R-Spec - What speed for maximum MPG on road trips?

[BLK5.0nonrspec]

It is a bit of a semantics game. 91 recommended for improved performance but not required. 87 work's well. Some feel they get better performance with the higher octane. Pretty much a "mind of the beholder" thing. My 2015 Acura TLX indicated premium recommended. I never noticed any difference in performance or mileage between the two grades, so I used 87. In my neck of the woods the difference in cost between 87 and 93 is around 50 cents/gallon on a 20 gallon tank, the difference seems worth it to me.

I use 93octane on my 2012 5.0 along with wix filters and pennzoil ultra platinum 5w30 the weather is really hot in south Texas I installed a air intake temperature relocation kit moved my iat sensor rite where the mass air meter would be drilled with a step bit and tapped it . Know instead of always reading 140DEGREES on a 90 degree day now it reads around 105 to 110 the hottest it's read was 115 on a 100 degree day way better then 140 . I capped the air silencer. Going to remove the flap in a air filter box that opens at 4k rpm and going to smooth out the bottom of the air filter box

 

[johnicon]

2014 R-Spec here. Going on a long road trip next week (1K miles round trip). Car has 49k miles on it now with new shoes. About to go get an oil change as well.

Curious - what have you all found is the ideal speed for crusing on road trips for optimimum MPG? Also, what tire pressure for MPG / comfort balance?

Tonight I did a 75 mile road trip. Filled up with regular (I typically use Premium 91) just before leaving. Had the cruise set on 69 (speed limit is 65) the entire time and averaged 25.1 MPG. Not too bad, but I think there's room for improvment.

Thanks in advance for the feedback!

In my 2012 3.8, I once set the cruise control at 65 on a cross-coutry trip, and after going through a full tank the mpg displayed 33. Probably overstated, but I was still impressed. Since then, I've never gotten more than 30mpg. Usually average 28.5mpg on long trips.

 

[jep604]

In my 2012 3.8, I once set the cruise control at 65 on a cross-coutry trip, and after going through a full tank the mpg displayed 33. Probably overstated, but I was still impressed. Since then, I've never gotten more than 30mpg. Usually average 28.5mpg on long trips.

My 2014 3.8 averages 31-34 mpg on long trips as long as I keep it below 78 mph.