I have a 2006 MDX with the 5th gear auto trans and I am getting roughly 16mpg in the city and 20 on the highway... while i guess that is reasonable compared to other SUVs I would assume there is some kind of change that can made that is not some ghetto ebay computer chip or something.

 

You may just need a simple tune up or air in the tires. You also need to see if there are any codes in the computer that have not yet turned on the CEL. Also there are several items that can be out of spec but not set a code such as a MAP sensor that is not near 1 volt DC at a fully warmed up idle, or an O2 sensor that is not up to par but is working to a point but is wasting fuel, what are your fuel trims, you will need a scanner to see the scan data and whatever is there can be used by some folks here to tell you what may be wrong, check the misfire counter and the idle air control valve numbers also, etc. Let us know what you show.

 

Why are you disappointed? Did you do any research on the MPG before purchasing it? Sounds spot-on to me.

 

EPA Fuel Economy Est - City 17 MPG
EPA Fuel Economy Est - Hwy 23 MPG

those are the standards for the 2006 Acura MDX which is ok... im looking to see what people have done to improve these marks without compromising the luxury of the vehicle. loud exhaust is not an option lol

tune up is correct... i am going to do a valve adjustment as well

 

Given what have already been said, I would consider taller tires.

You ride on 17" OEM right? So your tires are 235/65. Want to try 235/70?

Keep in mind that Honda does not know what its customers will do with the Pilot, so they had to gear it one way to make everyone happy.

Some will tow a boat. Some will never leave paved road. Which one are you?

If you don't need to tow, taller tires will be like taller gear. IMO, it will help with MPG. Just keep in mind of the slight speedo/odo error.

You may want to see if there are lighter wheels. Again, Honda may have made the wheels more heavy duty than something for a street car. Just make sure you don't go larger (more weight). New wheels can be expensive so you decide if it's worth the investment.

 

Taller tires will most likely make the mileage go down, not up. More rotational mass farther from the hub, it will take less rotations of the tire per mile, but it won't make up for the gain in mass.

 

So you think 12mm will be a factor?

 

i agree your gas mileage is fine, the rdx's only get like 17 lol, but there way to fun to drive

 

Yes, unless you're only driving on the highway where you rarely start and stop and always go the same speed for hours at a time, the slightly taller gearing will not make up for the increase in unsprung weight. I've gone to a slightly larger tire with several vehicles and I've always lost mpg in the process.

 

Don't drive it
Seriously though, the EST (estimated) is just that. It's not set in stone, and your driving habits are a huge factor in the equation. Remember, you're driving something that weighs almost twice as much as a Civic and is nowhere near the aerodynamic equivalent of such. I put a K&N air filter in our 05 Pilot last night, so we'll see if that does anything for us in the mpg department (and performance, of course!). Already noticed a difference with my Civic (bone stock) in performance, and seems to be a hair better in mpg too.

 

did you calculate the the larger tire size when you went to do your mpg?

 

No need to, when you drop from 20 mpg to 16 mpg, but only went from a 32" to 33" tire, it's pretty apparent that gaining 1/32nd in overall circumference size isn't going to make up for a 20% loss in mpg.

 

You can't do one calculation and decide not to do another, thinking it does not matter.

A larger circumference will record an incorrect number in terms of mileage, and therefore wrong MPG.

I'm not going to debate your result with a larger tire, but it's important to do both and include the difference.

 

Ok, we can do the calculations if you need to see it. We know my odometer is now off by 33/32 = 1.03125. So if it says I went 100 miles, I really went 103.125. Therefoer, instead of me getting 16 mpg like I calculated using the odometer reading and the amount of fuel put in, I should multiply by 1.03125, so I was really getting 16.5 mpg. I only lost 3.5 mpg due to changing the tire size.

Personally I think it's easier to compare the two ratios, but if you want to see the math, there it is. If my mpg remained unchanged using the same calculations instead of dropping to 16, then we would have known that I was actually traveling farther using the same amount of gas, but that didn't happen.

 

It's not accurate to mutiply the 1.03125 by 16MPG. Because your 16MPG is not correct to begin with, with the bigger tires.

I would use miles driven X 1.03125 and then divide by gallons of fuel use to get MPG.

 

160 miles driven divided by 10 gallons of fuel = 16 mpg
(160 miles driven x 1.03125) divided by 10 gallons of fuel = 16.5 mpg

Same numbers, since it's the exact same math.

 

You are right. Interesting. Same math.