I bought my P5 with 67k a year ago. I replaced the Champion plugs with NKG Vpowers of the long reach variety based on suggestions here, as well as the wires.
The Champion plugs were pretty black, and of course the new long-reach NKG's and wires made a difference, so I could not compare to good short reach plugs. Everything was great, except I did notice some knocking when going up steep hills sometimes; slight, but there.
One year and 13k later, I just threw new plugs in. I used NKG short-reach. The old plugs looked in very good condition, a bit of white residue, but pretty damn clean (not black, like the champions). After driving for a couple days, my impressions are these:
1) judging by my superb butt dyno, the car doesn't pull as hard. If I had to put a number to it, I'd say 5-10% less. Obviously that's highly inaccurate, but that's the feeling.
2) Idle is just fine. Obviously, the Champion plugs were trashed, and new long or short reach plugs would've helped out. I don't see a difference between the two.
3) No pinging! Lugging up a hill, not a peep. 'Nuff said!
So though I did enjoy the long-reach plugs, and do feel they added a bit, if only subjectively (hell, everything is subjective with these cars, how can something so low-rent and slow be so awesome?!); however, I'd like to avoid pinging, and so I will stay with the short-reach plugs.
The Champion plugs were pretty black, and of course the new long-reach NKG's and wires made a difference, so I could not compare to good short reach plugs. Everything was great, except I did notice some knocking when going up steep hills sometimes; slight, but there.
One year and 13k later, I just threw new plugs in. I used NKG short-reach. The old plugs looked in very good condition, a bit of white residue, but pretty damn clean (not black, like the champions). After driving for a couple days, my impressions are these:
1) judging by my superb butt dyno, the car doesn't pull as hard. If I had to put a number to it, I'd say 5-10% less. Obviously that's highly inaccurate, but that's the feeling.
2) Idle is just fine. Obviously, the Champion plugs were trashed, and new long or short reach plugs would've helped out. I don't see a difference between the two.
3) No pinging! Lugging up a hill, not a peep. 'Nuff said!
So though I did enjoy the long-reach plugs, and do feel they added a bit, if only subjectively (hell, everything is subjective with these cars, how can something so low-rent and slow be so awesome?!); however, I'd like to avoid pinging, and so I will stay with the short-reach plugs.
