A Comparison of S2 and Twin Cam Seats
The purpose of this article is to explain the difference between TC/Special and S2 Europa seats, see picture 1 with S2 on the left and TC on the right. (Note this article applies only to the federal version of Europas.)
Seat Rake
While autocrossing my helmet would hit the roof in my TC. The S2 seats lean back more than TC seats (see picture 2, S2 is in the foreground with TC behind), so I bought a pair of S2 seats. The thinking was that a seat leaning back more would allow more headroom.
Once purchased, I tried fitting the S2 seats in my TC. The firewall of the Europa directly behind the seat is contoured to fit the seat exactly, so my TC seats when adjusted all the way back fit this contour perfectly. The S2 seats with a different rake do not fit the contour of the firewall, thus limit the amount of front-to-back seat adjustment possible.
I do not own an S2 but I assume S2s bodies are also contoured to fit the increased rake of the S2 seat. Thus a similar problem would occur when fitting TC seats to an S2.
Seat Rail Spacing
The seat rails bolt to the underside of the seats and to bobbins fiberglassed in the floor of the car. Both TC and S2 use the same seat rails. Picture 3 shows the seat rail bolt spacing for the TC, Picture 4 shows the same for the S2. It can be seen that the TC has roughly a 1 inch wider seat rail spacing than the S2.
This means the seat mounted rails will not line up to the seat rail bolted to the floor when swapping seats from one model to the other.
You can relocate the bobbins on the floor or make an adapter for the floor rails. Relocating the bobbins is more work than I wanted and a rail adapter would add height, negating the headroom advantage of S2 seats.
I have also heard of people bolting the seats directly to the floor and not using rails. This lowers the height of the seat and allows more headroom. Of course, then you have no seat front-to-back adjustment. I didn’t like any of these options.
Seat Construction
Picture 5 shows the seat width for the TC, Picture 6 shows the same for the S2. The TC seat is roughly an inch wider than the S2.
The seat bottom for the TC is made of rubber webbing (Picture 7) while the S2 is sheet metal. On my car, the rubber webbing offers little support. Some place a piece of plywood or foam under the seat, else your butt will sink straight to the car floor when sitting in the seat. The S2 seat bottoms, while solid, are notorious for rusting.
The seating position in an S2 is akin to than of a F1 car of that day. Arms and legs straight, leaning way back. The TC seat has an extra thick cushion for additional thigh support (picture 1). Thus you sit with knees and elbows bent while being more upright. The siting position in a TC is closer to a street car.
After examining both types of seats I concluded it be difficult and impractical to swap seats from one car the other.
Ron Dawson
