I have social engagements on the weekends that I don’t want to miss, but otherwise I’m flexible - anywhere between 10 a.m. and 10 p.m. EDT on a weekday works for me.
[quote=“Packbat”]
In the interest of getting the thread back off the subject of my being an ass: does anyone have suggestions for data to analyze in the BRC field of entries? Besides the stuff on the trump cards, I made columns in my spreadsheet for:
[ul][li]Valvetrain Type & Valves/Cylinder[/li]
[li]Fuel System (e.g. triple single barrel carburettors, twin four-barrel carburettors, &c.)[/li]
[li]Max Torque RPM, Max Power RPM, & Redline[/li]
[li]Performance Index[/li]
[li]Peak Economy (g/kWh) & Peak Economy RPM[/li]
[li]Economy & Economy * Power @ Max Power RPM (I figure the latter is probably a good proxy for rate of fuel consumption during a race)[/li]
[li]Engine Weight[/li]
[li]Max Wheel HP[/li]
[li]1st Gear Redline & Top Gear Redline[/li]
[li]Differential (spoiler alert: there aren’t any manual lockers this year)[/li][/ul]
Anything else I should be thinking about when I look at people’s cars?[/quote]
I think camber would be interesting to compare because of it’s influence on tyre wear. Otherwise maybe Cx and engine cooling ?
Front and rear camber, sportiness and driveability from the yaw rate curve, engine required cooling, engine cooling, cooling fraction, and brake cooling added. [Edit: And brake fade.]
…what’s Cx? Coefficient of drag? Effective area?
By Cx I meant the aerodynamic efficiency value in the “test track” tab
Got it - thanks! Added to my spreadsheet.
(I’m not sure, but I think I can get almost all the data out of the .lua files without opening Automation - the only thing I’ve looked for and not found in the past is the whp and gearing data from the transmission tab.)
(…mua ha ha! I will steal ALL your significant figures, Automation! I HAVE NOTEPAD++!)
Nearly everybody used this body for the competition, so I decided to build one too. Not an official entry, of course, as I could never abandon my super awesome coupe, which sucks, as we all know.
Honestly, I don’t know how you guys are doing those sub-100 second passes with this. Wheel options are tall and skinny or short and not-as-skinny. To actually get 175mm I needed a 10" wheel, which allowed for…no brakes at all. Seriously, how do your cars even consider stopping??? With 11" wheels I managed to get 195mm brakes and 165mm tires, which eventually stops this vehicle in a psychotic 53m…with +8 on brake quality… Aren’t 11" wheels used for go-karts and motorized wheelchairs??? As a small child, my bicycle had 16" wheels. I know my car is probably a lot heavier than most (nearly a tonne) with a large displacement (for the era) V8 (5.3L) under the hood, but still!
1955BRC-07CobaltGirl-Sprite.zip (18.7 KB)
If anyone would like to play with my latest frankenmonster, I’ve attached it below. There is more left in it. $500 left to play with and probably another 3-4 seconds if you know how to tune the suspension/gearbox (I’m not very good with these components). Anyway, I just wanted to share my bastardized Sprite model.
OMG, that torque curve! Very nice.
But, isn’t the rpm a bit low, even for a 1955 engine? I know you are limited by the power/weight ratio, but still.
Overhead Valves. Let me elaborate:
Well, I can make the power at a higher RPM, but then I have to bump the car’s weight because the power goes up substantially. Remember this is a 5.3L V8 OHV engine, so in 1955 the RPMs aren’t going to go tremendously higher (near 5k max), but power most certainly will. This engine is leaned out to 14.0 a/f ratio and only 7.7:1 compression (if I remember correctly). The only places to drop power was with timing and/or cam settings. To give you an idea, I made it to specs and managed about 295hp out of it before detuning for weight restriction. I detuned the engine down to around 165hp at it’s lowest point, using 7.0:1 compression and a moderate cam, and then brought it back up to where it is now. I dropped the cam settings to get that beautiful torque curve (it actually is really nice!), and upped the ignition timing to maintain the power/RPM. Like I stated, feel free to download it and make your own version. It’s not like anything else can be entered at this point, right? It’s not even my entry, as I used a coupe powered by a Chevy 265 V8. This is 100% a toy to play with. As posted, this car will turn 9:35s on Green Hell and 1:46.xx on ATT, so it isn’t awful, but is actually still slower than my coupe, despite weighing some 80kg less. This is most likely due to the car being so front heavy (58.x/41.x), and my complete lack of suspension tuning skills. It should be able to get into the 1:41-1:42 range on ATT, I would think. All said, it is my “hmmmph” at all the Sprite bodies on the track. 
