The setup --
My RV-7 (2018) has stock Lycoming YIO-360-A1B6, Avstar Fuel Injection, Dual Lightspeed Plasma III ignitions with "mini-sensor" option.
As mentioned on another thread I was doing some work getting fuel flows a little more predictable. Since the cowling was off, I decided to change out my spark plugs because I had noticed a little stumble at idle when the engine was warm.
Iridiums baby --
I started out with NGK BR8EIX's kind of by accident -- I used them as a replacement for the DENSO W24's from way back when. They happened to be on the shelf, and I didn't want to continue using or trying to find DENSO plugs. So, in the BR8EIX's went and ran and ran and ran for 200 hours.
New plugs --
In preparation for this exercise, I sourced NGK BKR9EIX's -- 5/8" hex, colder heat range, other than that, it's the same plug.
Initial flight testing, using same fuel flow, LOP °, altitude (5500MSL, 30.02InHg altimeter, OAT 20°C, 2500RPM, 24.7" MAP, 10.5 GPH,) etc. , showed a reduction of CHT's.
BR8EIX CHT 1: 305°F, CHT 2: 327°F, CHT 3: 305°F CHT 4: 282°F
BKR9EIX CHT 1: 299°F, CHT 2: 318°F, CHT 3: 303°F, CHT 4: 281°F
FWIW, the BR8EIXs looked fine, aside from the gap being a little more open after 200 hours...
Oh, and the stumble is gone -- so that's nice.
My RV-7 (2018) has stock Lycoming YIO-360-A1B6, Avstar Fuel Injection, Dual Lightspeed Plasma III ignitions with "mini-sensor" option.
As mentioned on another thread I was doing some work getting fuel flows a little more predictable. Since the cowling was off, I decided to change out my spark plugs because I had noticed a little stumble at idle when the engine was warm.
Iridiums baby --
I started out with NGK BR8EIX's kind of by accident -- I used them as a replacement for the DENSO W24's from way back when. They happened to be on the shelf, and I didn't want to continue using or trying to find DENSO plugs. So, in the BR8EIX's went and ran and ran and ran for 200 hours.
New plugs --
In preparation for this exercise, I sourced NGK BKR9EIX's -- 5/8" hex, colder heat range, other than that, it's the same plug.
Initial flight testing, using same fuel flow, LOP °, altitude (5500MSL, 30.02InHg altimeter, OAT 20°C, 2500RPM, 24.7" MAP, 10.5 GPH,) etc. , showed a reduction of CHT's.
BR8EIX CHT 1: 305°F, CHT 2: 327°F, CHT 3: 305°F CHT 4: 282°F
BKR9EIX CHT 1: 299°F, CHT 2: 318°F, CHT 3: 303°F, CHT 4: 281°F
FWIW, the BR8EIXs looked fine, aside from the gap being a little more open after 200 hours...
Oh, and the stumble is gone -- so that's nice.