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View Full Version : Denso Iridium Spark Plugs


weitau
03-21-2002, 02:39 AM
Are so much better that they are worth $14 each?Link to web merchant (http://shop.store.yahoo.com/racinglab/denirsparplu1.html)

I'm doing a tune up soon, replacing the Bosch 4 prong platinum plugs.  Anyone have any ideas?  thanks!

9591
03-21-2002, 02:54 AM
The advantage that platinum and iridium plugs have over "normal" plugs is that they last a long time. No performance gain (some people even argue that they give worse performance in certain situations, tho' I'm unconvinced). Why are you replacing your platinums? And on a related note, why'd you get those four-prongers in the first place? Dontcha know that the spark is only gonna use one of 'em at a time? Just go with good ol' NGK  (Nissan's choice).

weitau
03-21-2002, 03:29 AM
The car I just bought came with them.  I took one plug out, looked grey.  I have no idea how many miles are on them, and plugs are cheap to replace anyway.  1 prong=1 spark, 4 prongs=4 sparks?

9591
03-21-2002, 03:55 AM
Electricity takes the path of least resistance. You've heard that, right? It's true. One prong or four or two, there'll only be one spark. It's a nice sales gimmick, though, and it worked pretty well for Splitfire.

9591
03-21-2002, 04:10 AM
(I seem to be having a problem tonight with absorbing *entire* posts)
Spark plug color is an indicator of how the engine is running (grey is good), not spark plug condition. Not knowing how long they've been in use is *not* a good reason for replacing them. Just check the gap, adjust if necessary, and reinstall. If the electrodes look excessively worn (eroded), then replace them. Not likely, though, with platinum plugs.

burgy240
03-21-2002, 09:56 AM
What is the proper GAP and what does altering it do? <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/blush.gif" border="0" valign="absmiddle" alt=':blush:'>

diabolic hippo
03-21-2002, 11:36 AM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (9591 @ Mar. 21 2002,02:54)</td></tr><tr><td id="QUOTE">The advantage that platinum and iridium plugs have over "normal" plugs is that they last a long time. No performance gain (some people even argue that they give worse performance in certain situations, tho' I'm unconvinced). Why are you replacing your platinums? And on a related note, why'd you get those four-prongers in the first place? Dontcha know that the spark is only gonna use one of 'em at a time? Just go with good ol' NGK (Nissan's choice).</td></tr></table><span id='postcolor'>
i had irridium plugs in a 95 200sx with cai, n-1 exhaust, jw cams, and nos, overall it did not make a difference what so ever.

weitau
03-21-2002, 03:08 PM
OK, I'm beginning to form a theory here...
From the point of physics, you can light gasoline with either a match or a blowtorch. &nbsp;Either way, it's going to burn. &nbsp;Now if you're not getting a clean burn, then you're going to get uncombusted byproducts in the exhaust (ie. soot/smoke). &nbsp;So installing a new set of plugs will help out only if the plugs are bad in the first place. &nbsp;But so long as the new plugs are doing what they are supposed to do, all of them should work the same. &nbsp;Does this sound right?

Hmm, it was tempting to think I could get 3 hp from iridium plugs.

weitau
03-21-2002, 03:13 PM
So what about the distributor/rotor? &nbsp;I took a look under the distributor, and the electrodes had a powdery substance on them, which easily brushed off. &nbsp;but the electrode terminals seemed to looked intact. &nbsp;

Now the distance between the electodes and the rotor - is that a factor? &nbsp;If so, then to get the proper clearance, I should replace them, right?

Thanks! <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

TwinTurbo
03-21-2002, 09:12 PM
Bocsh platinums suck. They have a high failier rate. I fell victome to a bad Bocsh+4. Two of the electrodes broke off and and cost me a head in my Daytona turbo. I posted about it on another forum i belong too (MX6.com) and as it turns out many people have noticed cracks around the botom of the electrodes with only a couple thousand miles on them. I only had a little over 600 miles on my plugs new top end when it whent boom. So as far as the +4's go i cant stress it enough to just trash them.

As for worn plugs. Electricity travels on the surface and little deposits and bits of corosion that you might not even be able to see will affect the acuracy of the spark and will change the level of combustion. When a larger spark is created it egnites more fuel at once, causing a hotter and more powerful combustion.. Inside the combustion chamber the explosion starts at the plug and moves in whatever direction has the best A/F mixture. Hence the purpace of swerl or fast burn head desighns. So plug age ia a verry important factor in anny performance engine.......