Dag Bolenius

Koenigsegg engineer who developed the in-house HydraCoup hydraulic coupling for the Regera, conceived by Christian von Koenigsegg.

Bolenius was born on 12 December 1954 and died in Stockholm on 27 March 2021. Koenigsegg's 2026 CCGT1 release called him an engineer and fabricator. On the Fonus memorial, Christian von Koenigsegg left a donation message thanking him for the years in which they had created things together. The funeral, arranged by Fonus Köping, asked for gifts to Cancerfonden.

The CCGT was unveiled at the 2007 Geneva Motor Show. Koenigsegg's 2007 press release named Bolenius head of the development team; the 2026 CCGT1 release says he worked with Christian von Koenigsegg to bring the car in well under the 1,100 kg GT1 class limit. In 2026 von Koenigsegg told Carup that a minimum crew led by Bolenius, with two or three helpers, took the CC8S and CCR chassis and body and made the endurance racer.

Koenigsegg's HydraCoup page names him as the engineer who developed the in-house hydraulic coupling conceived by Christian von Koenigsegg for the Regera. The part is a compact torque converter with lock-up, made by Swedish craftsmen to factory specification, and is the coupling that lets the V8 feed the car's single-ratio final drive. He was later named as co-inventor, with von Koenigsegg, on Koenigsegg Automotive patents for a multiple-plate wet clutch and a multi-shaft gearbox, both filed in 2020 on 2019 priority applications.