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Complete n55 tuning
This is a nice update from shiv. I look forward to the future of the n55, wonder if one will ever keep up with me
We finally finished porting over v4 to the n55. This is not a "entry level" tune. I don't know what that is. Kinda like an "entry level" jockstrap. You either know how to protect your goods and you do so. Or you don't and cross your fingers.
So all the usual goods are functional: Timing control, Autotuning, Command Center, wastegate compensation, full diagnostics, code reading/clearing, in-dash gauges for boost/meth/afr, etc,.
A few things we've learned about the n55:
1) On pump gas, expect 340-350whp/370-380lbt-ft TUNE ONLY at 14-15psi peak. This is in line with tune only n54 engines. But unlike the n54, don't expect there to be another 100whp waiting to burst out with full mods and race gas/meth. The turbo won't support it by the looks of it. Judging by wastegate DC logs, I'd guess that the most we'd see after adding full mods and race gas is in the 380-390whp range. But i'd love to be wrong
2) A 340whp n55 with 7DCT feels about as fast as a 380whp n55 with 6AT/MT. The engine is always in the right gear and doesn't lose an ounce of steam between gears. Truly exceptional. Shifting manually results in zero throttle closure and aboslutely no loss of boost between gears. The only time you see a boost drop/throttle closure is when you let the transmissions shift itself at 7000rpm (see log below)
3) The new n55 DME has completely different knock control logic than the n54 DME. Namely, you can actually get the engine to knock audibly if you just raise boost and don't retard timing through the tune. So sloppy boost-only tuning will not work. And when the engine knocks, you can certainly hear it! So play with boost controllers at your own risk.
4) The n55 is more responsive than the n54, all things equal. Especially in the midrange where it will easily light up the tires in a 2nd gear roll on. Pretty amazing. There is less turbo so the reduction in lag is understandable. But the smoothness of the engine during these boost transitions is incredible. There really is something to Valvetronic.
5) Unlike other Valvetronic engines, there is a throttle body. But unlike in conventional engines, it works very differently. Don't be surprised to see the throttle blade fully open at idle once your car warms up. Pretty neat seeing it work the way it does to reduce pump loss/improve VE during different driving conditions. During the tuning process, I displayed CAN throttle blade angle on my oil temp gauge just to learn how the throttle blade worked in a traditionally throttle-bladeless Valvetronic engine.
6) The MAF sensor is different. Not only does it Frequency based, it also reads inverse. So low airflow reads high freq and high airflow reads low freq. The MAF plays a big role in the engine tuning. Lot bigger than I initially expected.
7) The ignition timing tables are different. In general, the n55 runs 2-3 degrees less ignition advance than the n55. I'd guess that most of that has to do with the better cylinder filling the Valvetronic engine provides.
More info to be posted early next week. This includes some tasty dyno results, pricing and availability.
2007 335i Coupe
Mods: Check the Garage