jhu's Forum Comments
Showing all comments by jhu.
What are these engine options?
You should probably get rid of options that don't make any sense then. There are no 2 or 3 cylinder Jettas, for example.
posted by jhu January 30, 2010 at 10:47 PM
Diesel still better than hybrids?
It is a little strange. Over here you can drive a PZEV vehicle for thousands of miles before emitting as much pollution as using a lawn mower for one afternoon.
posted by jhu January 23, 2010 at 5:10 PM
Notice I said "passenger car." Trucks are in a completely different class. In the USA, not only do they not have as strict emission standards, but they also have much less strict CAFE standards. It's a big mess that should be change in a few years.
posted by jhu January 22, 2010 at 7:03 PM
There is also something else that the Europeans get with their diesels: dirtier emissions. Current passenger car diesels have to meet Tier II bin 5 if they're being sold in the USA, and they're just barely making that. Current Euro 5 standars are less strict. But once Euro 6 standards hit, watch the European diesel MPG numbers go down.
posted by jhu January 22, 2010 at 8:34 AM
fuel economy question
Oxygenated blend in the winter is one factor. The other factor is that the air is colder, hence denser. That means more air enters your engine on the intake stroke. To compensate, for emission purposes, more fuel is injected.
posted by jhu December 20, 2009 at 2:47 PM
Engine size + RPM + MPH = Best MPG?
"I'd like to see traffic enforcement for slow driving, because this forces others to pass, and drive faster (wasting fuel), and making the drive, less safe...
These things will have a grater effect, than what gear, or speed you drive (assuming, you going at least the speed limit)..."
The majority of semi drivers would be ticketed if that were to happen.
posted by jhu November 8, 2009 at 6:00 PM
Potential Savings Per Fuel-up Suggestion
I'm getting >50% of EPA, so it's not impossible.
posted by jhu October 25, 2009 at 11:02 PM
Engine size + RPM + MPH = Best MPG?
You also need to take transmission/gearing into it too. With that said, the easiest way would be to get the BSFC map for a particular engine and go from there. Unfortunately, I don't really know where to get these, although if you have a Scangauge II you could probably map it out for your engine.
posted by jhu September 14, 2009 at 2:39 PM
Location filter?
What is "H4" and "L4" anyway?
posted by jhu September 4, 2009 at 10:09 AM
TDI EPA figures off?
"You don't need to be an eco-nazi right-lane vigilante to get better mileage out of *any* vehicle - just be engaged and drive SMART."
No. You actually do really need to drive slower, and therefore in the right lane, in order to get the kind of numbers you're getting. I see your best is about 56 mpg/tank. You're either driving slower (ie, <= 65 mph) or you're using imperial units. There's no way around the laws of physics.
posted by jhu August 21, 2009 at 7:46 PM
comparing apples to oranges...
Also, I thought "L5" means it has 5 cylinders. If so, the '09 Jettas certainly do have 5 cylinders as the base gasoline engine in the USA.
posted by jhu August 17, 2009 at 12:55 PM
Can you add a filter by year and by car generation? The only ones I see are engine type and body style.
posted by jhu August 17, 2009 at 12:48 PM
What is the most efficient DRIVING SPEED? I have a Toyota Aygo ( and a Citroen Xsara Picasso)
To OP, what kind of transmission do you have? If you have an automatic, the slower you are able to go in the highest gear with torque converter lockup, the better your gas mileage. On the highway, usually the lowest people can generally tolerate is about 55 mph (if you have nerves of steel, you can go lower, or if you don't you go faster).
If you have a manual, generally pulse and glide works better than constant speed.
posted by jhu August 5, 2009 at 5:31 PM
TDI EPA figures off?
There seem to be a lot of hypermilers in the TDI crowd on this site, but the average TDI owner is not and is likely getting close to the EPA numbers.
posted by jhu August 5, 2009 at 5:25 PM
Picture / data issues
The faster IE 6 can die the better (at least so I've heard).
posted by jhu July 18, 2009 at 8:11 AM
VW Jetta fast riser
While it's true that the gassers are driving down the average mpg of Jettas as a whole, it's easy to see that there are two peaks on that graph. Also, the lead-foot TDI owners aren't helping either. Hell, I'm doing better than 1/3 of the TDI owners!
posted by jhu July 17, 2009 at 10:42 AM
New cars don't get along with fuelly
You let people drive your car???
posted by jhu June 8, 2009 at 8:06 AM
Reasonability checks on input
Hmm, actually 2.7 L/100km is 87 mpg. That's not really a practical possibility on a non-hybrid Civic, which would entail something like pulse & gliding between 10-20 mph with the engine off while coasting and doing that for the entire tank. However, on a hybrid Civic, it should be a practical possibility.
posted by jhu June 3, 2009 at 11:42 AM
48 mpg on a Civic is doable, especially if it's a manual since there are a few things you can do in a manual that you can't do with an automatic. Hell, I used to get ~40 mpg/tank on my '96 Civic, which was an automatic.
posted by jhu June 3, 2009 at 11:26 AM
AC on and fuel milage
According to my ScanGauge, at least at idle on my car, A/C uses 0.1 GPH. Normal idle uses 0.3 GPH, but with A/C on that increases to 0.4 GPH.
posted by jhu May 24, 2009 at 8:25 AM
Jetta vs. Jetta TDI
Results can be filtered by engine type, so there's really no need to make separate categories.
posted by jhu April 18, 2009 at 9:46 AM
Potential vs. EPA?
The new EPA numbers are on the fueleconomy.gov website. Or are they not in a format conducive to automatic updating?
posted by jhu April 10, 2009 at 9:58 AM
Jetta vs. Jetta TDI
As others have pointed out, there's really no need to separate Jetta and Jetta TDI, otherwise there'd need to be diesel versions for all the other cars. OTOH, there's the A4 and A4 Quattro.
posted by jhu April 10, 2009 at 9:08 AM
I don't think it matters. The shape of the fuel economy curve for Jettas has two peaks so i guess it's pretty easy to tell generally which ones are gasoline and which ones are diesel, although there's a recent TDI in there getting 30 mpg (how do you get that low on a diesel?).
posted by jhu April 6, 2009 at 11:57 AM
Pulse and Glide?
Pulse and glide - something that I was skeptical of until I actually tried it. It really does work. So what does this entail? The idea is to accelerate to a higher speed at about 3/4 throttle, then coast in neutral to a lower speed. Once the lower speed is achieved, put the car in gear and accelerate again to the set higher speed (eg, accelerate to 70mph, coast to 60mph to get an average speed of about 65 mph).
Now when the car's coasting in neutral, you can keep the engine on or off if you're driving a manual. If you're driving an automatic, turning off the engine will damage (most likely depending on your car, check your owner's manual) your car's transmission. If you're driving a manual and you coast with engine off, you can bump-start the engine instead of using the starter. Be aware that with the engine off, you'll lose power steering and lose power brakes after 3 full pumps of the brake so don't do this until you get some practice in low traffic areas such as an empty parking lot.
So, why does this work? Well, at cruising highway speeds your vehicle will really only need to use 20hp. But your car's engine is most efficient at low rpms and high engine load.
Results: I used to get about 30mpg on the highway. Now getting low-to-mid 40mpg on the highway is common.
posted by jhu February 22, 2009 at 10:57 PM