Single tip spark plug/multi tip plug?

[Adidas]

I have a 93 911 with factory twin spark plug heads. Previous owner ran 3 tipped Bosch and NGK plugs and our host calls for them as well in my car. Is it Ok to run single tip spark plugs instead of multi tip ones ? Thanks in advance. Bill

[Flieger]

Yes. There is only ever 1 spark. Three tips just spreads out the wear so the plug lasts longer as the electrode naturally erodes from arcing. That is if it is not clogged with carbon before.

[ratpiper71T]

You'd think with the bosch name, these would be good. But, these multitip plugs are nothing but a gimmick. Does anyone know of a vehicle that they are designed for and benefit? My knowledge isn't that great but I don't. Every vehicle I've tried these in; sporty compact import, American suv, v8 import, import sedan- these are dissappointing to say the least. They're marketed as long-lasting, durable, high-performance, etc. They seem to perform well at first, but give it a while, it doesn't last. Pull them
and check the electrode, maybe 15000 miles if that and it's significantly worn and degraded.
Don't use them. Period.

[tobluforu]

I used the bosch 3 prong plug up to a year ago and it was the only plug that worked well in my bastard of a car (16 years I used them). The last set I had lasted about 8 years before I threw them away, but they no longer make them. Now i'm trying different heat range ngk's.

[uwanna]

The Bosch FR5DTC triple tip plug is the plug that came in your car when new. Opinions on plugs, are kind of like opinions on oil, a lot of emotion, but not a lot of facts! For a stock motor, I for one stick with the plugs the manufactuer recommends. I have been burned several times on other vehicles and my high performance boat by using the latest "whizbang" plugs i.e. platinum,iridium,etc.
I put some "high performance" plugs in my Ford GT40 motor in my boat, ran like crap! Then put back the stock $2.00 Motorcraft plugs and all was well. Learned my lesson.
My '91 3.6 transplant motor is coming up on about 60K, and I need to pull it for some tranny work, so I've bought a new set of Bosch FR5DTC to replace while it's out. The motor still runs strong as dirt, so I'm prolly just making myself feel good, but it's the old "while your in there itis". Anyway I think Porsche's plug choice was made for a good reason, and I defer to their expertise!

[cashflyer]

What do you think of this spark plug design?


The ground electrodes are to the side - leaving the spark 100% exposed to the a/f mix.
Also, the center electrode is much heavier than most standard plugs.

Gimmick? I don't know.

It reminds me of the plugs in my air-o-plane.

[dshepp806]

looks to make perfect sense.

Doyle

[ratpiper71T]

You'd think with the bosch name, these would be good. But, these multitip plugs are nothing but a gimmick. Does anyone know of a vehicle that they are designed for and benefit? My knowledge isn't that great but I don't. Every vehicle I've tried these in; sporty compact import, American suv, v8 import, import sedan- these are dissappointing to say the least. They're marketed as long-lasting, durable, high-performance, etc. They seem to perform well at first, but give it a while, it doesn't last. Pull them

and check the electrode, maybe 15000 miles if that and it's significantly worn and degraded.

Don't use them. Period.

Edit to my rant. The three tipped spark plugs referee to by the original poster, I have no experience with. My anger is and was directed toward the +2 and +4 platinum plugs that are marketed in AP stores. Maybe a different animal altogether.

[db_cooper]

I've had very good results with the NGK BP6ET multi ground plugs in my 3.2. The BPR6es plugs are excellent. The ignition system is hard on plugs in the 3.2. If you ever pulled the OEM Bosch platinum plugs after 15k miles, the center electrode would be worn away.

The BPR6es plugs wear better, still worn after 15k. The BP6et will still be going.

The et's do not have a built in resistor for noise suppression. No problem with the old radios. Aplenty of resistors in the rotor and plug wires.

Available at the local NAPA store for less than $3 each.

I would suggest using the multi ground NGKs in the correct heat range with confidence.

[lvporschepilot]

The Golden Lodge plugs above are no better than vanilla NGK plugs. When there is a good ignition system in place, there is no issue with flame propogation which are the Golden Lodge plugs claim to fame.

[911pcars]

As stated earlier, there's only one spark no matter how many electrodes there are. The extra electrodes are to provide alternate ground paths, the spark picks the one with the least resistance to ground.

Some folks think if one is good, than more is better. Unfortunately, additional ground electrodes block exposure to the A/F mix slightly. Computer-designed combustion chambers might mitigate this slightly. Computers smaller than your bedroom weren't available for most car companys back then much less the software even if they had the hardware.

For oem's, they balance the need for efficient combustion with a goal for longer service intervals. Spark plugs on some modern engines are very difficult to access, thus the 100K mile spark plug replacement interval on most late model vehicles.

One can understand the need for an extra ground electrode in an aero-plane spark plug - redundancy and all. Don't want to fall out of the sky unnecessarily.

Sherwood

[Flieger]

I heard somewhere that Formula One sparkplugs use the whole circular rim/base as the ground electrode. They are small diameter and very short.

[JP911]

Originally Posted by Flieger

I heard somewhere that Formula One sparkplugs use the whole circular rim/base as the ground electrode. They are small diameter and very short.

Yeah, the F1 plugs are totally different. Here's a pic comparing (from left to right) an F1 plug, GP bike plug, and a standard production car plug.

[Flieger]

Wonder what kind of voltage the F1 guys use?

[HawgRyder]

I used barrier gap plugs in my Mazda RX7 for years.
That type of plug has no ground electrodes, but relies on the gap between the center electrode and the ground ring for the spark.
If regular ground electrode type plugs are used in a Rotary engine they have to be changed every 10,000 miles or risk one of the grounds coming off.
In a Rotary engine, that would destroy the rotor or chamber and definately put the engine out of commission.
There are reasons for using different types of plugs in some engines, and not all engines can or will benefit from a change.
Use what works for your unit...smile...and let the rest of the ppl try to figure out why yours runs better than theirs.
Bob

[Flieger]

Must be a piston/valve clearance thing for the racing engines (high compression).

[SCOTITUDE]

Ill pass along the readers digest version I got from a "champion" employee and friend. The spark can only fire once no matter how mant tips there are. So the multi tips, especially the split fires are just snake oil. I was advised to keeep the electrode very square with crisp corners and they will work great. Worn rounded edges delay the spark firing as the spark will fire from the sharpest squarest point on the electrode . Again, passed on to me, the split fire plug is owned by a guy who will advertise the hype every couple of years to gather new "customers" then disappear. once the snake oil product reviews fade and there are a new bunch of drivers out there the ads will resurface. I guess plain ol single electrode plugs, kept sharp and indexed are the best solution. I pulled a bunch of those +4's out of a car recently and almost every one had one if not more of the electrodes missing. dunno if I want that floating though my motor.

[RoninLB]

Originally Posted by 911pcars

Unfortunately, additional ground electrodes block exposure to the A/F mix slightly.

Sherwood

i never thought of that

thx