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      02-24-2011, 05:43 PM   #61
Forced Induction FTW!
roninsoldier83's Avatar

Drives: E90 BMW 335xi N54 6MT
Join Date: Oct 2010
Location: Denver, CO

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Originally Posted by View Post
Most of these guys have a hard time getting their heads around closed loop timing which as far as I can tell is exclusive to the N54 platform. It's a complete game changer. This thread belongs on a Subaru forum somewhere.

Interesting concept... Please enlighten me sir. Fuel is closed loop under light accel/idle on all modern cars. This is done through the use of either a narrow-band or wideband O2 sensor(s) that constantly monitor AFR/lambda & adjust fuel accordingly in order to try and target around 14.7:1 AFR. These cars (N54/55) are unique in that they apply this basic function under heavy load/WOT... they have x2 WBO2 sensors last I checked, and an adaptive ECU/DME, that combined with a more detonation resistant DI design (injectors point almost directly at the spark plugs), it's no wonder that they're able to run such lean AFR's under load, or run closed loop fuel under WOT.

Fuel is fully closed loop on these cars, there's no debating that.... but timing? If this is truly your belief, please breakdown how you believe this "closed loop timing" works. No sarcasm intended, I would truly like to hear your theory.

Are you implying that the DME is constantly attempting to advance timing with no maximum load based values? If so, that would mean that running something like VP 110 (or any other designer racing fuel out there) would advance timing with no theoretical limit... and there would be no extra power to be made by advancing timing (manually/tune ECU for more timing) when octane permits (via race gas, meth ect) as the DME should constantly max out timing values based on knock input with no load based limits at any RPM... is that what you're suggesting?

If so, do you happen to have a technical write-up of some sort we could take a look at?

If not, well, '07 AP support and ATR will be out soon... I suppose I'll find out for myself
Current- 2015 Subaru WRX

Former- E90 BMW 335xi 6MT N54 - SOLD