Project #YAE92 M3: Part 3 – It’s The Little Things


While putting the car back together we also got the opportunity to add some all-important horsepower! While power is always good, we aren’t going to be going crazy with power modifications on this build. One of the reasons is that we’re running in a class which is determined by power to weight ratio and our first focus is going to be on weight. Less weight is going to equate to better tire wear and fuel mileage which is very important in endurance racing.  More horsepower tends to have the opposite effect on tire wear and fuel mileage.  While we will still likely be underpowered for our final race weight adding a lot of horsepower reliably is very expensive so we decided to keep our car NA with just basic bolt-ons.

One of those bolt-ons is a cat-less exhaust system from ESS Tuning. Not only does it save a tremendous amount of weight over the stock exhaust but it also provides much better flow and sound. We decided to retain the mufflers and resonators as some tracks we may attend will have a sound limit. Not to mention driving an incredibly loud car for hours on end can be annoying to the drivers especially if it’s loud to the point where it becomes hard for the driver to hear radio communication from the pits.

The factory M3 air box is really well designed and efficient but that doesn’t mean there wasn’t room for improvement.  Macht Schnell recognized the efficiency of the stock design but provided a simple intake kit that retains the well-designed factory air box. Where their intake offers improvement comes from a larger higher flowing air filter that fits inside the stock air box as well as replacing the factory accordion style intake charge pipe with a polyethylene version that is much smoother inside to reduce turbulence. The Macht Schnell charge pipe is also 18% larger in volume than the factory version.

The only other power adding modification we’re performing at this stage in our build is a set of Macht Schnell pulleys. The key component is an under-drive crank pulley made from 6061-T6 aerospace aluminum that is much lighter weight than the factory pulley and machined with high quality and attention to detail to ensure that the factory harmonics of the engine remain uncompromised. To counteract the smaller diameter of the crank pulley they also include an overdrive accessory pulley to ensure that the alternator and accessories are still working at the same speed as BMW's engineers intended.


The ESS Tuning exhaust system features cat-deletes, a Siamese X-pipe, and a simple yet beautiful design with top notch construction.

Macht Schnell realizes that the M3’s stock intake box is pretty well designed which is why they have only made slight changes to improve efficiency. The kit features a larger high flow filter housed inside the factory sealed air box. It also replaces the factory accordion style intake pipe with one that is smoother to reduce turbulence as well as 18% larger in volume.

The almost finished product! Can you guess which brand of tires we’ll be running?

By the time you read this, our car will be deep into one of the most important parts of the build; a stand-alone ECU and custom wiring harness. Aside from that, the parts are piling up here at Yost Autosport just waiting to get put onto the car for final assembly and race prep!  Check back soon for Part 4 of our build journal!

Yost Autosport #YAE92 M3: Part 1 – We Officially Void the Warranty

Yost Autosport #YAE92 M3: Part 2 – Why Do We Have All of These Extra Bolts?


Yost Autosport

Mode Carbon

APR Performance

ESS Tuning

Macht Schnell

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