Project E46 M3: Part 15 – more exhaust testing and weight reduction


Here’s the entire Megan Racing and Scorpion exhaust installed. We have got to hand it to these companies (as well as VAC Motorsports, where we got our headers from), because the fitment was top-notch. We’ve already installed this system on the car twice, and the whole thing went back on straight both times.

To further lighten the car, one of the things we’ve been doing is running an Optima Yellow Top D51R battery to replace the factory 44-lb unit. I’ve had pretty good luck with Optimas in the past, having now run Red Tops and Yellow Tops on five different cars. However, if you look on the Optima site, it won’t show that the D51R Yellow Top will fit the E46 BMW M3.

That’s because, in order to make it fit, you need to do a small modification to the bracket that was once holding the factory BMW battery. Because the Yellow Top is taller, all we had to do is cut the factory bracket at the bottom, as shown here (that little shiny line across the bracket is where we cut).

This gave enough space for the clamp on top to be buttoned down without worry. So, here is our Optima Yellow Top D51R, secured in the factory location with a slightly modified factory clamp.

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