Quote:
Originally Posted by aardvarcus
Since people like analogies so much… This conversation reminds me of something else…
Person A:
Did you know you can heat your house from the sun? South facing windows, size the overhangs to reject summer sun, extra insulation, etcetera.
Person B:
No. I do not believe it. Unless you pay extra for a special house with a special certificate from a governing body regulating low energy construction, no house can be made or modified to be heated by the sun. You can’t mimic details to get there. You cannot copy construction techniques to get there.
Person A:
But wait, it works. I applied some rules of thumb and some hard math and calculated…
Person B:
Rules of thumb don’t work. The sun does not work. You see, not every house is heated by the sun- it must be wrong! Other houses have south windows, overhangs, insulation but they require supplemental heat. Houses can not be heated by the sun. You must have central HVAC, you see all houses have central HVAC. All architects design to have central HVAC.
Person A:
But I actually built one, and it works. See, here are some plans.
Person B:
You might have accidentally found something that worked for you, but it will not work for anyone else. Nobody listen to this other guy, he is wrong. See this plan has 12% glazing and this one has 10% glazing. Inconsistent. They don’t agree. Must be wrong. Everything is wrong. Install central HVAC or I will taunt you some more.
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You can use all the analogies you want, but it's best to pick parallels from car modification. And there are plenty - rules of thumb / inappropriate historic parallels / incorrect logic are often used in car modification by people who want simplistic answers to complex questions. Here are some parallels to the template:
- Car air/fuel ratios - A lean cruise AFR of 16:1 worked on Fred's car and so that's what I am going to use on my car. Also I've seen that many standard cars use 16:1 so that must be the right value.
- Car ignition timing - That ignition timing map worked really well on the car I used to have and so I am going to cut and paste it for my new engine - it will be great, after all, it was before and that's all the evidence I need.
- Suspension natural frequency - Frederick Lanchester found about 100 years ago that a suspension natural frequency of 1Hz is best for ride comfort so I am going to set my car up with 1Hz natural frequencies. After all, the research was all done 100 years ago!
Subwoofer design - I was listening the other day to John's sub and it sounded great. So I've bought the same driver and I am making a new box for it. The box will be about one-quarter the size of his but I know it will sound good because it's a great driver and I heard it sound good.
Gearbox ratios - I've been looking at what car makers do with their top gear ratios. I found that a ratio of 0.72:1 is really commonly used - it's like it's a 'secret ratio' that all designers know! So I am going to use that ratio because all those designers can't be wrong. What's that? No, I haven't decided on my final drive ratio - does that matter?
...and so on and so on.
Rules of thumb / inappropriate historic parallels / incorrect logic all make for poor car modification approaches.