Joseph

The first 5 Series to sport the M5 badge was the 1985 E28, which inspired the market with its sportyscar performance packaged inside a luxury four-door sedan. Cars sold in the United States and Canada, beginning with the 1988 model, came with a S38B35 engine, a detuned version of the M88/3, equipped with a catalytic converter and producing 256 horsepowerhp. Production of the North American specification M5 began in November 1986 and ended in November 1987. With a total production of 2,241 units (1,239 in U.S. spec) the E28 M5 remains among the rarest regular production BMW Motorsport cars, – after the M1 (456 units), M5 (E34) Touring (891 units)ii and the 850CSi (1,510 units). 

This car was built in May 1987 and was sold in the US by Dan Boone BMW, Inc., Houston, Texas, ion September 1987. It spendingspent most of its days in California, where it was tuned by Dinan Engineering Inc.; updates started , beginning in June 1992 and included receiving performance engine software, CAM kit, St-1 suspension, and aesthetic upgrades. The car was in very good condition when I purchased it from the MOTORVAULT here in Indianapolis. I knew the owner and it came with literally four inches of documentation, including the original window sticker. The car went through a Pre-Purchase Inspection (PPI) at Reggie’s Motorworks to ensure there were no major issues. As expected, the car came back with an anticipated punch list. However, the S38B35 engine was in great shape, as well as the body and frame. 

Work began in December 2022 with teardown and inspection following the initial PPI punch list.  Of course, the more you probe the more you find, and it became apparent that there were additional issues to address. Fortunately, all the work— from mechanical, body work, paint and upholstery— could be completed locally. For the next ten months, the car received all the expected seals, filters, power steering rebuild, hoses, belts, restored E34 brake calibers from (a previous common upgrade), upgraded the AC compressor, replaced the cracked windshield, new exhaust, restored headlight bezels, recovered back seat, – steering wheel and dashboard in leather, recessed the U.S. “diving board” bumpers, and properly addressed the limited body and paint blemishes. At last, the M5 was placed on the dynamometer, revealing a maximum crank hp of 288.4 at @ 6,243 rpm (117.7 MPH!) and maximum torque at the crank of 296.4 foot-pounds@ 4,454 rpm (at / 84.0 MPH). 

When I took on this project, I pledged a commitment to preserve and share this remarkable piece of driving history. A goal like this is not possible without the vibrant car culture, enthusiasts and artisans. The car remains a work in progress as parts for this car are extremely hard to find. I'm currently looking for the oem air box / intake assembly / intake silencer Part No. 13711311531. Please let me know if you happen to have one not being used or know someone that may have one. I believe the air box for a 1988 e24 M6 Part No. 13711309765 will work as well with a few minor adjustments. I've attached a picture with the air box circled in yellow and the page from REAL OEM below. Thanks! -Joe