2GN.ORG

darthroush wrote:Your beloved FuelEconomy.gov site also says that the Neon only gets a combined of 25MPG and 29MPG on the highway:
http://www.fueleconomy.gov/feg/noframes/20694.shtml

We must all be lying about the gas mileage we get too.

LOL. Nah no way. Further proof that you should never trust the government.

What is the difference in ''actually driving'' and cruising? My statement stands and my observation only backs it up. You said it isn't great for mileage, care to explain why?

Once calibrated, my scangauge has been right on under a wide variety of conditions. Anything from commuting around town to driving 10 hours and using a full tank. Once calibrated, it's great. I think the most it was off before calibration for me was 3.9%. It doesn't sound like your testing is too solid.

The the other charts make it plain to see that lower speeds in top gear is where it's at.

Cruising is considered maintaining a certain rpm at low load/vacuum.

Transmissions have an efficiency. Say the input shaft is spinning 60rpm, the output shaft would be at say 5 rpm in first and 28rpm in fifth. It's obviously more efficient at the higher output shaft rpm. The same linear logic can't be said about engines though. Look at a dyno sheet, the power produced by an engine is not linear across its rpm range. If you can overlay that with actual, logged fuel consumption (not what some OBDII device is telling you based off engine vaccum), then you'll have better idea of what gear you should be in to get optimum efficiency.

This image does a much better job of indicating optimum shift/cruise points. lowest rpm is now always best.


It's all circumstantial. Going 20mph in 5th gear while climbing hills not going to give you good gas mileage. You're going to be close to WOT, and the PCM will be in open loop, using a richer table. Not to mention if its at a low enough rpm, the engine will lug and buck[/img]

darthroush wrote:

fusion210 wrote:

darthroush wrote:Changing my dirty air filter helped a bit too
I changed it at it's normal interval, but it was much dirtier this time around. The only difference was no air silencer. Who knew it was actually good for something?

Changing your air filter from a dirty one to a clean one does not have an effect on gas mileage in a newer car. http://www.fueleconomy.gov/feg/pdfs/Air ... 6_2009.pdf

The study says there is no significant effect on fuel economy, and it did not show 0 improvement 100% of the time. You cannot conclude that a new filter will NOT help at all based on the results, such as they did. I did not say the clean filter gave me 5MPG. I simply said it helped a bit. When you drive ~2,500 miles per month and don't have a decent amount of expendable income, every little bit helps. Dirt was falling off of the filter when I tapped it, as well as the element being a completely different color than the new one. It was well used.

Your beloved FuelEconomy.gov site also says that the Neon only gets a combined of 25MPG and 29MPG on the highway:
http://www.fueleconomy.gov/feg/noframes/20694.shtml

We must all be lying about the gas mileage we get too.

It was a controlled test in a lab by professionals, reducing the variables to the air filter and tested over three cars. Are you comparing it to your observation that includes many more variables that would skew the results? How could you consider that anywhere near a valid comparison? How can you, darthroush, make the argument that their 3 cars in a lab under controlled conditions with the air filter being the only change isn't good enough, while your daily driving is?


How could I not conclude that it doesn't help unless the filter is severely clogged/damaged as it was when they worked their way up that extreme? There was even a slight increase when it was just clogged. There a difference of just 1.1-1.8% at most for the severely clogged test, the filter restricted to such a point it tore itself. I'd say that's a bit more than a color change and ''dirt falling out''.

The link you posted to a neon getting 25mpg city/29mpg highway is under the EPA's drive cycles. I have no problem believing that under their testing conditions that those ratings are close. They are only estimates.

City cycle

* Trip length: 11 miles
* Test time: 31 minutes
* Number of stops: 23
* Time spent idling: approx. 18%
* Maximum speed: 56 MPH
* Average speed: 20 MPH
* Engine temp at startup: Cold (75 degrees outside air temperature)

Highway cycle

* Trip length: 10 miles
* Test time: 12.5 minutes
* Number of stops: None
* Time spent idling: None
* Maximum speed: 60 MPH
* Average speed: 48 MPH
* Engine temp at startup: Warm

New method (2008 and later)
It's common knowledge that EPA fuel economy estimates do not reflect real world mileage, and are particularly advantageous for hybrids. Because of these known discrepancies, the EPA decided to revise its testing methods. Tests will continue to use a dynamometer. Changes will include:

* Higher speeds - up to 80 MPH on the highway cycle
* Colder temperatures - tests will now start at 20 degrees Fahrenheit rather than 75
* More rapid acceleration
* Use of accessories - the air conditioner will be operated 13% of the time

If you're saying that because people get different mileage than the epa tested estimates, while driving under different conditions than their tests, and that because the two things come from the same website it makes the air filter test invalid... wow

ZeroChad wrote:

What is the difference in ''actually driving'' and cruising? My statement stands and my observation only backs it up. You said it isn't great for mileage, care to explain why?

