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Old 06-25-2016, 12:19 AM   #66 (permalink)
Daschicken
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Join Date: May 2012
Location: Georgia
Posts: 743

Cibbie - '88 Honda CBR 250R
Motorcycle
90 day: 48.49 mpg (US)

Rarity - '06 Honda Accord EX V6
Team Honda
90 day: 29.88 mpg (US)

Baby viff - '86 Honda VFR 400R
Motorcycle
90 day: 42.15 mpg (US)

Latios - '08 Suzuki SV650SF
Motorcycle
90 day: 64.56 mpg (US)

Mazda 3 - '14 Mazda 3 i Sport
90 day: 43.25 mpg (US)
Thanks: 618
Thanked 261 Times in 174 Posts
Quote:
Originally Posted by gizzardgulpe View Post
This has been a fun read. I just bought a 2007 Accord V6 with the automatic transmission. My tank averages have been between 26 and 30 mpg so far with no modding, so I'm really pleased to see that the car responds well to little more than careful driving.

Still a bit jealous about that ~36 mpg tank. Awesome for a V6.
Good to see i'm attracting other accordians!

I have not driven any honda automatics at speeds higher than 15 mph, so I can't offer advice there, but try to keep the torque converter locked up, and don't be afraid to coast in neutral as long as the engine is still on. As of now, I do ZERO engine off coasting, and it will continue to stay that way until I can wire up a kill switch. Those are some pretty decent tank numbers, especially for an automatic, I just checked the EPA ratings and it looks like you have a 1 mpg highway penalty. However, EPA ratings for manuals are so much easier to beat.

For the last 2 months I have been without my scangauge, still have one month to go until I get this stupid insurance thing off my car. I'm up to a 22% discount . After that one month, I can resume hard braking for fresh red lights and turn off my engine for lights again. Along with those techniques restored, I will get my scangauge back so I can properly drive with load again, maybe block some of the upper grill for short trips, and I will be getting 2 new tires, likely Goodyear Assurance Fuel Maxes. I will finally get to see how my intake spacer affected mileage, yay!

My recommendations to you as for getting good fuel efficiency with this car, well, there is a big list of things.

Driving style:
The city rating for this V6 is pretty abysmal, at 18 mpg. I can confirm that it is an accurate rating. The secret to getting good city mileage is to avoid having to start from a stop. These are heavy cars, and this engine drinks fuel when accelerating, so try to coast as much as possible.

This engine also drinks fuel at idle. In mine, the scangauge indicated .35 gph at warm idle, my 4 cylinder accord idled at .21 gph. If you are going to be waiting longer than 30 seconds or so, shut off the engine. The starter is very easy to replace in this car, so don't worry about that. I always shift to neutral when I come to a stop in an automatic, it is usually good for a 20-25% reduction in fuel consumption at idle.

The highway rating is what is really impressive for these cars. They like steady driving. Stock aerodynamics are decent, but the underside leaves something to be desired, so try to keep the speed down.

Maintenance and mods

1. Air pressure. The door on my car specifies 32 psi front, and 29 psi rear. I laughed at the sticker and instead set the front to 48 psi and the rear to 44.

2. Maintenance. Cleaning out the intake in my V6 was good for a 10% improvement in fuel economy, if my back to back trips were accurate. Not only did it improve economy, but also power. Cleaning the intake in these engines is deceivingly easy, just unbolt the intake manifold cover, and below it are the bolts holding the manifold to the runners. You will have to unplug some stuff and disconnect a few hoses, but it is fairly simple.

After removing the manifold, you will see the 6 intake runners, and they will likely be filled with carbon. Mine were. Grab at least 2 cans of intake/throttle body cleaner, spray it onto a rag, and then wipe all that carbon off of the runners. The carbon inside the manifold is much harder to clean off since you can't reach all of it, but try and reach what you can. Clean the throttle body too, just make sure to unplug the electrical connector if you are going to move the throttle plate. I have taken that area of my engine apart probably 4 times now, and have yet to replace any of the gaskets, so don't worry about them.

One big thing to be concerned about with the accord v6 engines of this time period is loose spark plugs. The number 5 spark plug is notorious for coming loose and popping out. Cylinder number 5 is the front middle cylinder, closest to the bumper, as opposed to the firewall. My number 5 plug was actually fine, but my number 2 plug was HAND TIGHT! Check yours!

3. Mods
As far as aero mods go, I would suggest that you make an engine undertray first. I noticed an improvement in coasting when I installed mine. I would not suggest trying to add onto the existing front undertray thing, instead I suggest starting at the bumper and making your way back. That is the best way to make sure your undertray stays ON your car.

After that, I would suggest making a lower radiator panel like the one I made in post 48. It will reduce lift and improve the cooling system efficiency, therefore making you more confident in a grill block. I know the 4 cylinder automatics have a transmission cooler built into the engine radiator, but i'm not sure about the V6s. So don't get too carried away with the lower grill block.

After I get some sleep and get back from work tomorrow (LATE!) I will post some pictures of the underside of a V6 accord of our generation. Mine looks the same underneath. I will also post some comparison pictures of what mine looks like now with the undertray on it.

Good luck with the modding!
__________________
-Kaze o tatakaimasen-

Best trip in V6: 52.0
Best tank in V6: 46.0
Best tank in Mazda: 49.9
Best tank in CBR: 61.3
Best tank in SV: 83.9

Quote:
Originally Posted by MetroMPG View Post
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The Following 2 Users Say Thank You to Daschicken For This Useful Post:
gizzardgulpe (06-25-2016), Joggernot (06-25-2016)