Quote:
Originally Posted by PrematureApex
That is just plain incorrect.
What "fail safes" are you referring to, and why do you think a piggyback would have anything to do with their functionality?
The stock timing control, knock control, etc. are all still in place with a piggyback. If anything, the flash tunes alter the stock, conservative timing curves.
Not that flash tunes don't have their benefits, or that I prefer piggies...but let's keep the facts straight.
A FMIC isn't gaining you power. It'll stave off heat soak longer, so you'll have your peak power more consistently. A DP on a tuned car is going to gain you somewhere in the 15 whp peak, but sometimes more significant gains in the midrange. I do agree it can be de-prioritized for many people though, as the tunes are really where the majority of the power is at. But DP gains are noticeable, for sure.
That's the thing. It's all E90 xdrive underneath.
It's simply a raised 335 xdrive hatch back, or a smaller 335 touring. It is not an SUV at all. It doesn't weight significantly more than a 335 xdrive sedan, and some models weight less, in fact.
In that sense, it made no sense for BMW to raise an E90 hatch a couple inches and call it a crossover. Thus, it actually makes a lot of sense to lower this car back down, unlike an actual SUV like the X3 or X5, imho.
Closest thing to the 335 touring that many of us want, and BMW never gave us.
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Hey man, check out this thread (I used to have a z435)
http://e89.zpost.com/forums/showthread.php?t=936224
great gains from FMIC and cobb dynos showing gains from FMIC
http://www.cobbtuning.com/bmw-n54-power-gains/
It's possible this is N54 specific info that I'm incorrectly mapping to N55.
Regarding piggyback vs flash tune, my understanding has been that piggyback is "tricking" the ECU by intercepting signals, so because ECU is not aware of the actual engine load, it can't advance or retard ignition effectively and it will only retard timing when the knock sensor detects something (e.g. piggyback can't alter fueling and timing at a very granular level). That's why BMS uses the "back end" DME flash (e.g. flash tune) in addition to the piggyback.
When i was looking into RB turbos for my N54 days, the ideal setup seemed to be combine both, such as cobb flash tune to control fuel, timing, vanos, and JB4 piggyback to control boost and methanol (with the methanol being the key trigger to add JB4)
I think for tune only, it probably doesn't matter between JB4 vs. Cobb, and the nuance matters if its a more heavily modded situation. I always would like to go flash tune whenever possible for the timing and fuel control (i.e. I am using EPL flash tune on my 996TT right now)
39xx lb car is too much for me, I get that it is a great car and does well to hide the weight. Even my 34xx lb 996, I am thinking about maybe converting AWD to RWD to get the weight down even lower
full disclosure, in my garage, the 996 (and F80 M3 before that) got the modding attention, the X135 continues to be a great (stock) family hauler.