Beware old and new aero data

[California98Civic]

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.

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.

Exactly Fat Charlie (three words that sound like a 70s TV jingle).

Julian, it is not a reply to you. It is a reply to freebeard. And it is not a refutation of freebeard's quip, either. It's my own assertion, riffing on my experience of what goes on here.

[Fat Charlie]

Originally Posted by JulianEdgar

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.

Because while perfect is great, I already have a job. And a family, a house, and all sorts of other things that take a lot of my time. And with a couple fast and dirty mods and no testing, my best tank in this car was 56 mpg over 575.9 miles in a car rated 29 mpg combined. Maybe that tank could have hit 57 mpg if only I'd devoted more time to aero testing, but alas! I have other things to do with my time. I dropped my kids off at camp every day, got to work on time, picked the kids up, got to the grocery store, and did all sorts of other things.

I knew deep down that my car wasn't the ideal aerodynamic shape, but I tolerated it because it carried the family and groceries and other things, and with attentive driving and a couple mods that apparently are only worthy of scorn, I still got nearly double the EPA rating for the car.

Maybe if I'd put more time into testing I'd have gotten 57 mpg on that tank, I don't know.

[JulianEdgar]

Originally Posted by Fat Charlie

Because while perfect is great, I already have a job. And a family, a house, and all sorts of other things that take a lot of my time. And with a couple fast and dirty mods and no testing, my best tank in this car was 56 mpg over 575.9 miles in a car rated 29 mpg combined. Maybe that tank could have hit 57 mpg if only I'd devoted more time to aero testing, but alas! I have other things to do with my time. I dropped my kids off at camp every day, got to work on time, picked the kids up, got to the grocery store, and did all sorts of other things.

I knew deep down that my car wasn't the ideal aerodynamic shape, but I tolerated it because it carried the family and groceries and other things, and with attentive driving and a couple mods that apparently are only worthy of scorn, I still got nearly double the EPA rating for the car.

Maybe if I'd put more time into testing I'd have gotten 57 mpg on that tank, I don't know.

Worthy of scorn? Yet again, people putting words in my mouth.

And you are quoting test results - but I thought testing was worthless? So how is mileage testing worthwhile, but literally a few hours of testing alternatives is not?

You make your own life priorities - and that's fine.

But I see people here wasting countless hours pursuing courses of action that some simple testing could have shown them wouldn't work. (Or would work, of course.)

[freebeard]

It is a reply to freebeard. And it is not a refutation of freebeard's quip, either.

Thanks for that, but really, it was Frank Zappa's quip.

[Fat Charlie]

Originally Posted by JulianEdgar

Worthy of scorn? Yet again, people putting words in my mouth.

And you are quoting test results...

My mods were not based on testing and were never evaluated by testing. Your views on testing led me to believe that your views on non-testing would be at least similar, if not stronger. I wasn't pretending to quote you, but was simply stating your position. I believe I was correct.

The numbers I cited were not test results at all, just logs. Calling them test results is quite the mischaracterization, Mr. Wordsinmymouth. I would expect an author to have a finer touch with the language. I based my mods on hearsay from this forum and was very happy with the results. I've left the grille block in and continually maintain my tire pressure, without ever having tested either, but I've gotten impressive results from them. In my position, it doesn't matter what percentage gain I may get in mileage from a mod, I just want a gain. What mileage do you get in your ride, or is it all just aero-theory? Don't get me wrong, the aero threads are very interesting to me, I do read them and I'm glad you've brought up the deficiencies in older testing. It's a great point and has been a great read.

But you do bring to my mind mind David Hobbs laughing at how the aerodynamicists had to be beside themselves when F1 cars turned faster lap times when racing with damage than they had in qualifying under perfect conditions. Because theory is great, but application matters more. I'm just in the application end of things.

[JulianEdgar]

Originally Posted by Fat Charlie

The numbers I cited were not test results at all, just logs. Calling them test results is quite the mischaracterization, Mr. Wordsinmymouth. I would expect an author to have a finer touch with the language.

I am sorry, but a mpg result is a 'test'. It is an assessment of an outcome, in this case a modification.

Originally Posted by Fat Charlie

I based my mods on hearsay from this forum and was very happy with the results. I've left the grille block in and continually maintain my tire pressure, without ever having tested either, but I've gotten impressive results from them. In my position, it doesn't matter what percentage gain I may get in mileage from a mod, I just want a gain.

That's great, but read some of the other threads about people who tried things that didn't work, and so needlessly wasted lots of time and effort.

Originally Posted by Fat Charlie

What mileage do you get in your ride, or is it all just aero-theory? Don't get me wrong, the aero threads are very interesting to me, I do read them and I'm glad you've brought up the deficiencies in older testing. It's a great point and has been a great read.

I can get anything from 84 US mpg to 47 US mpg, depending on how I drive it. (And that's with about 80 per cent more power than a stock Insight. And I don't have IMA!)

Originally Posted by Fat Charlie

But you do bring to my mind mind David Hobbs laughing at how the aerodynamicists had to be beside themselves when F1 cars turned faster lap times when racing with damage than they had in qualifying under perfect conditions. Because theory is great, but application matters more. I'm just in the application end of things.

I am a bit puzzled by what you say. Nearly all that I write here is about practical applications - how you can do some tests in order to find out what works best on your car. It's certain other people on this group who endlessly talk about theory!

[aerohead]

It appears that Fachsenfeld 'invented' the 'separation edge' (burst edge in Chrysler parlance) in the 1930s, at the FKFS.
Fachsenfeld also invented the 'splitter' and 'wing car,' 'ducted car,' the list goes on and on.
See: Aerodynamiks des Kraftfahrzeugs,' Baron Reinhard Koenig-Fachsenfeld, self-published,1951.