Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Denso Plugs

Hey have you guys ever heard of Denso Iridium Spark Plugs? I saw them on ebay, and they guy said it'll give you 5-10 HP, is he full of poopy or what?

Originally posted by XTheTigerX:

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is he full of poopy or what?

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Most definitely...

i don't think you'll get that much horsepower from just spark plugs...and damn $10 a piece for plugs,no thanks...his ebay ad also says those plugs made 50 more hp on a honda race motor...o.k...i wouldn't reccomend those at all....

Changing spark plugs in a properly tuned engine will net 0 hp +/- 1, unless the old plugs were damaged or severely worn. In that case, you just get back whatever power the old plugs were robbing.

[yoda]Poopy man, he is yes?[/yoda]

Originally posted by PA 3L SVT:

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Changing spark plugs in a properly tuned engine will net 0 hp +/- 1, unless the old plugs were damaged or severely worn. In that case, you just get back whatever power the old plugs were robbing.

[yoda]Poopy man, he is yes?[/yoda]

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I don't get where you folks are coming to such conclusions. Whether based on Hypothisis, here say or even supposed engineering background, such claims are not accurate or true.

I won't even get into detail of why this is the case but you guy's need to stop making inaccurate claims. People here will believe anything they see, unfortunate the case!!!

There so much more to understand than you may think you know........

Well for what its worth..I recently had my ECU reflashed by 2 ex-Ford guys with 20+ combined years in the ford ECU tuning buisness (with dyno correlation for each tune) and the subject came up from a Cobra guy. What these guys said was that on an N/A/no nitrous car with streetable lvl compression they have never seen a plug gain more than OEM Ford plugs or autolites. And in many cases, power loss was evident.

Just repeating what I heard..because I feel these guys know what they are talking about.

You will see an improvement over bad plugs (like has been stated), but there will be no performance increase over new-ish stock plugs. Hell, even plain copper ones (which won't last very long).

The Denso Iridium's don't have double sided plating, which is needed for the rear bank (because they fire backwards).

A spark is a spark. If it starts a flame kernal, it's done it's job.

Originally posted by wattspxr:

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Originally posted by PA 3L SVT:

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Changing spark plugs in a properly tuned engine will net 0 hp +/- 1, unless the old plugs were damaged or severely worn. In that case, you just get back whatever power the old plugs were robbing.

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I don't get where you folks are coming to such conclusions. Whether based on Hypothisis, here say or even supposed engineering background, such claims are not accurate or true.

I won't even get into detail of why this is the case but you guy's need to stop making inaccurate claims. People here will believe anything they see, unfortunate the case!!!

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Show me a case of where two different plugs, both basically the same (heat range, gap, etc.) and from a quality manufacturer, have a significant performance difference. Data will make me a believer, otherwise I stick to my claim.

The statement was made basically that, "There could be no performance increase with 2 new plugs of the same heat range/gap!"

The fact is a performance increase can be had from one new plug to another depending on the motor and modifications. To simply state that this is not so is absurd!!! Put on a new copper plug with heat/gap same as a High Tech Plug like a Denso Iridium and there'll be definate advantages.

A spark is a spark is a spark. Once the mixture is ignited the spark is out of the equation.

Even professional racers in all types of racing use standard copper plugs.

Different alloy plugs (Platinum, Yttrium, Irridium for instance) are used for longevity purposes so you can extend the service intervals. They may last X times longer, but they do not make 1 iota of extra power from the engine.

I do agree certain makes of plugs work better then others in specific applications. Like a Motorcraft (Autolite) in a Ford product for instance. Champion in a Mopar and so forth.