Spark Plug info for FAQ

[ptownTSI]

not sure if there is a spark plug info FAQ but here is some info that could be added to it.

If you go to NAPA auto parts and give them part # W8LCR (as a non napa part #) you will get a few results.

one of them is the NGK plug $2.59 (ZGR5A) which is napa part # NGK 5839.

the champion copper plus ($1.39) are part # CHA 404

the autolites ($1.39) are part # ASP 64

[MrK]

Just out of curiosity, isn't the W8LCR a non-standard sparkplug for the m20? AFAIK the oem spark for the m20 is the W8DC. The LCR is a colder plug, and only suitable for m20s that have raised compression (i.e. like mine. It ran horribly with its stock DCs and I had to switch to the colder LCR)

Am I right?

[RobertK]

I believe the W8LCR is the Bosch Super plug that the M20 loves so much. I've heard the NGK replacement is just as good as the super but I've never tried it before so I cannot testify.

[ptownTSI]

bsh 7509 is the correct bosch part number for the e30's then at napa.

the ngk is listed as a stock replacement.

[arsevader]

Just out of curiosity, isn't the W8LCR a non-standard sparkplug for the m20? AFAIK the oem spark for the m20 is the W8DC. The LCR is a colder plug, and only suitable for m20s that have raised compression (i.e. like mine. It ran horribly with its stock DCs and I had to switch to the colder LCR)

Am I right?

The D doesn't refer to the heat range of the plug. Bosch codes are as follows.

W - Type of thread and seat

8 - Heat range (higher number colder plug, which is why ETA use a 9 plug)

L - Thread length and spark position (which is probably why your car ran like crap. The D's electrode is 3mm long while the correct L is 5.

C - Electrode material (Copper, Platinum, Silver etc)

R - Version

There you go

[Erick]

Anyone interested, for turbocharged cars I recommend the NGKs BP7ES.

[AdamF 88iS]

W8LCR is the best thing out there for a stock M20. M30s too for that matter. The main thing as that they are coppers. Silvers dont work as well, and platiums are right out.

The best plug for M42s and M50/52 or S50US/52US are the NGK BKR6EQUP. These are quad electrode and I've had very good expereince with them in customer cars. A Bosch alternate to these are the F7LDCR; but they don't last as well as the NGKs in the long run. I've had some isolated problems with the Bosch ones seperating the porcelin from the metal base after they get some miles on them.

S14s use Bosch X5DC stock, but if you run a chip or higher compression ratio the X4RCS can be used to help against pinging.

[AdamF 88iS]

8 - Heat range (higher number colder plug, which is why ETA use a 9 plug)

On Bosch, higher numbers are hotter. NGKs are the ones that are backwards.

[arsevader]

On Bosch, higher numbers are hotter. NGKs are the ones that are backwards.

Yeah sorry that's what I mean't, honest ;)

[arsevader]

W8LCR is the best thing out there for a stock M20. M30s too for that matter. The main thing as that they are coppers. Silvers dont work as well, and platiums are right out.

I'd have to disagree here as ETAs and M30s should be using Silvers.

[AdamF 88iS]

I'd have to disagree here as ETAs and M30s should be using Silvers.

As long as they arent platiums.

[arsevader]

As long as they arent platiums.

Yeah Platinums are the scurge of older engines that's for sure.

[MrK]

Thanks for the clarification guys. I guess you learn something new every day :)