[vineethvazhayil]

Originally Posted by chevelle

I am not just pointing fingers to Hyunda/Kia. It is applicable to Ford Escape too as i have not read one review that says it matches the EPA. Most of the time it is huge difference.

Yes, there are many brands/products that have been designed to ace the EPA test and which fall short in real world conditions. I think the Chevy Traverse/ GMC Terrain twins fall in that category. I read a lot about their mpg discrepancy when I was looking for an entry level CUV.

[VLOCT]

For the mpg concious;

As everyone knows, mpg measurements are purely driver related. Your driving habits are going to decide it, period. Case and point; in one Top Gear episode, they compared an M3 against the Prius. The M3 driver followed the Prius around, essentially mimicking the Prius driver. Guess what, the M3 ended up with the better mpg, I'm sorry, I couldn't contain myself. From an auto enthusiasts perspective, the Prius driver has given up everything dear to a genuine driver for the holy grail of mpg and environmental conscientiousness, and here comes his antithesis and thumps him in his home field. There surely is a god in heaven.

Common beliefs are sometimes not that correct, as I have observed when it comes to hitting the sweet spot for mileage. The theory is that driving at 65 mph will save substantial fuel compared to 75 mph (up to 25% savings, they claim). However, my observation for powerful cars is that, usually 70 -72 mph gives a better average than 65 mph. I attribute this to the fuel savings from the higher momentum generated by these cars.

It is well worth it to try out different speeds on different days for your commute, to find your cars' best cruising speed. Generally, speeding during urban commute is the biggest waste of gas for almost no gain in time unless, the commute is longer than 60 miles one way and all highways/freeways.

[amitoj]

Originally Posted by VLOCT

Case and point; in one Top Gear episode, they compared an M3 against the Prius. The M3 driver followed the Prius around, essentially mimicking the Prius driver. Guess what, the M3 ended up with the better mpg, I'm sorry, I couldn't contain myself. From an auto enthusiasts perspective, the Prius driver has given up everything dear to a genuine driver for the holy grail of mpg and environmental conscientiousness, and here comes his antithesis and thumps him in his home field.

I had to look this up so that i could send its links to all my snooty tree hugging friends in CA. Sadly, I could not because this comparison was done on a race track where Prius was driven pedal to the metal which was just cruising speed for M3. It was M3's home turf actually. Still, good fun though.

But i do see your point and agree that how you drive matters a lot. What you drive also matters though in everyday driving conditions.

What I have found most beneficial is to find a speed at which you dont have to give too much input to either brake or accelerator. The longer you stay in cruise control mode, more are your chances of getting a better mileage.

[vineethvazhayil]

I just read this about the VW Passat TDI, a high mpg car. About.com on the Passat Tdi. There is a comment on the fuel efficiency of these cars being routinely higher than EPA rated and the fact that manufacturers compromise on shift quality and throttle response. I have owned the last gen Jetta TDI and used to go more than 550 miles without filling up on the highway, very often. So it used to routinely meet or exceed the EPA estimated 41 mpg rating. I would have driven normally (5 to 10 above speed limits in Texas) with no intention of achieving high mpg. So the variance is very much there in engine to engine, car to car etc on top of your own driving style.
On a side note, My Subaru has started giving better mpg in the Mid West(flatter roads) as opposed to what I used to get in the North East.

[maddy42]

Originally Posted by chevelle

Thanks for coming out of closet to reveal your identity.

What kinda mileage you get? I have many friends who don't get anywhere close to EPA estimates on their Sonatas and Genesis. When i had hyundai rentals, it was the same issue.

Haha thank you thank you. Good under the belt joke

Anyways my GC is good. Just got back from an indian vacation driving a fortuner so the genesis is a drastic change.

Mileage- 19 in city 22 or 23 in the highway(Winter)

and the funny part
Summer - 16.9!!! City. 22 highway. No idea but the faster the ac and the hotter the outside air the lower the mileage.

Anyone has a sonata and knows the mileage of this car?

[Technocrat]

My car is pretty close to EPA estimates, I thought those figures would be like the bloated ARAI figures in India but that isn't the case

The EPA estimate for my car(2008 Accord V6 Sedan) is 19 mpg city, 29 mpg highway and 22 mpg combined.

I get around 22.xx for my regular city commute, Highways its around 28.xx.

The worst in city driving was 17.xx & best 25.xx. Highways Best 29.xx & worst 26.xx

[Jomz]

Originally Posted by VLOCT

Common beliefs are sometimes not that correct, as I have observed when it comes to hitting the sweet spot for mileage. The theory is that driving at 65 mph will save substantial fuel compared to 75 mph (up to 25% savings, they claim). However, my observation for powerful cars is that, usually 70 -72 mph gives a better average than 65 mph. I attribute this to the fuel savings from the higher momentum generated by these cars.

Some engineering facts.

