I really want to know why they aren't good for DSM, but they work the best on every other car. I've heard they don't work well on turbo or supercharged cars. But I just helped my brother with his car(GTP) and his car came stock with platinum. I just got NGK Platinum plugs(stock range) and I really don't understand why they won't work as well as coper plugs. Please anwser these questions.
Why are platinum plugs not good for DSM???
97GSTAT
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I really want to know why they aren't good for DSM, but they work the best on every other car. I've heard they don't work well on turbo or supercharged cars. But I just helped my brother with his car(GTP) and his car came stock with platinum. I just got NGK Platinum plugs(stock range) and I really don't understand why they won't work as well as coper plugs. Please anwser these questions.
I believe the main reason that although platinum lasts a lot longer than copper as an electrode, it actually isn't as good of a conductor. Thus, you have a slightly weaker spark, but much longer plug life. In most cases this slightly weaker spark will not affect the ignition of the af mixture too much, but as the psi rises, so does the risk of having the spark blown out and not having a properly ignited AF mixture increases. The platinum plugs work fine in the GTP because, among other things, the GTP runs 8-10psi stock, and most DSMers are running more than 15psi.
Do a search on the Talon digest archives. I'm sure Matt Blue, our very own digest NGK spark plug engineer, must have posted a discussion on that somewhere in the past.
Do a search on the Talon digest archives. I'm sure Matt Blue, our very own digest NGK spark plug engineer, must have posted a discussion on that somewhere in the past.
Well, I did a search on the digest myself and here's what Matt has to say :
I use the BPR6EVX (the Platinum plug) and I am very happy with them. Not only will the plug last longer, but it has better sparking characteristics. The center electrode is able to maintain a smaller diameter because of the
stronger material (Pt). A smaller center electrode lowers demand voltage (V necessary to spark across the gap). It also creates a more concentrated spark (i.e. more powerful).
So although the resistance is higher the lower voltage required to spark might offset it. Heh, looks like my previous post wasn't entirely correct.
Bottom line though, people seem to have had problems with the Bosch platinums, and most DSM users seem to have reported good results using NGK plugs.
I use the BPR6EVX (the Platinum plug) and I am very happy with them. Not only will the plug last longer, but it has better sparking characteristics. The center electrode is able to maintain a smaller diameter because of the
stronger material (Pt). A smaller center electrode lowers demand voltage (V necessary to spark across the gap). It also creates a more concentrated spark (i.e. more powerful).
So although the resistance is higher the lower voltage required to spark might offset it. Heh, looks like my previous post wasn't entirely correct.
Bottom line though, people seem to have had problems with the Bosch platinums, and most DSM users seem to have reported good results using NGK plugs.
Ok that makes me feel a little better. I just didn't want to spend $40, and not have the same or better performance as the stock plugs. And for some reason, like you said, the only PT that have had probelms are the Bosch, not the NGK. In fact I don't think I've ever heard anything about NGK PT's, good or bad. Anyways thanks again.
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Are dsm engines really spark limited? Looking at a reference guide, platinum is almost 6x more resistive than copper per unit length of the same cross-section, which is about as bad as iron(...) Put it this way, putting 1mm of platinum is equivalent of adding 6mm off copper wires (of the same cross section).
Plug manufacturers only plate the electrode with platinum so it's a very thin coating. So the overall resistance is miniscully different! (measured in milliohms or less!)
But we all are using BPR(6|7)ES plugs which already have a resistor built into the ceramic! Surely that resistor could be made smaller to compensate for the Pt so it'd be the same...
Aren't high static CR engines affected too? They should be as well.
I want to get down to the bottom of this for sure.
The alternate explanation is that the electrodes on specifically the Bosch platinums are tiny. In reality we don't want sharp points, they tend to discharge faster with poor heat distribution. Two dull, rounded, LARGE points usually is the best way to produce a visible, hot spark. Granted we don't have much space to play with in that tiny plug hole so we'll have to force more current through. However the driving force behind the spark is carefully controlled and strengthened (because of the ignition system), so even the sharp point issue really shouldn't be one. Maybe it is enough of a difference because it's much sharper than stock units. I don't know...
I haven't seen the NGK Pt's, but the Champion Pt's also are sharply pointed (look carefully?). Anyone got a picture? Hmm... I'll take a few macro shots of the plugs sometime...
Oh well, just some thoughts about this...
