Thanks everyone for the responses.

Saab uses the ionization current measurement to detect knock.

So, in my owners manual, it stated the OEM replacement plugs are Champions. Am I incorrect? I would like to stay with the Bosch coppers, if that is acceptable.

I am glad Volvo only used the plugs to spark.

Have a good one,

tony

I relace my plugs on my LPT every 50,000 miles but even then they show no indication of needing to be changed at that time. No change with the new plugs so I think 30,000 miles (recommended by Volvo) change is overkill. I also only use Volvo plugs.

Stick with volvo plugs or do like me and save a bundle by using Bosch.

My LPT turbo volvo does very well on Bosch Super plugs(copper electrode), and at 99 cents each they are a bargain. I replace them at half the volvo rec interval, that is every 15K miles.
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'88 240, '92 745, '98 v70 John, Tampa Bay

Saab has a very unique feature, the ion-current measurement.
The ignition system sends a small current through the plug to measure some parameters inside the cylinder just before ignition (or possibly after, I dont remember). That could possibly be a reason you can not use any spark plug...? As far as I know, Volvo has no such thing. But it seems to work as well without it :)

That's a new one for me, I always thought good plugs were good plugs. For Volvo, all you need are good plugs and they last a long time. I am of the old school and replace mine every 30K miles, some other folks let them go for 60K miles, and newer Volvos last 100K. I just get worried that the plugs will get frozen in to the manifold and then can't be backed out without ruining the block.

Klaus
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98 V70Rawd(101Kmi), 95 854T(85K mi), 75 164E(173K mi)