Tegger, you've been lurking at USENET far too long, welcome to BITOG. Fellow Canuck here with a Honda obsession myself. My 99 Civic D16Y8 (SOHC VTEC) has about 144k miles on it. Consumption was non-existent until about 80k miles on the clock. Since then it's been a consistent 2,500 miles per US qt. Since new until 115k I was running Mobil1 @ 5k OCI. Then started AutoRX with some Esso XD-3 15w40. Now nearly at the end of an oil brand/weight experiment. I've tried these oils @ ~3k OCI:
Esso XD-3 15W40 HDEO
AMSOIL AMT Synthetic 10W30
Valvoline MaxLife Synthetic 10W30
Castrol GTX High-Mileage 5W30 (2qt/4250k)
Havoline Synthetic 10W30
Valvoline Synpower 10W30
Still to come:
SuperTech Synthetic 10W30
TropArtic Synthetic Blend 10W30
Meijer High-Mileage 10W30
Castrol GTX High-Mileage 10W30
I've observed no significant difference in consumption, even with a new PCV valve, air filter, and home-made PCV catch can. Auto-RX did increase my compression numbers as much as 25psi for Cyl#3.
What I do notice, however, is that my driving style pretty much controls consumption. I drive about 80 miles/day, mostly around 80mph (3,750rpm). Consumption increases above 85mph (4,000rpm). And I do notice a hazy spray from the exhaust between 6,000-7,200rpm (rev-limit) with certain oils (eg Valvoline SynPower). Recently I've slowed things down to about 70mph to see if things improve, not that I care at this point. My mileage certainly jumped from 32mpg to 38. So I am glad about that.
Anyway, worth noting that Castrol GTX HM 5w30 did cut the consumption in half for the first 1000 miles, then I take a comptession test, add LC20, and for the next 2-3000 miles consumption was up again. So maybe without LC20 GTX HM could've held up better.
When it's all said and done, I think I will stick to TropArtic Synthetic Blend 5w30 for $1.48/qt (Detroit) and top it up @ 1k, 2k of a 3k OCI (1qt total top-up).
Good luck and thanks for years of support on USENET and Honda FAQ.
PS. BITOG can be quite an obsession. Just read about those with hundreds of quarts in their secret stash. Beware of the BITOG bug!