I do have a smaller engine (4.3L) based on the same block, if you’d like that one too? AMC “Rambler” V8s came in 250-287-327 varieties, but the 250 couldn’t be made properly due to bore:stroke restrictions, and ended up being 264 cubic inches. I scrapped using it because it was not a proper replication of the motor. I also have a 287 version of the block, which is proper. It didn’t change the distribution much, but dropped ~25kg from total weight. It’s definately not a race-inspired engine, however, with its 2bbl carb.
EDIT: I am also pretty sure I did not use quality sliders at all with this engine. Not even with the valvetrain! I could be wrong, though.
That power/weight limit is playing merry hell with the nicer engines we like to make. 
And its gonna be more and more problematic if the limit is increased in the same manner, .25 in 1965, .30 for '75 and finally .50 in 2015.
That power/weight limit is the only thing keeping my OHV engines remotely competitive. Without it, I might be able to use this engine fully tuned, but anyone who slaps DOHC on theirs will double my output without a second glance. The only real advantage to the OHV engine is compactness (and some reliability), so this 5.3L won’t fit into the Spriteless as a DOHC (or will it?).
With the Sprite body having a heavier engine it’s a huge disadvantage. If you want to stop the car with brakes fitted in 10-11" wheel means LOW weight. That’s why mine it’s 527kg. (tiny tiny high revving DOHC 1 liter V8)
Clearly you do not pay attention to MY cars. mwahahaha
Hey ColbaltGirl, looking over the car you posted I noticed that it weighs a bit more than the real life 327 (313kg vs 270kg) and also should be using forged crank and conrods. Also, upping quality in the valve tab smooths out the RPM graph in the high range. Gonna see what I can get out of the engine while keeping it true to the 327 because I am bored and lack the motivation to work on my car company currently. 
Also, was cast log the actual exhaust type used on 1955 cars? Not sure if short cast or tubular could be put on for weight reduction and better flow.
@TheBobWiley: I’m betting a lot of the engines had different headers, but the illustrations I can find (like this person’s 1/6th scale model) look aesthetically more like cast log than short cast. From a standpoint of simulating airflow, though, I could buy the argument for short cast … and certainly there would be people replacing the headers with tubular ones for racing.
The cast tube is giving the smoothest RPM curve, but I did find an entire second by using comfort rear brake pads, even if the car takes even longer to stop now
EDIT: Just got 80-120km/h in 3.2 seconds… this thing is a beast past 100km/h!
I played around with it quite a lot. I couldn’t go for full engine specs as the contest is limited in several ways. With the zero quality, that engine will actually push out a lot more horsepower/torque, especially if you go for the forged components. I had it up to nearly 300hp myself. The main areas to find more time will be suspension and gearbox. Just be careful with the weight reduction, as it’s already on the edge of .20 pwr/wgt as I posted it. Reducing weight means reducing the power even further.
As for cast logs, most cars of the day were using them, unless they were truly performance cars, much like today. Tubular exhaust was generally reserved for aftermarket applications. I used the exhaust to limit the power a bit.
Its fun trying to make “bad” cars better, but I’m just having an awful time with suspension since the 1945 BRC… nothing I do seems to help much. However I changed the engine around a bit (same bore, stroke, etc.) and it now makes a whopping 427nm of torque @ 2200 rpm and 192 hp @ 3800 rpm. I think the economy is a tad better but I forget what the original values were. Reliability is down about 2 points, and responsiveness is down a lot, but the 165mm tires make lots of spin already. Was using 92 octane fuel at one point, but now its at 97.7. Had to remove the radio, but upgraded to a premium interior
Maybe I can find some more time in the suspension, but the weight of the car makes the settings very twitchy.
I’m just glad someone decided to play around with it. Since we have a 1-2 more weeks until the BRC begins again, I thought it might be fun. Just don’t make it something other than OHV, as it just demolishes what I was attempting to do. American V8 in a European Roadster. 
I haven’t made a lot of tests with the sprite, but I know that on the mini-truck it makes a huge difference.
A DOHC 4L V8 doesn’t fit with, but IIRC a 5.3L does fit if one uses OHV with the small tubular exhausts.
I’m not at my computer right now, but when I get home I’d like to take a crack at your car with an all aluminum Buick 215. The timeline is a little off, since the 215 didn’t see commercial availability until MY 1961, but since the AMC V8 didn’t hit production until 1956, and the Buick was seen in concept car form as early as 1951, it should be interesting as an experiment. The later Rover V8 connection also works well within the US/UK hybrid spirit.