short question: what brands&models do you use?
else read long story:
have some difficulties to choose correct spark plugs. having some performance issues, and i think my problem is weak/wrong projected spark.
my car is 146 1.7 16v boxer, but i think 33 and sud`s have the same
after engine rebuild gone 2000 km.
started with DENSO Q22P-U
plugs. they were perfect, had torque improvements at 2200 rpm and at 4000-6000 sometimes.
later i bought DENSO IK22
(iridium). i have LPG so platinum/iridium is more preferred.
and performance was lost with IK22. car accelerates flat, no torque increases (acceleration tests only with PETROL
i inspected IK22 visually, it seems a bit shorter (less projected) ~1 mm than Q22P-U.
taken from the engine both plug models are looking fine, white insulator nose, no fouling, so temp range is correct.
started to look after air leaks etc.. bought new genuine Bosch MAF
. situation is better, a bit smoother, but no fun acceleration.
will use Q22P-U again, and hope performance will be back, but.. what the hell are correct plugs for this boxer???
for me it is not problem to change plugs every month, if i will be forced to use nikels, but if to look something for longer period platina/iridium, i don`t want to spend money for bad choice.
so what do you use?
(from 2010 catalog):
Q22P-U (i have - ok)
IK22 (i have - lost some power)
PFR7B (colder for LPG?)
did not found any NGK cheap nikels.
shoud i make spark plug gap a bit smaller, like 0,7 for better performance?
changed two sets of new cable sets:
MAGNETI MARELLI MSK518
TESLA T812C (cooper wires, currently using)
(to be sure it is not the problem, but no difference..)
was BOSCH, now BREMI 11883
also have a bit shaky idle
.. tried to sinchro throttle bodies with no much luck for nice idle. cyl2 has a bit less compression (150 psi instead of 175 but it has extremely hard access, hope maybe i did not seal correctly..), will repeat compression test with hot motor, did only cold test.
was driving a few weeks with iridium (IK22). when starting cold had only 3 (sometimes 2?) cylinders working, had to wait max 1 minute for all 4 to dance.. now with new MAF seems a bit better startup, at least no stall, but still not perfect.
will see if Q22P-U eliminates missfiring.
that`s the story..