spark plugs
 

i have a 3.5 litre Nissan Altima and need to change the plugs and wires. I want the best performance but here contradicting theories on what plugs I should run. Motorheads of the TFP please give me your thoughts.

My understanding of spark plugs is that those with multiple tips generally won't give better performance. They'll just last a bit longer.

I don't think fancy colored wires will improve performance by themselves, either.

I am asking more about platinum verses irridium

also as far as the wires go, can you get a wire which is too efficient for a stock application?

No, you can never get too much power to the plugs. Platinum pugs will probably be just fine, I can't see the irridium plugs really being a necessity, and don't bother with multiple electrode plugs, they are a gimic to lure the unsuspecting.

wow, mm, you start out making very good sense, then completely lose it with respect to the plugs, vis-a-vis multiple electrodes.


rider, with respect to the plug material: platinum is pretty much standard, has been for about 5 years or so on OEM plugs. platinum plugs will last anywhere from 60-100k miles, as long as no other problems exist in the engine that can damage the plugs. irridium is something new to the market since I've worked in the biz. I dont know much about it, but Id bet that unless your are looking for the ULTIMATE in performance, cost be damned, then I'd say platinum is the way to go. do not settle for anything less than a plug which has platinum on both the center wire and the side electrode.

as for the electrode configuration, multiple electrodes expose more of the flame kernel (ie the initial flame that is created by the spark) to the fuel-air mixture than do standard single electrode plugs. go into any parts store and ask to see the brochure they most likely have for Splitfire or Bosch's Platinum+4 (4 electrodes) electrode plug. There is a picture in one of these (cant remember which) that shows very simply why multiple plugs is more fuel efficient. simply put, multiple electrode plugs burn more of the air-fuel charge with each fire, thereby producing more power without using more gas. more power with each plug fire means better fuel economy. in the long run, multiple electrode plugs MORE than pay for themselves in gas savings.

as for plug wires, as long as you meet or exceed OEM standards, you are fine. and as mm said, NO, you cant deliver too much power to the plugs. what you are mostly paying for with expensive wires is either long lasting materials or (for performance geeks looking for every last hundredth of a second in the 1/4 mile) the most amount of energy that the wires can deliver to the plugs (ie least electrical resistance). basically any of the name brand wires will do you fine. hell, even most of the super cheapie brands are as good or better than OEM. just look for a lifetime warranty and you can pretty much forget about them for as long as you own the car.

Sion:

Are you suggesting that multiple-tip plugs will have the electric current arc at both tips instead of just one of them?

under PERFECT conditions multiple electrode plugs might spark at 2 MAYBE even 3 of the tips. As soon as any engine conditions are less that absolutely perfect, one of the electrodes will be of least resistance, and that ONE will get teh spark. Pull out a mutli-electrode plug and spit power through it. You will see it only sparking to one of the electrodes, maybe even two. They will alternate the electrode which gets teh spark, but basically never will they spark to more than one tip. Unless its a rotoary engine which uses special mutli-electrode tips, they are pretty much a gimic for those who dont understand that electricity goes to the path of least resistance, rather than all the paths possible.

Peryn:

My thoughts exactly!

multiple tip plugs are not designed to have multiple sparks. that is not the point of them. yes, the spark will travel the path of least resistance to only one of the tips. it is the fact that the spark is more exposed to the air-fuel charge that is their unique advantage. thus you get a larger flame kernel which results in more of the air-fuel charge getting burned with each spark. the result is more power and better fuel efficiency.

I have always been told that good old solid copper electrode plugs out perform (from a resistance standpoint) all other plugs on the market. I have run them in every car I have every owned and have never had a problem, nor did I see any benefit the one time I did spring for platinum plugs.

platinum actually is more cinductive than copper...

True, but "Platinum" plugs are actually just steel plated with a layer of platinum, so you gain nothing. Remember, the area of highest resistance determines the overall resistance of the circuit.

first off, the biggest advantage of platinum as a material for spark plug electrodes is that platinum does not degrade nearly as fast as copper over time. also, platinum plugs have better "self-cleaning" properties. (I know this not just from the promotional materials that Bosch, et al put out, but from personal experience. I had a vehicle that needed new rings, but since it was just an old work car, I had no intention of rebuilding the engine. so I put in a set of Bosch platinums. Previously, I had been using Champions standard copper plugs. They would last about 3 months before becoming so oil/soot fouled that the car wouldnt run. With the Bosch platinums, I got 18 months out of them before finally unloading the car. I pulled one out just before I got rid of it, just to see how it looked. While most of the plug was filthy and fouled with soot, the electrodes (both the side and center) were clean as if I had installed it the day before. Convinced me.) it comes down to the fact that platinum plugs last longer than copper ones. by a factor of about 2 or 3 to 1. ever seen a copper plug that can last 100,000 miles? I havent, but that is commonplace with platinum.

secondly, if the platinum coating runs the entire length of the electrode and fully encompasses all the steel within, then your point about resistance is meaningless. the current will travel through the platinum coating, completely bypassing the steel and its heavier resistance. now, if the platinum only coats the tip, then you would be correct, as the current would of necessity have to pass through the steel first. for reasons like this, it is good to know the exact design specifics of a product. some plugs with platinum electrodes do indeed coat the entire electrode, while others only add it at the tip. but, as I said above, conductivity is NOT the reason to use platinum plugs.

Very good points (no pun intended), but they also cost 2 to 3 times what a CU plug does. I guess it comes down to convienience at that point. I change mine once a year regardless, so to each his own.

