I've been running the Super Series "24 mins of Le Mans" (Circuit de la Sarthe) with the Mazda LM55 VGT, and 'push the pace' set at the start. No further input needed as I think a lot of the cars pit due to rain but you don't. £279k x2 login bonus = £558k every 26-ish minutes (24 mins including finishing the final lap off).
I haven't tried the 24 Minutes of Le Mans at all with B-Spec, but if the actual completion time is 26 minutes, that'd make it like 2-3 minutes shorter than the Nürburgring 24 minute race (which tends to take 28-29 minutes in my experience). That could make the 24MoLM more attractive than its payout initially makes it seem. Still, the cost of the cars necessary to beat it (in this case, the LM55 VGT) could be a limiting factor.
I think what needs to be done is a really detailed breakdown of Cr/minute. I've been playing with the idea but haven't done it yet.
For instance, the Nürburgring 24 minute race pays 614,000 Cr and takes approximately 29 minutes to finish, so that's 21,172 Cr/minute.
Alternatively, "Like the Wind" takes about 4-4.5 minutes and nets 140,400 Cr. So that breaks down to 31,200-35,100 Cr/minute.
The trick with these, IMO, is to factor in loading times. Shorter races get dinged more by the PS3's slow loading times than longer ones do. (And, of course, we'll all have to factor in our own preference for how frequently we want to have to babysit the thing.
)
Next, you have to factor in the cost of the car and the cost of upkeep on the car. If you need the 1,000,000 Cr LM55 VGT to beat the 24 Minutes of Le Mans, that will cut into the profit of running it instead of, say, the 24 Minutes of the Nürburgring with the KTM X-Bow.
Given all that, I'm pretty sure "Like the Wind" comes out to be the most profitable, but the cost of the cars you need to beat it might a limiting factor. I think the cars capable of beating the Nürburgring are generally cheaper. (Though if "Like the Wind" can be beaten with a well-modded C6 Corvette, that'd probably be no more expensive than the X-Bow.)
And on an unrelated note, I'm annoyed that, even though I sold it, my GT6 stats say the KTM X-Bow R is my "favorite" car based on mileage and the Bugatti Veyron is my "favorite" car based upon wins. Both stats used to be the RUF RGT, and that
is my favorite car, dammit! (This
really shouldn't annoy me as much as it does.
)