Is the variability in MPG's from the 91 octane vs recommended 87?
If so, does that mean that the engine has higher compression than the indicated 10.5:1?
In my experience with relatively low compression engines is that running higher octane fuel resulted in lower MPG's vs running lower octane fuel. I have always attributed the lower MPG's to the additives that boosted octane ratings, which sometimes can be just more ethanol which has octane rating of almost 100 or another shorter hydrocarbon chain which requires more fuel to be injected to generate the same amount of energy in a low compression engine.
That's great to see, I just like the VCM Muzzler since it makes the van react alot better in traffic or stop/go situations. I'm using the lower amperage and when sitting at idle or a hot place the ECO light DOES go on... Get going and it disappears if you get the air flow. Well worth the $$$$
2011 Odyssey Touring, HID 55w 5K H11, HID 35w 5k fogs H11, 9005 LED DRL, Weathertech Mats, K&N Drop-in Filter, H&R Springs, VCMuzzler
Hold on, I thought we can't use 91?!
2017 Honda Odyssey TE - VCMuzzler - OEM Footwell LED Mod -
2017 Honda Accord EX-L
2014 Honda Civic EX-L
2010 Honda Odyssey EX-L (USDM AF!) VCMuzller - Catless Down Pipes - Test Pipe - Custom SRI/CAI - TB Coolant Bypass - Thermal Gaskets - Coilovers -
I can only speak for towing in the 3,000-pound range, no aero drag (bass boat)....with 91 octane and using the same throttle lever angle on my ScanGauge II, the engine was able to hold slightly more positive ignition advance on the truly hot days (greater than 40C or 104F) when I was pulling up a hill.
Otherwise, if not towing, 91 octane did nothing for me. I did not observe an MPG change between octane ratings during hum-drum driving. 87 all the way for day-to-day driving.
2003 Ody EX-L RES 158k miles, OEM fogs & hitch, bbylon5 screen mod, chuck k fog mod#2, cnn 82C t-stat mod
2002 Ody EX RES 164k, Ditto on above.
1998 Accord LX215k. DIY: Haynes 676 ATF cooler; T & acc belts & tensioners.
1982 Ebbtide DynaTrak bass boat, 200hp Merc, DIY re-fit 2006-07: CMC jackplate, Teleflex Canada Steering, Torque-Shift 14-26 vari-pitch SS prop
SNAPPER mower 5.5hp Honda