Your best bet for plug replacement is what the factory recommends. Multiple electrode plugs are worthless, although if that's what the factory calls for (some VW and Audi are this way), then go ahead. Either way, I'd buy a OE plug. Meaning, your Nissan would get Nissan part numbered plugs. My GM's get AC plugs usually, although this last time around, I threw NGK's in the Pontiac.

Biggest benefit of multi-electrode plugs if the car doesnt require it is that pretty little lightning bolt they print on the package...

I've seen a lot of people (particularly ricers) spring for the multi-elec. plugs to compensate for their own stupidity, particularly when they throw a plug in without gapping them, causing a miss. One of the best excuses I ever heard was from a "friend" back in high school, who put in a set of the multi-elec plugs and told me "that his cold air intake made him too much power to use regular plugs, and that his motor wouldnt run unless he used the multi-trode Boschs." He had his old plugs in the car, and I took a peek at them; gaps were so small and inconsistent I can't imagine a car being able to run with them.

Don't waste the money, nothing hurts like dropping 40 bucks for plugs (have to for my rx7).

How exactly is the spark more exposed? You still gap multi-elec. plugs to the same specs as single elec. plugs, so the spark's not gonna be any longer at all. The plug is sitting down in the fuel/air mixture whether you have multi or single. The rate of burn of the mixture is determined by the octane of the gasoline and the oxygen content of the air, not the length of the spark (which is consistant across plug types anyway assuming you gap them properly).

Multi-electrode plugs are BS. You're getting the same result that you do out of regular plugs, but you're paying more to be ripped off- - - after all, why wouldn't the companies tell you about this advantage in their advertisements if it were true rather than basically flat out lying about the plugs? (showing sparks coming off all 4 electrodes is plain and simple false advertising since it will NEVER happen in real life)

Yeah those NGK plugs for the rx7 hurt a lot to buy. But they last a long time. Replaced some a little while back...look like the original plugs from 100k miles ago. Expensive, but they still last quite a while. Plus most people freak out seeing those and not knowing what to do :D

You guys that say that multi-electrodes are not good...

If the spark always travels least resistance to only one electrode...are you not getting a better chance of getting the best spark possible by having four times the electrodes with only the best sparking? By the way thank all of you for your input!!!

I buy pre-gapped Champion single-prong platinum plugs for my 928. They perform very well for me. OEM are Bosch of the same type, but they were out of stock when I went to buy them.

As for "getting a better chance of getting the best spark possible" it's a matter of gapping the plugs correctly. If you can gap a one-tip plug properly, you shouldn't have to worry about gapping 4 tips. If you can't gap a one-tip right, well, good luck on getting a 4-tip right.

1) Buy platinum. Iridium is another gimmick

2) Buy single prong. Multi-prong is marketing ploy.

3) Spend the bucks to get quality plugs with the above features. It's cheap insurance.

As many people have said, platinum is wonderfully long-lasting. I was stunned at the difference in durability when I put my first set of platinum plugs in. I had a 302 that tended to run rich, thus causing the plugs to foul quicker. I tended to replace every other month due to the carb probs I was having. When I went to platinum, I did not have to change the plugs again (vehicle was totalled about 9 months after the plugs were last changed, thus the "ever again" comment). I've run nothing but plat-plugs since and have been wildly pleased with them.

Pure electrical theory tells me that multi-prong plugs, especially those silly Splitfires, won't work. Normal electricity produces one arc only in the situations arising within your engine. One, period. When you see pics of multiple arcs, it is because the arc is 'jumping' too quickly for the eye to process. What you see as multiple arcs is nothing more than retinal afterimage.

At first blush you would think so, but you have to look at what's really happening to the spark plug over time. The electrode with the path of least resistance is the one that's going to be used. The other three will sit there doing nothing but getting crap on them from the less-than-100% combustion in the cylinder. In other words, by the time the one electrode is fouled (has too much crap on it to fire properly) the other electrodes are fouled as well. Time to replace the plug.

I think the new plugs are more for longevity than performance. I would just buy new oem plugs and spacers to dial in the plugs to face the center of the cylinder. This way the spark is facing the air/fuel mixture.

Uhm, a 3.5 L Altima (2002/2003) and you NEED to change plugs and wires?

Maybe you meant you WANT to change the plugs and wires.

Unless you have very, very, special circumstances, there is no reason to change the OEM setup with performance improvement in mind. If you think you will see performance gain by means of a switch of sparkplugs or cabling on this engine, you are in for a surprise.

Things could improve somewhat if you had a '67 <insert your favourite muscle car manufacturer here> stored since '76 AND still holding the original plugs and cables...AND in need of a tuneup, but spending $ on plugs for a Nissan VQ30DE? :rolleyes:

There is a LOT of marketing money behind fancy plug advertising. For every single set of "advanced" plugs, cables, intakes, tinted bulbs, exhausts, pads, wings, scoops & you-name-it thing sold out there, there are hundreds of accountants laughing all the way to the bank.

Do not believe everything you read & see.

Buy some music with the money. Spend it with the GF on a good time.

:)

I've still got the original wires on my '85 928....the insulation is beginning to degrade a bit, but performance is still great.

I'd replace them, but the price is ridiculous....$300 from 928-dedicated vendors (and much higher at local auto parts stores).....for OEM 7mm wires and connectors on a 8cyl car!

Since my wires are 18 years old and still work, I'm shocked that a 2002/2003 model car would need new wires already.