[ira968]

When I bought my car six months ago it was bone stock except for a K&N air filter and Bosch Platinum II plugs. I was truly impressed with the engine performance at that time.



Since then I did the air box mod, a RS barn stage one chip, all new ignition parts and NGK iridium plugs -- everything went in at once so I never felt the difference each "improvement" made. The RPM hump was gone and I guess it did seem to run a bit stronger, but nothing that awfully noticable.



Last weekend I got the bright idea to go back to the Bosch Platinum II plugs that were in the car when I bought it --- WOW -- suddenly all that engine performance I lost, or gained, or whatever was there. It's hard to believe a plug can make such a difference in one of these engines. Honestly, my engine pulls so much harder and revs to redline so much quicker it's hard to belive it's just the plug.



Curious if anyone else has experienced this? For $12.00 I would fully endorse giving it a try!

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[flash]

that's very odd - possibly your iridium plugs were just tired - they don't last that long - i find i have to change them in less than 10k to get full performance



in general, iridium will outperform platinum, but platinum will outlast iridium - wire size does play into this though



there is a really good breakdown of how this works on www.sparkplugs.com

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[bob blackwell]

I am with Flash on this one, the NGK Irridium plugs improved my 968 performance after I replaced the Bosch plugs that were in before. Good luck, Bob Blackwell.

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[ira968]

My iridium plugs were new with less than 500 miles. They still look new and should as they are designed for 100,000 mile plus service.



If you switched from the OE copper plugs (or equivalent) to iridium there was probably an improvement. But if you have not actually installed Bosch Platinum II plugs you should as they give a BIG power boost in these engines versus the NGK iridium. I can't comment on the standard or platinum IV plugs as I have not tried either.



I have read a lot on the subject of plug materials and come to the conclusion that the only difference between iridium and platinum is hardness and life expectancy. Plug design is the real key. Bosch's thin wire, open air gap design clearly performs much better in my engine.

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[flash]

yes, the wire size is the key there - i haven't yet found a platinum plug with a wire as as small - i will have to look at the platinum 2 - i haven't even found them in a google yet



any chance you have a pic or source for a pic?



i'm always up for something that is better

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[flash]

never mind - went to the bosche site - saw the 2s and 4s - 4s would be something to look at for me, since i want maximum power - worth trying, but i'd like to see some data on the "surface gap" thing, in comparison to single electrode thin wire iridiums



easy way to try it myself though - i'll order some and give it a go - bosch has a money back guarantee if you don't see an improvement

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[ira968]

I can't speak for the platinum IV as I have only used the Platinum II design. Bosch claims the IVs are bigger and better, but who knows, maybe not in our engines? I have seen many on-line comments on the IVs (good and bad) but can't remember reading any comments on the IIs (people with 968s probably tend to go bigger and better for an extra $1.50 a plug).



The surface gap design makes sense to me from this standpoint -- when you look at the OE designed plug, with three ground electrodes, you see a very similar design to the Platinum II or IV. I would have to believe Porsche specified this design to Bosch for the 968 engine and not the other way around. The NGK plug uses a single ground electrode in what I would call a "conventional" design.



I'll be eager to hear other forum members comments if they try the Platinum IIs.

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[flash]

well, the 4 is basically a double of the 2 - so, if 2 is good, 4 is better would be my thought, which also seems to be bosch's thought - they list the 2 as "optimum" and the 4 as "maximum" in performace



i get the concept, and am willing to try it for sure



way too much gravity is given to the idea that porsche did things for performance reasons - there is actually a lot more involved than that in designing a car - i don't automatically assume that porsche made any decisions for any reasons other than economics when selecting many of the part for this car - they had a contract with bosch - so, they used their plugs - from a performance standpoint, there is a laundry list of inferior parts in this car - however, from an economic standpoint, and considering the intended buyer, they made sense at the time

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