Bosch Platinum +4 vs. AC Delco

[guido666]

The problem with +4s and platinum plugs in general is that it is easier for the spark to jump. It results in a colder spark with less energy because it didn't have to work as hard to make the jump. It's like busting down a door, an easy door you just walk right in (no energy), but a big door you have to do the old Chuck Norris ass-whoop to and come crashing through like an action hero (tons of energy). So they are not all they are cracked up to be. Chris Jacob's has a good book called "Performance Ignition Systems" that you should read. He is the original man when it comes to knowing everything about high performance ignition. He is the one that makes the Jacobs Ignition Systems (now owned my Mallory I think). He explains it better then me.

 

[Jagged]

any ideas on what to use those $6 Bosch's for.

Wait a month, and hang them on the x-mas tree.

 

[botboy]

Ive been told that platinum is actually a poor conductor of electricity, so i guess they're just designed for certain engines and longevity.

Thing about that is...so is an air gap! (especially under the high pressure of a combustion chamber) At high enough voltages it doesn't matter what resistance something has to electrical current since the high voltage ionizes much easier than a low current would.

If I'm not mistaken most plugs have either a tiny tiny center electrode and the outside electrodes are made of a less rare/expensive material, or a common element for center and outside electrode(s) with a thin platinum coating. All in the name of longevity...and maybe so they can increase profit margins when some shmuck pays $6/plug for their ride.

On a side note:
I suspect that for certain cars that seem to run worse than normal when equipped with +4 plugs, the reason is that the gaps seem about the same size as regular ac delcos, and the ignition systems for cars not designed for that (most, I'd assume, are coil-on-plug or DIS systems) means that either the weak spark goes thru the shortest path (1 out of 4 possible paths, weak spark, enshrouded by the other ground electrodes no less) or the too-weak spark fouls the tiny platinum center electrode real fast and even a strong spark won't make it recover. I'd be willing to bet that platinum +4's cost power on engines with stock dizzy/ignition systems, but produce more power over regular delcos on engines with heavily modified ignition systems (CD or second strike box, good thick wires, hipo coil or DIS & megajolt, etc)

 

[Cricket]

I just got finished with a bad plug experience, did the last testing today on AC Delco Rapidfire #2's. They made my 350 run like it had a miss. Factory gap .045 and .050 gap produced the same results. The larger gap was actually worse even with MSD ignition.

Put regular Delcos back in R44TX and it runs smooth again. Gapped at + .005 or .050 with an MSD.

Weird. Had the same problem with plus 4's.

 

[wegel11]

Well I have been running the platinum 4's for about 5 months now. The engine acually has been running good, but now with this colder weather it has been acting up a little. Therfore making an excuse to dump the platinum 4's and buy what it was made to run with. I was thinking maybe I could rig up a spud gun with sparkplug hooked to a coil and battery , instead of just throwing them away. Or i could go with the xmas tree idea.

 

[2High4U]

Delco's for three reasons.
1. the other ones are wayyyyyy overpriced!
2. no noticable performance gain and if there is its not worth the money
3. Delco's are inexpensive and do the same thing either way your getting spark and about the same performance.

Im guilty for buying them before because of the hype.
I bought Iridum plugs for my 99 silverado for $104 for 8! no different than the original ones ive learned my lesson!

Split Fire for my 73 K5 ran just the same with the ac's $50 for 8 of them

AC Delco's For Me From Now On!!

http://www.autozone.com/servlet/UiBroker?UseCase=C001&UserAction=performMoreDetail&Parameters=TRUE%7C%7ESPARK+PLUG%7C%7ENONE%7C%7EDENSO%7C%7EIRIDIUM+++++++++++++%7C%7EFALSE%7C%7EFALSE%7C%7E429210%7C%7E1831%7C%7E5325%7C%7ENONE%7C%7E%2412.99%7C%7ECHEVROLET+TRUCK%7C%7ESILVERADO+1500+2WD%7C%7E1999%7C%7ENONE%7C%7E0.45%7C%7ENONE%7C%7EB

 

[Thunder]

I'm gald you posted up with your experience with the Bosch P4 plugs. Thats about what I figgured would happen to you. My experience with Platinium plugs in older engines is pretty much the same. They Run good for a while then they start missing. It just aint worth it to run platinium plugs in older engines.
In newer engines that have ignition systems are designed for them they work great. They come stock on many new engines now. My 99 Z34 Monte Carlo came stock with IRIDIUM plugs at about $100 a set. And from what I have read about it I am pretty much stuck with Irridium cuz the ignition/computer system requires them. So at that price I had better get 100K miles out of them

 

[Beast388]

Definately run AC Delco's over the Bosch's. They are a much better plug.

Just make sure you have the correct heat range for the engine.