. If you’re not quite sure where you want to start don’t be afraid to consult our team of Mod Experts who will gladly offer you advice on what your options are based on your priorities. They can be reached at (714) 582-3330 or by email at [email protected]. We also have live chat available at Modbargains.com during normal business hours.
Note from the Author:
While I have you here, if you’re interested, I wanted to share my priority list and why I would address them in this order. This is all personal opinion so your list of priorities might look completely different, this is just my thought process:
- Maintenance – Tending to proper maintenance is a given and the first thing you should attend to.
- Driver Skill – I’d run a few sessions focusing on learning the limits of the car and how to control it properly, you don’t just jump into a game before you know the rules right?
- Suspension – I personally love fiddling with suspension so to start off with I’d probably get some KW V1 coilovers or similar, just for a bit of lowering and better spring-rates. KW springs are available for purchase separately so I’d probably up the spring-rates by 1 or 2kg/mm. Their street kits are notoriously soft (as stated on page 8) and the dampers can handle the slight change in rate. I’d also purchase camber plates separately just to make future alignments and wheel fitment easier. BC coilovers come with camber plates and can be ordered with custom spring-rates so they are also a decent option although their damping is not my favorite.
- Weight Savings – I’d focus on getting rid of extraneous interior pieces (maybe keep the stock seats for now) because that’s basically free performance and better braking.
- Gauges – Oil pressure and temp gauges for safety.
- Wheels – solely so I could fit wider tires. A set of 18×9.5 ET22 Sportline 8S is pretty affordable and lighter than the factory wheels by a few pounds.
- Max Performance Tires – to get a feel for how the brakes and suspension react to higher stress. Brakes aren’t a bad idea to address before tires for safety reasons, but stickier tires help you assess the brake system’s limits better, just don’t go crazy trying to cook the system.
- Alignment – Since you have to get an alignment after installing new wheels and tires anyways, might as well fix the horrible factory configuration.
- Brakes – now that I have tires that can handle some extra braking force and I have driven with the stock pads for a while I’d feel confident that I could utilize the extra braking power and heat resistance. At this time if I hadn’t already I’d also upgrade to DOT 5.1 fluid. Racing pads can deal with much higher temps than street pads so it is ok to pair them with a very high temp fluid. Initially it is preferable to keep DOT 4 fluid in your car until you upgrade pads. If you pair DOT 5.1 fluid with stock pads your brakes could vapor lock with little to no warning at all. If you have a lower temp limit fluid you’re more likely to experience a squishy pedal as an early warning sign before the pads actually lose their friction.
- Ergonomics – The car would feel pretty good after wheels tires suspension and a good alignment so I’d chill with the big mods for a bit and focus on making the car better to drive by installing a short-shifter and a bucket seat.
- Extreme Performance Tires – by this time I’d have gone through at least a few sets of tires so I’d want to upgrade on the next set.
- Forged Wheels – Flow formed wheels are decently strong, but if you’re tracking hard they’re not going to put up with it for that long. A forged set is worth it to get if you’ve been tracking consistently and need the extra durability and lighter weight.
- Upgrade Suspension – at this point i’d feel ok investing in a more track oriented suspension setup.
- Intake / Exhaust – for fun, benefits are minimal.
- I don’t really care about big power or exterior mods so I’d probably leave it at that. I like to keep cars nimble and simple.
If you’ve read this far into this article, thank you. I put a lot of time and research into making it as informative as possible so if you found any of it helpful or learned something from it I consider that a success.
- Engine Bay
Performance and Safety…(page 9) – Current