BRC 1955 - The Golden Age [Qualifying R5]

[Packbat]

Okay, so I subscribed to Pyrlix's "High Quality Essentials" workshop modpack, went to 1965, selected "Last 10 years", and went through the available two-door cars using Der Bayer's liters per square meter criterion.

First, assuming the Size dimensions listed are width x height x length, the not-Sprite (1.31 m x 1.04 m x 3.31 m) would have a 30.35 l tank, corresponding to something between 21.2 and 23.4 kg, depending on what density Der Bayer assigns to race fuel (the latter corresponds to 0.77 kg/l, which Google suggests as the default). In the first race of BRC 1965, various not-Sprites had starting fuel loads between eleven and twenty kilograms, more or less, but that includes a three-kilogram margin of safety; if we assumed that the fuel consumption figures are not grossly different in 1965, all of these cars would require one pit stop in a 75 minute race.

Second, looking at some of the other sports cars: the Ferrari-like car (1.79 m x 1.21 m x 4.56 m) would have a 57.14 l tank, or 44.0 kg. (Sorry, 07CobaltGirl, I think you would have to take a fuel stop as well.) The boxy sedan I used (1.79 m x 1.28 m x 4.17 m) would have a 52.25 l tank, or 40.2 kg. Many of the newer options would be in a similar range, I think, but the biggest two-door - the 70s Large Coupe - is 2.13 m x 1.22 m x 4.88 m for a whopping 72.76 l tank: 56.0 kg of fuel.

...actually, I went ahead and built a car in that body - 185 inch tyres, but otherwise according to the '55 rules - and got it down to 2:41.82 on the test track with a lean enough fuel mixture to keep fuel consumption according to my rule-of-thumb down to 48.6 kg over a 75-minute race, requiring no pit stops.

The new tyre model might change things, but in B151001, that's what I'm seeing.

[TheBobWiley]

All of this sounds very interesting and awesome. Hoping to see these ideas implemented in future races in order to add more variability to the field. I personally am going to stay away from the non-sprite as I dont much care for its design, nor how much of an advantage it naturally has. I will be using the Porsche 917 looking body. Hitting almost 300 kph top speed and only 5 seconds slower than the sprite times someone posted earlier.....
Now I need to get that magic suspension tuning spot like I did in the 1945 race so I can be competitive.....

[Packbat]

Fun fact: it is, in fact, possible to build a FWD not-Sprite in 1965 that gets 0.2 hp/kg. It is hilariously unreliable, a fuel hog, and not particularly competitive.

[KLinardo]

I was toying around with the not-sprite for my first anticipated entry into the BRC. I don't have the experience of the 1945 and 1955 seasons and I'm really a novice in tuning suspensions, but I have a car right now that's at .25 hp/kg and well under the $8000 total cost of 1955. It also is considerably faster than the 1955 versions on the ATT, but I have no clue what the season-to-season improvement will be with 10 years having passed. I'm going to tune some more, but I am curious to see what the actual requirements will be and how much progress has been made by top competitors.

[Packbat]

Mm - I did some quick experimentation: in the old build, my (slow as balls) car did a 2:46.90 on the Automation Test Track, but the new build has much higher cooling requirements, much more brake fade, and generally higher prices, so the hastily-updated version I just made (with 2LS front drums) clocks in at 2:49.44. Moving to 1965 on engine and vehicle while making no substantive changes (except a switch to front discs) and building to the same cost and power-to-weight ratio, the combination of a lower profile tyre and all-around better technology takes this car down to 2:44.17 - five seconds [edit: or two and a half from the old-build time]. That would be my ballpark for how much improvement you should find solely from Der Bayer advancing the year.

[koolkei]

Mm - I did some quick experimentation: in the old build, my (slow as balls) car did a 2:46.90 on the Automation Test Track, but the new build has much higher cooling requirements, much more brake fade, and generally higher prices, so the hastily-updated version I just made (with 2LS front drums) clocks in at 2:49.44. Moving to 1965 on engine and vehicle while making no substantive changes (except a switch to front discs) and building to the same cost and power-to-weight ratio, the combination of a lower profile tyre and all-around better technology takes this car down to 2:44.17 - five seconds [edit: or two and a half from the old-build time]. That would be my ballpark for how much improvement you should find solely from Der Bayer advancing the year.

but that's barely any improvement for a decade skip.

and if i remember, the 60s were the somewhat golden age of racing.

the age of muscle cars. the shelby cobra & shelby GT350, the dodge charger, pontiac GTO, the original mustang came out.
the age of Ford GT40.
the Hemi engine came out.

niki lauda started his racing career, and crashed

(and i just cant ever forget the motorbikes. honda suddenly climbed to the top of a lot of bike race.
with their RCxxx bikes. the 8speed inline4 125cc engine, or better, the inline 6 250cc 7speed engine that revs up to nearly 20k O_O both with 4 valve DOHC, making 65HP. ON 1966!
https://www.youtube.com/watch?t=75&v=eaRop_ZMwo0
here's the sound of it. impossible to recreate in the modern world

also suzuki with the 14 speed 50cc engine on 1967 O_O)
sorry cant stop myself


anyway back to topic.
i'm more on the drastic changes of the rules. like a big jump in cost and weight-power-ratio allowed. maybe introduce new rules, like minimum weight?

[Der Bayer]

Rules will stay as easy as possible while allowing for good balance and hopefully also allow for a better variety of entries. No detailed news as I didn't have time to experiment and didn't finish the Simulation Tool yet.

Maybe there will be bigger changes in the rules. I'm not looking forward to the complaints of those who scaled up the rules from previous challenges and already invested hours in tuning. But I always said that the rules are not done.

[Packbat]

but that's barely any improvement for a decade skip.

