Iridum plugs for regular plug money

The only problem is that the Iridium plugs do not come with the screw on ends that are necessary to fit the Ferrari plug wire caps. They will probably work fine if you can get the ends. The PMR7A plugs do not have screw off caps so you can not use the caps from the old ones.

 

I've been using NGK Platinum D7EVX plugs for the last few years in my 3.2 Mondial. They have been discontinued by NGK and replaced by the Iridium plugs. I was also please with their price being $4.00 less than the platinums. NGK doesn't make a "7" heat range plug in Iridium so I got the DR8EIX plugs. It turns out the "8" heat range is what NGK recommends for the 3.2 engine. They've been in for a month now and seem fine.

Better AND cheaper? How un-capitalistic can you get!?

 

Why are the Iridums better? The only plug feature I'm concerened with is fouling. I've had best luck with Autolite in my Lotus; Bosch were good but I like the Autolite's better for my particular car. Would NGK's be any better?

Ken

 

Preventing fouling is the main benefit of the exotic small diameter center electrode plugs -- the exotic materials have higher melting temperatures so the electrodes can be made smaller causing them to run at a higher (more self-cleaning) temperature. There's also some mumbo-jumbo given about the higher charge density of a smaller electrode being somehow beneficial for initiating a spark (but I've never seen a real clear explanation). The pecking order is:

Standard (2.0mm diameter) -- NGK ES series
Palladium (1.0mm diameter) -- NGK EV series
Platinum (0.8mm diameter) -- NGK EVX series
Iridium (0.7mm diameter) -- NGK EIX series
(but the cheaper Palladiums are no longer available)

Really made a difference in my high-mileage carbed ex-308 -- took the fouling interval from a few hundred miles with a standard 2 mm diameter plugs to 5~10K miles.

I wouldn't like paying a dealer $15~$25 each, but for $6~8 each from www.clubplug.net why not try a set in your Lotus (they even show Lotus in their application table)? The photos show a 2mm diameter standard NGK ES vs the NGK EIX:

 

I have installed the NGK Iridium plugs in my 512TR about a year ago, and quite pleased with their performance. The factory specified Champions were only available at the dealer for big $$, and when twelve are needed.... over $300 for spark plugs was not acceptable. So, I was driven to find a better solution, and since the Iridiums are newer and better technology for significantly reduced costs, it was a "no-brainer". I obtained the NGK's from Clubplug.net, located in Canada, and shipping times are a little longer than normal.

Yes, the NGK Iridiums do not come equipped with the screw on end caps, but a trip to the local "Wally-World" and purchase 12 of the cheapest plugs($.97) that had the screw on end caps fixed that issue.

Because of the much finer and more highly focused center electrode, you actually get a more defined spark with higher energy, which enabled me to open the gap another .002in. Electricity always likes the path of least resistance, and the sharper the point, it is more likely that the electrical discharge will occur at the center point of the electrode, causing nearly all of the energy to be released in one large burst, instead of bleeding off onto the sides with the older and wider center electrode.

If you have the time, you can also "index" the plugs, which will focus/aim the spark energy right at the intake valves, which is where you will find the highest density of air/fuel, thereby causing more complete combustion. This is an old trick from the drag racing world.

Jeff, I must say a good job on the research for F355 spark plug wires and such. This type of research and information is quite valuable, and I would like to see more of this on Fchat. Sourcing these types of parts for cars such as the 512TR(and others) is important, because if you can find a pair/set of wires for the 512TR you are very lucky, and must have a fat wallet as well. We all know the dealership pricing on parts is way out of line. Keep up the good work !!!

 

Hi.............

Two questions:

1) What effect does an increase in plug gap of 0.002 inch have on combustion efficiency and/or plug life ??

2) Do you "index" plugs with changes in washer thickness; if so, must you change the installation torque ??

Frank............23005
www.masiarz.net/bb_resource

 

Use the factory plugs I just made the mistake of buying the NGK plus and they have the wrong reach and will produce the wrong combustion pattern

 

comparison
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Does anybody have any experience with the Bosch 4?

 

Tommy, only use NGK.

 

I haven't found any of the Bosch +4 plugs compatible with my 348, but I used the +4 plugs on my 95 Corvette and 86.5 Porsche 928, the former seeing a four hp increase in back to back dyno runs replacing new Champions with the +4's.

Frankly, the single grounds of Champions/AC Delco and NGK is/are century-old technology. It's a dated design.

I've used the Splitfire Triple Platinum V, the AC Delco, and the NGK on my 348 with good results.

Bosch's newest "Fusion" plat/irid +4 plug has perhaps the best new ground design, though. It's spark is fully exposed to the cylinder's air/fuel mixture...none of the spark is shaded by the center ground electrode of the older designs.
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Has anybody tired Densco plugs on a F355. One of the Japanese Ferrari website used them but the text was in Japanese so I tell why they were recommending them.

 

Four horses?? I think I may be needing plugs soon

 

If you want Iridium plugs for a 355, looks like Denso makes one that fits:
http://www.densoiridium.com/find_part.php
If you check their cross reference, the IU22 even crosses directly to the NGK PMR7A.

I have not compared the length or tried them yet, so YMMV.

 

I bought a 400i for my daily. Although the Champ plugs looked OK, I changed them to the Denso IW24 Iridiums, just because (I'm crazy). I am amazed at the improvement. I will be putting them in the Spider as well. I never thought a spark plug could make such a difference.

Also, Jeff and anybody else: I am thinking about changing the 400i over to electronic fuel injection. Can you recommend a controller. Something less than $1k. If it costs more than that I'll make my own. (Crazy, not cheap) Maybe an all in one unit so I can run cops and efi from the same box.

 

That sounds like very wishful thinking...

 

When you get the Denso Iridiums for your 355, please let us know if they are of the correct length (nose protrusion).

Thanks,
Dave

 

I was looking around and found a company called Haltech that makes a fuel controller in the sub 1k price range.

I'm not sure about the model, but their F10X looks like it has promise.

Also, does anyone know the K&N part number for 400i air filters?