bosch plantinum 4+ spark plugs worth it? Topic is solved

[carlo]

I bought my '96 850 GLT last month with 115k miles. I did a tune up a few weeks later, because the previous owner did the last one at 70k.
The spark plugs I took out (Volvo) were worn out. I replaced them with Bosch platinum 4+ plugs (I also replaced the rotor, distributor cap, and wire set).
The difference as a result is very minute, if any - maybe very slightly smoother RPMs. To be honest, I expected to feel more of a difference after the tune-up - especially what I read about Bosch 4+ plugs. Bosch also promises up to 4% lower gas usage. I am curious, what others can say about their experience. Also, does it mean that the conventional Volvo plugs are very good, despite being worn out substantially?!

Cheers,

-Carlo, NYC

[matthew1]

There's *lots* of debate about spark plugs out on the net. I've read people who swear by a certain brand and others who try one brand after another, never noticing anything.

But their claim of 4% can be verified -- just not (very accurately) by just one person. Wind direction can cause +-4% in your fuel milage.

If you don't see it coming yet, I'm not going to answer you directly because I simply do not know. I think I have Bosch regular plugs in now, and when they went in I remember trying to detect any difference at all -- to no avail.

Funny thing is, in my owners manual for my 97, it actually lists Champion as a replacement plug.

I think that the best way to approach plugs would be to buy any name-brand, and check the gaps every 6 months and re-gap them. IMHO, this would do more for your economy than getting $30 set of plugs every 18 months.

[potroast]

I had a set of bosch +4 in my volvo, and then I just replaced em with a set of double-platinum autolite plugs on monday... Performance is the exact same, and the autolites were $10 out the door for all 5.

[charliekowalchuk]

After studying Volvo Plugs, which go for $60 for 5. It should be noted that Volvo plugs are simply rebranded Bosch plugs. (and IPD says the same). However, they stay away from pure platinum, they go with a compound of such. The performance on this is minimal, but they last longer, which is what they're going for. Think about it, if the plugs needed to be replaced every 30,000 or the engine will start to die, then that doesn't help them sell cars.

What Volvo is going for (which I like, really) is a mixture between performance and realibiity, and that is why their old flowed up plugs perform close to what top of the line new plugs give out.

Personally, I'ver heard don't use pure platinum for Tubro models (which the reason being, platinum's melting point in lower then copper and may melt because of the extra heat a turbo charger puts in the engine.

Being the fact, that Porsche uses Bosch pure platinum plugs in their turbo charged models, I tend to think that this rumor is simply just a Wife's tale.

And if your dealing with an LPT, again, this shouldn't really be an issue.

[Jot]

It's worth it for the parts store !

[turbotim2]

I went with the Autolite platinum plugs as well, only because there were just a couple available at the store when I went in and I have had good luck with Autolites before. I noticed no difference in fuel milage or performance from the Volvo's that were in it. I check my mileage almost every tank of gas (good way to notice a problem that may otherwise go unnoticed). I believe the real advantage to platinum over other plugs is longevity not necessarily performance.

[White850Turbo]

Just to clarify, turbo'd cars running any sort of respectable boost (at least 9 PSI) will have big misfire problems with platinum plugs. The platinum plugs are designed for longevity and not for performance/efficiency. They don't create nearly as "big" of a spark and it is easily "blown out" by all the extra air being pushed in by the turbo. That being said, platinum plugs are ok for N/A cars, but why spend the money when you can get a set of coppers for $5?