On Febuary 1st, 2008 a 2004 BMW Z4 got strapped to the rollers in our lab for testing.
The stock plugs on this car have been the talk of the auto industry for some time now. The stock plugs in this BMW are the Bosch R3 or Platinum +4 plugs. The idea behind them is that 4 points of possible ignition will give you a much more reliable spark and the surface-gap discharge design should give you the most combustion chamber exposure.
With new stock plugs we run our first set of testing again. We got a 40mph to 80mph acceleration of 9.24 seconds over a distance of 0.16 miles. Peak horsepower was 211 at 6000rpm and torque peaked at 193 Ft-Lb at 4000rpm. Fuel consumption over the fuel economy test was 1174.99cc.
With new Pulstar BE-1 plugs we attained a 40-80 mph acceleration of 9.07 seconds over 0.15 miles. We made 218 horsepower at 6000rpm and 202 Ft-Lb at 4000rpm. Finally, our fuel consumption trace took 1100.34cc.
We did fairly well with this car; gained 7 horsepower (3.3%) and 9 pounds of torque (4.7%). We reduced passing acceleration by 0.17 seconds (1.7%) and fuel consumption by 74.95cc (6.4%).
In the market of performance modifications we fair well among the other options out there for Z4 owners. We cost $23.31 per hp gain. A CAI for this vehicle runs around $350 and typically gives the Z4 about 11hp making it a $31.82 per hp upgrade, again, remember that this is a wide open throttle figure and part throttle gains aren't to be had with a cold air intake. An exhaust system will run you about $750 and that's around $50.00 per hp assuming it gives you 15 hp(a reasonable number).
www.pulstar.com
