I have been doing research and keep coming up with different answers my build is a 13.0:1 84mm gsr running e85. I am wondering what spark plugs are people using with their high compression builds. Or if anyone customizes a spark plug to work better with higher compression as rocket used to do (don't know if he still does). Any information is greatly appreciated . Thank you in advance.

 

I have some Rocket Autolite's I'll sell to you. They make you an additional 10+ hp just by adding them.

 

We use rocket modified plugs on our 240hp 82x89 setup.

 

Clean rice how much? Send me a pm

 

Clean Rice is being sarcastic...

 

since e85 burns "cooler" could the op use like a 7 range instead of an 8 range?

im currently using 8's at 12:1

 

R5671A-8 at 12.7:1

 

I've been hearing stock heat range be ok and others recommending one step colder, just want to know whats the advantage of a step colder, will it hurt performance at all sticking with stock heat range? I've thrown a lot of money into my build over past year and half and just want to make sure I make right decision with the plugs.

 

I can get any plugs at my work, just looked at the R5671A-8 , u run them at 12.1 , would they be sufficient at 13.0:1?

 

Well it's not like you'll start ripping on your new motor without checking your plugs regularly on the first miles, that's what i do anyway.If you are worried though NGK comes in 9's and 10's too R5671A-9/10.

 

Yea I saw that speed factory web sight says 12.0:1 and up to use R5671A-8 so I'm going to go with them n see how they do, thanks for information man I appreciate it

 

Lol..

First off, almost all tuning systems will tell you, don't use non-resistor plugs because of the Electrical interference.

IF you're on E85, i'd start with 7's.. see how many threads discolor and how the timing marks look, from there you can determine if you have too hot or too cold of a plug.

 

Stay away from protracted tip, like the NGK ZFR series.

I like Denso U-Groove (Q22PRU) or Autolite 3922 for your app (NGK heat range 7). Works better when modded.

The modded plugs have worked nicely in many elite motors including the 200whp B16 Project and PRE's 240whp LSV.

If you need colder, I like NGK R5671A series (like jimmysxxl posted), which are retracted tip.

 

anyone running accel plugs and having any luck

 

ngk bkr8eix gaped on 1.1mm on my dd b18c 11.1:1cr

 

How are the fine tip denso iridiums?

 

Nice stuff. I use those on the turbo cars a lot for those on methanol injection.

 

Thanks for the reply, I have been thinking of picking up a set recently, try something different then my normal cheap but good ngk v-powers.

 

Please explain why retracted tip over protruded tip. Pros and cons in applications like stock block/head NA, high comp NA, turbo, or a nitrous car. Thanks for explanation.

 

That is a good followup question. What are you guys thoughts.

 

very uhm... non technical on my part,

we use the retracted tip on high dome + milled head setups

mostly on e85 runners that let us run way too high of a comp and get away with it

 

Why?

 

Anyone?

 

retracted tip has more protection on the insulation also it has a shorter ground electrode which is easier to cool. So you can run 1 point hotter or so.

 

like i said.. my take is untechnical...


high dome + milled heads = less piston to head clearance