I have a 2007 Grand Caravan SXT with the 3.8 liter engine.

Was wondering what people have experienced with changing spark plugs in the 3.8 liter.

I know there is a lot of speculation as to whether "high performance" Iridium spark plugs and such do much in the way of
adding performance. Some say they do, some say they don't.
I'm sure if they did, it would be minimal anyway.

But that being said, if I could help maximize the performance of the minivan by simply doing a spark plug change
I wouldn't mind doing it.

Therefore, what spark plug do you guys recommend for the 3.8 liter engine that will help maximize performance, gas mileage and NOT harm the engine.
The reason I say NOT harm the engine is I also hear of replacing spark plugs with ones that spark too hot can actually do more harm than good.

So, if you've changed your spark plugs in your 3.8 liter and have gotten great results which ones did you use?
Further, please pass along any research findings you may have learned in the process.

Thanks

 

The key to performance in a spark plug is knowing that sparks like to jump from a sharp edge to another sharp edge. As spark plugs wear, the electrodes deteriorate and the edges get rounded off and the gap increases. So maintaining gap is another important feature. Traditional copper plugs actually are the best electrical conductors. But they have the poorest wear features--which is why they barely last 25K.

Platinum has a much higher melting point, which is why many manufacturers have started using them. They maintain gap much longer. Iridium is supposed to be the "gold standard" when it comes to wear resistance and maintaining a sharp edge. Double platinums are used in a "waste spark" ignition system where one coil fires two plugs at the same time. The cylinder that's on the compression stroke get the bulk of the fire power, the partner cylinder is where the spark jumps from the side electrode to the center to return to ground. That's why they use a second pad of platinum on that electrode. A Coil On Plug (COP) doesn't really need double plats.

The Bosch +4 plug design uses Yttrium which has a lower melting point than Platinum. They claim that because the ignition area is open, it directs the flame front downward and thus produces better air fuel ignition when compared to the "J" design of traditional plugs. The reason the +4 has four electrodes is because they are "sacrificial" electrodes. As one wears down, the spark prefers to jump to the next closest one. Bosch also claims that the larger gap in their plug doesn't matter because it is so efficient in starting the flame front. LOTS of pros disagree with them and report far more problems with Bosch plats than any other brand.

I happen to like the Iridiums. The crazy part is that there's a huge difference in price between the Denso and Autolite brands. Denso is almost twice the price.

That's my two cents.

 

Thanks.
So does that mean the Denso Iridium plugs are the best for performance, spark, efficiency, etc?

 

After 170K miles on the original sparkplugs, I treated my 2002, 3.3 FlexFuel Grand Caravan Sport to a set of Bosch +4 Platinum plugs. That was about 50K miles ago and they are still running great. I'm using Mobile 1 Synthetic oil & a K&N Air Filter and getting about 26 mpg (Mostly highway driving.) I have been using the Bosch +4 plugs in my BB512i, as well, with no problems.

 

I always use the autolite from the Walmart. I replace them rather then adjust since I have them out anyway and the cost is not that much. I normally replace them about every 30K simply because the van has a lot of miles on it and it keeps the gas mileage on 25mpg on highways.

 

I have an '01 with the 3.8L and just today changed plugs. I had been running the Bosch +4 plugs and now put in Champion double platinums. Overall, I can't say that the high price was worth it on the Bosch plugs. They claim increased power and fuel mileage, but I saw minimal, if any, of either. In fact, I think my fuel mileage went down a fuzz. Mind you, I can say it was the plugs for sure, as it could have been a myriad of other contributing factors. I switched back to the Champions due to reading I've done regarding spark plugs in this engine, with more than one source suggesting that the Bosch plugs aren't the best suited. So, we'll have to see what the Champions can do. They were certainly cheaper so if the performance is as good or better, I'll stick with them.

 

The guys on some of the Dodge truck forums like the Autolite double platinums. I'm running NGK's Platinums in my Caravan and so far, I like them. I think most peeps use either Champion copper or platinums, from reading forums.
I used Bosch single electrode in an air cooled VW and like them. I tried the 3 electrodes in a Ford and they missed upon installation, so I won't be using them again. I then went to Autolite Platinums and after 45K I don't see wear.