I just boosted my car on e85. What kind of spark plugs should I be running? I have heard I should be running a colder spark plug?

 

Yes

Im running 10's on mine. Works great, 11's might be too cold. But as long as it starts easy and runs smooth on idle i think you should be fine.

JT

 

What's coldest? Copper? And is a higher temp rateing hotter or colder?

 

Higher number is colder

Im running the NGK R7420 plugs. These are iridium plugs.

JT

 

I'm running 9's and having issues with the car not even able to go passed 5k it's like it hits a wall and just spits and sputters. I have 10.5's going in to hopefully correct that but out of curiosity, what is a good place to start with timming. I'm running the same timming map as I did on 91 Oct. And wondering if maybe I should get more aggressive on the advancement. Right now at low boost 10 psi it's logging 18 degrees advanced. Would that be a potential problem for the spit and sputters at 5k?

 

bogging out like that sounds like you are too rich. what are the AFR's when the cut off occurs?


Im running Trailing plugs all around BUR9EQ

 

AFR are at 12-12.5 then bang brick wall at 5k hmm we even took out a ton of fuel just to see and then it backfired and went to 14-15 but still only went to 5k. That's why I would think timming?

 

I know this is a bit late but did you figure this out?

Check to make sure that your plug wires are in fact correctly located. I've known a few people as well as myself that have run into that same problem in the past. Wrong coil on the wrong rotor in the wrong L/T position would give you the same kind of symptoms