GT Sport Update Brings Huge Mid-Season Balance of Performance Changes

[Shayden_CPT]

So Gr.4 is still the RCZ vs TT trophy...

Yes you are correct. Would you believe it if I told you I was in a lobby with 12 of them . Just my Lexus, a Viper and a Vantage. There was a M4 , but he left before we even started.

 

[LeGeNd-1]

Okay......... this is the result of a LOT of 10 lap races with different weight and power settings for the Alfa.

My best estimate is that each % of power change makes 1.60 seconds difference to total race time, and each % of weight change makes 1.33 seconds difference to total race time. So I agree with Adam that power makes more difference than weight, but it's nowhere near the double that PD has used in the BoP changes.

So here is an updated estimate of the impact of the Gr.4 BoP changes, expressed in terms of change in total race time for the race parameters given. The Alfa works out at 8.75 seconds slower than with the old BoP, which is reasonably in line with what I said earlier in this thread.

The conclusion is the same - for Fuji, at least, the Alfa stands no chance because you will qualify around the back of the grid, and your early race pace will be hopeless compared to cars like the Jag and Ford. Even for the last few laps, with a tyre wear advantage, you'll still be slower than the Jag and Ford, just by a smaller amount of time. On a track like Monza, I'd guess the Alfa would do even worse. I don't know if there are any extreme handling tracks where the Alfa would be competitive, I'll leave that to someone else to test. It still seems like a mistake, to me, to slow it down by so much.

@watto79 I'll send you a PM. I've had enough of driving around that track for today!

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Great work testing all these 👍 Do you happen to have the raw race times for before/after BOP as well? I feel just looking at the time change doesn't give the full picture. Alfa looks really bad here but we all know it was OP before the update. Vice versa with Chevy.

The simplest possible, most easily repeatable way with the fewest variables: hammering it out from the pits at SSRX at max chat and not letting up until the 50mph limiter cuts in.

The car has max fuel, you run it until it has no fuel, and the distance covered is how far it can go - no corners, no braking, no gearing worries. Although I did it at 50x fuel use because **** driving 3,800 miles in Gr4 cars on SSRX; it does mean that some cars that appear equal in value will be a mile more or less efficient than each other, but ultimately that's not a huge concern.

It give the best possible baseline value, and anyone should be able to achieve exactly the same results by doing exactly the same thing. As soon as you start introducing variables like braking, cornering, accelerating again, gearing, and anything else, you have things that can give you different results from the person that tested it (especially if they're loads better than you, like T-W is loads better than me). Perhaps the Citroen can get out of Fuji's corners in a higher gear than the Alfa, which makes it more efficient at that circuit (don't know, haven't checked)

I will be adding some further circuit tests in later - and I have the tyre tests to do, which cannot take place at SSRX - I just thought it was interesting that the Cayman could go so much further than anything else (with the Megane Trophy a distant second).

IMO testing fuel is a lot more complicated than just hammering it at redline or letting AI drive the car for a couple of laps (like the stickied fuel consumption thread - which hasn't been updated in ages).

With some cars their powerband requires you to shortshift even if you're not saving fuel (e.g. Gr.4 McLaren and BMW), so their fuel consumption is actually "better" than what your tests will give. On the other hand, some cars will look to have good fuel consumption on paper, but because they lose a ton of laptime when you shortshift they end up being less good in a fuel saving race overall (e.g. Gr.3 Lambo). Some cars have very wide powerband and they can set similar laptimes revving to redline or shortshifting (e.g. Gr.4 Audi and Citroen), making them quite versatile in all types of races.

If you really want to make the end-all-be-all spreadsheet for car specs, there is no substitute for learning how to maximise each car's powerband and how to optimise their fuel consumption. Then you probably have to do 2 runs: consumption with no saving and consumption with shortshifting (just to be consistent, let's say half rev bar). Calculate the km/liter for each run and take the ratio. That will give you the true "efficiency" number for each car.

