BRC 1955 - The Golden Age [Qualifying R5]

[Der Bayer]

Basically the same thing happened to Caterham, which is somewhat comparable to our Sprite-problem, multiple times:

Wikipedia:
"The car was banned from racing in the USA in the 1960s, as being "Too fast to race" and again in the UK in the 1970s for the same reasons, which prompted Caterham Cars boss Graham Nearn to produce 'T' shirts with "Caterham Seven, the car that's "Too Fast to Race. ..". Both bans were later lifted[citation needed]. In 2002 an R400 won its class (and came 11th overall out of 200 starters) at the 24 Hours Nürburgring race by 10 laps, ahead of competition that included Porsche and BMW racecars, leading, once again, to a ban on entry in subsequent years."

[Packbat]

For the fuel tank size I'd go for footprint[m²]*7 = tank size[l], this should give realistic values.

Sounds good - scaling proportional to the footprint makes perfect sense to me. (Checking the density of gasoline very quickly, this would be about footprint[m²]*5.5 = tank size[kg], for comparison to prior series.) And given how different tracks have different levels of fuel consumption, a car which is faster but shorter range might have one stop on some tracks (and win) and two stops on others (and lose) ... adds another level of variability to the competition!

...hm, I just had an idea. Be right back, doing some research.

(But yes, I'm frankly much more enthusiastic about this idea in and of itself than I am about this idea possibly adding diversity to the field - although I will be thoroughly chuffed if it does. )

[Packbat]

Okay, I went back to my fuel economy data for the field and compared it to Der Bayer's fuel allowance for Race 1 (i.e. expected amount of fuel consumed in 30 minutes plus three kilos). I want to emphasize, as I said before, that the total fuel consumption varies by track (Nurburgring Nordschliefe is a fuel hog, for example), but for back-of-the-envelope calculations, this should be good within ~30%:

  Code:

Race Fuel Consumption [in kg] = (Time of Race [in hr])
                                * (Engine Economy @ Max Power RPMs [in g/kWh])
                                * (Engine Power @ Max Power RPMs [in kW])
                                * 1 kg/1000 g
                                * 0.52

Among the entrants to the BRC 1955 at the Automation Test Track, actual values for the 0.52 secret-sauce ratio ranged from 0.436 to 0.614; I went with the median (the mean is 0.519). If you want to be a statistician, the standard deviation in my data was 0.0434, or about 0.0835 times the mean, but I am not a statistician.

You can eyeball the numbers from the in-game graphs (as I said, back-of-the-envelope), but if you're like me and want ALL THE SIG FIGS you can read off the exact numbers for engine economy and power from the Results/Curves section of the engine variant .lua file - here's an example from an engine in my hard drive at the moment:

  Code:

   Results={
      AdjustedAFR=12.75,
      AverageCruiseEcon=453.43594397352001,
      BaseEcon=338.99330784286002,
      BaseTorque=293.31209796106998,
      BaseVE=0.93100000000000005,
      CoolingRequired=88.864391049931996,
      Curves={
[...]
         {
            6500,
            199.28471402951001,
            135.65301510020001, -- <-- this is the power in kW
            523.85505501344005, -- <-- this is the economy in g/kWh
            23.536122865397001,
            RPM=6500
         } --[[table: 0x0f26e668]],
[...]
      PeakPower=135.65301510020001,
      PeakPowerRPM=6500,
[...]


(I include the PeakPower and PeakPowerRPM lines because that's where I looked to find which table from Curves to look at to find the numbers.)

I expect this engine would, in a thirty-minute BROBOT race at the Automation Test Track, burn approximately 18.5 kg of fuel.

[koolkei]

*SNIP*

>BaseVE=0.93100000000000005

wowowowowowow..... 93.1% Volumetric Efficiency????

that's kinda absurdly high for a 1955 car isn't it?? even when it's a race car?

NormanVauxhall Edit: please don't quote such big "above post". Thanks

yup. derp. sorry

and about that..... why doesn't this forum have spoiler feature??

[Packbat]

*SNIP*

>BaseVE=0.93100000000000005

wowowowowowow..... 93.1% Volumetric Efficiency????

that's kinda absurdly high for a 1955 car isn't it?? even when it's a race car?

Sorry, it's not a race engine, actually - it's a naturally-aspirated 1994 SPEFI 2.4L V6 I built in open beta 150707 for a mid-engined sports car. I was only using it as an example.

