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Discussion Starter · #1 · (Edited)
It's that time of year, and I'm debating what type of plugs to use for my upcoming change out. I was told by a friend of mine (non-VW) that he likes Denso Iridium plugs, but I wasn't sure if they'd fly on our setup. I tried searching but the large chunk of results I got were for V6 plug options and little that talked about Iridium plugs.

I know mine has NGK stock plugs in them right now, and I'm sure they work fine, but I want the best for my baby ;)

The Denso website listed these plugs as their recommended Iridiums for my engine: http://www.densoproducts.com/resultsSearch.asp?s=9&txtPartNumber=IK20
 

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If you want the best, stick with the stock NGK.
 

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And if you want to spend ridiculous amounts of money for peace of mind, get Bosch F5DPORs. They're the OE plug for the B4 S4. I've been running them since 40K miles. I'm at 120K now. Car always starts on the first crank. (FWIW)

Kenny
 

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Discussion Starter · #5 ·
And if you want to spend ridiculous amounts of money for peace of mind, get Bosch F5DPORs. They're the OE plug for the B4 S4. I've been running them since 40K miles. I'm at 120K now. Car always starts on the first crank. (FWIW)

Kenny
I'll check those out, I assume they're platinum?

Platinums and Iridiums are fine for working forever. My searching on those Bosch plugs led me to this link... http://forums.audiworld.com/a4/msgs/1541554.phtml

Which is the way I think. Copper single-electrode is the way I'll go.
Yeah, but replacing plugs every oil change? Seems like a lot of work for not a lot of gain? On a stock system would I really see that much of a performance boost? Maybe I misunderstood what he was saying.
 

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A spark is a spark. If you have a low-voltage ignition system (which VWs don't have), then the metal's ability to discharge electrons into the air will matter. Otherwise, the only difference between expensive spark plugs and cheap spark plugs is how long they last before they zap their electrodes to pieces.
 

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Be careful with spark plug recommendations not based on engine code. The DBW cars use a different type of plug than the cable-throttle cars.
More here: Triple-Electrode vs. Single-Electrode Spark Plugs

... get Bosch F5DPORs. They're the OE plug for the B4 S4. I've been running them since 40K miles. I'm at 120K now. Car always starts on the first crank. (FWIW)

Kenny
Good plugs, but they may be killing power between 6000 and redline. Not that many people would care. But I've run a lot of dynos recently, and the projected-tip, triple-electrode FR5DTC gave me consistent power all the way to redline vs. F5DPOR, which died dramatically after 6000.
http://www.passatworld.com/forums/showpost.php?p=1485408&postcount=51
http://www.passatworld.com/forums/showpost.php?p=1492448&postcount=64

A spark is a spark. If you have a low-voltage ignition system (which VWs don't have), then the metal's ability to discharge electrons into the air will matter. Otherwise, the only difference between expensive spark plugs and cheap spark plugs is how long they last before they zap their electrodes to pieces.
On general principles, yes; but with specific application, sometimes no. The overall design of the spark plug has a lot to do with this, see above. The cable-throttle engines seem to work best with the triple-electrode copper Bosch plugs. The DBW cars seem to work best with the single-electrode copper NGK plugs. No hard data, but I've seen a lot of spark plug threads on this forum, and that is my mental summary of all those threads. :rolleyes:
 

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And if you want to spend ridiculous amounts of money for peace of mind, get Bosch F5DPORs. They're the OE plug for the B4 S4. I've been running them since 40K miles. I'm at 120K now. Car always starts on the first crank. (FWIW)

Kenny

i have to disagree. those plugs are for heavily modified setups and a simple chip doesn't really constitute as a heavily modified car. i had them on for a while too, sure car ran fine but i later switched over to ngks, 1 range colder and the car ran with better results.
 

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Discussion Starter · #9 ·
Be careful with spark plug recommendations not based on engine code. The DBW cars use a different type of plug than the cable-throttle cars.
More here: Triple-Electrode vs. Single-Electrode Spark Plugs

Good plugs, but they may be killing power between 6000 and redline. Not that many people would care. But I've run a lot of dynos recently, and the projected-tip, triple-electrode FR5DTC gave me consistent power all the way to redline vs. F5DPOR, which died dramatically after 6000.
http://www.passatworld.com/forums/showpost.php?p=1485408&postcount=51
http://www.passatworld.com/forums/showpost.php?p=1492448&postcount=64

On general principles, yes; but with specific application, sometimes no. The overall design of the spark plug has a lot to do with this, see above. The cable-throttle engines seem to work best with the triple-electrode copper Bosch plugs. The DBW cars seem to work best with the single-electrode copper NGK plugs. No hard data, but I've seen a lot of spark plug threads on this forum, and that is my mental summary of all those threads. :rolleyes:
So if I have a 2004 (AWM? -- don't fully remember off hand) you're saying the Bosch triple-electrode FR5DTC would be the best plug?
 

