Spark Plugs with Two-Step
 

Who has a spark plug recommendation? I have been running Autolite AR in both cars for a while but I have to change the stocker plugs often and the sub 3000RPM two step launches seem to foul them up. Have tried AR24 and AR25. A fresh set of plugs sounds very crisp on the two step but declines after 10-15 runs. Leaning out the two step hurts the launch. I check at least 1-2 plugs after every run to keep an eye on it. Is it possible that plug quality isn't that great anymore I was thinking of checking out Denso due to their being a contingency sponsor and trying to sift through their many plug options.

Re: Spark Plugs with Two-Step
 

I run Autolite 985 plugs in the Jeep 4.0 (Factory heat range). Have no problem with fouling (2800 on step). I run them 20 runs and replace them. Fouling might occur an the return road?

Re: Spark Plugs with Two-Step
 

I used to think it was pits driving and return road also so I really honed in on those areas and actually have it tuned slightly lean to protect myself in those low RPM, low load areas and running in closed loop down there so when I check plugs after warming her up in the morning and driving through the pits at operating temp they are kinda white when I get back.

Re: Spark Plugs with Two-Step
 

We run the plugs from the start of the year until BG points race then we put in a fresh set getting ready for Indy.

Re: Spark Plugs with Two-Step
 

I run my engine on the rich side on the 2step and only change them once or twice a season,no problems. How long are you on the 2 step?

Re: Spark Plugs with Two-Step
 

If you are tuning your air/fuel ratio with your wide band, when on the 2 step, it is actually very rich. The misfireing on the 2step puts a lot of oxygen in the exaust, which equates lean to an 02 sensor. All they measure is oxygen content, to calculate air/fuel ratios. You will see a bogus lean condition on your data logger. Rich there will dirty up the plugs in just a few runs. I have never had to change plugs during a race season. I put new plugs in each spring, just because. The plugs I pull out still look new. I've put a stock converter in mine to get a look at the actual WOT air/fuel ratio at as low as 3000 RPM. Sometimes it is hard to get the dyno to hold one that low for tuning at that low an RPM. Hope this helps. Just how I do it.

Re: Spark Plugs with Two-Step
 

As soon as 4 bulbs are lit I get on it. 2-3 seconds I guess. It's probably my tune still needs help in that two step area then. Yes Ed it always shows lean on two step so I try to use converter flash to tune the two step. It is the riches part of the run, when the converter hits.

Re: Spark Plugs with Two-Step
 

Bobby, on Patterson's dyno we were able to load mine at 3000, I set it to 12.5-1, richest part of my runs as well. Looks like about 15-1 A/F sitting on the 2 step.

Re: Spark Plugs with Two-Step
 

Bobby this what I have been using NGK UR45. Mine are grey to white. On the 2 step same as you. You can run lean around the pits and return road cause you have very little load on the motor. With out fear of burning a piston. Somebody correct me if I am wrong still learning.

Re: Spark Plugs with Two-Step
 

16 VT battery system and problem fixed. Use to have to out a set in every race with the Cleveland. Got smarter and started using it to play the qualifying game