My setup is in the sig. I currently run NGK R5672A-10 gasket type plugs. Is this to cold for 8# of boost on a daily driver? I just got the car back together and I fouled out two sets of plugs already. My wideband says 14-15 A/F at part throttle and idle. Then it goes down to about 12-13 A/F up to around 4000rpm with no boost. I haven't beat on the car yet due to this problem. My engine builder told me to run this plug due to beating it up on the dyno. I ran the TR6's with 8# pounds on a stock motor. I think 10 is alot colder than 6 and I thought the TR6's were already 1-2 ranges colder. I need another set of plugs so what should I get? What heat ranges is everyone else running on similiar setups. Thanks for any info or suggestions........John

 

I'v had trouble with ngk cold plugs. Same fowling problem. Especially @ start-up. I leaned the open loop fuel map out. I have an almost identical set-up... 383/ D1/ 72# injectors/ MSD. / 15# pulley/ afr 190's. I went with a zex plug. I don't know about the plug gasket, but, I think the afr's I have are a tapered seat. Anyway, the ZEX plug works great. I have not fowled any plugs yet. The car is running good, and, strong.

 

Thanks for the reply.What NGK's were you running? Do you have a part number for the Zex plugs? Thanks again....John

 

Also running an MSD 6A with 8208 coil.
NGK... BPR6EFS 0.035 gap
Zex... 82071-8 0.034 gap. Available @ zex.com