BRR BMWE92 335i side

BMW E92 N55 335i – All About BMW Performance Parts

All our customer projects have a set of objectives, and often a theme, and this one is no exception. This customer wanted a stunning, show quality car, that also had some more GO to it to complement its looks. We would often then select from a wide diversity of our quality suppliers, but this time, the customer wanted to go mostly the OEM route. BMW is one of the few car manufacturers that has decided to get into the aftermarket performance parts market. They delved into the market in about 2008, and have been expanding their offerings each year. The BMW E9x 335i came out in 2007, and was a perfect target for BMW to develop and expand their BMW Performance product offerings. They now have products that tick most of the normal upgrade boxes: (1) engine performance, (2) wheels, (3) exterior body enhancements (4) exhaust (5) interior enhancements. Our customer would take advantage of almost all of these from BMW Performance in this project, plus add those additional elements to truly make this project complete.


You think the interior on a BMW is nice to begin with, but BMW Performance offers some nice upgrade options. The customer elected to have the full Carbon Fiber (CF) interior trim set added. This is a very high quality CF kit, not one that you need to worry about the clear coat fading or cracking over time, or the original quality not matching the original OEM look and fit. Fit is perfect, the look is stunning, and the kit includes the front dash, the door trim elements, and the complete center console (front and rear sections).

BRR BMW inter




BMW Performance has gone one step farther than just doing the interior trim. They have created several different performance steering wheels. You can get just a standard steering wheel w alcantara cover, or a different shaped steering wheel w alcantara covering, or even one with built-in shift lights and data display. Our customer wanted the full effect, and selected the BMW steering wheel w alcantara and data display. The steering wheel also offers the option to have the center element of the steering wheel (normally thought of as the multi-function area) also covered in alcantara. Again, the fit is perfect, the electronics are all “plug and play”, you maintain the airbag feature, and the feel is something you cherish every time you drive the car. (NOTE – you’ll see in the images below, we had completed the steering wheel install after the interior trim, but before the center console section, which was done later).





If we are going to do the interior, then, as a complete project, we need to upgrade the exterior as well. BMW Performance parts are available for the exterior as well, including the front spoiler / splitter, front grills, rear trunk lip spoiler, and rear diffuser. To these, we added some more elements: front body colored side markers, matching front BMW hood emblem in all black.




One piece that is just REALLY cool, and simple, but adds that full BMW OEM touch is the door light. This is the light in the base of the door, that when the door is open, displays and lights up the ground, to help you see at night and make getting in and out of the car easier. But, rather than just have a standard LED light, you can now have the BMW Roundel emblem display on the ground….how cool is that??


The car is a later model E92…or called the E92 LCI version, so the car came with the newer LED rear tail lights.


Therefore, we needed to add the upgraded (aftermarket) LED angel eyes to match the lighting look of the car.


Engine Bay – Trim

This element is not about performance, this is about WHAM! The “oh my gosh” type of upgrade, that truly makes the project unique and amazing. There are lots of intakes for the BMW N55 engine. Most look like they do something, but don’t really help. Some represent themselves as “cold air intakes” (CAI), but actually are worse than stock. The original BMW engine intake comes w air scopes positioned right above the radiator, to help direct that forced, cold air into the intake system. So, if you instead implement an air intake that is only exposed air filters in the engine bay, and you know that the BMW Turbo engine puts out a lot of is that supposed to help. So, we wanted a truly functional cold air intake, but also one that would look the part of the rest of the car. Conversely, if you ask most BMW owners what the nicest looking intake system on the market is, they will say Gruppe M. Most don’t want to pay the price tag for the Gruppe M system, but this project cried out for just that. The system is functional, is a true cold air system, and just is STUNNING in its looks. To make this even more functional, we added a set of RPi front intake scoops. A turbo engine gets hungry for air, we needed to feed the beast that lies within.








Staying with the BMW Performance parts catalog approach, the easy first step was to select the BMW Performance Power Kit. The kit includes updated engine management software and some additional cooling elements to properly maintain the cool of the engine. The good news about this type of approach, is that you maintain the BMW warranty, and for California customers, you get the of so needed “CARB” sticker for state compliance. If you go the BMW Power Kit approach, you do get a good jump in power, but not as much as some of the aftermarket tunes. So, we wanted the best of both worlds, so decided to add those natural other elements to help the engine perform better within the parameters of the new BMW tune….lets keep the turbo charge cool –> meaning, lets add a bigger and better intercooler, and, lets help the turbo’s spin, spool, and not struggle to exhail –> downpipes. We choose the ER (Evolution RaceWerks) intercooler. There are several facets / features to concern yourself with when selecting an intercooler…and its not just which one is the biggest, or the deepest. The specific factors are those that have the best drop in incoming vs outgoing “delta T” values (biggest drop in air charge temperature drop), and which ones at the same time, have the lowest “delta P” values. Lowest drop in pressure from entry to exit. On the “delta P” values, you need to think about more than just the measure across the radiator or heat exchanger section….where many IC’s get poorly implemented is in the end tanks and the flow into and out of the heat exchanger. For every change in flow direction, there is a loss in velocity and pressure….and a crude rule of thumb in CFD (computational fluid dynamics), is every 90 degree change in flow direction is a loss of 12% efficiency (we can put the CFD equation here if desired)….and another factor is the length of the pipe run. You will hear many manufacturers of how deep their IC is….that is not a critical element. We can even get into the design of the actual tubes within the IC and their effectiveness for heat transfer…..but, too much talk here about the engineering. The net….we like the ER IC and have used it in many cars w great results.

