Question for tuners, does the S55 have a Spool Mode? The stock bin just has "3" in the table for the max rpm for spool mode, it doesn't make sense 
For those who don't know, Spool Mode increases EGT (Exhaust Gas Temperatures) briefly by leaning out AFR (Air Fuel Ratio), to help the turbos spool as quickly as possible. Which decreases the amount of turbo lag perceived by the driver.
In other words, Spool Mode is a lean running mode, only happening at low rpm (below 3,000rpm), to speed up the urgency of spooling the turbos, and building boost as quick as possible at such low rpm. Lots of other manufacturers have Spool Mode on modern turbo engines, to decrease the turbo transient response. This isn't a BMW-only trick.
After the max rpm spool mode is reached as defined in the tune BIN below, the engine reverts back to running regular AFR targets as usual.
Here are screenshots off N54, N55, and S55 Max Rpm for Spool Mode. given that S55 only has spool mode set to 3 rpm, it obviously means it's disabled from factory on all S55 cars, can someone with more experience shed some light on this please?
Can we enable Spool Mode on S55 cars without much negative side effects?
S55 is very strangely only set to "3rpm":
N54 default is set to "2,600rpm":
N55 F series is set to "3,150rpm":
N55 E series is set to "3,150rpm":
For those who don't know, Spool Mode increases EGT (Exhaust Gas Temperatures) briefly by leaning out AFR (Air Fuel Ratio), to help the turbos spool as quickly as possible. Which decreases the amount of turbo lag perceived by the driver.
In other words, Spool Mode is a lean running mode, only happening at low rpm (below 3,000rpm), to speed up the urgency of spooling the turbos, and building boost as quick as possible at such low rpm. Lots of other manufacturers have Spool Mode on modern turbo engines, to decrease the turbo transient response. This isn't a BMW-only trick.
After the max rpm spool mode is reached as defined in the tune BIN below, the engine reverts back to running regular AFR targets as usual.
Here are screenshots off N54, N55, and S55 Max Rpm for Spool Mode. given that S55 only has spool mode set to 3 rpm, it obviously means it's disabled from factory on all S55 cars, can someone with more experience shed some light on this please?
Can we enable Spool Mode on S55 cars without much negative side effects?
S55 is very strangely only set to "3rpm":
N54 default is set to "2,600rpm":
N55 F series is set to "3,150rpm":
N55 E series is set to "3,150rpm":
Last edited:
