At this year's Bimmerfest we noticed the OEM+ style of Dave Aupperle's 318is. We appreciated that the enthusiast had expended so much time and effort to transform the neglected four cylinder 3-Series into a performance machine. We met with Dave at his home in Hermosa Beach, CA where he built the car in his crammed one-car garage. He was so passionate and knowledgeable about his project that he wanted to write his personal story and we offered to publish it. Over to you, Dave:
I've always been a gearhead by trade, which is why I'm now a full-time mechanical engineer. My passion for cars started in high school after blowing the engine on my '85 Toyota truck. A lack of cash meant there was no choice but to rebuild it myself. I spent most of my money and high school years turning this truck into a customized show vehicle.
As I neared the end of high school my buddy Kenny Jisser showed up in a new '92 E36 BMW 318is with a big smile on his face. I loved the style and handling and vowed to own a BMW myself.
Years went by and then my truck was stolen. I took the insurance payout to a BMW dealership to ease my pain and drove away in an 18-month-old '95 CPO 318is automatic with 25k on the odometer.
Typically, I started out saying I'd leave it stock and appreciate the OEM German engineering. Well, that didn't last long. But it was after I started full-time work that the cashflow increased and the mods started to arrive. The car came together slowly. I started with the usual wheel and suspension upgrades. Being a sensible shopper, I sourced most of my parts used from eBay and online forums.
In the early stages I cycled through three sets of wheels before finding the right set, finally settling on 18" Schnitzer Type 3 wheels. I then wrapped them in Toyo T1-S - 225 in front, 255 in the rear - once the rear fenders were rolled with a specialized tool I rented via mail order. To improve the suspension, I sat the car on Bilstein shocks coupled with Eibach Pro-Kit lowering springs. Rear end height adjusters were also added to give the car a sporty forward rake.
To improve handling in the twisties, I fitted Racing Dynamics sway and strut bars, K-Mac adjustable camber plates and urethane offset control arm bushings. Once again, installed by yours truly.
Not long after finishing the first phase, the car was involved in a minor collision. This launched the exterior mods and I sent the car to Ron's Auto Body in Torrance, CA for a facelift. It was outfitted in full Motorsport skirts, bumpers, door moldings and mirrors. I also upgraded to European headlights and clear blinkers. At one point I tried angel eyes, but pulled them out.
Driving a 318is auto with an M3 suit naturally encouraged name-calling from the fellas. And since `all show and no go' wasn't cool, the engine was the next step.
In the pursuit of power, most would toss the four-banger in favor of a throaty six, but I decided to go the supercharger route. I sourced a used Downing Atlanta blower and after a weekend in the garage, the car had 7.5 lb of boost available. It jumped to over 170whp from the original 105hp.
I also realized a tranny swap was in order. I researched the swap and sourced a 328i Getrag five-speed. I also added a B&M short shift, UUC mounts, Schnitzer pedals, '99 M3 clutch and 3.45:1 LSD. Then South Bay Independent BMW in Gardena, CA installed the tranny in just one day.
After enjoying the supercharged five-speed for a while I eventually wanted more power, but that required more boost and more fuel. The problem was that custom programming for the OBD1 ECU was non-existent and Downing Atlanta relies on a rising rate fuel pressure regulator for the additional fueling. With the 10.5:1 compression, stock ECU and an FPR controlling fuel, the D/A kit provides little room for an upgrade.
On the flip side, the ODB1-governed M42 motor has forged internals, which is a darn bulletproof powerplant. So I decided to tackle the fueling myself. A stand-alone computer was out of my financial reach, so I opted for a piggyback fuel controller. Mark Amarandos at Split Second came to the rescue and I opted for their ARC-2A dial-controlled unit so I could make adjustments on the fly without integrating a laptop.
I toiled in the garage and wired the controller, mounting it in the glovebox. I was then able to swap my restrictive vane airflow meter in favor of an MAF from a '99 M3. Of course, additional fueling was beyond the stock injectors, so I got a set of 28 lb injectors. With fuel control at my fingertips, I increased the boost to 10psi using a custom pulley from Chad Cheung at It's All About Speed (IAAS). I was then able to street tune the fuel curve and dial in an air/fuel ratio of 12.0-12.5 at wide-open throttle with the customary 14.7 ratio controlled in closed loop.
Although the car ran well up top, the higher boost brought pre-detonation issues in the SoCal summers. To combat this I installed an Aquamist methanol injection system. It engages at 1.5psi boost, shielding the engine with a cooling mist of 50/50 water/methanol. Although the system requires frequent refilling of the reservoir, it does cool the intake to prevent pre-detonation.
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