The 3.2 liter engine’s bottom end uses a stock crank with stock WPC treated bearings from a post 2004 S54 engine. WPC treatment usually can increase a bearings load bearing capacity by around 20%! These bearings stopped the notorious S54 spinning bearing issues and Essa Autosport has no bearing problems at all even with tons of power and wet sump oiling. 0.010″ oversize 12.5:1 JE forged pistons are supported on Wiseco Boostline connecting rods. The Ignite Red ethanol fuel is one of the big secrets to being able to run compression this high on a boost engine. The high compression helps spool the turbo quickly and is one of the main reasons why the engine has such a wide powerband.
S54’s were known to have oiling and bearing issues when they first came out but it was due to the bearings not the oiling system itself. The stock wet sump system has pumps, a main pump, and a scavenge pump that gets the oil out of the front part of the oil pan and transfers it to the sump.
One of the big secrets to the BMW’s awesome power is the Borg Warner 9280 EFR turbocharger. Introduced in 2019 this is the biggest of Borg Warners high tech EFR line. It features a 91mm forged and 5 axis machined extended tip compressor wheel with a huge 73.7mm inducer. The forged billet wheel is inherently strong which allows the engineers at Borg Warner to thin out the blades and hub to improve the wheels aero. The extended tip helps build boost faster at lower shaft speeds reducing lag. This new compressor wheel flows 110 lbs per minute at a 117 krpm shaft speed with a laid over map with plenty of surge margin and wide efficiency islands. This is enough flow for more than 1100 hp. The 9280 is quite efficient, only 23 psi of boost is needed to make those 1015 whp!
If you were curious, the interesting looking megaphone is from the discharge of the twin 38mm Tial wastegates.
The 9280’s compressor housing has a 4″ inlet with a ported shroud. The ported shroud reduces the likelihood of potentially damaging surge by letting air bypass the compressor if the engines swallowing capacity is exceeded. The housing has provisions for a speed sensor as seen in use here and has an internal blow off valve to reduce engine room clutter and make for cleaner and more reliable packaging. The tan plastic cover on the discharge side of the housing is over the diaphragm of the internal blow off valve. Nice, neat and clean!
The 9280 has an unusual feature for a consumer based turbo, an alloy center section! This is the sort of stuff normally found in limited production hand assembled motorsports department turbos earmarked for factory works cars! The alloy center section will never look rusty and gross and saves a whopping 7 lbs off the total weight of the turbo. The center section also contains Borg Warner’s dual row ceramic ball bearing supported shaft. The frictional and viscous drag reduction of ball bearings can speed the spool of a turbo up to 15% over your typical floating sleeve bearings found in most turbos.
The exhaust side of the turbo uses another Borg Warner innovation, the Gamma-Ti or Titanium Aluminide turbine wheel. This material is one of the lightest refractory materials that can withstand the mechanical and thermal shock loads of a turbocharger turbine. The large 80mm turbine wheel has about 20 percent less inertia than a conventional turbine wheel which also greatly improves spool time. Another feature that improves response and reduces lag is the investment cast stainless steel twin scroll exhaust housing. Investment casting allow the turbine housing to have a less bulky profile and thus weigh less than your typical sand cast iron exhaust housing. In addition to not rusting, stainless has about half the thermal conductivity as rusty iron so the exhaust heat is used to drive the turbine and not heat up your engine compartment.
9 comments
Some very nice little details – I very much like the adaptation of the blade swaybar end to the splined bar, and the use of multiple batteries as not-technically-ballast amuses me. There’s definitely a feel like… about a well sorted car where there’s not much excess, which you would figure.
It’s interesting how some shops swear by using the latest in performance bearings for their rods or mains. And then there are the ones who check their clearances and successfully run stock bearings (not even WPC etc. treated).
In my experience a crank with too much runout or oval/worn journals is the main culprit of bearing failures, not the mechanical properties of the bearing itself.
I’ve even noticed that some performance bearings have less crush height than OEM ones, especially on Honda engines.
PS:
Using performance bearings in daily driven engine is also a recipe for disaster. They just don’t absorb contaminants as well, leaving them float around in the oiling system and grind away on your precious polished crank journals.
Great article Mike! The E46 has quite a long wheelbase (2720mm) relative to its overall external dimensions. The current Mustang is also in the 2720mm range. The BRZ (2570mm) and S15 (2520mm) are significantly shorter in wheelbase
The A90 Supra has a 2470mm wheelbase.
As horsepower and speeds increase in top level competitions do you anticipate more competitors moving to long wheelbase platforms for improved high speed stability.
Would the short wheelbase of the A90 Supra hinder it’s high speed stability to a significant degree? Is the BMW E92 Coupe at 2760mm.wheelbase the new benchmark platform for top level drifting?
I think the wheelbase sweet sport is around 100 inches.
The power steering cooler looks like a low pressure unit but it does not look like a CSF product… possibly a Setrab ProLine STD range cooler?
Curious as to why 6 speed transmissions are starting be the norm. I’m not aware of many tracks where a 4 speed would not suffice
Most sequential transmissions with enough torque capacity are six speeds.