BRC 1966 - Gentleman Brobots Club [RACE 6 P&Q]

[koolkei]

^le sigh

https://www.youtube.com/watch?v=DUT5rEU6pqM

[Packbat]

Fair enough, numbers don't lie

[image: "There are three kinds of lies - lies, damned lies, and statistics." (Mark Twain)]

Hmm - I see your point: while I have printed out a nice, shiny, data-laden graph, I haven't actually demonstrated in any substantive way that it supports the conclusion I argued from it.

(footnote: quote was popularized by Twain, probably didn't originate with him.)

Well, I went ahead and did a quick check: if I reassign the championship points completely randomly to the players and calculate the same trendline, assuming I'm right and the correlation is not meaningful, I should frequently see correlations as strong as the one in the actual data by pure chance. And, in point of fact, out of 30 runs, 9 had an R-squared greater than that shown in the actual data.

(Also, two effects I forgot to mention earlier: first, tyre wear increases with weight, and second, because the heavier cars have more power, they have a higher Sportiness - which means a less favorable Drivability/Sportiness ratio and more driver errors.)

[KLinardo]

I wasn't actually trying to make a point, but I took a class entitled "Critical Thinking" about 3 years ago and one of the books we used was How to Lie with Statistics (http://www.amazon.com/How-Lie-Statistics-Darrell-Huff/dp/0393310728) and I've always loved the quote I reproduced. I actually didn't remember who said it first, but the picture I pulled looked the most satisfying on the first page of my quick google search.

I took statistics in high school and had to dabble in it during my time as a Political Science major, but most of what you said went straight over my head. If I gave it a few minutes of thought it probably makes much more sense. That's much more my fault than any being assigned to you, but I'm happy that you've gone back and revised your findings based on my jovial quote. It shows you have statistical integrity, and that, I remember from my studies.

[Packbat]

Heh - well, you may not have been trying to make a point, but you did, nonetheless. The power of hackneyed sayings!

And thank you. I imagine I have a similar level of formal statistical education (or less - I was a mechanical engineering major) - mostly I'm just going by my mathematical intuition and neat tricks I read about in blog posts. I do try to be intellectually honest, though.

(Speaking of which: the results are not substantially changed if you restrict the analysis to vehicles which have scored in the points in at least one race - which seems like a reasonable proxy for "competitive". At least, not on the resolution that I'm measuring, which at only 30 data points is pretty rough.)

[KLinardo]

So are we saying that the jury is still out on lighter cars, or are there enough factors in B.R.O.B.O.T. to give a clear advantage?

I still think your FF set-up defies the IRL laws of physics.

[koolkei]

wow you two.

seems like that joke was a little to ABSURDist for you two wasn't it?

[KLinardo]

ABSURDist

You're trying way too hard.

Edit: Typo

[Packbat]

So are we saying that the jury is still out on lighter cars, or are there enough factors in B.R.O.B.O.T. to give a clear advantage?

There's no clear advantage. If there were a clear advantage, you'd be able to see it by eye just looking at the scatter plot without a trendline, and no - you can't.

I am not a statistician, but when I try to analyze the data statistically, there's still no convincing advantage. If we had ten times as many cars and the same slope to the trendline, or if the slope of the trendline were three times as steep, then my tune would probably change, but as it stands? There's no clear advantage.

[KLinardo]

I think it would be interesting if we could control for something that will surely be as variable as the suspension tuning. I definitely think my car would have been more competitive had I gone for a lighter and less powerful build. It would be better on tires, use less fuel, and be more driveable. I think the combination of those things would make a difference overall.

[pyrlix]

FWD can bend physics man! Who do i have to send my FF racer to?

[koolkei]

everything is a compromise of course.

but didn't you already tried and calculated those when you build the car? at least eyeballing the calculation like i did?

lighter cars are cheaper which means more money for stuff, but you have less power, less top speed. which means the quality and speed of your car relies more on your fine tuning capabilities and to some extend, luck

heavier cars have more power, more fuel carried, and more capabilities to brute force the race with top speed on tracks that allow it. this is why i see thatn bigger more powerfull cars are a 'safer' option, but with the compromise of, more tire wear due to tire size limit, more fuel consumed mean you have to carry more fuel which is even more weight carried around, and possibly effect your pit stop strategy

as for being more drivable, i don't think that's the case

[AirJordan]

Lighter cars are not necessary cheaper. In case of this BRC is the opposite. Steel vs alu on engine or even plastic on chassis. Lighter cars are cheaper only when talking about correlation to balast (interior) and safety.

[Packbat]

FWD can bend physics man! Who do i have to send my FF racer to?

GenJeFT, are we doing more reviews?

Assuming we are, send it to GenJeFT and myself.

I think it would be interesting if we could control for something that will surely be as variable as the suspension tuning. I definitely think my car would have been more competitive had I gone for a lighter and less powerful build. It would be better on tires, use less fuel, and be more driveable. I think the combination of those things would make a difference overall.

I'm not sure what I should say. The average weight of cars in the competition is 892 kg (std. dev. 165 kg); the average weight of cars in the points is 899 kg (std. dev. 124 kg); and the average weight of cars in the top ten is 911 kg (std. dev. 111 kg). Your car weighs 1000 kg. There's no real suggestion that a 1000 kg car can't be competitive - mine weighs 1104 kg and is sitting in second right now - and you might not be finishing in the top ten, but you're well in the points. (Tied for 31st with GenJeFT, in fact - top half of the field.)

If you want to PM me your car, I can look it over and offer my thoughts. If you want to PM it to GenJeFT and I (again, assuming we're doing more reviews), we can include it in a future episode. Otherwise, I don't know what to suggest.

[koolkei]

Lighter cars are not necessary cheaper. In case of this BRC is the opposite. Steel vs alu on engine or even plastic on chassis. Lighter cars are cheaper only when talking about correlation to balast (interior) and safety.

well if you're comparing steel vs fibre glass, then yes.

but we're talking bigger car vs smaller car with the same panel types, the smaller ones is more likely going to need less material, so at least there's a bit in price difference?

[Absurdist]

Thank you so much guys for the review, I really enjoyed it. I'm glad my engine made an impression, you had me laughing all while you were working out it's layout. XD

To address a few points, I think for me, if nothing else, I want my cars to be known for their wide power bands, it's what won me the BRC45 and I think it will continue to be an effective strategy as we go on. As for it's reliability, honestly, that's just a cost I feel of making the V12 competitive. I spent a lot of time getting it to work. As for fuel, I've constantly been one of the highest for fuel use. With the theory that, if I can go as fast on a full tank, I'll beat you on a low one.

The exhaust -8 gave me huge benefits, in fact, from memory, you lose power if you raise it up. Seemed to me to work similar to adding a baffled exhaust which can sometimes push up the torque curve. Also by this point I was chasing cost cutting.
I based my gears off the top speed I expect, sure, it could get 242, but not on any track in the series.

One major down side of the V12 was price. I was really on the edge with that. But in the end it gave me one of the quickest cars in a straight line despite all the downforce. I definitely sacrificed some in handling at lower speeds.

Thank you for the eyebrow raising. That made me happy