How we do it: 

 

A unibody car uses the rear "c" pillar of the roof as part of the structural strength of the chassis. All of the cars we choose to modify are blessed with strong 4" to 8" subframe chassis rails under the floorpan that takes a huge part of the load on the car.  When you cut the rear roof "c" pillar extension that goes to the trunk of these cars(whether for a factory convertible like the Audi A4 or the VW mk4) the chassis is reinforced at the factory with stronger add on panels to accommodate for the loss of strength that the roof "c" pillar provides.  The VW/Audi cars as well as the Charger are very tough as cars so they make great foundations for a conversion.

 

To make a convertible or any cut version out of a unibody the big auto companies add a heavier floor panel under the rear seat area and often a riveted structural support under the sill area to make the modified cars safe and strong. Since we are keeping the front cockpit and roof intact all the way to the "b" pillar with the Smyth truck conversion, our job is much easier.   We only have to replace the strength lost in the small sheet metal "c" pillar  extension behind the rear door as it goes up to the roof AND we don't have to have an opening for the rear doors.  Instead of using thin steel stamped and spot welded into a box, we are free to use very thick aluminum plates on the side wheel wells and we are free to put double-wall door filler panels in place of the rear doors. This is the engineering work (using Solidworks 3d cad software) that we employed to make a design that would transfer the load of the rear "c" pillar extension evenly from the roof to the floor with a thick vertical plate just behind the front door. 

 

This load path is the key to both loading strength as well as torsional(twisting) rigidity of the Smyth conversion. If you look closely at the plate you will see round holes in the little quarter window area.  These holes are used instead of a big window cut out because we are using this thick plate to transfer loads to the existing cab.  Additionally the new front wall of the bed that mounts just behind the driver, drastically improves torsional rigidity while increasing side impact strength. The wall that is now a foot behind the front seats now transfers impacts to the other "b" pillar as well as the strong floor. The double side walls of the bed and door filler plates are used to transfer heavy truck loads evenly to the front door plate area and roof.  Using 20 years of race car design experience at Factory Five racing, Mark Smith has delivered a strong yet simple design that also is easy to assemble.

 

In addition to this beefy structure, the Smyth truck no longer has passengers in the large rear seat area...this adds almost three feet to the crumple zone in the rear,  almost seven feet of crumple distance. Smyth designed car to truck conversions keep the ENTIRE floorpan and all the heavy duty lower frame members of the cars we modify, we even keep the rear factory high stregth steel bumper assembly under our roll pan.  We need this overkill in the design because we are building trucks here...people are going to overload this vehicle every now and then and we wanted to make a tough and safe platform for truck use.  Your finished Ute drives with the performance of a car with the utility of a light truck.

 

The quality and fit of these parts reflects a lifetime of leading the kit car industry and driving/racing what he designs. Mark Smith, Michael Gallant and the rest of the Smyth Performance team will deliver to you one of the best car projects you can build and quality that you will enjoy for years.

 

Join us at Smyth Performance as we help you turn cars into the best performing trucks in the world.