There are two versions to choose from the OE one and the upgrade newer technology plug from NGK. I would recommend staying away from all the hyped plugs as BMW tend not to tolerate them.
IMHO I would go with the
NGK 6418 BKR6EIX IX Iridium Plug. As it provides a
non shrouded center electrode fine wire which tends to provide cleaner tip in acceleration and some fuel economy. Mostly you will feel a smoother idle and the step in acceleration off idle. The 4.8is came with these. I installed the multiple side electrode versions and noticed the idle quality drop off compared to the 40,000 mile old fine wire. I switched back to the Iridium ones and the idle quality came right back on first fire up.
Gapping
Since the gap size has a direct effect on the spark plug's tip temperature and on the voltage necessary to ionize (light) the air-fuel mixture, careful attention is required. While it is a popular misconception that plugs are pre-gapped from the factory, the fact remains that the gap must be adjusted for the vehicle that the spark plug is intended for. Those with modified engines must remember that a modified engine with higher compression or forced induction will typically require a smaller gap setting (to ensure ignitability in these denser air-fuel mixtures). As a rule, the more power you are making, the smaller the gap you will need.
- See more at:
NGK Spark Plugs
Gap setting .032"
Everyone will chip in with other options I am sure.
__________________
2005 X5 4.8IS
The
Blue ones are always FASTER....
Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green