Do Spark Plugs Make A Difference

[m3f_San Diego _b8e3666b37]

I was just reading about Denso Iridium Spark Plugs, are they as good as they are touting? Can you tell the difference between the stock Bosch and a "high performance" plug? Just wondering.

[m3f_Serious_eeb8859403]

NGK's are better then denso's or bosch. main difference is the smoothness at idle but you can feel it with good plugs in.

[m3f_shim]

good plugs will help your engine run smoother & better. especially with hot temperatures where other plugs can fail.... i would go with NGK or denso iridiums, a little better than platinum and much more consistent that copper

[m3f_Supabimma_cc72c2aa80]

i dunno if im mistaken but aren't NGK and Denso now the same company (i thought one bought out the other), thought i heard that somewhere

[m3f_AMPowerJ_e8f979e5cd]

NGK's are better then denso's or bosch. main difference is the smoothness at idle but you can feel it with good plugs in.



What makes you think that? :nixweiss:



I replaced my NGKs with Denso Iridiums and noticed a much better idle. Months later and after my car has not been started for over a week, it fires right up and goes into a smooth idle. Spark plugs definitely make a difference.

[m3f_riuster]

What makes you think that? :nixweiss:



I replaced my NGKs with Denso Iridiums and noticed a much better idle. Months later and after my car has not been started for over a week, it fires right up and goes into a smooth idle. Spark plugs definitely make a difference.



cause its new...both are iridium...Denso or NGK..doesnt matter..



Yours are NEW, thats why.

[m3f_Eric1855_e8e56eaefb]

The only difference you will notice in iridium plugs over platinum, over copper, is that you wont have to change them as much. On the same ignition system you wont have any noticeable difference between one plug and another so long as they are both properly gapped.

[m3f_cpm399_be3d0cdd14]

I was just reading about Denso Iridium Spark Plugs, are they as good as they are touting? Can you tell the difference between the stock Bosch and a "high performance" plug? Just wondering.



My independent BMW mechanic (He is a BMW specialist for the past 30 years and only works on BMWs)...Reccomends that you do not deviate from the plugs your engine was designed for...it will only harm your engine versus any improvment. And believe it or not, each engine year (same model) whether it be a 98 or 99 could potentailly reccomend differnent types of plugs...I have the 99 and it is reccomended to use the copper plugs. Now I am sure there will be a lot of disagreement out there....We all want to believe the "platinum is better" or nickel, whatever but I for one take my mechanic's experience and credibility over anything else. So based on these factors, I'd say you are waisitng your money going with any different type of plug.

[m3f_San Diego _b8e3666b37]

Well, I appreciate all the input, I do a major tune-up once a year (because I drive 30,000 miles a year, so, i need my plugs to last at least that long without losing performance.

[m3f_riuster]

The only difference you will notice in iridium plugs over platinum, over copper, is that you wont have to change them as much. On the same ignition system you wont have any noticeable difference between one plug and another so long as they are both properly gapped.



the only difference.



www.ngk.com



www.boschusa.com



take a look at their FAQs on platinum, iridium and cooper and then you might want to just EDIt what you said.



big difference

[m3f_badgtho_2cb87af10e]

My independent BMW mechanic (He is a BMW specialist for the past 30 years and only works on BMWs)...Reccomends that you do not deviate from the plugs your engine was designed for...it will only harm your engine versus any improvment. And believe it or not, each engine year (same model) whether it be a 98 or 99 could potentailly reccomend differnent types of plugs...I have the 99 and it is reccomended to use the copper plugs. Now I am sure there will be a lot of disagreement out there....We all want to believe the "platinum is better" or nickel, whatever but I for one take my mechanic's experience and credibility over anything else. So based on these factors, I'd say you are waisitng your money going with any different type of plug.





I would say that your mechanic is a typical old school type mechanic who believes stock is best, and that may be the case for some things. after all with a cautious approach often little is lost, however much can be gained from simple experiments. It is this fact that keeps the aftermarket alive. On some vehicles larger sparks can throw off computer controlled timing and such. In fords with an EEC IV for example, hotter plugs can have an adverse reaction on the ECU's ability to properly control timing. OBDII cars are much smarter. In the over 10 years since e36s were designed plug technology has advanced significantly. For the same reason as recalls and computer updates are so common for many cars, technology advances and improves.

[m3f_Eric1855_e8e56eaefb]

the only difference.



www.ngk.com



www.boschusa.com



take a look at their FAQs on platinum, iridium and cooper and then you might want to just EDIt what you said.



big difference



Yeah, I always look to manufacturer's publications for "unbias" information. They are trying to sell you something. You will not notice a difference. In multiple tests in race engines I have built in the past you will not see a difference between a copper or iridium plug. The only difference is the iridium has a longer duty cycle.



The basics is that a more powerful spark will create higher cylinder pressure which will create more power. The power of a spark is determined by its voltage, i.e. more voltage = more powerful spark.



The amount of voltage required to jump across the gap of a given type of spark plug is determined by the plug gap. A smaller plug gap requires less voltage to jump across the gap and a larger plug gap requires more voltage to jump across the gap. There is a way to reduce the amount of voltage required to jump across the gap of a plug. By increasing the number of sharp edges that the spark can jump from and to as in SplitFire plugs or by using an electrode material that is a better conductor than the standard steel, i.e iridium or platinum, you can decrease the amount of voltage required to spark across the gap of the plug. The only problem is that these plugs will produce a less powerful spark than a standard plug will at the same gap. This means that, as long as your ignition system can provide enough voltage to jump the gap on the spark plug all of the time, with iridium plugs installed in your car your engine will produce less power than it will with steel spark plugs. The only way you can regain the power lost with iridium plugs is to open their gap out farther which allows for more voltage and a stronger spark. But then you are just fighting to bring the car back to where it should be to begin with. Moral of the story? Stick with the specified manufacturer's plugs.



Want all those things that they say a plug upgrade gets you? Then upgrade your ignition system, wires, coils, etc...i.e. MSD box or Electromotive.



But take it or leave it, what do I know. I am just a degreed chemical engineer with a specialty in materials science.

[m3f_AMPowerJ_e8f979e5cd]

Yours are NEW, thats why.



Maybe plugs haven't made a difference for you all but I am telling you that they made a big difference in my car's cold idle. I have no reason to mislead any of you over this.



I had my plugs replaced at about 30K miles with OEM plugs and I had the rough idle immediately like we all talk about having. 30K miles later I switched to the Denso's and it went away completely. Maybe it was the gap or the temperature range or maybe because they are iridium but whatever it was it made a huge difference that I am not imagining.

[m3f_Eric1855_e8e56eaefb]

Replacing old worn out plugs with any plug will help smooth out your car. But new for new there wont be a difference. If you are having bad idle and rough running than your plugs are bad or improperly gapped, it is not because they are the cheap copper and not the iridium or platinum.

[m3f_AMPowerJ_e8f979e5cd]

Ok :nixweiss: Must be the gap then which means the gap on all OEM plugs is wrong. What else would explain a rough idle from the factory and it magically went away with different plugs?