BRC 1955 - The Golden Age [Qualifying R5]

[strop]

Sports can pull at least 1.20G in the circle test, so they aren't that bad.

And it shows in the rankings, while the very top is mainly slicks, me, Norman and Leo were running sports and we all got top10.

So while slicks still seem like the way to go, the increased wear might change things around a bit.

Not to mention as you did say, sports are also capable of producing times nearly on par of that with semi slicks, and possibly a lot more consistently given a significant bonus to drivability (if set up correctly.) Plus there is a tiny boost to top speed, reduction in fuel consumption, and a few more dollars to play with

[Packbat]

@trackpaduser: Cam profile has a big effect on fuel economy at the top end - more aggressive cams mean less valve lift mean less fuel used per horsepower at high RPMs. My previous car claims 8.24 L/100 km economy and my new car 7.91 L/100 km, but I expect the latter to be much more than 4% more efficient.

[JasonPoland]

Just saw the test vid.

Positives: I'm not last.
Negatives: I have no idea how to improve.

Fully honest now: I have no idea how I'm not last. I am the worst engineer in the cup, yet I somehow managed to get 2:30 in 40s small body. I won't be surprised if I'm the only one using that body and there's a great chance that every fast guy uses "the queen of ugliness". I can't find the download link for that, and I'm way too stubborn to use it. Plus it's SO UGLY...
1955 will be exactly like 1945 - fight for qualifications, ending the 1st race last and messing up everything in 2nd

[UltimateBMWfan]

How many more test sessions will we be having before we start the races?

Also, I'm happy to continue the commentary, was quite fun the last two races.

[Dobble]

@Dobble: The two things that occur to me are, first, tyre camber and compound affect tyre wear (more negative camber = more wear, sport compound lasts longer than semi-slick [edit: and is cheaper to start with]), and second, as strop said, you'll want to take into account the fifteen to twenty kilos of fuel that the car will be carrying at the start. (Don't be fooled by the official fuel-economy estimate - BROBOT calculates fuel consumption directly from instantaneous throttle input and the engine performance graph, so low-end economy will have approximately zero effect on fuel burned during the race.)

On which note: Der Bayer, how exactly is fuel weight added? Is it just added directly to the center of gravity? Does it displace the ride height downward, with all the drivability effects thereof?

Thank you Packbat! It's going to be interesting picking a fuel strategy with no experience the same goes for a chassie set up with low camber.

[Packbat]

@Dobble: Don't trust my judgment, because I certainly don't, but I'm running fairly high camber for this test: -2.20 degrees. Was trying to make a compromise between tire wear and grip, and going down to -1.9 degrees cost me more time than I thought the reduced wear was worth.

[strop]

Agreed, I'm running somewhere in that realm myself. Cutting back on the camber in BRC1945 cost me a LOT.

[TheBobWiley]

Guess I need to try sports out, ran that test with something like -2.8/-2.6 camber and really saw the grip falling off. For some reason I can't find a "low" camber setting for my car this time, going below -2.6/-2.1 starts eating into my lap times significantly no matter how I play with the rest of the suspension :\
Really on the fence about how I wanna play the 1955 event as I am leaving the country in 2 weeks and am running short on free time to tune. If I don't find any significant improvements by the start of next week I am going to run my monster coupe I think

[strop]

Bob, the large differential in the front and rear camber will contribute to more uneven wear on tyres and implies that perhaps going with 165 fronts would still be better. At least, you should be able to drop the front camber and find a good time. Though I'm curious as to just how those times compare.

Just as a guide, my original entry returned an automation test time of something like 2:38.1, IIRC.

[TheBobWiley]

Dang strop, thats over a full second faster than my car. Glad to see you doing so good after the 1945 fiasco

[TrackpadUser]

@trackpaduser: Cam profile has a big effect on fuel economy at the top end - more aggressive cams mean less valve lift mean less fuel used per horsepower at high RPMs. My previous car claims 8.24 L/100 km economy and my new car 7.91 L/100 km, but I expect the latter to be much more than 4% more efficient.

Maybe, but I don't think the difference between ~75 and ~100 cam will be huge in terms of fuel consumption during the race.

One thing for sure is that the more aggressive cam will mean a peaker powerband and maybe even some reliability issues due to the higher rev limiter that might be required to take full advantage of the performance.

The difference between running 13.5 AFR compared to 15.0 AFR is quite massive though, and is the main reason in my case why my new car does 5.1L/100km compared to 6.8L/100km.

An other thing that also fudges up the comparison between "rated" fuel consumption vs the racing fuel consumption is the gearing. I know that I can get mine under 5L/100km with economy gearing, but that's not very useful in a race.

[strop]

Dang strop, thats over a full second faster than my car. Glad to see you doing so good after the 1945 fiasco

Failure is a great motivator

Or, in this case, I was away for most of the BRC45 trials and far more preoccupied with rooting up some of the early bugs in this release, so not only did I send in a half-assed car, I vastly overestimated the effect of fuel and tyre wear and said "oh well, if this runs in the mid-field that's fine by me". I should know better than to do that!

[Lothoren]

Maybe, but I don't think the difference between ~75 and ~100 cam will be huge in terms of fuel consumption during the race.

One thing for sure is that the more aggressive cam will mean a peaker powerband and maybe even some reliability issues due to the higher rev limiter that might be required to take full advantage of the performance.

The difference between running 13.5 AFR compared to 15.0 AFR is quite massive though, and is the main reason in my case why my new car does 5.1L/100km compared to 6.8L/100km.

An other thing that also fudges up the comparison between "rated" fuel consumption vs the racing fuel consumption is the gearing. I know that I can get mine under 5L/100km with economy gearing, but that's not very useful in a race.

I believe my economy is under 5l/100km and i still pound around the ring under 9:25. although my tyres are going to be destroyed.

Ok its closer to 9:20 but meh.

[Packbat]

@trackpaduser: Cam profile has a big effect on fuel economy at the top end - more aggressive cams mean less valve lift mean less fuel used per horsepower at high RPMs. My previous car claims 8.24 L/100 km economy and my new car 7.91 L/100 km, but I expect the latter to be much more than 4% more efficient.

Maybe, but I don't think the difference between ~75 and ~100 cam will be huge in terms of fuel consumption during the race.

...well, that's probably another reason why I'm not competitive - I was going from ~30 to ~50 cam when I was tuning my most recent engine.

But the main point I had in mind was that aggressive cams reduce the reported in-game fuel economy by reducing low-RPM efficiency, but under race circumstances you never run at low RPMs. So the in-game fuel economy stat is going to be very deceptive.

[BlastersPewPew]

I use the graph and try to keep the engine RPMs at the lowest point on that for racing, that entails high cam profiles since during the race you are hardly below 5-6k where you will get hit with poor economy.