Further reading reveals that the turbo motor does not use the lightweight alu-mg block. So by my admittedly ghetto math, just going from the N52 in the 130i to the N54 gains 34 kg, which puts the 135i at 1484 kg without any of the upgrades which will undoubtedly accompany the turbo motor. . .
Quote:
http://en.wikipedia.org/wiki/BMW_N54
Surprisingly the engine block of the N54B30 is similar to the older generation BMW M54B30 engine - all aluminum with cast iron cylinder liners. This is due to the fact that the newer N52 aluminum-magnesium engine block was not deemed as suitable for turbo-charging with the above-mentioned engineering goals. As a result, the N54B30 is physically heavier (195kg/429lbs) than the very light (161kg/354lbs) N52 engine. |
335i. . .1600 kg
135i. . .1484 kg and counting
http://en.wikipedia.org/wiki/BMW_N52 N52 = 272hp stock Euro?
Call me crazy, but I
think I would prefer a valvetronic N52 with snappy throttle response tuned for, say, 300hp+ to a turbo N54 that weighs 75 lbs more and is a bit sluggish. Apparently the elimination turbo lag by using smaller turbos is still wishful thinking.
Quote:
http://www.bimmerfest.com/forums/sho...=165585&page=2
Quote: Originally Posted by LBV
Shiv - It may have just been me but when I test-drove a 335i I found it lacking in "snap" off the line or when tipping into the throttle while driving. Any idea as to whether part-throttle can be tuned for that?
In all honesty, when I got back in my chipped 330i the throttle was way more snappy. Then again, the 335i had less than 200km on it so the throttle adaptation may have been on the slow side. | Originally Posted by Shiv
BMW tuned the ecu to limit boost at partial throttle (ie, 1/2 throttle=1/2 boost). This is very unlike conventional turbo cars that can still make full boost at smaller throttle openings (esp. at high rpm). So there is a still bit more torque that can be extracted through tuning.
But some of the low RPM "softness" you feel is indeed boost lag. I think the hill assist also takes away a bit of "snap" upon take off as well (since it applies the brake once the clutch goes while the car is at rest). We did get rid of some of that low end softness through reworking the ignition table (the factory mapping is very conservative down there-- esp off boost). So yes, it can be improved. But no, it will never behave like a non turbo car. But I think that's a good thing when viewed wholistically |