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You don't have to change copper plugs every 4-7k miles. More like every 12-20k. Platinum and Iridium plugs can go 100k miles or more.

'Heavily Modified' can mean different things to different people. When you stop and think that the stock 150-170hp has changed to 200+ with the addition of a chip, along with different air/fuel maps and timing, and an extra 8-12psi of air pressure, that sounds pretty modified to me. ;)

But not as much as people might thing. The one range colder plug is always an idea for hotter-running engines. The big thing is how the plug performs with all of that extra airflow. Does the spark blow out?
 

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So if I have a 2004 (AWM? -- don't fully remember off hand) you're saying the Bosch triple-electrode FR5DTC would be the best plug?
NOnononononono... :) You have a DBW car. Use the factory-recommended plug, which should be an NGK single-electrode copper plug. PFR6Q IIRC.

You could try the triples, but I have no idea what the results will be.
 

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Discussion Starter · #13 ·
NOnononononono... :) You have a DBW car. Use the factory-recommended plug, which should be an NGK single-electrode copper plug. PFR6Q IIRC.
:rolleyes: I'm so confused... stock it is! :D

Oh, DBW = Drive By Wire? Not my actual engine code.
 

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Be careful with spark plug recommendations not based on engine code. The DBW cars use a different type of plug than the cable-throttle cars.
More here: Triple-Electrode vs. Single-Electrode Spark Plugs

Good plugs, but they may be killing power between 6000 and redline. Not that many people would care. But I've run a lot of dynos recently, and the projected-tip, triple-electrode FR5DTC gave me consistent power all the way to redline vs. F5DPOR, which died dramatically after 6000.
http://www.passatworld.com/forums/showpost.php?p=1485408&postcount=51
http://www.passatworld.com/forums/showpost.php?p=1492448&postcount=64

On general principles, yes; but with specific application, sometimes no. The overall design of the spark plug has a lot to do with this, see above. The cable-throttle engines seem to work best with the triple-electrode copper Bosch plugs. The DBW cars seem to work best with the single-electrode copper NGK plugs. No hard data, but I've seen a lot of spark plug threads on this forum, and that is my mental summary of all those threads. :rolleyes:
Hrm. I changed my old plugs a while ago; they were tri-grounded bosch plugs...maybe I'll pick up a new set and try them out if they don't cost too much.
 

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NOnononononono... :) You have a DBW car. Use the factory-recommended plug, which should be an NGK single-electrode copper plug. PFR6Q IIRC.
Yes, my AWM came with NGK PFR6Q plugs. NGK says they are "laser welded" platinum plugs. Since they are VW OEM they are explensive as hell at most places, whereas the superior iridium plugs for the same applications, NGK BKR6EIX, are pretty inexpensive. I'm thinking of giving them a try, but at 54K mi the stock plugs look great.
:cool:
 

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Yes, my AWM came with NGK PFR6Q plugs. NGK says they are "laser welded" platinum plugs. Since they are VW OEM they are explensive as hell at most places, whereas the superior iridium plugs for the same applications, NGK BKR6EIX, are pretty inexpensive. I'm thinking of giving them a try, but at 54K mi the stock plugs look great.
:cool:

i use the ngk iridiums w/o any probs since 42k mi. stock 1.8t
 

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(continues to think about what Rusty said)

You know, if the best spark plug is a plug that conducts electricity AND heat really well, so that it makes the hottest possible spark and yet can cool itself down enough to keep from pre-detonating the next fuel/air charge, then copper really is the only way to go; silver would probably be the absolute best plug ever, but I bet it's too soft to last even a few thousand miles.

I remember a few years ago my dad's company was hired to make a solar heat storage device for a satellite. It consisted of a block of carbon wrapped in a very thin layer of iridium, and when it got heated by solar radiation the carbon would melt and the iridium would hold it together. Furthermore, iridium is very good at releasing electrons from its surface without a lot of resistance. I wonder if a copper plug coated with a thin layer of iridium would last a long time and still allow the hot-spark/cold-plug effect that copper plugs have.
 

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I put Bosch Platnium4+ at 40 k miles. They have been working fine at 85k. I was wondering if I should replace them again since its been 45k miles. But the gas mileage is fine and the car starts on the first crank. So I am thinking I will wait another year and see what happens.
 
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