An already blindingly fast sedan to begin with, this BMW M5 makes well over 360 whp after
Ten years ago, when you thought about a family sedan, how often did the words, "six-speed" or "400 bhp" come to mind?
Today, however, the words family sedans and powerful are almost synonymous. Case in point: Mercedes-Benz has a few that are knocking on the 500-bhp door. And BMW's new 2005 M5 will be doing the same.
With BMW winding out the last of its E39 M5 sales, I thought it would be appropriate to explore the sedan's performance potential. With some basic bolt-on modifications, I hoped to place the E39 M5 in the elite group of monster horsepower sedans. In this first part of a two-part series, I think we're already there.
Although rated at 400 bhp, M5s are typically dynoing between 300 to 335 hp at the wheels (SAE corrected) on the widely used Dynojet 248C dynamometer, with a few exceptions slightly higher than that. For this test, I used a 2002 M5 owned by Dr. Ronny Ghazal, an orthopedic surgeon in Redlands, Calif.
The Supersprint exhaust system eliminated 36 lb of unwanted mass. Although not too loud, t
With absolutely no upgrades this car already seemed extraordinarily fast. We took it to Vadim Federovsky of evosport inc, and he concurred: "This is one strong M5!" evosport technicians strapped the car to the dyno and, sure enough, this car was making well above normal power-344.7 hp to the wheels.
This good news started to place doubt in my mind as to whether I'd be able to see any gains at all with some basic bolt-on upgrades. Maybe the exhaust on this particular car was a perfect specimen, or maybe the factory tuning is unbeatable. I gave it a shot anyway.
Initially, I told the M5 owner that if I got a 20-hp peak gain at the wheels I'd be happy. I also promised that it would in no way involve going inside the engine. All I had in mind was software, exhaust, pulleys and replacement air filter upgrades.
The first of the tests involved the cat-back exhaust and software. Supersprint's quality exhaust systems have been tested on a variety of cars here at european car: the Volkswagen Jetta 1.8T, Mini Cooper S and a few E36 BMWs, including 3.0- and 3.2-liter M3s, and a 325is. The Italian company states it performs more than 1,000 dyno test runs each year. I've always liked the quality and overall build of the exhaust systems, so I ordered one from Supersprint North America's primary distributor of BMW-specific exhaust systems, BMP Design.
The crossover pipes are required in order to fit the mufflers properly to the car.
With a retail price of just over $1,700, the Supersprint exhaust features left and right mufflers and a crossover midsection pipe. The entire system is TIG welded stainless steel with mandrel-bent, 1.5mm tubing. The factory system was pulled off the car as one piece, weighing in at more than 93 lb. The three-piece Supersprint system weighed 57 lb, good for a 36-lb weight loss.
Evosport's software for the E39 M5 was designed as a "Stage 1" software program to run with the Supersprint exhaust system, so I decided to test the two together. The software program extends the rev limiter to 7300 rpm and maximizes fuel and timing for maximum reliable horsepower with 91 octane. It also eliminates the 155-mph speed governor. I wasn't about to test that, so I'll just take evosport's word for it. Be sure whatever tires you use are rated for the speeds you drive, even if only on a racetrack.
Back on evosport's dyno, the car made 354.3 hp at 6700 rpm in fourth gear. Torque also rose from a baseline 333.7 lb-ft at 4550 rpm to 342.2 lb-ft at 4400 rpm.