Yes, but that's improvement from technology advances alone - that's without any increase to budget, tyre width, or power-to-weight ratio.

Honestly, between game updates, BRC engine updates, and the fuel tank size restriction (assuming Der Bayer extends the race length - I suggested 75 minutes above), I think there will be enough major changes to be interesting already. I wouldn't object to other major changes, but I think incremental increases in tyre width, power-to-weight, and budget would be enough for me.

Preview-Edit: I'm glad of the messing-around that I've done in 1965, but the fact that you haven't decided on '65 rules is why my messing around has been using the '55 rules. I'm just playing with the systems to get an idea of the possibilities.

[KLinardo]

I agree with Packbat. I'm entirely aware of the fact that the $9000 budget and 0.25 HP/Kg ratio are speculations on our part. That being said, I have no grounds to complain if you roll out a rules package that looks more like 1945 or looks completely different. I wanted to build a car to spec to see where I fell among the 1955 competitors. My 1965 spec is complete guess work and a way for me to entertain myself while I eagerly anticipate my first opportunity to compete in your series. I'm actually glad that we're in a new build with new parameters and a new simulation because that makes it much easier for me to enter in 1965 without having the experience of competing in 1945 or 1955 (although I followed the 1955 series closely once I became active on the forums). Keep up the good work Der Bayer.

[Packbat]

Addendum to my fuel estimation formula:

  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

I can find two clear design factors - as opposed to track factors - affecting fuel consumption relative to this formula: gearing and the ratio of redline to peak power RPMs. (The absolute value of the redline is not predictive.) The more time your car spends near, at, or above the peak power RPMs, and the higher the RPMs that it spends this time at, the more fuel it consumes. There are probably exceptions - one engine reached its peak torque at the redline but the car still exceeded my estimate by 12% - but as a rule, if you're revving way past the redline in every gear, budget additional fuel.

(For the record, I'm probably going to collate all this fuel-estimation stuff and post it in-thread for the BRC 1965 when entries are opened. I figure anything that helps people get their designs close to ideal before the first pre-season testing is a good thing.)

[07CobaltGirl]

Rules will stay as easy as possible while allowing for good balance and hopefully also allow for a better variety of entries. No detailed news as I didn't have time to experiment and didn't finish the Simulation Tool yet.

Maybe there will be bigger changes in the rules. I'm not looking forward to the complaints of those who scaled up the rules from previous challenges and already invested hours in tuning. But I always said that the rules are not done.

Pffft...if they complain, screw them. I built several cars based on logical progression because I needed something else to work on. I sure as hell won't be complaining about unexpected rule changes (unless you specify a single body to be used because that would be so boring too )

[Lordred]

I expect to be the only Frame with Solid axle submission for 1965

[koolkei]

true...... the exact same car, rebuilt a decade later will perform better.

but as you said. the main differences may not be the car itself. but the whole event altogether.
new racing simulation engine, new parameter, new limitation, new calculation in-game.

i didnt thunk of that before

Pffft...if they complain, screw them. I built several cars based on logical progression because I needed something else to work on. I sure as hell won't be complaining about unexpected rule changes (unless you specify a single body to be used because that would be so boring too )

what about minimum weight?

I expect to be the only Frame with Solid axle submission for 1965

oh hold your horses buddy. im still trying to develop an FF racer here.

so far i've succesfully made it faster than my experimental 4x4 non-sprite racer. around the corners. with 2:34 around the test track

also... how do you import a car? i accidentally deleted a car. fortunately i've exported it before

[07CobaltGirl]

Pffft...if they complain, screw them. I built several cars based on logical progression because I needed something else to work on. I sure as hell won't be complaining about unexpected rule changes (unless you specify a single body to be used because that would be so boring too )

what about minimum weight?

While I don't see it happening so long as the power/weight ratio is active, I would be ok with the weight minimums. My cars have all been so fat. It would be nice to see fewer "skinny kids" racing around the track passing me. hahahaha

[Packbat]

Another addendum to my fuel consumption calculation: while I couldn't get good starting fuel load numbers for the other races, I could for Race 4 at Norisring. Examining that data showed two things:

1. The same methodology works on both tracks - almost every car that exceeded my fuel consumption estimate on one exceeded my estimate on the other, and vice-versa.
2. On Norisring, the secret-sauce coefficient goes up from 0.52 to 0.64 - I'm guessing because it's such a point-and-shoot-y track that the cars spent a lot more time on power. I checked car-by-car: almost every vehicle had 20-30% more fuel consumed on Norisring.

...and I'm vaguely remembering now that the Automation Test Track was toward the low end on fuel consumption, now.

So, latest updated:

  Code:

Estimated 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
             * r

...with likely ranges for r being 0.44 < r < 0.61 for the Automation Test Track (point estimate 0.52) and 0.53 < r < 0.75 for Norisring (point estimate 0.64).

My recommendations:

• Design using the point estimates, but expect fuel consumption towards the upper end of the ranges if your driver revs way out before shifting - that is, if the redline is well above peak power RPMs and your gearing is such that you upshift at redline in most/all gears. (Note: the inverse is not a safe assumption.)
• If Der Bayer does pre-season testing on the Automation Test Track, measure testing fuel consumption versus time spent on track, assume your maximum fuel consumption on some tracks during the race season will be 20-30% greater than this observed fuel consumption, and plan accordingly.

Edit 2015-11-27: I stumbled over an old post of mine with my old car's fuel consumptions on the BROBOT tracks from 1945 - in that dataset (Automation Test Track, Brands Hatch Indy, Airfield Track, and Nurburgring Nordschleife), the highest fuel consumption relative to the ATT was Nordschleife, which was only ~15% more. Adding it to this post for future reference.