It takes a lot of work and to be honest in a race situation there are still a lot more variables that can affect it e.g. if you're slipstreaming behind someone, you can maintain low laptimes while saving a lot more fuel than usual. At the end of the day, I don't think the fuel consumption stat is that important except in extreme cases (fuel >5x), and those races are thankfully quite rare per season. Gr.1 is the only exception because of the hybrid cars, but that's another story...

 

[breeminator]

Great work testing all these 👍 Do you happen to have the raw race times for before/after BOP as well? I feel just looking at the time change doesn't give the full picture. Alfa looks really bad here but we all know it was OP before the update. Vice versa with Chevy.

I didn't test all the cars, only the Alfa. I tested the Alfa holding power constant and varying weight, and then holding weight constant and varying power. I kept getting better at driving the car and track combo so had to repeat tests, and ended up just re-testing the extremes directly after each other, to minimise my own improvement between tests. It took basically an entire day just to do that. So that is where the estimates for mapping % changes in weight and power onto time changes came from. It's just an estimate, it would be different for each car, and also it was clear from my testing that it's non-linear, taking 5% off the power doesn't cost the same time as taking the next 5% off. So it's all fairly approximate, but I think it's useful as it makes it much easier to see which cars have won and lost, and by how much, compared to looking at a list of weight and power changes.

For the actual race times, I'd recommend looking at Windfire's tests on YouTube, he has been going through the cars pretty quickly since the update. I've been downloading the videos to get accurate timings, but what I've learned from doing that is that he's pretty consistent with how he edits the videos, and if you simply note down the time youtube shows when the car crosses the line, you'll have it correct to within around a second. The Mustang is the fastest Gr.4 car he has tested so far at Fuji, with a total race time 7 seconds faster than the Alfa, and a fastest lap 0.95 faster. Good job they buffed it, eh

 

[Famine]

IMO testing fuel is a lot more complicated than just hammering it at redline or letting AI drive the car for a couple of laps (like the stickied fuel consumption thread - which hasn't been updated in ages).

With some cars their powerband requires you to shortshift even if you're not saving fuel (e.g. Gr.4 McLaren and BMW), so their fuel consumption is actually "better" than what your tests will give. On the other hand, some cars will look to have good fuel consumption on paper, but because they lose a ton of laptime when you shortshift they end up being less good in a fuel saving race overall (e.g. Gr.3 Lambo). Some cars have very wide powerband and they can set similar laptimes revving to redline or shortshifting (e.g. Gr.4 Audi and Citroen), making them quite versatile in all types of races.

Yes, I'm aware, hence the second half of my post.

It give the best possible baseline value, and anyone should be able to achieve exactly the same results by doing exactly the same thing. As soon as you start introducing variables like braking, cornering, accelerating again, gearing, and anything else, you have things that can give you different results from the person that tested it (especially if they're loads better than you, like T-W is loads better than me). Perhaps the Citroen can get out of Fuji's corners in a higher gear than the Alfa, which makes it more efficient at that circuit (don't know, haven't checked)

I will be adding some further circuit tests in later - and I have the tyre tests to do, which cannot take place at SSRX - I just thought it was interesting that the Cayman could go so much further than anything else (with the Megane Trophy a distant second).

I'm still doing more testing at other tracks, but they are baseline values, free from track-specific considerations, that I found interesting.

 

[breeminator]

If you really want to make the end-all-be-all spreadsheet for car specs, there is no substitute for learning how to maximise each car's powerband and how to optimise their fuel consumption.

Windfire appears to correctly short shift cars that require it for best power. Going beyond that into fuel saving territory is very dependent on the track and tyre+fuel settings, e.g. it depends how the fuel tank emptying would fit in with wanting to pit to change tyres. You could get a bit of an idea if you tried to make all cars have 50% fuel left at the end of his test, say, to see what that does to total race time, but it would take hours to optimise that for each car, and he already spends several hours on each car to make sure he gets the best out of it, so you're probably looking at months rather than weeks to complete that testing.