Beware old and new aero data

[freebeard]

I'd be surprised if any significant shortcoming fell through the cracks. We'll see.

I have no idea - I simply don't speculate without evidence.

So I guess we are all in agreement?

I just wish others did the same.

I guess speculate I should just shut up then.

[JulianEdgar]

Originally Posted by freebeard

So I guess we are all in agreement?

I guess speculate I should just shut up then.

I think the problem with car aerodynamics speculation is that either:

1) the analysis is overly simplistic, and so people start believing that it's as simple as looking at a shape with an expert eye

or

2) if the analysis starts to consider any of the myriad of inter-relating factors that are likely to be actually applying, it has to become even more speculative.

Not quite a perfect analogy, but it's a bit like commenting on cam specs by just looking at the shape of the lobe.

[freebeard]

Another problem is that 'stuck in quarantine' as I've been for more than a decade is it's the only thing available.

If I put the Dasher on the road, I might test fins on the [38°] hatch of my Dasher and use your throttle stop technique (not that it needs it ) but that wouldn't say much about the Cybertruck.

[California98Civic]

Originally Posted by freebeard

... I guess speculate I should just shut up then.

DIY is mostly not science, and it is partly the spontaneous art of necessity. EM is a science-interested DIY community, not a DIY-interested science journal. Science is highly valued, but then we mod the vehicles on the basis of what we have and can do. Speculation necessary.

[freebeard]

...because that's how you get your wooden motorhome.

[JulianEdgar]

Originally Posted by California98Civic

DIY is mostly not science, and it is partly the spontaneous art of necessity. EM is a science-interested DIY community, not a DIY-interested science journal. Science is highly valued, but then we mod the vehicles on the basis of what we have and can do. Speculation necessary.

Good example of a strawman argument.

What does the use (or not) of science have to do with speculation?

[freebeard]

https://en.wikipedia.org/wiki/Hypothesis

Quote by Frank Zappa: "Without deviation from the norm ...
https://www.goodreads.com/quotes/440...s-not-possible
Frank Zappa — 'Without deviation from the norm, progress is not possible.'

[JulianEdgar]

Originally Posted by freebeard

https://en.wikipedia.org/wiki/Hypothesis

Indeed. So to argue that speculation wouldn't occur if this were a "DIY-interested science journal", and can occur if this is a "science-interested DIY community" is to develop a strawman no one has used as their premise - ie that a "DIY science journal" precludes speculation.

And, as usual, the reply simply muddied the water by not actually addressing either point I made, viz:

I think the problem with car aerodynamics speculation is that either:

1) the analysis is overly simplistic, and so people start believing that it's as simple as looking at a shape with an expert eye

or

2) if the analysis starts to consider any of the myriad of inter-relating factors that are likely to be actually applying, it has to become even more speculative.

Not quite a perfect analogy, but it's a bit like commenting on cam specs by just looking at the shape of the lobe.

[Fat Charlie]

Actually, most of what happens here is speculation. Educated guesses, really.

Based on what I read here, I inflated my tires to max sidewall, and observed less speed lost in coasts and an increase in both short and long trip mpg. I could have ABA-ed it, I could have tried to eliminate variables to find exactly what improvement I was getting and studied the effects of even higher tire pressures, or I could have done what I did- accepted that it improved things and stuck with it.

A year after I got my current car, I put in a grille block. Again, based on reading here that it generally improved things. I found a greater amount of speed retained in coastdowns and come the next winter the increase in cabin heat allowed me to take my gloves off after 10 miles (down from 20) and my hat off after 20 miles instead of still having it on at the end (over 40).

Hardly science. Maybe more science than current public health policies employ, in that my actions were informed by science, but still not sctually scientific. And that's okay. It was actually a crappy grille block, stealthy, yes, but held in place with a couple wires and some duct tape. It came partly loose after it punched through its first snowbank, losing some of its aero benefit but probably enhancing its thermal benefit by being against the radiator. Don't know, don't care. The aero was still better than stock and the coolant temp never got higher than I was comfortable with, even in traffic in August.

