RSR 3.8 engine street spark plugs
 

Hi Folks,
My engine is a 3.8 with lightweight RSR pistons, 964 heads and DC-20 cams. Mainly street driven. Now broken in, I am wondering about my spark plug choice. Should I stay with the stock 964/993 plugs or use the 4 electrode 993 RS plugs?
Thanks,

I have never seen any evidence that the multi-electrode plugs work any better than the single electrode versions. I use NGK's for my 2,0 and 2,2, it's cheaper to replace them than to clean them.

The stock plug is a 3 electrode version - Bosch FR5DTC. RS 3.8 runs a four electrode FR56

Dr. Cramer is correct, of course. Multi-electrode plugas were designed for longevity.

Your engine's configuration and usage determines the appropriate heat range and you can use the FR5DTC's for the street. If you do track events, you might need something a bit colder.