BRC 1955 - The Golden Age [Qualifying R5]

[Packbat]

Doing The Right Thing: It Sucks, But Less Than The Alternative.™

(...we really need to come up with a better slogan.)

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:

• Valvetrain Type & Valves/Cylinder
• Fuel System (e.g. triple single barrel carburettors, twin four-barrel carburettors, &c.)
• Max Torque RPM, Max Power RPM, & Redline
• Performance Index
• Peak Economy (g/kWh) & Peak Economy RPM
• Economy & Economy * Power @ Max Power RPM (I figure the latter is probably a good proxy for rate of fuel consumption during a race)
• Engine Weight
• Max Wheel HP
• 1st Gear Redline & Top Gear Redline
• Differential (spoiler alert: there aren't any manual lockers this year)

Anything else I should be thinking about when I look at people's cars?

[TheBobWiley]

Clearly you are missing the most important factor..... style.

[RobtheFiend]

This "pre season" rewiev is gonna be so much fun. Can't wait to hear what they think of my barge.

[Packbat]

Clearly you are missing the most important factor..... style.

I'll do my best to oblige.

[GenJeFT]

Dont forget to submit your car for the review (send it to me).

Packbat, when is the best time for you.

This weekend will be tough for me since I record and process all the videos for my youtube channel on the weekend (2 episodes a day for the week). And I usually have a get together with RL friends on Sunday.

Monday I go to take my first flight towards a pilots license.

EDIT

The broadcast I did the other day is being uploaded now.

It will be available at https://www.youtube.com/watch?v=Dk_Ol_A ... e=youtu.be.

It was fun to watch for editing so I hope everyone enjoys watching it.

Due to the odd turns the conversation took at times I added a disclaimer in the description.

[Packbat]

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.

[pHanta]

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:

• Valvetrain Type & Valves/Cylinder
• Fuel System (e.g. triple single barrel carburettors, twin four-barrel carburettors, &c.)
• Max Torque RPM, Max Power RPM, & Redline
• Performance Index
• Peak Economy (g/kWh) & Peak Economy RPM
• Economy & Economy * Power @ Max Power RPM (I figure the latter is probably a good proxy for rate of fuel consumption during a race)
• Engine Weight
• Max Wheel HP
• 1st Gear Redline & Top Gear Redline
• Differential (spoiler alert: there aren't any manual lockers this year)

Anything else I should be thinking about when I look at people's cars?

I think camber would be interesting to compare because of it's influence on tyre wear. Otherwise maybe Cx and engine cooling ?

[Packbat]

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?

[pHanta]

By Cx I meant the aerodynamic efficiency value in the "test track" tab

[Packbat]

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++!)

[07CobaltGirl]

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

(18.72 KiB) Downloaded 164 times

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.

[RobtheFiend]

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.

[07CobaltGirl]

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.

[RobtheFiend]

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.

[07CobaltGirl]

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?).