Vintage UK Porsche electronics developer, Classic Retrofit, has updated its Bosch CDI replacement ignition unit with circuitry tweaks and a harmonised product range.

Based in Sussex, Classic Retrofit’s parent company is a respected supplier of mission critical electronics to the aerospace and defence industries. Run by British Porsche enthusiast, Jonny Hart, the idea for a ‘plug & play’ upgrade to the ageing Bosch CDI box came when Hart was nearing the end of a full restoration on his Porsche 911 SC.

“Having spent so much time on the SC restoration, including a full engine rebuild, I was unsure about refitting a tired thirty year-old ignition system. Why not try to incorporate some of the technology we were designing for our clients, which is completely reliable and can be fully customised? I sat down with our system designers and we came up with the Classic Retrofit CDI+ box: cutting-edge technology in a classic package.”

Bosch CDI Replacement Upgrade

Hart spent more than two years researching and developing the Classic Retrofit CDI+ ignition unit, inviting fellow 911 owners to assist with extended product testing. Back-to-back engine dyno tests of the finished product by noted Porsche engine specialist, BS Motorsport, showed a marked improvement over the original Bosch units, with one happy customer proclaiming: “Of the 98,000 miles I have done in my 1969 Porsche 911S, the 160 miles to Goodwood and back today (with my new CDI+ box fitted) were possibly the most enjoyable I have ever had.” High praise indeed!

The latest CDI+ unit features a number of tweaks to the circuitry to add more functions. There is also a modified CDI+ box aimed squarely at historic racers. “Our standard CDI+ ignition unit incorporates a huge range of functions, including adjustable hard and soft rev limits and shift light adjust,” says Jonny. “CDI+ also comes with a laptop cable, to allow detailed setting tweaks and software updates. The race box comes with a longer, waterproof version of that cable attached, for quicker changes during a race meeting.

“The big difference between CDI+ and the market incumbents is that CDI+ runs upgradeable software: it is not a dead-end product. We’re constantly upgrading the software that runs our Porsche ignition unit, and buyers can download the latest version straight from our website. There is a growing community running CDI+ units and users are coming up with ever more imaginative ideas for our flexible circuitry, including controlling K-Jet fuel curves and MFI fuel cut-offs. Classic car owners investing in our CDI+ box will be able to upgrade to new software at any stage in the future and take full advantage of some very exciting developments.”

Further product range details can be found on the Classic Retrofit website.