Last post on May 16, 2013 at 9:38 AM
You are in the Honda Accord
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Honda Accord, Fuel Efficiency (MPG)
#2031 of 2925 2007 V6 5AT
Jul 02, 2008 (3:23 am)
Over the last 4 tanks, my V6 has averaged 26.2 MPG in city driving.
Needless to say, I'm very light on the throttle. The transmission usually upshifts somewhere in the 2000-2600 rpm range and I hardly ever let the engine rev past 3000. I coast as much as I can and I always manipulate the throttle slowly and smoothly when accelerating. In fact, I'm so careful with the throttle that my right ankle often aches during driving from modulating the throttle so precisely. I sometimes wonder why I try so hard when the results aren't really that spectacular. If I were to drive how I wanted to drive (quick acceleration and higher speeds), my mileage would only drop 3 or 4 MPG, I'm sure.
I've noticed that my mileage has improved quite a bit in the last few months (warmer weather?). During the winter, it would never rise above 24 MPG no matter how carefully I drove. Most of the time it was between 22 and 23.
I should note that I fill up exclusively with Shell V-Power 93. The J30A5 runs much smoother and stronger on this gas than on regular 87. I quit filling up with 87 within the first 1000 miles because I noticed severe pinging/knocking during acceleration, especially uphill. I could even hear it with the radio at a moderate volume. That's how severe it was. Once I switched to 93, the pinging stopped, and within a few tanks I noticed a considerable increase in torque (especially in the low-end) and better fuel economy (up at least 2 MPG, on average, couldn't do better than 21.X MPG city on 87). At first, I thought the increase in power and efficiency was attributable to the engine breaking in, but after trying a few tanks of 87 every so often, I've found that there is quite a difference between the two. After running 93 for several tanks and then suddenly filling up with 87, I notice a slight drop in power and the mileage for that tank is usually about 2 MPG lower than the previous tank of 93. I've yet to try mid-grade, but I really don't see a reason to. It may not ping like 87, but it likely won't perform like 93.
For all you 2003+ V6 guys out there, I highly recommend using premium gas. Sure, it costs more up front, but in my experience the greater power and efficiency more than makes up for the couple of dollars per tank premium. In fact, since my mileage is around 2 MPG higher on average with 93 versus 87, I'm actually SAVING money in the long run using the more expensive 93 octane.
If you do decide to give 93 a try, have patience. You're not going to notice an increase in performance and mileage right away. It takes a few tank-fulls for the engine's computer to optimize the ignition timing advance for the higher-octane fuel. The difference between regular and premium is far easier to feel when downgrading from 93 to 87, since the engine has to immediately pull the timing advance back to avoid detonation. It takes much longer for the engine to "see what it can get away with", so to speak. It takes time, usually 300-500 miles or up to two tanks of gas.
If you have a 2002 or older V6, stick with 87 octane. Anything higher will actually hurt your performance and gas mileage as their engines can't optimize the ignition timing for higher octane fuel like the newer engines can. On the Accord, that nifty "feature" was added in 2003 with the introduction of the J30A4 (when the 7th gen Accord debuted, a Honda engineer even stated that using 91+ octane in the V6 added 10 HP and 10 FT-LBS for a total of 250 HP and 222 TQ). As far as I know, this applies to the 2008 Accords as well, probably even more so since the J35Z2 has a higher compression ratio than the J30A4/5 (10.5 vs. 10.0).
On a side note, isn't it amazing how far engine management has come in recent years? 10+ years ago, you couldn't have imagined an engine with a 10+:1 compression ratio running safely on regular gas while making decent power. Now, they can...and then some. The new direct-injection 3.6L V6 in the CTS comes to mind. 304 HP on 87 octane. Wow. Heck, even the 06-07 Accord V6's 244 HP on 87 is impressive (though, from my experience the engine doesn't like 87 much at all).
Well, I've gone on long enough, so I'll shut up now
#2032 of 2925 Premium Fuel & 2008 V6
Jul 02, 2008 (3:34 am)
Has anyone tried 2-3 consecutive tanks of premium to see if there are any improvements?