Plug manufacturers only plate the electrode with platinum so it's a very thin coating. So the overall resistance is miniscully different! (measured in milliohms or less!)
But we all are using BPR(6|7)ES plugs which already have a resistor built into the ceramic! Surely that resistor could be made smaller to compensate for the Pt so it'd be the same...
Aren't high static CR engines affected too? They should be as well.
I want to get down to the bottom of this for sure.
The alternate explanation is that the electrodes on specifically the Bosch platinums are tiny. In reality we don't want sharp points, they tend to discharge faster with poor heat distribution. Two dull, rounded, LARGE points usually is the best way to produce a visible, hot spark. Granted we don't have much space to play with in that tiny plug hole so we'll have to force more current through. However the driving force behind the spark is carefully controlled and strengthened (because of the ignition system), so even the sharp point issue really shouldn't be one. Maybe it is enough of a difference because it's much sharper than stock units. I don't know...
I haven't seen the NGK Pt's, but the Champion Pt's also are sharply pointed (look carefully?). Anyone got a picture? Hmm... I'll take a few macro shots of the plugs sometime...
Oh well, just some thoughts about this...
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What in the world did you spend 40$ on?97GSTAT said:
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platinum plugs can not be used on turbo-charged cars, am i correct? something about a difference in engine compression, and that platinum plugs shouldnt be used on cars with turbo.
Ive used Champion and Botch Platinums. The champions lasted longer then the Botch but shorter then stock.
Even though Botch will list theirs for DSM theit electrode is to small and cant handle the violent environment of our turbo cars. I experimented with different brands over a 1 year time period in which I was driving a lot. In TWO seperate cases the platinum tip actually fell out of the spark plug. I dont know about you but if you want metal floating in your cylinders use Bosh. And yes that one cylider was later tested at 25% less compression then the others. Champions electrodes seemed bigger which would account for them lasting longer.
Newbies: You will be told not to gap the platinums. You will feel a "gain"(which was really just a gap increase) on low end but once you hit 18 PSI your spark will start to misfire after 2-3k your car will idle rough and you will soon find that the "2 HP gain" that the Honda guys cheer about is advertising hype an plug gap; not to mention more like a 10+ hp loss as you car pulls timing do to misfirings.
Keep in mind Im talking about Bosh"platium" plugs not their "platinum +4". but shouldnt matter, as far as I know the +4 plugs are the same except that they have four prongs, someone correct me if Im wrong. Also I have not used NGK plats but concidering no ones(forget exceptions) using these on a street/strip car Im in no rush. Go with the "tried and True" method for DSM turbos NGKbpr6(and7), and be happy someone saved your cylinder walls from being Botched.
Even though Botch will list theirs for DSM theit electrode is to small and cant handle the violent environment of our turbo cars. I experimented with different brands over a 1 year time period in which I was driving a lot. In TWO seperate cases the platinum tip actually fell out of the spark plug. I dont know about you but if you want metal floating in your cylinders use Bosh. And yes that one cylider was later tested at 25% less compression then the others. Champions electrodes seemed bigger which would account for them lasting longer.
Newbies: You will be told not to gap the platinums. You will feel a "gain"(which was really just a gap increase) on low end but once you hit 18 PSI your spark will start to misfire after 2-3k your car will idle rough and you will soon find that the "2 HP gain" that the Honda guys cheer about is advertising hype an plug gap; not to mention more like a 10+ hp loss as you car pulls timing do to misfirings.
Keep in mind Im talking about Bosh"platium" plugs not their "platinum +4". but shouldnt matter, as far as I know the +4 plugs are the same except that they have four prongs, someone correct me if Im wrong. Also I have not used NGK plats but concidering no ones(forget exceptions) using these on a street/strip car Im in no rush. Go with the "tried and True" method for DSM turbos NGKbpr6(and7), and be happy someone saved your cylinder walls from being Botched.
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These are, from left to right,
Champion RN9YC (??? I think this is stock regular)
Bosch WR8DPX (Platinum, that inner electrode is TINY!)
Autolite 65 #1 (Regular)
Autolite 65 #2 (Regular)
These were actually in my car
Luckily the tips didnt break off, but will they? I can't believe they are so shoddy that they will break - and the same question is posed again, why aren't 10:1 compression engines having the same difficulty?
Now they're all BPR6ES's instead of these mismatches...
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