FFR Mk4
Prototype of the Mk4 Roadster in the Factory Five Racing Wareham factory
On January 30, 2010, FFR announced the Mk4 which began shipping in March 2010. The development of the Mk4 is consistent with FFR's incremental upgrade strategy, and the Mk4 addresses a number of weaknesses identified over the years by the builder community.
Specifically, the Mk4 improvements include:
- new body molds that more closely mirror the vintage 198 roadster driven by Dick Smith
- revised front suspension geometry
- enlarged footbox and seat designs that accommodate taller and bigger drivers
- thinner period-correct roll bar
- minor improvements to radiator overflow, battery location, fuel tank access, among others
The Mk4 release triggers a long-awaited price increase on FFR Roadster kits. See Build Budget discussion.
Detailed comparison to the Mk3
Most new builds in 2010 will be Mk4 kits since Mk3 production will be phased out in the early part of the year. The following table compares the two models in the context of the modifications described on the this build site.
| Functional area or feature | Mk3.1 as built on Mk3Build | Mk4 | Comment |
|---|---|---|---|
| front body mount fasteners | exposed bolt heads on brake duct opening | hidden fasteners | period-correct flush mount, minor appearance improvement |
| side body mount fasteners | exposed bolt heads near side pipes, tight access | hidden under body | period-correct, minor appearance improvement |
| front chassis X-member | square tubing | round tubing | period-correct round tubing, minor appearance improvement |
| front suspension geometry, KPIA¹ (kingpin inclination angle) | modified | improved grip, but road test comparison not yet available | |
| cockpit footboxes | enlarged | more passenger foot room, accommodates drivers with large shoe sizes | |
| seat harness mounts | re-positioned | easier belt adjustment, no safety impact | |
| cockpit aluminum | revised templates | panel modifications described here still apply | |
| battery location | Breeze box in engine bay | back of trunk | Breeze box engine bay location more convenient for re-charging |
| trunk floor | lowered by 3” | hides fuel tank from exterior view, period-correct, but trunk floor no longer flat | |
| fuel tank access | trunk access | trunk access | no difference |
| rear suspension | 3- or 4-link flexibility | does not apply to IRS builds | |
| overall chassis | slightly lighter with minor torsional rigidity improvements, road test comparison not yet available | ||
| body design, fender flares, front openings | period-correct refinements | appearance difference not obvious to general public | |
| gel-coat | black | red, better finish | estimated 50% reduction in body prep time and expense |
| hood design | one-piece | flat with bolt-on scoop | no appearance difference since optional bolt-on scoop added |
| rolled edges | added during body prep | part of FFR body shell | no appearance difference, but likely reduction in body prep time and expense |
| roll bar | 2” width | 1.5” width | period-correct appearance (2” width remains an option) |
| trunk | hidden hinges | hidden hinges, round shape | eliminates “perky butt”, hides fuel tank, period-correct rear end |
| radiator overflow tank | Breeze cooling parts | new FFR unit | no functional difference |
¹ The inward tilt, measured in degrees from the center line of the ball joint relative to true vertical, is the kingpin inclination, a nonadjustable directional control angle with fixed relationship to camber settings. One reason to change the KPIA is to reduce the need for excessive camber.