Once calibrated, my scangauge has been right on under a wide variety of conditions. Anything from commuting around town to driving 10 hours and using a full tank. Once calibrated, it's great. I think the most it was off before calibration for me was 3.9%. It doesn't sound like your testing is too solid.

The the other charts make it plain to see that lower speeds in top gear is where it's at.

Cruising is considered maintaining a certain rpm at low load/vacuum.

Transmissions have an efficiency. Say the input shaft is spinning 60rpm, the output shaft would be at say 5 rpm in first and 28rpm in fifth. It's obviously more efficient at the higher output shaft rpm. The same linear logic can't be said about engines though. Look at a dyno sheet, the power produced by an engine is not linear across its rpm range. If you can overlay that with actual, logged fuel consumption (not what some OBDII device is telling you based off engine vaccum), then you'll have better idea of what gear you should be in to get optimum efficiency.

This image does a much better job of indicating optimum shift/cruise points. lowest rpm is now always best.
[img]http://i87.servimg.com/u/f87/12/17/44/51/saturn11.jpg[/i mg]

It's all circumstantial. Going 20mph in 5th gear while climbing hills not going to give you good gas mileage. You're going to be close to WOT, and the PCM will be in open loop, using a richer table. Not to mention if its at a low enough rpm, the engine will lug and buck[/img]

None of this has to do with what I said. You implied that cruising at a speed in a gear is different than driving at that speed. I want to know what the difference is. Climbing hills going 20mph in fifth gear with a bucking engine is ridiculous. If you think that's what I meant, then you are mistaken. Lower revs, but not the lowest revs. My car would be at ~800rpm going 20mph in fifth. Unpossible.

I'll ask again, how is cruising in a gear not, as you put it, "actually driving?" Driving includes a lot of cruising at the same speed unless it's city driving/heavy traffic, thus what I said applies greatly. What I said about someone cruising at 35mph in fifth is dead on. If you're talking about stop and go driving, highway driving, city driving, add in some racing and idling at a drive through while picking up some Taco Bell than cruising at 35mph clearly isn't going to work. If trying to make cruising in one gear under changing conditions is what spawned this whole thing I will be a sad panda.

I already know how BSFC works it's way in, you can see that from a previous post I've made in this thread. I said nothing about shift points, that's a whole other chapter.

It's all circumstantial? Well, yes, the circumstances have been pretty well laid out on my end. The only ones you've mentioned are driving up a hill going 20mph in fifth at near WOT.

There is no need to get a really fancy tool to measure the exact fuel consumption in real time because you don't trust anything else. It's been tested over tanks of gas under different speeds by many people. 40mph is always better than 70mph, for example. There is nothing wrong with the way OBDII instruments can measure fuel consumption. The margin of error is more than acceptable and the results of going slower in top gear have been proved time and time again by calculation fuel use by dividing the fuel consumed measured at the pump vs distance traveled. There are also bunches of fuel measurements from on board factory computers showing top gear/lower revs are optimal, but I'm not sure if you trust those either.

How can I make that argument? I read the conclusion of the test. Nowhere did it say that an air filter change resulted in a 0% gain 100% of the time. 1%, though very low, is still more than 0. What about that doesn't make sense?

If you're saying that because people get different mileage than the epa tested estimates, while driving under different conditions than their tests, and that because the two things come from the same website it makes the air filter test invalid... ROFL wow

I never said the air filter test was invalid because of that. Where did I say that? The test itself, that you linked to, said exactly what I typed (I plagiarized for all academic purposes here).

First you say we must agree the air filter test is 100% accurate of a 0% gain, 100% of the time with a clean filter because it was done under controlled conditions, but people getting different MPG ratings than under their controlled tests is a no-brainer? Pick a side.

I don't really care too much if the new air filter really gave me an extra 1% MPG or not. The thing was dirty. It needed to be changed. I'd venture to say something about silicone in engine oil, but I'd hate to hear how that isn't affected by a dirty filter...