[Greimann]

I saw a good deal on the Bosch Platinum +4 plugs so I thought I would try a set. After about 1/2 hour of running around. The car started to stumble and buck off the line. It gradually got worse to a bad idle. Back in went the NGK Iridiums and all is well.



Anyone else have problems with the Bosch +4's? I had a good look at them and measureed the "gap" with drill shank. Turns out they have a non-adjustable gap of about .060. The stock spec for the 968 is .032. Presumably to fire reliably in the high compression.

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[Eric_K]

I've used them before with no problems. I wonder if you got the wrong ones or something?



Eric

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[Greimann]

I double checked the part number and it is good. I did a search and peoples results have been inconsistent. Some have problems, and some run just fine.



Plug Wires are new and the pine tree air freshener is still in the cellophane <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" />

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[Bart]

FWIW



A friend of mine owned a import shop until recently and he "repaired" many cars that came in just by pulling out the platinum plugs and replacing with non platinum plugs. He wouldn't put them in any car he worked on. From what I recall it was platinum plugs in general and not a specific brand.

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[flash]

in general, platinum plugs are great for mileage, but lousy for performance



i bought into the hype a few years ago, and had similar issues too, though i never tried them in anything buy hopped up cars, and only a few before i gave up on them



i read something about proper applications (might even have been at sparkplugs.com) that said these were not the best idea for high compression hot burning engines



for this car, the iridiums have been the best thing i've found so far, and certainly a better performer than the stock copper

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[Spieln968]

I am running the +4's and do not seem to have a problem. However, I too was told by one of the parts houses (can not remember which one now) that Porsche's do not like the platinum plugs. I was going to try the NGK's next time to see if it made any difference.

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[jeffm40]

You can't go wrong with the Irridium plugs. They burn hot, never heard of a problem, however, more and more people are complaining about the performance (or lack there of) of Platinums.

Thanks for bringing this issue up again

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[Cloud9...68]

I have Bosch Platinums in mine, and I haven't had any problems, so it must be a hit-and-miss thing. From all the comments, I think I'll go with the NGK Iridiums next time, though.

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[Tom in Austin]

Anybody have the NGK Iridium part number on hand?

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[Greimann]

[quote name='Tom in Austin' date='Feb 24 2006, 08:27 AM']Anybody have the NGK Iridium part number on hand?

[right][post="16502"]<{POST_SNAPBACK}>[/post][/right][/quote]

6637 BPR6EIX



Here is a page at sparkplugs.com

http://www.sparkplugs.com/results_app.asp?...=1&AAIA=1263776

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[Harvey]

[quote name='Greimann' date='Feb 23 2006, 08:26 PM']Anyone else have problems with the Bosch +4's? I had a good look at them and measureed the "gap" with drill shank. Turns out they have a non-adjustable gap of about .060. The stock spec for the 968 is .032. Presumably to fire reliably in the high compression.

[right][post="16483"]<{POST_SNAPBACK}>[/post][/right][/quote]



I had them in my '85S 928 32V and it missed...so I took it to a 928 specialist in Seattle thinking something bad was wrong and he took them out and tossed them and put in stock plugs....missing went away.



Harvey

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[gryphon]

I've been using the Bosche Platinum+4 plugs for about 1000 miles with no misfire, but I wonder if they are the cause of my lower fuel mileage than other owners, namely about 15 mpg. This is a combination of city and freeway miles, but no extended trips yet.



Tom

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[jaap]

IS this the same as the Bosche super 4? I think the OEM plug (bosch super?) with the 3 leads is no longer made and bosch recommends the super 4 as it replacement.



Jaap

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[Greimann]

[quote name='jaap' date='Feb 24 2006, 02:19 PM']IS this the same as the Bosche super 4?

[right][post="16515"]<{POST_SNAPBACK}>[/post][/right][/quote]

There is no Super 4. There is the +4 and the super: http://www.boschusa.com/AutoParts/SparkPlugs/

The super is the single electrode copper core and that should work fine. The old 3 prong Super had the proper gap (.032) preset and one would presume the single electrode versions would be the same or could be set.



The problem with the multi-electrode is the gap is preset and can't easily be reset. The +4's have a gap of .060 and in some instances that is too big to fire in all conditions. It obviously varies from car to car. Like any spark, static or lightning, there is a threshold of energy that has to be crossed before the spark will jump. If the gap is too large, the spark won't jump all the time, but when it does, the fire is big. If the gap is small, the spark will jump reliably, but the fire will be smaller. The trick for maximum power and economy is to maximize the gap while having fire each and every time.



Porsche says .032 is good and that works for me.

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[jaap]

It seems Bosch has a different range in europe compared to the US. Here we have the super 4 ( http://www.boschautoparts.co.uk/pcPlug4.asp?c=2&d=1 ) which seems like older technology then the platinum. I am not sure what the gap is on these. I already bought them so will give them a try and if they don't run very well maybe switch to the NGK (if they are available over here)



Jaap

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[orphanowner]

Been running the WR5DC with no problems. Same plug I ran for years in all my 944's. Colder spark plug=less chance of pre-ignition. Colder plug should allow increase in combustion deposit formation but I've never seen evidence of it. Perhaps with 20,000 typical street miles in an engine that burns a littler oil, there could be an issue.



Have heard of issues with the Bosch platinum in certain circumstances, but I'd agree, the G man's issue is one of spark gap.

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[flash]

i also run a colder plug in the iridiums - i change them about every 10k, just to have fresh ones, but they look fine - definintely a snappier response than i had with the bosch - worth the extra money to me

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[Harvey]

[quote name='Tom in Austin' date='Feb 24 2006, 09:27 AM']Anybody have the NGK Iridium part number on hand?

[right][post="16502"]<{POST_SNAPBACK}>[/post][/right][/quote]



I went to Greimann's link to plugs (great link, BTW) and am interested. Is there consensus that the Iridium plugs are the way to go? Any particular brand, heat range, cheaper vendor, etc.?



Thanks,



Harvey

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[flash]

www.sparkplugs.com

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[odb812]

Harvey, most of the people here have the NGK plugs from what I see and enjoy them. I have the Denso iridium plugs and I think these plugs are wonderful as well. I just started my car for the first time in a couple of months and I put a little too much oil in the head before I started the car, so my plugs must be oil fouled as I've never seen plugs oil fouled before and they performed fine.

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