I've posted a couple spark plug threads in the past but I figure it's time to post an Unofficial Ultimate Spark Thread here, and sell some spark plugs.
I'm going to try to recap a lot of the information from other threads in this one to avoid the necessity to search amongst them all. but feel free to ask a question and I'll answer it the best that I can. Others should feel free to chime in, as long as you know what you're talking about. If you don't, just read or ask.
Generally our OEM plugs are multi-electrode, and I don't like multi-electrode plugs. The theory behind them is that as one part of the center electrode starts to wear, a different side electrode will fire because it will be closer than the side electrode than has worn down the center electrode. This will help with longevity. I'm more of a performance guy, so I would prefer to not try to squeak every last mile from my plugs. Here's a picture to illustrate a side and center electrode. I'll include pictures of the actual plugs below.
Lets start with the most common plugs for our cars, and my recommendations for most M50/52 & S50/52 engines.
NGK BKR6E - $1.83 - Copper plugs from NGK's V-Power line. These plugs will give excellent performance, but should be changed more frequently than Iridiums. I run this type of plug in my daily driver (see sig).
NGK BKR6EIX - $7.22 - Iridium plugs from NGK's Iridium IX line. These plugs will give excellent performance and long life, they will last longer than standard copper plugs. Copper plugs will produce better performance, although probably not noticeable, even by me.
Denso IK22 - $9.74 - Premium plugs from Denso's Iridium line. These plugs will produce excellent performance and long life. They are expensive, and I have never heard a complaint from anyone who has used them.
Below are some other plugs that some have had good results with. Because I've seen mixed results with these, I generally do not recommend them. But if you know that your car likes them, here they are.
Note: I'm not saying that these are bad, but some cars do not like them even if they are OEM plugs.
NGK BKR6EQUP - $7.96 (4 prong)
NGK BKR6EK - $4.64 (2 prong)
Bosch F7LDCR/FR7LDC+ - $4.04 (2 prong)
Bosch FGR8KQE - $5.87 (4 prong)
And of course a Bentley Repair Manual if you don't have one.
If you have any questions or aren't sure which plugs to go with, just ask.
Spark Plug Gap
The gap of a spark plug is the distance between the center electrode and the side electrode. The gap is only adjustable on the single prong plugs using one of the two tools below. The plugs listed above come pre-gapped at .032", which is the correct gap for our cars.
FI guys may want to use a colder temperature plug, and may want to close the gap a bit. This is done so we don't overheat the plug. But because our coils still produce the same amount of spark, we need to close the gap to ensure that our plugs fire when they're supposed to. If the plug gap is too wide it can cause a misfire, if the gap is too small it can cause pre-ignition.
Here are two images of the most common type of spark plug gapping tool, and how they are used. I like to re-check the gap when installing, but it isn't necessary since these come pre-gapped to the correct gap. The tool can normally be found for $.99 at an auto parts store.
Note: Do not use the edge of the gapping tool to open the gap. Use the smaller circle labeled ""GAP OPENER" to do that.
You need 6 plugs for an M50/52 or S50/52.
If anyone sees a mistake, feel free to correct me. I have no problem editing the post to clarify or correct information.
Cliffs Notes:
Best Copper plugs: NGK BKR6E - $1.83
Best Iridium plugs: Denso IK22 - $9.74
Good Iridium plugs with a slightly better price: NGK BKR6EIX - $7.22
To order the plugs please click the image below and enter the part number. Then click go and take it from there.
Last edited by ParadigmGuy; 12-04-2007 at 11:09 PM.
K
I bought Denso Iridiums from autozone a year ago and 5 of them were not gapped correctly (all were wider than the .32)
I suggest checking the single prong plugs just to be certain.
ESS 625RAGE AGAINST THE MACHINE
Nice. Clear and concise w/o a lot of techy mumbo jumbo. I need to do plugs soon, for your efforts you should be getting my business.
so are the NGK BKR6E - $1.83, the best plugs to buy performance wise (and they are the cheapest!) ?
I've seen the copper plugs are even said to improve power in FI cars beings they pull heat away better than other plug types. Either way, I've read a number of places to change them every oil change for the best performance.
what have you heard about the NGK BKR6EQUP?
Did you buy IK20's or IK22's? IK22's are gapped to .032". IK20's are gapped to .044". Some places will list IK20's as the right plugs for our cars. Although they'll work, they're hotter than stock and the gap is too wide. I.E. you won't see the performance benefit of spending the extra money on them.
Thanks, sounds good.
Yes.
I change mine about every 4K miles. But I don't think that's necessary for the majority of cars (i.e. not FI).
Some people (and their cars) like them, some do not. I ran them on my car when I was NA and it didn't like them. They are designed more for longevity than performance.
Do you still have to gap the 4 prong sparkplugs? / how?
Paradigm Guy, so you run the BKR6E on your FI M3?
#71 SM
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Excellence is a habit, not an act.
very nice.. thanks for the info!
-M3J0N
great write up, i'll be ordering some from you soon
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ParadigmGuy: Thanks for superb thread. Oh, I finally got the Extreme Motorsports SD Checkout system to work for me. Excellent service with fast shipping. Highly recommended!
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...And if you need kurt to tell you this, step away from the BMW.... do not attempt this yourself
Good thread Kurt, GREAT info.
FWIW... I am running the 6equp's. I decided on them after doing a long search on the e36m3 forum. It seems that these are (were at the time) the hot plug to get. It seems as though when a person says something is great, everyone wants to jump on the bandwagon..... when they say something sucks, same deal.... all aboard the bandwagon. (witness the whole crank pulley scramble of '04, the seafoam extravaganza of '07 lol)
Last edited by xjeeper; 10-24-2007 at 05:40 PM.
1/4 mile in 13.1 @ 106++ (calculators put this at 0-60 in "4.21" seconds.)
NGK BKR6E - $1.83
you selling these pre-gapped? And the difference between what I am running and these are what now?
Thanks..
1/4 mile in 13.1 @ 106++ (calculators put this at 0-60 in "4.21" seconds.)
I have the NGK V POWERS in my 98 M3. Does anyone else have these???
First car:Avus1993 325is Second car:Titan.Silver 1998M3 Current car:Cosmos 1999M3
Let's just say that the question has been PM'd to me more than once.
Makes me laugh, but it's OK. Everyone has to start somewhere.
I even tried the QUP's myself back in '04 before I went turbo. My car didn't like them though.Good thread Kurt, GREAT info.
FWIW... I am running the 6equp's. I decided on them after doing a long search on the e36m3 forum. It seems that these are (were at the time) the hot plug to get. It seems as though when a person says something is great, everyone wants to jump on the bandwagon..... when they say something sucks, same deal.... all aboard the bandwagon. (witness the whole crank pulley scramble of '04, the seafoam extravaganza of '07 lol)
Yeah, my web guy was working on the spacing issue before the fires came rolling through SoCal. I haven't heard from him in the last few days though. He lived on one of the areas that was hit the hardest too. I'll try to get the spacing fixed soon though.
Yeah, the come pre-gapped at .032"
The BKR6EQUP's are "Laser Platinum" plugs and as you know are 4 pronged. They're great for longevity and would do just fine in most daily driven cars. But they aren't performance plugs.
The BKR6E's are single electrode copper plugs. They're more oriented toward performance, and won't last nearly as long as the QUP's.
The BKR6E's are V-Powers, there are a lot of people running them. How do you like them?
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