I'm thinking about installing Bosch Platinum +4 spark plugs, but I was wondering if anyone has tried them or know if they are worth the extra money?

 

how many miles do you have?

if you have low miles than just wait until about 20k

the stock ngk are pretty good right now

i had denso iridums in my accord and didnt feel crap...

sidemarker

 

I'm about to take my 01 CL-S in for its 22500 service......do you know if Bosch makes the +4's for the CL? Denso's website said those spark plugs were about 13 bucks each, that seems steep.

 

well the manual states that you dont have to replace the spark plugs until 100k miles

but i dont think it will hurt to change them out

i have not used the bosch but i heard they work well

but dont expect any big gains

sidemarker

 

I agree! I haven't replaced my CLS's plugs yet, but I did on my supercharged Thunderbird. I spent the money and used the BOSCH Platinum + 4's and could not tell one bit of difference.

 

WOM: WASTE OF MONEY !

Bordem has a price !

 

Avoid long life platinum plugs like the plague.

The reason they last long is because you are probably giving up performance. There is normally a trade off.

If you don't mind changing plugs every 30k miles I'd go with the NGK Copper plugs. I think they are called V-Power or something like that.

Copper is a better conductor than Platinum and 6 copper plugs will cost you less than two of the expensive stuff. Just make sure you get the right heat range.

 

Get the conventional Bosch platinums, not the plus 4s. They are cheaper than plus 4s and last much longer than copper. Performance is identical.

 

Our cars already come with platinum plugs. That's the reason for the 100K change. The consumer report did a test on the 4-tip Bosch plugs and found no difference in performance and mileage compared with their regular platinum.

 

Supports what the auto store told me. I looked into them last year and the guy at the counter said he had everyone returned to him (Bosch had a "guaranteed better or your money back" thingy).

Here's a good point that I pulled from another board: The extra metal at the tip makes them more prone to detonation than a standard plug.

I'd recommend standard platinum plugs, but not Bosch's. I used to buy Boschs for my old car, and the last time they were changed out, there was 3 out of 8 plugs where the platinum plug was gone! NGK makes a great platinum plug, which is used by pretty much all the auto makers.

Oh yeh, electricity flows to the shortest path, so don't be fooled into believing a V groove, or those Splitfires actually give 2 hot sparks. It's just going to spark from the path of least resistance.....

 

I have heard a few people using the Denso Iridium spark plugs, are those better than platinum, and are they really 13 bucks a plug?

 

1st - Why change the ones you have now? I don't think you will see a noticeable diference, either way, if you change the plugs.

When I change my plugs, I always go to the regular Bosch Platinums. I have never noticed a difference either way. Maybe a slight better performance, but only because the old ones had about 75,000 miles on them.

juice

 

The benefit of platinum plugs is they don't burn like copper. So the gap at 0 miles = the gap at lots of miles. Copper plugs are severely worn at 6000 miles. As the gap gets wider, performance and fuel economy drop. My guess is if you checked your 75,000 mile plugs that the gap was probably still correct.

You're right though, it's a waste of time to pull out the stock plugs.

 

Are the spark plugs in the type S and regular CL the same?

 

No, they're different. Just check your owners manual for the part number, and you can cross reference that with any other plug. The 6 speed uses a different plug as well.

 

AS mentioned above the CL and CLS have a different heat range. The higher compression alone can account for this.


IMO, stick with the stock plugs (unless you have some compelling reasons to change)

The CLS and CL 2001-2003 have a very high energy, fast rise time coil/module sitting right on top of every plug. The general rule is: the weaker the stock engine's ignition system is and the more power you try and run through it (turbo, S/C, mods, etc), the more a plug, wires, multi-spark (MSD) ignitions can help.

People forget is that a car is not always sitting at WOT on a dyno (those graphs for the some of those plugs look like free HP -- hey? ) Unfortunately, you don't always get that gain in a well maintained engine with a good ignition system (our car) and very few people give a second thought to subtle changes in:

Emissions
Part load performance
Longevity
Subtle combustion changes (that are not always for the best)
Heat range issues that only show up intermittently (fuzzy end stuff that makes for a pain in the ass problem).
And the piece of mind that comes from not having one more mod for some knuckle-dragging tech to blame for an engine problem.


IMO, "If It ain't broke--don't fix it" applies to our plugs (stock or with I/H/E/P etc) (notice I left out the S/C...)