BMWs are some of the most versatile platforms across the range of generations that are available at nearly every price point. While some of the more desirable older generations are climbing in value, E46 and E90 generation cars have become relatively affordable, especially when you consider their potential for performance. In a recent article, we highlighted some of that potential in the E46 platform, which we highly suggest you read if you haven’t yet. We make a good case for picking one up while they’re still relatively untouched by rapid inflation. But this article isn’t just about the E46. This is another high-level overview of some of our favorite upgrades designed for the BMW enthusiast who wants more from their Ultimate Driving Machine.
Before we begin, it’s important to make a distinction between the more “traditional” naturally-aspirated BMWs and the newer, predominantly turbocharged, performance models. While many of the fundamentals for performance improvements are the same in principle, like drivetrain mount upgrades, brakes, suspension components, and interior modifications, the similarities start to diverge at a certain point. So, to split things up, we’ll first take a look at upgrades that are our favorite universally for BMWs, then move onto specific engine performance upgrades for both NA and Turbo cars.
There are two schools of thought for street-oriented suspension upgrades. The first is to simply swap your shocks, struts, springs, and upper mounts for a set of coilovers. In terms of adjustability and fine-tuning, this is a supremely appealing option. Whether your goals are centered around a specific ride height or dialing in the perfect settings for canyon carving and mild track days, coilovers cover all the bases. They do have a higher initial cost for some of the more competitive options, like Bilstein, KW, and H&R offer, but if you’re just after a look, you have great options suited just for you. Our ECS Adjustable Coilovers are an excellent choice for the budget-conscious BMW owner, which give you many of the adjustability settings you need to achieve the perfect ride height without sacrificing comfort. A more middle-of-the-road option comes from BC Racing, who have become the go-to for many of us over the years. BC coils tend to find their way into almost every car I’ve owned at some point, simply for their custom valving and Swift spring options, interchangeable pillow ball upper strut mounts, and their overall value for what you get. If you want to replace a ton of wearable components at once with exactly what you need to achieve your ideal looks and feel, a set of coilovers from any of these companies will be an excellent bet.
The second school of thought is a “cup kit” as they were once commonly known. I’ve heard this term less and less over the years, but back in the day, the “cup kit” was the gold standard in improved handling and looks. Effectively a precursor to the true coilover, cup kits are a combination of upgraded shocks and struts with a set of your choice in springs to achieve the perfect ride height and spring rate without sacrificing comfort or drivability. While they don’t offer the same kind of adjustability as coilovers, they’re a “fire and forget” option that do not require you to spend hours dialing in ride height, damping settings, or other alignment settings. Everything is worked out on the front end, so you’re simply just installing the parts and enjoying them as soon as you tighten the last wheel bolt. The lowering spring option has also regained some popularity in the newer BMW models equipped with electronic damper control systems in the shocks and struts, which allow the valves to adjust on the fly or change to a different stiffness in different settings and conditions. Without spending an arm and a leg on coilovers that are compatible with those systems, lowering springs give you the ability to retain that feature and bring the ride height down to an enthusiast’s standards. Plus, lowering springs on their own are significantly cheaper than coilovers (in general). The only downside is that you have to install them yourself, which means using a spring compressor, and it’s best practice to replace anything you remove while doing the job. So, if you’re picking lowering springs simply for the cost savings, we’d encourage you to scroll back up and check out our ECS adjustable coilovers to save money overall.
Drivetrain deflection robs power by allowing some of it to “deflect” through soft rubber mounts and never make it to your wheels. On street-driven cars, you want to strike a balance between performance and comfort. While solid mounts completely eliminate deflection, they also increase noise, vibration, and harshness to nearly unlivable levels. We suggest polyurethane mounts, which are softer and offer a more comfortable alternative. Poly mounts for the engine, transmission, and differential will significantly reduce that drivetrain slop for a crisper feel and more power going where it needs to. Turner Motorsport offers options for nearly every BMW, but we have yet to get into some of the swap mounts that grant the ability to bolt-in engine and transmission swaps correctly. For that, you need to turn to either Condor Speed Shop or Revshift, both of which are enthusiast-centric companies dedicated to helping the BMW community build their goals. Whether you’re 24v swapping your E30 or just looking for a tighter feel from your E90 daily driver, upgraded drivetrain bushings will have it feeling sharper than ever.
I’m going to commit car enthusiast heresy here: upgrade your brakes according to what you need them to do, not how cool, expensive, or “track oriented” they are. In years of over-upgrading many of my cars, I’ve come to find the best options for brake upgrades are simply replacing your old brake components with slightly improved versions. Ideally, a good pad compound suited for mild to aggressive street driving, combined with a full-face or slotted rotor, and fed by stainless steel lines with fresh fluid is the best setup.
For pads, you have tons of options from OE to competent under the hardest street and mild track day conditions you would expect to encounter. HAWK, StopTech, EBC, and Powerstop offer options I’ve enjoyed in many of my BMWs. However, I keep finding myself coming back to both HAWK and StopTech for my choice of pads. I just think they’re neat! Joking aside, make sure you’re buying something that is designed to have a high initial bite and resist fade longer than a stock compound. A big, wide, plateau of optimal conditions is what you want for something that spends most of its time on the street. Any of these pad choices will be exactly what you need, just buy based on budget if that’s your concern.
