1991 BMW 850i, Stage 3 Dinan Conversion with dual turbos

This 850i was purchased new in 1991 by Donald Rojas of Austin Texas. In June of 1996 Donald sent the car to Dinan Engineering in Mountain View California for a Stage 3 factory performance conversion. At the time of the conversion, the 850 mileage was 44,696 miles. This is one of only seven 850i stage 3 conversions

performed by Dinan. The conversion consisted of increasing the engine displacement to 5.6 liters, same as the later 850 CSI, installing twin turbochargers and intercoolers, new computer chips for the engine and transmission, free flow exhaust system, high flow intake manifolds, transmission cooler, high stall torque converter, improved brake and suspension systems, and other improvements. The engine was then dynamometer tested showing 607 horsepower at 5,500 RPM and 666 foot pounds of torque at 4,500 RPM.

The 850 was sold to Jay Cooper from Edmond Oklahoma in 2005 and then purchased by me in 2006. At approximately 65,000 miles, an engine ticking noise was noted that sounded like a valve train noise. After over a decade since the conversion this seemed like a good time to refresh everything under the hood from the big stuff to hoses, belts, etc. The engine was sent to Dinan Engineering for an engine rebuild, overkill but since the engine was out it seemed like a good idea.

Golz in Deerfield Illinois rebuilt the heads including new lifters and other valve train components before assembling the heads to the new engine block assembly from Dinan. Since the engine was out of the vehicle and the 850 had accumulated. 65,000 miles, it was decided to replace all the other mechanical components such as the water pump, fan clutch and blades, all belts and hoses, new improved turbochargers and waste gate valves, new DK motors, steering box, and other components.

The 850 has been well cared for. The body, paint and upholstery are totally original. It is absolutely free of rust and in excellent mechanical condition. I have had it insured as a classic car by Hagerty Insurance and it has only been driven to car shows and other special occasions the past several years.