balthazar

So you are no longer talking about fuel economy as realized by a vehicle owner, operating their vehicle in the real world on public streets and contemplating when to change their air filter; the way you opened this thread ("when driving "normally" around town or cruising down the freeway"). The only way these statements make sense to me is that we're now talking about an engine on a test stand in an controlled atmosphere with minimal to almost no variables, and certainly no vehicle/ drivetrain/ road speed/ variable terrain involved. Because: not 100%. 'Fuel economy' is expressed as 'MPG'; a calculation that incorporates distance covered. One can achieve the same mass air flow in park and get 0 MPG. A car's instant MPG reading is NOT solely based on mass air flow. Does a 30% throttle plate opening at 15 MPH result in the same MPG as 30% throttle opening at 75 MPH? Does a 30% locked-open throttle plate give the same MPG traveling UP a 25% incline, as DOWN it?

I feel like we're dancing round semantics. I'll agree that technically speaking, the gas pedal opens the throttle plate and fuel flow reacts to that. It -technically speaking- is somewhat different with carb'd vehicles as there is an initial physical 'pushing' of fuel via the accelerator pump. I don't see this as a relevant point however, because altered fuel flow is an inevitably linked result of opening the throttle plate, and -with a small lag- increases in step with air flow & engine speed. Gas pedal may not be physically connected with fuel flow in an FI engine, but you WILL get increased fuel flow when pressing the 'gas' pedal. It is not "throttled" by fuel supply, but it is it operated on BOTH. If we're talking here about fuel economy, we're talking about operating a vehicle in the real world, no? Watch a modern vehicle's instant mileage readout. Step on the 'gas' pedal from a stop and see a modern 4-cyl car return instant numbers of 3, 5, 11 MPG. This is a comparison of vehicle speed to fuel metered, IE; fuel economy. Same vehicle at level, highway speeds can return MPG numbers FAR above ratings- in the 50s and 60s. Lift off the pedal and see it go to 99 MPG. It is possible to place a lock on the throttle at -say- 30% and accelerate from a stop to 75 MPH. MPG will vary tremendously over that run as a byproduct of fuel metering (steady here) and speed (variable). But people in the real world won't accept accelerating from a stop @ 30% 'throttle plate opening'.

Pic I took a few years ago; Caddo ~

This is only true AT A GIVEN INSTANT in time. There will be a lag as fuel flow ramps up in accordance with engine speed, but if there was NO correlation, no engine could ever turn above idle speed and there would be no gas pedals. Carbs have this ability, readily. But would your scenario be achievable in actuality? If a given air filter (with many many times more surface area), either clean or dirty, can both pass more air than the throttle plate can, they both are rendered minimal factors. The result is the core variable is a throttle open 50% and one open 65%. I think this would be a real, demonstrable experiment if the air filter had the same area as the throttle plate (while wide open). IE; and 85mm throttle plate with an 85mm air filter.

I don't know about that. Snap-On does a roaring business with ridiculous, top tier pricing even though there are scads of cheap, reconstituted-crap Chinese tools on the market. Yeah- they sell too obviously, but quality can and does trump price in many instances.

The couple systems I watched videos on with lane departure warning, the systems read the reflectors in the roadway ahead and beeped at you if you crossed that line. They weren't demonstrating approaching traffic from the rear, only car positioning looking forward.

Model 3 currently starts at $42,450.

You are basically correct WRT carbureted engines; the pump of the gas pedal squirts some fuel into the intake (low pressure), while the starter rotates the pistons and starts (slowly) drawing air (and the fuel) into the combustion chamber. FI cars start squirting the fuel (high pressure) directly into the C chamber, eliminating the need to pump the pedal. MoPar carb'd vehicles didn't need to have the pedal pumped, since it took their engines a good 10 secs of starter cranking to fire when tuned/operating correctly.

