Spark Plugs with Two-Step

[Bob Mulry]

https://www.msdperformance.com/produ...ols/parts/8735

[Jeff Blanchard]

I did not see any mention of open or closed loop. Maybe if stayed in open loop on 2-step, could keep from adding unwanted fuel, and then go to closed loop very soon after releasing brake. You would have to be close on your fuel map. Also, you might consider talking to the tech line guys at NGK. I have found them easy to get a hold of, and very knowledgable. I have always been impressed with the quality of NGK plugs.

[Ed Wright]

Originally Posted by Jeff Blanchard

I did not see any mention of open or closed loop. Maybe if stayed in open loop on 2-step, could keep from adding unwanted fuel, and then go to closed loop very soon after releasing brake. You would have to be close on your fuel map. Also, you might consider talking to the tech line guys at NGK. I have found them easy to get a hold of, and very knowledgable. I have always been impressed with the quality of NGK plugs.

You most certainly do not want it in Closed Loop on the 2 step! Only at WOT. If you use a FAST XFI, there is a delay after start up you select in the Closed Loop enable paramaters, I don't remember how many seconds my delay is set to now, but it goes in Closed Loop part way into first gear. Some time after the launch.
I have had to replace so many new NGK spark plugs to cure misfires in customer's vehicles on my dyno, when my shop was still open, that I won't use them. I have had fewer problems with Autolite spark plugs than any others.

[Bobby Fazio]

FAST goes into open loop automatically whenever the two-step is activated. I have closed loop pretty much turned off at high rpm high load. I only use it around the pits to keep the plugs clean.

What are your thoughts on irridium vs platinum vs copper?

[Ed Wright]

Bobby, mine doesn't automatically go into Open Loop on the 2 step. Are using the FAST 2 step?
WOT is the only place I use Closed Loop. Unless you have really long collectors, or the O2 sensor before the collector, at idle & low RPM driving around the pits, cams with a lot of overlap like we use, it will pull clean air back in the collector during the overlap cycle. That looks lean to the ECU, and it will add fuel. I had a muffler shop make me a long slip-on extension with a 30 deg bend, for tuning my idle and part throttle. That stopped it from pulling in clean air during overlap, and made the sensor read correctly. I put in closed Loop for that, and just kept tapping the L key while I drove up & down the return road with that extension on it. Then back to open Loop there.

I use closed Loop going down the track. It never makes corrections anymore. My VE table is pretty well dialed in for any weather & elevation I run at any more.

[Bobby Fazio]

Ed I have the sensor in a primary so the closed loop would be somewhat accurate around the pits. My tune going downtrack has a good reading and I have a sensor in the collector for that. I think a great new option for any EFI company to set themselves apart from the competition (hint hint) would be to use multiple widebands at different RPM or Loads. For example, it would be cool if under 4500 RPM or certain load %, my closed loop is controlled by my primary tube's o2 sensor and then when I transition to a full throttle RPM, above 5000RPM or over 80% load let's say, it switches its closed loop decision making to the o2 sensor in the collector.

[Ed Wright]

Bobby, after I put the long collector extension on mine, and did the part throttle tuning, I pulled it back off, and put it back in Open Loop there. I see no need for further corrections there. My spark plugs are always white, with the little tan ring around the bottom.

[Darrel Goheen]

Originally Posted by Ed Wright

I had a muffler shop make me a long slip-on extension with a 30 deg bend, for tuning my idle and part throttle. That stopped it from pulling in clean air during overlap, and made the sensor read correctly. I put in closed Loop for that, and just kept tapping the L key while I drove up & down the return road with that extension on it. Then back to open Loop there.

Hi Ed, how long of extension pipe did you find was required to do the pit/cruise tuning? What's your opinion of having the WBO2 in a header tube vs the collector? Thanks.

[Ed Wright]

Darren, I had muffler shop next door to me make the extension. It was 24" long, with a 45 degree bend at 12". Swedged to slip over my collector. I made 2 band saw cuts, and clamped it on. Had to put it on at the track. Would not go in the trailer with it in place. I run one wideband in the collector. I race it going into closed loop at 6000. The funky air/fuel numbers from the 2 step are gone by then. I have worked on the intake air temp correction table so even in different temps it seldom ever shows more than 2% fuel corrections on the logger. I would not now run one without the air temp sensor. Helps a good bit with consistency. At first I just zip tied the sensor to a fuel rail, then pulled my head out, and screwed it into one of the bungs in the back of my Hogan plenum. The car is deadly consistent. It could use a better driver. LOL