Engine has been intermittently cutting out on the big end. This is the 6th Gen ZL1 LT4 motor. I've had the car for about 13 months now. It's got just over 5K miles, nearly all of which is to/from and at the drag strip. First, watch this half-minute video montage. The first clip was pass #4 on 27 Oct. The rest were from my 3 most recent trips. I've edited out all but the last few seconds from each of 5 passes (3rd and 4th gear). Then read the details below and tell me what you think.
Update 20180123: See
Post #5 for solution.
[Details]
Feels like engine cuts out completely one or more times for a split second while at WOT but only while pushing hard in 3rd and 4th gear. When this happens it's always around 5500 RPM. The worst time it happened, when I first really took notice, was my 27 Oct drag strip visit after I'd been using Torco fuel additive for several weeks. I thought at the time that it could be from too rich a mixture - ECM couldn't compensate for the high 107 octane.
It was pass #3 of the 27 Oct trip when it occurred in both 3rd and 4th gear, starting at about 5400 RPM in 3rd, then cycling the engine off and on about every 1/2 sec. After short-shifting to 4th it was okay 'til it reached about 5400 RPM when it started again. I stopped using Torco after that trip. Unfortunately, I forgot to turn on my GoPro for that pass and the microSD card in the PDR for that visit was in my pants pocket and accidentally got lost in the wash. So there's no video evidence of the worst case.
Looking back at previous videos I found other blips in engine output at 5500 in 4th as far back as Aug/Sep 2017 but not as noticeable as the ones in these clips.
I've been running nothing but E10 93 octane pump gas since the 27 Oct trip (3 track visits - 21 passes) but I'm still seeing these issues. I feel like there might be deposits on the plugs, injectors, and/or valves. Since this is a DI engine I don't see an easy way to clean the valves, though. Fuel additives can only potentially clean the injectors.
I'll be changing the spark plugs before I go to the track again this Sunday. Anyone recommend a good fuel additive? Besides tearing apart the engine, any ideas on cleaning the valves?
After reading the WEAPON-X thread "
Guide to fueling for higher horsepower LT4 ZL1s" I'm thinking that low fuel pressure in the lines or on the rail could be part of this, possibly brought on by clogged jets affecting fuel flow or dirty valves affecting combustion chamber pressure.
Any insights would be welcomed. Thanks!
--Cal