Fuel burnt/sec = Power required to accelarate + Power required to overcome friction + Power against wind drag + Power for accessories (negligible)

Power againt wind drag = 0.5 * Coefficient of drag * frontal area* speed ^2.

So depending on your car shape (lower and sleeker) the drag forces on the car would be lesser and the power against wind drag spend would be lesser. I think that is what you are seeing from the high horsepower cars, not high momentum generated or anything. If high momentum saves fuel, heavy cars like Hummers would be saving fuel, While light cars waste fuel.

And being involved with EPA mpg cycles, They are very close to 90% of the driving in the US. They are made based on a lot of market surveys , customer feedback and stuff-- and are revised frequently, the last revision was in 2008.

If anybody is interested here is the actual test cycle
http://en.wikipedia.org/wiki/FTP-72

[chevelle]

Originally Posted by maddy42

Haha thank you thank you. Good under the belt joke

Anyways my GC is good. Just got back from an indian vacation driving a fortuner so the genesis is a drastic change.

Mileage- 19 in city 22 or 23 in the highway(Winter)

and the funny part
Summer - 16.9!!! City. 22 highway. No idea but the faster the ac and the hotter the outside air the lower the mileage.

Anyone has a sonata and knows the mileage of this car?

Oh man, nothing like that. It was a poor attempt at humor.

Looking at your numbers, i feel good about my car that is giving same as yours but with v6 engine and porky 35xx lbs.

My close friend has a sonata. Her overall FE on daily commute is about 23 mpg that include 50-50 C/H driving. I don't know her driving pattern so can't comment.

[VLOCT]

@Jomz,

I wish you'll stop quoting engineering formulas to me. I practice engineering as a Principal Engineer of a company.

I'm not comparing brick shaped SUVs to cars. If you think momentum doesn't play a part in automobiles or in fact any object in motion, I am not going to say much. For all practical purposes, for most 'modern' cars, the effects of co-eff. of drag and friction makes a difference only at high speed limits, not at regular commuting speeds. Maintaining a constant forward momentum and the kerb weight is what will make the most difference in your fuel consumption.

That's the reason I said that each driver should find the sweet spot for his car 'cause it depends on factors such as weight, shape, momentum etc.

[Jomz]

@ VLOCT

Rate of change of momentum is what requires fuel. To maintain momentum, we don't need to burn fuel.

"An object that is in motion will not change its velocity unless an unbalanced force acts upon it. This is known as uniform motion"- Source Newton's First law.

The unbalanced forces which cause to drop momentum are friction and wind drag. So basically at a steady state, we are burning fuel to overcome friction and wind drag (at all speeds- not only high speeds) , not to conserve momentum. If conserving momentum needs fuel, all the satellites in orbit would be continously burning fuel.

But, you are free to believe whatever. I'm posting whatever I've read. This is a free board, I assume

[VLOCT]

@Jomz;

And as far as I know, unbalanced forces exists everywhere except in a vaccuum. And 'uniform motion' as Newton explained exists only in vaccuum. And we don't live in one.

I was talking about a 'maintaining a constant momentum' while, you're talking about conserving momentum. Your example itself proves my point. Satellites maintain a constant momentum (thanks to gravity) and hence require minimal on-board fuel.

All I said was, if you can maintain constant momentum you can save fuel. And my personal observation is that, it seems with more powerful cars you can maintain a higher speed for their optimal fuel consumption. I don't see why this sounds so controversial and needs such lengthy scientific dissection.

I'm done with this topic and readers can make their on conclusions. Thanks for the discusssion, anyway.

[Jomz]

Originally Posted by VLOCT

@Jomz;

And as far as I know, unbalanced forces exists everywhere except in a vaccuum. And 'uniform motion' as Newton explained exists only in vaccuum. And we don't live in one.

.

It does not exist outside a vacuum because of wind drag & friction.

Anyway let us agree to disagree and move on.

[maddy42]

Originally Posted by chevelle

Oh man, nothing like that. It was a poor attempt at humor.

Looking at your numbers, i feel good about my car that is giving same as yours but with v6 engine and porky 35xx lbs.

My close friend has a sonata. Her overall FE on daily commute is about 23 mpg that include 50-50 C/H driving. I don't know her driving pattern so can't comment.

Hey was just kidding

23 for a sonata is a bit low is what i think. Guess the elantra has better mileage. There is some issue with mileage i believe. But yeah the ride and feel is great.

Good mileage for a V6! My friends Mustang gives something similar.

Maddy

[Gandhi]

Submitted my claim for Hyundai's false mileage claim reimbursement. I will be getting $9.48 for the miles I've run so far .

[maddy42]

Originally Posted by Gandhi

Submitted my claim for Hyundai's false mileage claim reimbursement. I will be getting $9.48 for the miles I've run so far .

LOL! Sorry dude but i havent done it yet. I am still trying to get to the Millions of $ this is going to cost hyundai part!