Classic Retrofit CDI+ in a 3-litre 911 SC: user feedback

Pelican Parts user, Sailkane (Michael), recently posted an interesting thread about his upgrade from the classic Bosch CDI ignition unit in his Porsche 911 to our Classic Retrofit CDI+ unit. Bought from our recommended US reseller, Pelican Parts, the unit was installed in a 1979 Porsche 911 SC.

"My original CDI was working fine but, after trying to find a correct rev-limiting rotor for my 1979 911 SC that I autocross all summer long (and I really need the rev limit protection!), I decided to go the route of the Classic Retrofit CDI+ ignition upgrade. The benefits of the CDI+ should help to bring my ignition into the 21st century and reduce my worries of the 40 year-old unit failing or losing performance.

"The installation was very easy and the instructions are detailed and easy to follow. I just did the plug and play option and did not do any software mapping. I did adjust and calibrate my tach and set the hard and soft rev limit to my desired numbers. The car started right up and runs great. I will have the AFR adjusted to reap some additional power as suggested in the instructions.

"I also upgraded the ignition system with a new Bosch black ignition coil, new Beru shielded wires and new spark plugs as suggested by Classic Retrofit. Anyone hesitant about the cost should know this is a high quality, 21st century product with substantial benefits as compared to buying a original CDI box."

Sailkane also detailed some issues with Bosch silver ignition coils on his other classic 911: a 1976 911S with a 3-litre engine.

"I had some bad experience with Bosch silver coils. I replaced Bosch silver coils three times on this car before discovering on the Pelican Parts forum that the "made in Brazil" Bosch coils are no good. I only put 200-400 miles on the coil each time and they all left me stranded. I thought it was engine related and discovered the silver coils can’t withstand the engine heat. I replaced them with an MSD coil and just removed the sticker. My advice to other owners is don’t buy Bosch silver coils unless you like riding in tow trucks!"

"It's great to hear real-world feedback from satisfied owners," says Jonny at Classic Retrofit. "We've tested our CDI+ boxes at on V8 Ford Cosworth DFV Formula 1 engines running at up to 10,000 rpm, but we always love hearing back from new owners.

"Bosch coils are supposedly the best and the Bosch silver coil is the right spec, but it is known to have some manufacturing issues. Most other coils in the market are too slow, including the MSD. They can be used with our CDI+ unit, but the spark interval between the two sparks (our CDI+ is dual/twin spark) should be extended to 700us or the coil will cause poor running.

"We have been working on an idea to manufacture our own coils for some time - another project that may come to fruition eventually!"