Stage 2 is considered to be the ideal level of tuning for the S55 platform as it unlocks the great majority of the potential of the S55 without the downsides seen with some of the higher levels of tuning. 
   

S55 STAGE 2 FBO UPGRADES

After testing our stock F80 M3 on the dyno, we prepared it for Stage 2 by installing the hardware upgrades listed below:

-ARM Catless (Resonated) Downpipes
-ARM Intake System
-ARM Charge Pipes
-ARM J-Pipe

For the Stage 2 tune itself, we used the Bootmod3 OTS Stage 2 93 Octane file.  This is the standard file, no custom tuning was done, and it has a peak boost target of 22.4psi.

Our best Stage 2 FBO dyno numbers were 543whp and 547wtq.  Which is a peak gain of 73whp and 126wtq over our original S55 stock dyno results of 470whp and 419wtq.  Click Here for the full details on our stock dyno results.

While peak HP gains are impressive at 73whp over the stock dyno, what is even more astonishing is the Stage 2 FBO chart shows a 110whp gain over stock at 5,000rpm. 

Stock TQ peaked at approximately 3100rpm producing 419wtq, while Stage 2 FBO TQ continued to climb all the way up to 547wtq, a gain of 126wtq at 4,200rpm! 

STAGE 2 DRIVEABILITY

An FBO S55 versus a stock S55 is a different animal from the stock spec.  While the power and torque curves are increased throughout the RPM range, it is not uniform increase.  Rather, a massive increase in torque below 5,000rpm and a huge punch of midrange power combine for a very noticeable change in power delivery.  Careful in the corners, or you may find yourself in a ditch!

STAGE 2 TRACTION

It seems BMW intentionally kept torque lower early in the RPM range to help with launching and getting off the line.  After upgrading the S55 to Stage 2 FBO you will have to use your right foot to regulate traction from lower speeds, especially from a dead stop, to get the fastest times. 

With the newly acquired mountain of low-end torque, you will easily break the tires loose below 40mph, even on dedicated summer tires.  We were using 295/30ZR20 Toyo Proxes Sports on the rear, which have a treadwear rating of 240.  This should make them slightly stickier than the OEM equipped Michelin Pilot Sports, which have a treadwear rating of 300, and only a 275 section width on the Michelin.  Nonetheless, we still had to lay off putting the pedal to the mat until we were moving. 

STAGE 2 PERFORMANCE

However, once you are at speed, the large torque and power increases relentlessly propel the speedometer into triple digits, and beyond.  60-130 times were substantially faster, the best being 9.18.  For comparison, the stock best was 11.6 seconds.  

100% E85 TESTING

The horsepower plot on the dyno chart shows that the S55's OEM turbos are holding strong all the way to 7,000rpm.  Indicating that turbos are still efficient at producing the requested boost target of 22.4psi.  If the OEM turbos were running out of steam and getting out of their efficiency range, we would see a drop off in power closer to redline.  We are curious to see how much boost the S55's OEM turbochargers can support before falling out of their efficiency range.  To do this we will be testing E85 fuel and custom tuning by Cary Jordan.  

If you need help with your S55 build, whether it is for bolt-on's, fueling, or turbos, let us know and we'll be glad to assist you with yours.