I HATE that there's no mainsteam, volume American TV maker, phone maker, computer maker. There! But wait- how do we quantify this?? Apple is an American company, builds their phones in China. Does that make the phones Chinese?? Toyota is a japanese company that builds some of their raggedy vehicles in the US, does that make the raggedy vehicle American? Are South Carolina mercedes' now American vehicles? How come that never seems to be the case?

While I agree that the throttle body & air filter combined will place X amount of airflow restriction on a given engine, the general consensus would be a given driver will drive in a style that they are accustomed to. While steady-cruise is a irrelevant factor WRT fuel consumption, repeated acceleration/deacceleration runs (IE; around town/city) will show higher fuel consumption, as it is then that the vacuum is highest or W.O.. In order to go up 'Hill St' and make the green light at the top, a local driver may give their car 65% throttle. But decreasing airflow will have the driver give it more throttle/vacuum to make the light, which will increase the fuel flow accordingly. If an air filter had zero effect, racers looking for the last .100th wouldn't remove them on acceleration runs and show an improvement. Only way that happens is with increased airflow... which means increased fuel flow. Look at it this way: run the intake air thru 10 layers of dirty air filter- see if there's a measurable drop in FE.

'47 Buick Sedanette. Had to search a bit myself to ID it, and it did catch my eye as I posted it. - - - - -

I'm not dancing; I would like to see Tesla succeed. However, the blood already showed up for Tesla in Jan & Feb- leading the industry, one might say. Has anyone seen a single published blurb about Tesla's cratering sales? They are down 77% since December.

My target was actually lane departure warning. If you find this beneficial, you should not be behind the wheel.

Tesla's March sales numbers will be out in a few days- will be interesting to see if the catastrophic, cratering sales slide continues.

Having viewed various videos of these systems, I find it very hard to believe people would actually ask for them.

"ALL mercedes should have full leather standard, including a leather headliner and leather-clad wheelwells, then there should be 2 higher grades of leather available above that. I'd also like to see a fetal seal skin option."

I am reminded again that "all BMW grilles are made of metal, not plastic".

I have yet to see a personal running gag go on so long.

late 2021 = spring 2023.

Does audi build the A7 / A8s in the US or are they all imported? There has to be a considerable bottom (money) line when importing vs. building them in the market they are sold in.

Yeah- some indeed did. The MoPar 225 was one of the 'unkillable' I6s, but it came out in 1961. The old, decidedly unstressed Stovebolt 6 from Chevy was another- lasted forever, built for decades. But the Pontiac I6 was no longer lasting than their V8 (another very long-lasting 'plant). I'm not convinced cylinder arrangement is the leading cause of longevity- too many other factors. I have no data to contribute RE foreign I6s in this arena, tho.

I had that same 300 in my '94 F-150 - tough beast. But part & parcel of that longevity is the fact that motor was like what- 25 years old? All the bugs were long ago worked out of it, and the era it was gestated in was on the tail end of over-building motors.

I would agree that the amount of difference is too small to measure. However, I would disagree on a few points as stated. There have been a number of tests pitting different air filters against each other on a number of criteria. Where the said differences are much more measurable were found with oiled fiber (cotton) air filters (such as K&N units). The cornerstone of oiled filter's advertising has been 'increased airflow', and therefore increased speed at a given RPM, but these comparative tests showed repeatedly that oiled filters airflow rates decreased almost from Mile 1, falling steadily and quickly dipping below traditional dry filters. IOW; they only had higher airflow rates when completely clean. This is one reason OEMs don't ever use them (maintenance is another). If one is using an aftermarket filter, this may be a measurable factor. A short stretch of highway driving is not the ideal methodology to test MPG, as at-cruise operation uses very little fuel/airflow. A much better (but harder to duplicate exactly) would be an 'around town' loop where from-stop accelerations were repeated- much more typical of real world driving and encompassing higher airflow draws. This is where drivers would be better familiar with how their vehicle was performing relative to what they are accustomed to. This is where increased throttle position to match expected/desired/usual performance has a strong potential to indeed be measurable. But again; how to accurately reproduce this loop on repeated cycles.