Compared to the JB4?
While I do say you get a lot of bang for your buck with the JB we aren't getting anywhere near the gains they claim on their website. From two dynos I've seen it's about 20-30whp and 50-60wtq and these were cars running catless downpipes.
Hartge's numbers appear to be at the crank so not sure how it stacks up with the JB4 since numbers are measured at the wheels.
2014 LCI 550i M Sport | 3D Design Front Spoiler | BMW Performance Black Kidney Grills | BMW Performance Trunk Spoiler | BMW Performance Gloss Black Diffuser | Painted Reflectors | Wincos 30% Tint | Supersprint Quad Exhaust | AC Schnitzer Springs | MORR VS8.2 Brushed Finished Wheels 20x10R and 20x9F | Michelin PSS Tires 245/35/20F 285/30/20R | M550d 16mm RSB |||More Photos of my car here|||
Last edited by Alan L.; 10-20-2012 at 12:03 AM.