#2033 of 2925 Re: 2007 V6 5AT [th83]
Jul 02, 2008 (6:37 am)
Interesting analysis. Whether you are saving money or not is debatable depending on the price differential between 87 and 93 octane, and the difference in mileage.
Right now your theory holds true - if you get 24 with regular and 26 with premium, regular costs $3.99 here in NJ, and premium $4.27, and you travel 260 miles, you are better off with the premium - 10x$4.27 - $42.70 versus 10.83 regular x$3.99 = $43.22. If the price differential is $.33/gallon or more you are worse off.
I never had any pinging problems with our '04 V6 AT Coupe. Have to wonder about the quality of the gas you are buying, regardless of its being Shell or not. I once got a tank of water from a Sunoco station.
#2034 of 2925 Re: 2007 V6 5AT [th83]
Jul 02, 2008 (8:40 am)
Coming from a 2003 6spd coupe to my current ride, a 2008 6spd, I can also vouch for your statements about using premium gas in the Accord V6. The performance was noticeably better in my 2003 with the higher octane, and MPG slightly better (but not substantially, perhaps due to my heavy right foot... ) I had also read the analysis from the Honda engineer that hp increased from 240 to 250 using premium in the previous 3.0 motor. So far, there is nothing on vtec.net or other sites to suggest more than 268hp by using 93 octane in the 3.5 V6. Someone should be testing that soon, hopefully.
I have only used 87 so far in my 2008 6spd, pretty much following the recommendations from Honda. However, based on your suggestion, I will start using 93 octane in my 6spd to see how much better it performs. This new 3.5 feels significantly more stout than the 3.0, so I'm curious to see how it responds to premium gas.
The one downside to pushing higher octane is whether it will increase the torque steer, which can be noticeable if I floor it without a good grip on the steering wheel. I do run summer tires in the warmer weather, which improves handling and lessens the spinning of the front wheels. Given the greater performance of the 3.5 6spd, I've been pleasantly surprised that torque steer is really not that bad....so far.
Thanks for the tip!
#2035 of 2925 Re: 2007 V6 5AT [cstiles]
Jul 02, 2008 (8:43 am)
The performance was noticeably better in my 2003 with the higher octane, and MPG slightly better (but not substantially, perhaps due to my heavy left foot... )
So...you...ride the clutch?
I think you mean your "other left." I had to say SOMETHING.
#2036 of 2925 Re: 2007 V6 5AT [thegraduate]
Jul 02, 2008 (8:46 am)
You're fast. =) I just corrected it! Thanks....
#2037 of 2925 Re: 2007 V6 5AT [cstiles]
Jul 02, 2008 (8:53 am)
Haha - just messing with you. I do that kind of thing ALL the time and have to catch myself and correct it.
#2038 of 2925 Re: 2007 V6 5AT [th83]
Jul 02, 2008 (10:28 am)
It's funny you should say that the car runs better on premium than on regular. I swear I read a few days ago that the V6 is designed to run on premium. I think it was on Honda's website, not sure though. I remember looking at it and thinking that it was a little strange.
On a side note, in my 4 I recently got 27.5, using the A/C fairly often.
I think I may do some digging and see what I find when it comes to premium versus regular, especially since around here premium is generally around .15 difference. I'll post a link if I can figure out how.
#2039 of 2925 Re: 2007 V6 5AT [thegraduate]
Jul 02, 2008 (3:16 pm)
I know the original poster has since edited this, but he could have been riding the brake. Even worse.
#2040 of 2925 Re: 2007 V6 5AT [th83]
Jul 02, 2008 (7:29 pm)
I also notice less knocking with Premium fuel. However, I do not see any increase in FE of premium fuel, still under 20 mpg in city (stop & go). Mine is a 07 V6 auto. My shift point is mostly below 2500rpm. In my opinion, if there is a way to disable the Honda Grade Logic, maybe i can go above 20 mpg. This car cannot coast and force me to either brake or give it gas. Also when I apply brake, the Grade Logic downshifts very early and the rpm is always above 1200 to 1500 rpm . My other cars usually below 1000 rpm. It is designed to be driven on hwy rather (30 mpg combined easily 85%hwy/15%city)