Colder Plugs - 1988 924S

[Davie Boy]

I've been fouling my plugs pretty quickly and have been told I need colder plugs. I've been using the cheapy $2.75 Bosch plugs up to this point. How do I tell what in Pelican's inventory is colder versus hotter? My car has a few basic mods, e.g. chip, headers, etc. Nothing very crazy.

[Pauld_94S2]

First, which plugs do you have in your car now?
If you are running the correct plugs, you should find out what's fouling them first, if it's, oil, fuel, or ???.

And colder plugs will foul quicker, you want "hotter" plugs if that's what the problem is.

[Jfrahm]

More likely you have a fuel leak to the vacuum system (FPR or damper) or a hosing injector or some other problem. It could be the chip, maybe a dead O2 sensor or it's running too cold to go into closed-loop or the DME temp sensor or something like that also.

[Davie Boy]

I appreciate the advise... but assuming I need colder or hotter plugs, how do I tell which plugs are colder and which are hotter? Descriptions of the different plugs here on Pelican are very basic and don't explain much.

[Pauld_94S2]

If you are using Bosch, you can go to their website and search for a table or specification sheet.
Or, you can call Pelican and ask them to assist you.

Which plugs are you using now?

[Jfrahm]

Determining the heat range based on the part number depends on the plug, in Bosch WR7DC is hotter than 6 which is hotter than 5 but some plug numbers run the other direction.

https://www.boschsparkplugs.net/learning-center/article/225/heat-range-conversion-chart

[John_AZ]

Thanks Jfrahm for the chart!

J_AZ

[Davie Boy]

Originally Posted by Jfrahm

Determining the heat range based on the part number depends on the plug, in Bosch WR7DC is hotter than 6 which is hotter than 5 but some plug numbers run the other direction.

https://www.boschsparkplugs.net/learning-center/article/225/heat-range-conversion-chart

Great chart. Thank you.

[kevrobert]

Ok firstly about Spark Plugs...when its comes to engineering German of course, when it comes to electrics Japanese.. Bosch, Motorcraft, Champion...no thankyou. If want performance use NGK R plugs or NGK Platinum etc. If you want to run a slightly hotter plug you can go for NGK R plugs BPR6EY which is what I run in my 8v engine . Lower numbers are hotter higher colder.

[Davie Boy]

Just a quick follow-up note...

I went with the NGKs mentioned about. The car has never driven better. For the past 9 years, I've gone with nothing but the standard Bosch plugs. It looks like I'll be on the NGK bandwagon from here on out.

Thanks!