...what does volumetric efficiency mean?

[koolkei]

Sorry, it's not a race engine, actually - it's a naturally-aspirated 1994 SPEFI 2.4L V6 I built in open beta 150707 for a mid-engined sports car. I was only using it as an example.

...what does volumetric efficiency mean?

there's the wiki available but i'll put it here

  Code:

Volumetric efficiency in the internal combustion engine design refers to the efficiency with which the engine can move the charge into and out of the cylinders. More specifically, volumetric efficiency is a ratio (or percentage) of the quantity of air that is trapped by the cylinder during induction over the swept volume of the cylinder under static conditions. Volumetric Efficiency can be improved in a number of ways, most effectively this can be achieved by compressing the induction charge (forced induction) or by aggressive cam phasing in naturally aspirated engines as seen in racing applications. In the case of forced induction volumetric efficiency can exceed 100%.

TL;DR
it's a measurement that gauges how efficient the engine is at being an air pump

and on 1955, DOHC are rare even on race cars weren't they?

also..

i just researched about it again. 93.1% VE on '55 race car is about average. but on production engine? not so much

for comparison

about a decade later
the production HEMI engine (it was known for high VE) , had a VE of just barely topping 100%. and that's with 2 Valve Push rod Technology, not 4/5 valve DOHC. also Naturally Aspirated

the decade before
the WW II plane spitfire, using Griffon engine, that engine was rated for 93% VE, that's WITH induction intake. and this is state-of-the-art technology because war

[Packbat]

Oh, okay.

...and the BaseVE score for my BRC 1955 engine (carburetted inline-six) is also 0.931, so I'm guessing it's based on some combination of intake type, valvetrain, and headers? Both engines are SOHC 4v with performance intakes and long tubular headers, but they're different dimensions and piston configurations, and they have different cam settings.

[Packbat]

Oh, a quick spoilery note because it occurred to me to check: two of the top three competitors were among the cars GenJeFT and I reviewed in the old edition, pre-updates. We took a quick look at all three at the end of the stream after the last race, but that was in the new build; if you want to see the stats in the competition build, here is the first-place car and here is the second-place car.

[koolkei]

Oh, okay.

...and the BaseVE score for my BRC 1955 engine (carburetted inline-six) is also 0.931, so I'm guessing it's based on some combination of intake type, valvetrain, and headers? Both engines are SOHC 4v with performance intakes and long tubular headers, but they're different dimensions and piston configurations, and they have different cam settings.

yes. but AFAIK.

carb vs injection also matters since carb uses the vacuum to work which means it's essentially limiting the engine to make the engine work. irony right?


but i dont know if bore and stroke matters..

[strop]

As somebody who missed the final race due to timezones, I reiterate my request to actually access the results of the final race and overall season standings, if they're available!!!

[Der Bayer]

As always: Pyrlix's last Twitch broadcast

[strop]

Thanks Der Bayer. I saw the link in an earlier post and gave it a shot, but for some reason the broadcast wouldn't load and the channel would only tell me that pyrlix was offline!

(Guess I can't Twitch).

May I take screencaps and post for convenience?

EDIT: lol I really can't Twitch, I just realised you can't screencap from the broadcast. I should have known that!

[Packbat]

Got it! Blurry, but I got it. Attached.

[07CobaltGirl]

My poor car just can't catch a break! I have Norman Vauxhall Syndrome!!

[strop]

Thanks for that Packbat. Also, it has been said before, but belated thanks to the commentators and Der Bayer for working on and hosting the biggest tournament undertaking, which is still developing!

I'm not sure what to think of mattmr2's strategy: it was crazy fast in qualifying and being a super lightweight, was aggressively tuned to take corners crazy fast, and so won the most races. I'm also not sure what to make of the race intake... reliability was a shocking 18.4 resulting in 3 DNFs, but the sheer strength of the performance in the other races handed him a massive lead in the end.

Killrob's strategy, on the other hand, was a heavier car with far more power, top speed, which clearly helped with the tracks with high speed segments in them.

As was said in the commentary, mer_at was very unlucky to DNF the first race of the final weekend (and then perform poorly in the second), and it essentially cost him a podium spot. For that matter, despite that DNF when I was running well in the points in the final race, I don't think it would have made any difference to my final position. 4th is actually punching above my weight, as I would have loosely estimated that my car was probably 7th-8th best.

I'm looking forward to seeing how the mechanics and balance are tweaked in the coming months!