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I looked at the milage logs, and the regular honda civic automatics are getting slighly better fuel economy on avg than the manuals (about 1mpg on avg).

this surprised me, as i thougt that the best fuel economy was always with a manual.
is this just a fluke, or is there something to this?


im planning on buying a used honda civic soon (2006-2009) and i want an automatic for convenience, but only if it gets about the same fuel economy as the manual.

i practice moderate hypermiling, nothing extreme though.

thanks for any input.

-phil

Honda MTs are notorious for their short boy-racer gearing. (I guess that's why it's so common for Civic MT owners to replace the gears.)

So, as long as most of your miles are cruising you aren't suffering the normal AT disadvantage. Plus the AT Civic can be flat towed which allows it to be FASed.

I don't normally have our 2008 Civic AT as my dedicated commuter, but last time I did I got two 44mpg tanks on mild spring commutes (20.6/20.8) just with max 55mph, NICE-on, smart braking, and some DWB and DWL.

If FE is your primary objective with the civic- then you need to consider where you drive- but in reality, the diff is probably nominal.

If it's mostly suburban routes that you drive -then the MT has the advantage. If it’s primarily long open stretches (i.e. highway, rural etc.) then the AT wins. I consistently get north of 45mpg via my completely suburban commute (9-10 miles with 10+ stop lights)- I think 50mpg is within reach. The AT’s taller gearing would make these numbers hard to reach. On the highway I max out at 46-47mpg- where as the AT seems able to get 50+ if HM.

I think the MT runs 500+rpms higher 60mph than the AT does.

The MT still has the advantage on the highway if you can do high speed P&G, but it takes a lot of concentration, good instrumentation, and strong shins. ;) DWL at highway speeds in my Elantra tops out somewhere around 37mpg. I can easily pull low 50's with P&G, though. In the right conditions with low enough speeds I can top 60mpg on the highway. Around town I'm at mid to high 70's in good weather.

This is with advanced hypermiling of course, but as always, YMMV.

On my tall geared 92 MT Civic, which predates the move to short gearing in Honda MT's, on the same flat road where I'm getting 100mpg in 5th (1925rpm@60mph), if I shift to 4th (2500rpm @60mph), the mileage drops to 80mpg. RPM's have a big effect on mileage which I don't know why Honda doesn't address in their new MT's. The highway mileage on the MT Fit and Civic could easily be bumped up another 5-10mpg by dropping the 60mph rpm's below 2000. Some of the Metro drivers at Ecomodder retrofitted lower ratio 5th gears in their transmissions and gained about 5 mpg highway mileage.

Too bad it is so expensive to have custom gear ratios created. :(

(Most modifications of the sort Eric references are done with swaps with gears from other transmissions which already have the lower ratio.)

If you don't have to go above 60 mph the short gears are not a problem. See my results below. ;) My 5th is like basjoos' 4th, 2500 at 60. The newer civics are about the same. Above 60 the automatic has the advantage. If you do mainly (80%+) highway I'd get the auto.

great input guys

these cars are all designed these days to be a happy medium between performace and fuel economy, which means they pretty much suck at both.

take the 2006 civic. the engine is much larger than a hypermiler needs. the gearing isnt optimal for fuel economy. the cam/torque curve isnt optimized for drivers that spend 99% of their time at 800-2000 rpm, etc, etc, etc.

I WISH THAT FACTORYS WOULD GIVE A FUEL ECONOMY OPTION FOR CARS - A special model that has all engine/tranny parameters optimized for fuel economy.

has anyone tried running oversized wheels/tires to try to reduce their overall RPMS throughout the driving range. i would think that would be a cheap/simple option.
although i know larger wheels have greater rolling resistance.

On my tall geared 92 MT Civic, which predates the move to short gearing in Honda MT's...

Better to say: "...which predates Honda's move to only having short gearing..."

My 1990 CRX Si runs 3000 RPM at 60 MPH. It's a real pain from an FE standpoint, let me tell ya! Of course, at that time they also had the CRX HF, which had very tall gearing. (No, I don't know the exact RPMs at 60 MPH off the top of my head, but it had a tall 5th and a taller ring and pinion ratio!)


I WISH THAT FACTORYS WOULD GIVE A FUEL ECONOMY OPTION FOR CARS - A special model that has all engine/tranny parameters optimized for fuel economy.

There's a Civic HF that's coming out soon, or is out now. It's supposed to be more optimized for FE than the standard Civics. There's also the Cruize Eco, and a couple of other options from GM and Ford. We can wish that they were pushed even more in the direction of FE, but at least there is some effort being made.

-soD

i just checked the gear ratios for the new body style honda civic

multiplying the highest transmission gear (5th/6th, etc) by the final gear = best overall gearing

(a lower number is better)

Automatic - 2.32

5 speed - 3.12

6 speed - 3.14

CVT - 2.08


the 5 and 6 speeds are not good. the last gear should always be the fuel economy gear,
and honda really misses the mark on this

as a comparison, take the z06 corvette's 6th gear * final = overall ratio - 1.915
with my z06, i could cruise around in 6th gear, running 600-800rpm, getting 30-40mpg!

anyway, the honda automatic will result in significantly lower rpms than the 5 speed.
so it looks like i will be buying the automatic

the CVT looks ideal, if they were just more durable

I'm pretty sure the CVT only comes with the 1.5 engine and a battery pack in the trunk... Hybrid.

The 1.8 isn't necessarily oversized, just overgeared. Honda's continual refusal to make good gears on their manuals has me looking elsewhere. My driveway has two Hondas in it, and they're likely the last I'll have. If someone else makes the right options available, I'll go there instead.

(The same goes for Ford and their Fiesta - terrible gearing)