If I encounter this a lot in my daily commute, what can I expect in terms of FE with the HAH? Do these constant stop and gos hurt the HAH? And finally, with this type of driving am I better off with a traditional gas-powered vehicle?

 

My wife drives an 05 hah and avg mpg in town is 26-28. Her commute rarely ever gets over 35mph and is only 7 miles long each way.

She drives the car gently and it rewards her with very decent mpg in town.

 

That's good to know. I guess the bigger question is what is the long term effect of continually starting and stopping an engine? Say I'm stuck in bumber-to-bumper traffic and have to edge forward a couple of feet for a few miles.

Theoretically, the engine could start and stop 50 times or more. Multiply that by years of operation. This can't be good for an engine, unless of course Honda has already considered this. Could this be why the viscosity of the reccommended oil is so thin?

 

Kelly,

If you're worried about this you may wish to consider a different hybrid. If I'm not mistaken the HAH is a mild hybrid which cannot be run on electric alone, so it's ICE only stops when the car is stopped. So it will be starting and stopping when you're stuck in traffic.

The Prius and Camry are full hybrids, meaning it can run on the ICE, electric motors or both together. So in stop and go traffic it's possible with mild acceleration to keep the ICE off.

The HAH and Camry are built to differing philosophy. The HAH takes a 6 cylinder engine and gets extremely impressive performance with a slight increase in fuel economy. The Camry uses a 4 cylinder engine, gets better performance than the standard 4 (but not as good as the 6) and gets about 60% more mpg.
If you're going to be doing a lot of stop and go you probably wouldn't be able to use the performance of the HAH. You may want to check out the TCH. Also, the TCH gets a $2600 tax credit, the HAH I believe is about $600.

 

My commute within a major metropolitan area is almost exactly like Tony's wife (8 mi each way, 35 mph max, stop and go), FE minimum is around 25 mpg and I can squeak 30 to 32 mpg out if it's not winter and I choose a little bit longer route with sections of streets with fewer traffic signals and short sections of freeway. So the average is probably 27-28 mpg.

Re: stop and go. Auto-stop will not function after 3 "stops" unless the vehicle travels over a certain mph (10 mph, from memory, but I could be wrong). So, if in a real "jam" and creeping forward, the ICE will run unless you create a gap so you can accelerate over 10 mph to reset the Auto-stop (and we all know what ususally happens to that gap ) . I don't know the long term affect of multiple restarts, but I have always wondered (and a little concerned) about starts and stops in extremely hot weather. When the ICE stops, the coolant no longer circulates, so it looks to me like the cylinder wall, etc. would heat up rapidly while the ICE is off, only to be suddenly restarted. I just have to assume (and hope) that those sharp engineers at HMC have this all figured out and time tested.

 

I thought Toyota reached it's 60,000 limit and all credits were cut back 50%?

 

Great info! Thanks for the post. The HAH is so darn complicated I think an extended warranty is pretty much a no brainer. That's what I plan to do.

 

They have, but you still get the full credit through the end of the next calendar quarter. In Toyota's case they sold their 60,000th hybrid in early June (2nd quarter) so you'll get the full credit for purchases through Sept. 30 (last day of 3rd quarter).

 

I average between 27-29 city ---> 7 mile commute: 5 stop signs, 3 stop lights, one ID checkpoint.

 

I think in the entire time I had mine, I never saw less than 26-29 in these conditions. However - it will vary greatly depending on the length of your commute and other factors like temperature, the greatest factor being operator input.

The sad part is having a nice average built up and then hitting a long traffic jam and watching your efforts up to that point go out the window (or, tailpipe, as it were)

IMO, the only two things to worry about, longevity-wise, would be the oil (possible shear / acidity buildup from the starts/stops), and the IMA battery getting extra wear from discharging during all of the auto-stops (you'll note the loss of one of the six charge bars for every four auto-stops you make in bumper-to-bumper traffic - till you get to one bar remaining, and then you'll lose auto-stop entirely). I had my oil regularly analyzed by a lab, and it held up very well (I used Mobil 1 5W-20 and changed at 7000-7500mi intervals when the 'service' light came on). W/ regard to coolant / engine temp - I don't see that as an issue, to be honest. I'd be more worried about the oil condition and it's ability to lubricate effectively. That's why they tell you to change it more often if you short-trip the car on a constant basis. Honda's 3.0L V6 is darned near bulletproof; however, it does still use a timing belt, so change it at about 90K or so to be safe (spec'd for 105K replacement interval per Honda)

Are you better off with a traditional gas-powered vehicle ? Well, it depends. Are you buying the car for the mileage improvement only, w/o regard for the refined power of the V6 ? Get the Accord with the 2.4L engine, because you'll never, ever make up the pricing delta between the I4 and the V6 IMA with gas savings alone - unless you drive the car for about 200K mi.

Are you buying the car because of the improved (greatly lessened) emissions ? In this case, the IMA Accord makes better sense - because of the auto-stop (makes more difference than you think), and the fact that it runs on 3/6 cylinders at steady-state cruise.

Would you not buy the car with a four, but only with a V6 ? (this was me, btw...) The IMA Accord makes sense here, too, because you've got the nice attributes of the V6 (very smooth and powerful throughout almost the entire RPM operating range, PLUS the added torque of the IMA motor!), but will also get about 10mpg better, especially if you do a lot of suburban / highway miles.

As an open road highway car, it has very few peers, from an all-round standpoint, and you can get low- to mid-40s with the car without much effort at all under those conditions. But urban city driving kills the mileage. Can't lie to you there.

Oh, and finally - the tax credit for the '06 HAH is $1300, as long as it has the 'calibration control update' (cars built after April have it from the factory, earlier cars have to be updated at the dealer).