vettewrench

need some help with spark plug choice ,1999 vette 402 cr 11.1 directport wet kit 300 to 400 hp with nano what spark plugs tr8/9 ??

Nick@HSW

iTrader: (4)

I would start with a 10 and work your way down. Always much smarter to start too cold vs. too hot. Let me know if you need any part numbers for the plugs.

Nick

ShiznityZ28

iTrader: (11)

10 or 11 you probably need an 8 on the motor. lol

vettewrench

nick the part # for the 10 s will be great >ngk reccomended b9efs or b8efs i would assume the 10s will be b10efs ? i am concerned about fouling out the plugs using such a cold plug? can i change the tune at idle for the colder plug i also plan on the gap being around 35 .does that sound ok

Chris@NitroDaves

Nitrous (two and a half steps colder)
Heat Range: 8
Plug: NGK R5724-8 (stock number 7317)

Nitrous (three steps colder)
Heat Range: 9
Plug: NGK R5724-9 (stock number 7891)

Nitrous (four steps colder)
Heat Range: 10
Plug: NGK R5724-10 (stock number 7993)


-Chris

Nick@HSW

iTrader: (4)

Don't go by the sticky up top anymore like Chris posted. Those are the wrong part numbers and have since been updated by NGK. They're all racing plugs but with projected tips...something we don't want. NGK gave you the correct ones for the 8 and 9 heat range. For the 10's you guessed right. I have a excel spreadsheet that cross references all of the plugs and lists their specs if you'd like me to email it to you? Sometimes the NGK's can be hard to come by and the autolites work just as well.

Nick

Nitro Dave's Nitrous Outlet

iTrader: (25)

We keep the 8s and 9s instock. We do not stock the 10s. If you are spraying 300 9s are plenty. If you go to the 400 10s may be a better option. These plugs will fowl easy so get ready to start changing plugs.
Dave