The Motion Motorsport Aluminum Underpanel for the E36 chassis is designed to replace the factory molded plastic front splashpanel sections that are known to tear and sheer off both on the street and at the track.

The Underpanel:

This piece is fully CAD designed with all pieces precision laser cut and CNC punched. Designed to be superior to anything else currently on the market, it consists of a 1-piece .080" aluminum panel utilizing a unique a bracket system which connects straight into the frame rails. The brackets have been engineered and tested to hold more than 300lbs of downward force without failure. Additionally, the easy removal system features threaded studs mounted into the bumper that allows for a very easy 2 minute removal and 5 minute re-installation of the underpanel. Finally, you can rest easy if you are missing or have damaged your OEM plastic fender liners or pork chops as the underpanel does not require these pieces individually or in combination since it relies on other points of strength (brackets straight to the frame rails and bumper studs) to remain fastened to the car. The Motion Motorsport underpanel positively postitions the fender liner pieces and supports the often flimsy plastic, as opposed to the common method of relying on them to support the rearward portion of the tray.

The underpanel protects the engine bay components like the radiator, pulleys, and belts from dirt and debris, and extends backwards, terminating just in front of the factory sway bar.

The hardware included in the kit is very high quality stainless steel, with the inclusion of PVC spacer nuts to secure studs to the proper depth, and allow compression when the underpanel is fastened to the studs to help keep the fasteners additionally secure. The frame rail inserts that aid in securing the brackets to hold the underpanel are of a high quality engineering grade nylon, rated to outlast the common grade nylon inserts as used by BMW in heat cycled environments, and are of a superior geometry, eliminating the weak stress points found in OEM pieces.

Aerodynamics:

Beyond the primary function and intent of a splash panel, airflow is a consideration in designing an underpanel, both under the front bumper, and through the auxiliary fan, AC condenser, and radiator assembly. Underneath the front lip of the car, the Motion Motorsport underpanel rakes upwards by a couple degrees front to back, supported and positioned by our bracketed design. This helps to assist in inducing a low pressure area underneath the front end at high speed for additional stability (supported by the contributed rigidity of our frame rail brackets) and isolate turbulent air moving through the auxiliary fan/condenser/radiator and into the engine compartment above like any other underpanel. Independant test mule cars have noted improved high speed stability over no underpanel installed.

A common concern of airflow into the radiator has been thoroughly researched with this piece. It was considered to add a type of deflector piece to guide air directly into the factory radiator, but observed that the geometry of the auxiliary fan, AC condenser, and radiator rendered any such piece useless for deflecting air up into between the radiator and condenser. The aux fan is positioned such, and with such close proximity to the bumper opening, that any air entering the bumper opening flows directly into the fan and shroud, and thus straight through the condenser, which then resides a narrow finger's width from the radiator. To try and deflect the lesser peripheral airflow exiting the lower 2" of the condenser (which extends lower than the radiator) immediately 90 degrees straight up gives no cooling benefit, and adds the risk of, when in a crash situation, puncturing the underside of the radiator with the vertical plane of material. Other offerings may have what appears to be a deflector for air into the radiator when in reality the purpose served would be to act as a brace to reinforce multiple sheets of stock fastened together to form one tray, and has no discernable airflow benefit.

Video Installation Guide:
http://youtube.com/watch?v=ZS5HoaVbrFo

Easy Removal System:
http://youtube.com/watch?v=8RqtVJBMZu8

Installation Guide