I would like some advise on what heat range plugs to use. After searching, this is what I came up with. NGK R5671-9 is good for 500-600whp. NGK R5671-8 is good for around 300whp.

I am making around 410whp on low boost and I want to be safe and run the NGK R5671-9 because I run pump gas on low boost (15psi on t3/t67). From what Ive researched, I found that the colder a plug is, it dissapates more heat.

So my question is : Is there any advantage/disadvantage from running the NGK R5671-9 rather than the NGK R5671-8 with 410whp on pump gas?

 

The heat range of the plug is in reference to the plug only. It has little or no effect on water,oil or chamber temperature.If you can run the -9 with out fouling them out then use them.I run two steps colder in my ls turbo dd year round with no problems.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jep &raquo;</TD></TR><TR><TD CLASS="quote">NGK R5671-9 is good for 500-600whp. NGK R5671-8 is good for around 300whp. </TD></TR></TABLE>

This might also vary in different setups. As for me, I'm using the 7 heat range (BKR7E) and the marking on the ground strap is right where it needs to be....and it's on 372whp. I could probably takethis plug to the 400's or so.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NJIN BUILDR &raquo;</TD></TR><TR><TD CLASS="quote">The heat range of the plug is in reference to the plug only. It has little or no effect on water,oil or chamber temperature.If you can run the -9 with out fouling them out then use them.I run two steps colder in my ls turbo dd year round with no problems.</TD></TR></TABLE>

how much whp are u making?

so the R5671A-8 shouldnt be too hot for 410whp 9.0:1 compression ratio? thanks for the advise all.

 

every motor is goin to be different some like colder plugs some dont just read the ground straps after a nice pull and that will tell you what you need