Since I don't have a wind tunnel or a budget, I'm not going to do the legwork to tell the world exactly what needs to be done to a 2nd gen Honda Fit to improve its aerodynamics the most. Because no one cares- The 4th gen is already out. And that's where we here at Ecomodder are at: we've all got the cars we have, for whatever reasons. We're all looking for ways to get the most out of them, and unless someone has the exact same vehicle and has done extensive, actual scientific research on it, all anyone here has to offer are generalities. They're ugly, but they're still helpful.

I've maintained that the best ecomod, even more than the nut behind the wheel, is vehicle choice- but we all have needs and restrictions. I consider myself lucky that my circumstances let me buy a relatively fuel efficient vehicle that met my needs. I would have come across it in my search, but kudos to PaleMelanesian for showing the Fit's capabilities. Thanks to him it was already on my list when the time came to get a new car.

But arguing over aerodynamic ideals, while interesting and educational to laymen, are totally irrelevant to people who already own cars. My grille block could have been better. Someone else's boattail could have had a more ideal angle. But my grille block helped me, and an imperfect boattail is better than my stock hatchback. And that's what Ecomodder is about.

[JulianEdgar]

Originally Posted by Fat Charlie

Actually, most of what happens here is speculation. Educated guesses, really.

Based on what I read here, I inflated my tires to max sidewall, and observed less speed lost in coasts and an increase in both short and long trip mpg. I could have ABA-ed it, I could have tried to eliminate variables to find exactly what improvement I was getting and studied the effects of even higher tire pressures, or I could have done what I did- accepted that it improved things and stuck with it.

A year after I got my current car, I put in a grille block. Again, based on reading here that it generally improved things. I found a greater amount of speed retained in coastdowns and come the next winter the increase in cabin heat allowed me to take my gloves off after 10 miles (down from 20) and my hat off after 20 miles instead of still having it on at the end (over 40).

Hardly science. Maybe more science than current public health policies employ, in that my actions were informed by science, but still not sctually scientific. And that's okay. It was actually a crappy grille block, stealthy, yes, but held in place with a couple wires and some duct tape. It came partly loose after it punched through its first snowbank, losing some of its aero benefit but probably enhancing its thermal benefit by being against the radiator. Don't know, don't care. The aero was still better than stock and the coolant temp never got higher than I was comfortable with, even in traffic in August.

You'd rather do mods that provide results less effective than you could possibly achieve, because you just don't want to do some simple testing of alternatives? That seems pretty strange to me, but your choice.

Originally Posted by Fat Charlie

Since I don't have a wind tunnel or a budget...

You don't need a wind tunnel, and modifying cars is impossible with no budget, but carry on....

Originally Posted by Fat Charlie

... I'm not going to do the legwork to tell the world exactly what needs to be done to a 2nd gen Honda Fit to improve its aerodynamics the most. Because no one cares- The 4th gen is already out.

What on earth does this have to do with modifying your car to get the best results?

Originally Posted by Fat Charlie

And that's where we here at Ecomodder are at: we've all got the cars we have, for whatever reasons. We're all looking for ways to get the most out of them, and unless someone has the exact same vehicle and has done extensive, actual scientific research on it, all anyone here has to offer are generalities. They're ugly, but they're still helpful.

That is simply not true. Anyone can test their car and its modifications. That you chose not to doesn't make it the only way. (And in fact lots of people here test their modifications - eg by long distance mileage.)

Originally Posted by Fat Charlie

But arguing over aerodynamic ideals, while interesting and educational to laymen, are totally irrelevant to people who already own cars.

Er, why? Arguing ideals is exactly the discussion you'll find when describing any good car modifications - from cylinder heads to suspension, from ignition timing to air/fuel ratios.

Originally Posted by Fat Charlie

My grille block could have been better. Someone else's boattail could have had a more ideal angle. But my grille block helped me, and an imperfect boattail is better than my stock hatchback. And that's what Ecomodder is about.

I hope not, but if you say so....