So I went to do the first tune up on the 99 XJ since I've owned it, and guess what? Pulled out plug #1...BOSCH PLATINUM. Now as an auto tech, I will always put Champion plugs in any Chrysler, except for the occassional NGK per manufacturer specs. So with that in mind, what are your opinions on Bosch plugs versus OE Champion plugs? Performance, fuel milage, etc...

 

Not impressed with platinum plugs. Platinum just increases the interval for changing plugs, is more expensive, and does not improve performance or milage. I like the stock Champions.

 

Bosch always in my BMW or MB but Champions in my lawnmower and my Jeep. No improvement in either of the last two and don't last as long either.

 

I haven't been overly impressed with Bosch Platniums outside of ignition systems designed for them.

But if you are running a hotter than stock ignition, the stock Champion might be too little plug for you

 

Nobody has mentioned autolite platinums. I had a noticeable gain when i changed mine in the ole Jeep. But the old ones were pretty fouled.

 

some vehicles are picky about this, xj's and jeeps are not, excluding some of this new daimler crap with hemi and so on. i had a jaguar in my shop that misfired because of the brand of spark plug, was still platinum and gapped right. bosch are good, i wouldn't have a problem with platinum being in there. won't change anything, and they last longer.

personally i don't like autolite as a brand. i've heard they are made by motorcraft though, and they are good for ford products. never really heard any probs with their plugs, but other products i have had problems with. i wouldn't put autolite in a jeep personally, especially when champion are the same price.

 

Another plug I'd stay away from is Accel.. SOrry but I put em in and took em out quickly...Put Champions in and it ran and started much much better..Shortly after that I had several jeep owners tell me don't use Accel they are crap and believe it..In all my cars accept this once I have always used either Champion or NGK..

 

stick with the O.E. I have NEVER heard of any significant gains of any type, between different brands of plugs. (when comparing new plugs) I put The O.E. back in mine, no complaints.

 

What did your 2000 come with as OE plugs?? Just curious what Cryco had decided to use in the late models of the 4.0L??

 

I have Accel's in my F-150.. Autolites don't like a .065 gap.... They run just fine, but I have a MSD blaster coil and the related other pieces.

I have them in my wheeling Jeep also.. But they are gapped the standard gap, as I can't find a hotter coil for my Renix. I haven't had one bit of problems with them.

 

My 2001 came with champions. I bought it with 84k on the ticker and still running the stock plugs. PO never did ANY maintenance on it.

 

Been runing Bosch Platinum's for years with no complaints.

I never see any issues when i change them (usually early prior to a trip) and never have any wear on electrode even with using an Accel coil and 8mm wires.

 

Thanks Mudd. I didn't think that they had changed but someone on a trailrun one time had Mopar plugs in his spares and I was wondering if the factory was using a different plug during the later years. I also heard that the Mopars were rebranded Champions so again IDK.

 

I have sworn off of Champions years ago. I don't even run em in my lawnmower.

I used run the Bosch cheapies.
Even in my 92 Bonneville 3800V6, ran awesome with them.
But they do have a rather (expected) short life-span

EXCEPT for our 4.0L's this time I decided to use the Platinums.
I have no complaints.
They are good plugs.

Would I recommend them to someone else?
NO.
Reason: Everyone's XJ runs differently and IS run differently. Therefore each and every owner expects something different. Therefore, I would not recommend them. This is THE best way to keep egg off one's face.

 

Gotta disagree there.
Platinum is a harder metal, so it will make the plug last longer.
There is less gap erosion with harder metals.
Irridium is harder/better yet.
Champion makes its own line of platinum/ double platinum/ irridium plugs.
Theyve been using them in the oilfield on natgas powered compressors for years.

Ive run Bosch platinums in my Fords for years.
The Bosch's are kinda unique though as the electrode is just a small point rather than an extrusion.
This concentrates the spark to a very small point.
Fords seem to like this in my experience.
Am still trying to decide on Bosch vs Champion for the XJ.
I may just go with Champion Platinums.

Or mebbe the Irridiums as i can get Champions cheap!