Take this as general info, it can probably vary from division to division and track to track. Best is to ask your track or division. I don’t think there’s necessarily a hard ET rule (yet) for the “Lower engine oil-retention device”, the NHRA rulebook states “as required by the class”. For us in division 5 a diaper ( or belly pan as mentioned ) is required 9.99 and quicker for ET bracket cars to run at the division 5 ET Finals event since 2012. NHRA is mostly concerned with the Divisional & National events. It’s the clean up time required for oil downs they want to minimize. For example by the rulebook a diaper is required for Super Street, even though that runs off a 10.90 index, so in that example the 9.99 isn’t the deciding factor. Beyond the National & Divisional events I think NHRA is still letting the tracks decide if they institute a rule for it at their local events. From what I’ve seen most of the bigger tracks have been moving to the diaper from 9.99 & quicker, but I’ve seen reports of tracks requiring them for 10.99 & quicker too. Best is to check your local track guidelines. I don’t think it’s been an issue at Beaver Springs for the FE Race & Reunion, but we didn’t go last year, and I don’t think it’s been pushed at Hot Rod Dragweek either, although that didn’t run last year.