The next part is the downpipe. The OEM downpipe has CA legal catalytic convertors, so, flow thru the “cats” is not great. Also, BMW made the OEM pipes to be easy to install and easy to manufacture….the parameter of it being the best flowing pipe was not as high on their objective list. Our priority is a better flowing pipe….so, size, shape, and the cell count in the “cat” were critical. We have run “catless” pipes, but that was outside the parameters of this project, as we hope to be able to still pass CA smog requirements. The best down pipe in our view is the AR Design pipe. Not only is the quality, design tops, and fitment / clearance is great, but they think through the complete kit, including the upgraded exhaust gaskets.

Evolution RaceWerks Front Mount Intercooler (FMIC)


BMW N54 Single Turbo AR Design “Down Pipe” – compared to the stock BMW version





There are many ways to go w suspension. Almost all of them create new benefits, but often w a matching set of trade offs when it comes to street cars. If this were a pure track car, then the decisions become more guided by budget than product selection, but when we are dealing with a daily driven street car, too often the decision is made more in the direction of performance, but, with the car hardly ever able to exercise that feature, the draw back is not worth the price. BMW, when they designed the car made the car for the mass public, many of whom could care less about driving performance, really. But, at the same time, BMW realized that a segment of their customer base did indeed desire a higher level of driving experience, so they created the BMW Performance Suspension Kit. That is what we implemented for this car, a new set of sport springs (front and rear), a new set of performance struts / shocks, that are valved to match the upgraded spring rate of the new springs, and a stiffer anti-roll bar to keep the car flatter under cornering loads.

In driving, the kit achieves the objective…better, crisper handling, a slightly lower more aggressive stance, yet a ride that can still take the beating from our wonderful freeways and roads without breaking your back or the car.







When you do upgrades, there is always good news and new results. The bad news, is you get hooked on the changes, and you want more. Such is the case w this project for our customer. The first set of suspension upgrades were great…but they started to show the areas that had not been touched. When you stiffen the suspension and sway bars…..what does it show next…that the bushings and frame attachments are not up to the same level…so, now the next phase must be accomplished.

That was the case here. Many also have seen and known of the issues w the BMW rear sub-frame. The stock bushings are just too soft, and while they do a great job of isolating road noise and vibration, they also do a good job of flexing under stress, and the car doesn’t respond like a “tight” suspension should.

The nice thing about the E82 / E90 / E92 / E93 chassis cars, is they all share the same fundamental underbody elements. The next good thing is the E9x M3 had some upgraded parts, and these bolt right on the E82 135i or E9x 3 series cars. So, staying w the BMW Performance or BMW stock upgrade path, we have some parts in the parts bin from BMW that will bolt right on.

The other good thing about a set of chassis platforms that span such a wide range of cars, is that it makes the market much bigger for aftermarket product developers, and therefore, a more attractive market, and, alas, more products have been introduced into the market to solve some of these product needs or BMW chassis shortcomings.

The BMW E9x M3 parts bin has some nice pieces – front tension / thrust arms, front lower control arms, front M3 sway bar, rear suspension upper guide links, rear toe links, rear sway bar, and rear M3 sub-frame bushings. All of these are M3 parts, and all fit this project directly. Each of them also has multiple benefits:

– front tension / thrust arm has stiffer inner bushings

– front lower control arm is both longer (creating more natural negative camber), and stiffer inner bushings

– front sway bar is larger, and has stiffer 2-part bushings

– rear upper guide links are shaped slightly differently, creating the room needed for clearance to the larger rear sway bar, and also have stiffer bushings

– rear sway bar is also larger, and like the front, stiffer 2-part bushings

– rear toe link – stiffer bushings

– rear sub-frame bushings are stiffer (all 4)

In addition, the aftermarket has entered this segment in many ways, and lots of options now exist in addition to the standard M3 parts. Front lower control arm bushings…you can go from mild upgrades, to full monoball / race type solutions. Rear upper guide links…now you can get them also w solid bushings, and adjustable lengths. The rear toe link, solid bushings, adjustable. Many different sway bar combinations.

