Mounting a race car seat: Driver comfort versus performance

Update by Tim Suddard to the Elva Mk VI project car
Aug 22, 2024 | Elva, Restoration, Vintage Race Car, Elva Mk VI

Photography by Tim Suddard

Before we could build a roll bar for our Elva sports racer, we needed to permanently mount our (now-repaired) seat. The seat has a threaded steel tube across the front bottom, and the remains of seat mounts can be seen on the frame.

At the top of the seat, we would need to build a bracket to link it to a metal plate on the frame.

As usual on a race car, there are always conflicting goals. The driver is most comfortable in a more upright seating position. In a juxtaposition of this fact, the lower and more reclined you can get the driver, the more aerodynamic the race car is and the lower the center of gravity.

Factor in that our primary driver is not built like a 21-year-old Formula 1 pilot, and the whole exercise got a bit tricky. And the chassis design of the car itself added to the challenge. On both the driver and passenger sides, there are diagonal tubes going right through the area occupied by the base of the seat. If we could remove these tubes (which we will not do), we could get the seat an inch lower.

We would also need to put both the pedals and steering wheel in place to accurately figure out where the driver, and thus the seat, would need to be.

Additionally, we’d use the space behind the seat to locate the car’s battery.

So, with some trepidation, we started by making a very strong, 1-inch-square tube with 3/16-inch-thick brackets on each end to secure the rear of the seat. While thicker than the rest of the frame, this square tube can be drilled to lighten it after we finish getting the rest of the seat mounting worked out. In our final fitting, we cut out 5/8 inch of the 1-inch-square tube to move the seat back a bit further. This solved our weight issue quite handily.

We started with the brackets being 2.5 inches long and soon realized that while this allowed the seat to reach the front mounting brackets, it placed the seat more forward than we would have ultimately wanted. Cutting these upper seat mount brackets back to 2 inches provided a better fit, but we decided that we would emulate the style of the front seat brackets but make them reach further back and up a bit to keep the seat just above the diagonal bar running through the floor area.

With the front brackets cut out and tacked in place, we test-fitted the seat again and found it to be quite comfortable.

We then came back in, made some adjustments, and then welded everything in place.

We would also need a bar under the seat to mount the required anti-sub straps. We did this fairly easily with the same ¾-inch tubing used in this area of the frame. We added a crossbrace and then another tube running fore and aft. We will mount a plate to mount the anti-sub belt once we finalize things later on.