toofast928

I been using the Bosch WR7DTC, 3 point ground strap. Getting deposit build up and gray electrode. Anyone using WR8? Any detonation?

toofast928

Ok for all that are interested. The WR7 is bit too cold for city/stop n go driving. It's fine for freeway, high RPM. But Porsche OEM is WR8, one step hotter.

Look at this link: http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

MarkRobinson

NGK BKR7E (one heat range colder than what's specified for my '94 3.6 turbo from NGK). Work great! I put in a fresh set last night after running AA chips with boost for a month, no signs of detonation, excellent driving characteristics (stock),

AND, they're cheap!! I set my gap to .030

toofast928

Thanks Mark but I'm a little confused on why you chose the NGK BKR7E?

The Bosch series prefix for the 5.0L is WR7 or 8. ex. WR8DTC
The NGK BKR7E does not cross over to WR series of Bosch.
The NGK BPR series is the equivelant to Bosch plugs.

MarkRobinson

NGK has a great breakdown of their part numbers, so you can look at the type of plug your car requires, figure out what heat range you want, & what electrode style you desire, then start looking through the listing of all their part numbers to see if your "ideal" plug exists, & ultimately choose the closest plug: BKR7E (BK: style of plug that fits appropraitely into a 928), R-resistor, 7-cold plug: opposite scale as Bosch), E is the electrode style (requires gapping, but the BKR7 was the most important thing: a resistor'd spark plug that fits the 928 head with my selected cool heat range.

Mark (I don't think Bosch has descriptions like this, so there's a bit more research to do. Any auto part store that carries NGK has this book where you can do what I did).

toofast928

NGK SP cross over. http://ngkaz.home.att.net/wsb/html/v...ome.html-.html

Herr-Kuhn

Bosch W5DC