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Discussion Starter · #1 ·
I am debating replacing my plugs again this weekend. I currently have NGK's in with about 5-7K miles on them. Car feels sluggish (although I suspect this is due to VANOS seals), and for piece of mind, I was contemplating swapping the plugs out again, but with Iridium plugs.

My questions are as follows:

1. who is using iridium plugs and what do you think of them?

2. what is the correct gap and heat range for our car (NGK's run @ 6 Bosch run @ 7)? I have seen gaps at .32/.8mm

3. does anyone understand crossreferencing on plugs? for example

bosch 4417 (+4) crosses with bosch 4503 (IR Fusion) which crosses with bosch 9604 (iridium). Does that mean that any of those would work even though they are not specifically listed for the car? I suspect that since 4503 and 9604 show up on Japanese car lists, they are probably gapped at .44/1.1mm and hence why they wouldnt work, but can anyone confirm?

4. How does the gap on a +4 plug work if some applications listed are at .44 and others at .32? Could this be why people have long term issues with the Bosch +4's? Or perhaps the heat range is the culprit?

5. what would happen if you used a copper plug?
 

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Discussion Starter · #7 ·
Car sounds like not maintained. Clean/reseal ICV, TB, DISA, MAF. Replace all fluids, filters, O2 sensors. definitely replace those vanos seals.
Thats all been done minus the vanos seals.

I just always feel that I need to be one gear lower than I should be. Especially getting on the xway....
 

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Thats all been done minus the vanos seals.

I just always feel that I need to be one gear lower than I should be. Especially getting on the xway....
Then change your damn VANOS seals already and enjoy the power being back.
 

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Discussion Starter · #9 ·
Then change your damn VANOS seals already and enjoy the power being back.
have you done it? I keep chickening out which is strange since I usually love projects like that. I have read the instructions so many times I could probably do it from memory. I think at this point in my life I am just afraid of getting halfway and getting stuck.
 

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Discussion Starter · #11 ·
I've done it. Many kids have done it also. It's easy. Just take your time and pay attention to what you're doing. Organization and cleaning up the mess is the hardest part
Mango - do you suggest changing the oil before or after?
 

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Spark plugs either work or dont. New ones are just as good as old.

Your problem is not in the plugs

Sent from my X10a using Bimmer App
 
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