As one should, we reviewed the objectives and needs for this project, and we selected the set that we believe most closely matches those set of objectives. We selected the M3 front tension arms, M3 front lower control arms w the M3 inner bushings, rear M3 upper guide links, M3 front and rear sway bars….but then we deviated from the stock M3 parts bin. We selected the DINAN rear adjustable toe links. We wanted a greater range of adjustment than what the stock M3 arm provides, and we didn’t want any toe deflection…and unlike where some choices of solid bushings will produce noise / hardness / vibration, that is not true w the rear toe, no downside to selecting solid bushings here.? We also selected PowerFlex rear sub-frame bushings….stiffer durameter, lifetime warranty. Makes perfect sense to us.

If we are continuing to add stiffness to the bushings and sub-frames, then it also makes sense that we need to upgrade the stock chassis reinforcement planes….so, we upgraded the front upper strut bar solution to the M3 version as well.

Here are the new bits and pieces.


Check out some of the pics that we have here in this project file for a review of the standard stock parts…and now we will follow w the upgrades.

Front suspension. All of the BMW cars / chassis in normal street mode are limited by what BMW does w the front camber and front tire size. Next, all the 1 Series and 3 Series cars suffer from front understeer, and the inner control arm bushings do nothing to help here (other than isolate noise and vibration). The E9x front lower control arm then helps in two ways….it is just slightly longer than the stock 1 series or 3 series lower control arm, so you gain some natural negative camber assist, and then the inner bushings are also firmer…a great upgrade. As mentioned, if this were a track car, we would likely use an alternative inner control arm bushing, but for the objectives of this project, the M3 firmer bushing is just what this car needs.

The other front lower arm is the tension strut or thrust arm. This arm is key to inducing stability under hard braking. If the inner bushing is too soft (liquid filled too in the case of the BMW design), then this bushing will allow “toe steer” under hard braking, a very disturbing feeling. The firmer inner bushings on the thrust arm prevent that deflection.

frt susp1

Sway bars to us are always a hard decision. They are “sin” solving a “sin”…so, they aren’t really improving things, but they do reduce the body roll, but in doing so, will at the same time reduce the “traction patch” of the opposite side. They are a great tuning aid on race cars, but no one “tunes” their street cars or alters the settings on the sway bar to accomplish a handling objective. But, nonetheless, the flatter a car the better, but don’t ever assume that “bigger is better”….not the case.

Rear Suspension / Sub-Frame Bushings. In race cars, we want all suspension elements, including the sub-frame, to be directly connected, solid so to speak. We don’t want any deflection or movement other than what is designed into the suspension geometry. But, the downside, if done on a street car, is noise and vibration, and given the state of our roads and freeways, is a big concern. Therefore, car manufacturers have put bushings everywhere to isolate this noise and vibration and harshness from transferring into the cabin of the car. But, this isolation means the road and the direct touch w what the car is doing is lost, and the car, due to the bushings, will deflect on their own, not when we want them too. On the BMW, one of the biggest areas of this is the bushings that isolate the rear sub-frame from the car. These are very large, rubber bushings, and under stress or load, they allow the whole rear of the car to have a mind of its own. So, out w those bushings.

If you upgrade to the larger rear M3 sway bar….then the clearance between it and the stock upper guide links is very tight, and under full “droop”, you may have interference.? This is why the M3 upper guide links have a “sway” or arc built into their shape, and this provides much more clearance. Plus, the inner bushings are stiffer, so again a “win-win” solution.


Toe links – if you are going to be driving hard, this is often one of the most overlooked, but important changes. Under hard cornering loads, the forces at play will cause all the bushings to deflect….that’s known.? But, when the toe links deflect, the actual toe in the wheels changes, and the car starts to steer on its own. To solve this, many choose to replace the toe links w adjustable ones….but many manufacturers don’t know how to properly size the toe link monoball bushings, and if too small, they will start to wear out and fail early.? The early failure will demonstrate itself by producing the “clicking” sound from the rear suspension. To ensure that didn’t happen here, we went w the DINAN set….one of the most well engineered sets on the market.


Here you can see many of the rear suspension pieces, location, and comparison between the original BMW 3series versions and the BMW E9x M3 versions, along w the YELLOW Powerflex rear sub-frame bushings.

rear susp comparo

Rear susp1

Finally, here you can see the DINAN rear adjustable toe links (rear suspension, left side), and you can also see the left rear sub-frame bushing (PowerFlex Yellow), plus the BMW Performance rear spring.


Below is the right side rear suspension, and the right side front sub-frame bushing.


NET – results.? Just what the doctor ordered….firmed up the suspension bushings, firmed up the rear of the car, it no longer drives in a different direction when pushed, car feels much more precise….but also, no harshness, no vibration, no new noises.















BRracing – creating EXCITMENT