Using Denzo Iradiam spark plugs? - The Unofficial BMW M5 Messageboard (m5board.com)

civic eater · 25th March 2007, 08:55

i was planing a trip to florda and my spark plugs were due to be changed so i went to buy the plugs and nobody cold get them in time ngk or bosh. the guy at the parts store sold me some denzo iradam spark plugs and assured me that these were comparible to the ngk. when i finialy replaced the plugs (took me 3 hrs.) i noticed that the factory ngk plugs had 2 tips and the new denzo ones only had 1 tip. have i down graded my using these $106 spark plugs? when i replaced the plugs i noticed a differance in power but my mafs were dirty at the time, and i have a feeling that the mafs messed up the air fuel mixture and has fouled the new plugs cause it acts like its a little donw on power again . should i remove these plugs and clean them or should i go drop another 100 somethig dollars and get the ngk plugs?

thanks for your help

robluvs2xlr8 · 25th March 2007, 09:10

Hmm...

When I got mine from the BMW parts dealer mine came with 4 tips

gherardini · 25th March 2007, 13:22

i'd take 'em back where you got them and tell them they they are definately *not* doing their job in a comparable manner despite the sales geek's assurances and to either give you the plugs you wanted in the first place or refund your money.

Need4Spd · 25th March 2007, 17:44

Quote:

i'd take 'em back where you got them and tell them they they are definately *not* doing their job in a comparable manner despite the sales geek's assurances and to either give you the plugs you wanted in the first place or refund your money.

+1 if you're unhappy and think it's the plugs. I seem to recall reading a thread here that concluded that our engines are sensitive to spark plug type and that to stay away from platinum plugs (the kind with 4 prongs), but that's just my faulty memory. Use the search feature and see what you come up with. IIRC, some have used iridium plugs with success.

6spd · 25th March 2007, 17:48

If you do a search for "Denso Iridium"(spelling) you can find the correct part number.
But if you installed new plugs and the car still ran bad, you have other issuses. Even a standard copper single ground electrode plug should run with no problems for 5000 miles in these engines.

$106.00 for plugs!

jaj · 25th March 2007, 21:10

As I recall it, anyone who's tried anything other than stock has eventually switched back. The stock plugs work best - if your local parts store doesn't have them then order them online or from a dealer. Four electrodes and made by NGK - BKR6EQUP.

Cheers
JJ

THRILOS5 · 26th March 2007, 02:39

Im using Denso iridiums for almost 2 years now and the beast is running better than ever

T-TRIM 540i · 26th March 2007, 02:58

I have been running them in My SC'd 540i since the begining and no problem producing a steady 440 WHP and 391 WTQ . AND I will be running them after the total rebuild and refit that will be more demanding on the plugs and I will let you know what the results are in about a month.... They are really well designed as far as I can read anywhere.....

mottati · 26th March 2007, 08:04

i ran denso irridiums for a year or two as well, no issues. Not any better, not any worse. As long as you have the correct part, i wouldn't worry about the plugs, but try to figure out your other issues. I think the 4 electrode thing is much to help extend the life of the plugs.

fwiw, i replaced my plugs today, got them from the dealer yesterday (bmw/ngk) for $8 and change per plug. I also replaced the little boots that connect from the coil to the plug, figure couldn't hurt after nearly 90k, for a couple bucks per cylinder extra.

Osodog · 26th March 2007, 17:31

Mike, do you get your supplies at Concord BMW? I need to pick up some oil for an oil change as I am about to head out on a drive to San Diego later this week.