For rotors, as I mentioned, a full-face rotor is preferred for the street. This is where I know the pitchforks and torches are coming. Almost as hotly debated as wheel spacers vs. no spacers, folks tend to disagree over the benefits and drawbacks of full-face rotors and drilled and slotted or just slotted rotors. Here’s the real nuts and bolts: full-face rotors offer the greatest surface area for ideal street braking and handling performance. No, they can’t shed heat as quickly and tend to be a pound or two heavier than drilled and slotted options, but that doesn’t mean they aren’t an upgrade. Directionally-vented full-face rotors are all you need on the street and will have a more effective stopping distance since there is more surface area for the pads to grab. It’s all about friction. Naturally, that will generate more heat under the hardest conditions, so if you plan to spend about the same amount of time on the street as you will a track, this message really isn’t for you. If you need something to shed heat and shave pounds, go for those drilled and slotted options.
While this doesn’t apply to every single BMW out there, an often forgotten upgrade is the steering rack. A quicker ratio rack will give you fewer turns of the wheel from lock to lock, which improves agility and gives you a greater range of direction without “feeding the wheel” as it were. Most folks opt for the E36/7 Z3 2.8i or Z3 3.0i rack if they have E30, E36, or even E46 models. For you newer BMW owners, I’ve heard rumors the Z4 3.0i rack works. Now, you’ll need to change tie rods and make some changes to your steering knuckle in most applications, but the steering rack upgrade is common enough that kits are available through companies like Condor Speed Shop and Garagistic. Newer BMW models may require a bit more creativity, but if you’re looking for one of the best upgrades in terms of driving feel that you can do, a quick ratio rack from one of the roadster models is an amazing improvement.
While you’re in there, if you decided to lower your BMW significantly or are interested in a bit more angle, this is a great time to fit your car with a Turner Motorsport Bump Steer and Roll Center Correction Kit. I’ll let Mike Day explain it in this handy video:
In most cases, a BMW interior is quite a nice place to be. Even my extremely cheap X3 is a cozy cabin with good bolster support and a stylish (but unintentional) black and tan two-tone. However, BMW interiors in the 90s and early 2000s aren’t known for their staying power. It’s rather common to have ripped up seats, quick release door cards, and saggy headliners. Why not give it some motorsport flare if you’re in that camp?
Corbeau seats and Schroth harnesses transform the look and feel of any cabin to a more performance-focused atmosphere. Plus, they just look great, feel great, and will make you enjoy being in your car again. Even if you’re not dedicated to tracking your BMW, replacing worn-out old seats or comfort seats that just leave you sliding around with something stable, lightweight, and brand new is a great way to fall back in love with your car.
For many of the interior panels, HARD Motorsport and MKAH motorsports offer interior delete panels that make a spartan interior feel intentional. Plus, weight savings! Really though, if your BMW is looking a little past its prime inside the car, deleting a ton of that original upholstery can be a good form of stress relief and minimalist style upgrade you’re sure to love.
Single and Twin-Turbo Performance Upgrades
BMW famously brought impressive power to the road courses of the 1970s with the 2002 Turbo, then promptly went back to NA engines for three decades. Then, in the mid-2000s, they brought it back with the N54. Since the love-it-or-hate-it N54, many of BMWs performance and even non-performance engines have been turbocharged. Now, almost every BMW available carries at least one turbocharger attached to its exhaust manifold. One of the biggest benefits of this type of engine is its tunability. With simple bolt-ons, you can dramatically improve your engine’s output. It’s a rather simple formula we’ve discussed many times, in articles like our N54 upgrade guide and B58 upgrade guide. But really, they’re all fairly similar in terms of your approach.
Upgraded intakes, charge piping, intercooler, blow off valves, downpipe, and exhaust. That’s it. I know that’s a hearty list and can add up quickly in cost, but if you do it in stages, you’ll get to your goals eventually. Generally, I recommend starting with an intake and a cat-back exhaust. You get some mild performance gains with solid engine noise improvements. A throaty growl and induction noise combo is enough to keep you motivated and engaged for quite some time before you get the itch for more power. Then, move onto an upgraded intercooler and charge pipes. Finally, downpipe(s) and a BOV for good measure will have you at “full bolt on” status. Just don’t forget to scroll down past the NA upgrades section to check out the software upgrades you’ll need to make all that work to its potential.
NA Engine Upgrades
While turbo engines offer a super high power ceiling with relatively little effort, NA engines simply don’t. That doesn’t mean they aren’t worth upgrading, though! Even the non-m engines, like the M52, M54, and N52 offer a great package out of the box, there just isn’t much you can do to them without fully blowing them apart and replacing everything. So, for mild upgrades, we suggest an intake, power pulleys, camshafts, headers, and exhaust. That’s effectively all you can do to improve these platforms without really spending some money, or going forced induction. But nothing sounds better than an opened up, cammed, straight-six breathing through high-flow equal length headers to a full exhaust. Just listen to one of my old E30s rocking S50 cams, Turner (clone) headers, and nearly three-inch true dual pipes in this old episode of “Enthusiast Built.”
Finally, to tie it all together, before you install any of those engine upgrades, you’ll want to select a tune that will be compatible with them. Your DME won’t know what to do with the increased capability offered from those upgrades, so it won’t use them to their potential. Fortunately, Turner Motorsport offers software upgrade packages you can install right at home for power at the push of a button. Your software upgrade of choice is going to depend on what upgrades you install or plan to install, so make sure you read through all the information about what each tune is designed for.
For the naturally aspirated guys, Turner Conforti Chip Tunes are solid choices if you have an old E30 or E36 in need of a bump in power. They’re about as simple as it gets and just require you to replace the original chip with our chip that contains a proprietary blend of herbs and spices.
That covers the gamut of our (my) choice BMW upgrade strategy for a well-rounded street car that can hit the corners or a weekend track day for some fun. We have tons of links for individual BMW models that list nearly everything mentioned in this article below, as well as plenty of model-specific upgrade guides here on the blog I’ve written in the past. Be sure to check all those out as you plan your next improvements! See you next week.