Ok, I've not read this thread in it's full entirety (but I've read a good 80% of it)
I recently restarted my race game with the intent of scoring the most a-spec points I possibly can. I'm still early on in that game (barely past 10%), so the budget I have to tune ad play with my cars is still somewhat limited.
Anyways, I have some notes on A-spec points jotted down in my race log book that I thought would answer a few questions raised in this thread and make some things a bit more clear.
All of this was observed on the Japan Championship with the field consisting of:
'02 RX7 Spirit R
'97 NSX S Zero
'99 WRX STI
'03 RX8 Type S
'00 Skyline GT-R Vspec II
I entered the championship (multiple times to test settings and observe effects to A-spec points totals) with a '98 300zx 2-seater.
My initial modifications were as follows:
Racing Brakes
Racing Suspension
Triple Clutch, Flywheel, Fully Customizeable LSD, Driveshaft
Racing Exhaust, Chip, Racing Intercooler, Stage 1 Turbo [not all equipped at the same time, only purchased them all so there would be some flexibility here during my testing]
Wing
A-spec points are not affected by:
Suspension Kit (any type), or its settings
Transmission, Clutch, Flywheel, Differential, Driveshaft (any types), or their settings
Brake components, or their settings
Driver Aids
Rear Tires
Ballast Weight Bias
Race Location
Starting Position
That is to say, A-spec points are determined only by:
Vehicle Weight (including ballast weight - but not it's location on the car)
Power
Torque
Front Tires
Wing Downforce Settings
Your car relative to the AI Cars in the field
Notes on Downforce Settings:
- The car was set to recieve 142 A-spec points with no wing equipped
- With a wing installed, but front and rear downforce set to 0, 142 A-spec points still awarded
- Wing at 30 | 30, points drop to 87
- Wing at 15 | 15, I predicted pts to be 114, or 115 - was awarded 112 pts (meaning the relation between downforce and A-spec points deducted is nearly linear)
- Wing at 30 | 0, 112pts
- Wing at 0 | 30, 112pts
- Wing at 10 | 20, 112pts
Therefore, the sum of your wing settings is used to determine A-spec pts. Where you place the downforce on the car is not of relevance.
Notes on Tires:
- S2 | S2 - 142pts
- S1 | S1 - 153 pts
- S2 | S1 - 142 pts
- S1 | S2 - 153 pts
Therefore, only the compound on the front tires is used by the game in determining A-spec pts.
Notes on Power and Torque.
Initially, with the car poised to recieve 142 A-spec pts, it had only racing exhaust and the stage 1 turbo equipped. The graph showed 337hp and 342ft lb tq.
By removing the stage 1 turbo and installing a racing intercooler and sports chip the graph changed to read 337hp and 348ft lb tq. A-spec pts dropped from 142 to 141.
Therefore, torque is considered in determining a-spec pts.
Notes on Power, Torque, and Ballast Weight
-note, the car had no weight reductions done. It was at a stock weight of 1520kg.
At 1520kg, 337hp, and 342 ft lb tq, 142 a-spec pts awarded.
PWR = (337hp / 1.52tonne) = 221.71
At 1520kg, 372hp, and 378ft lb tq, 108 a-spec pts awarded.
PWR = 372 / 1.52 = 244.74
To attain same PWR as previously, ~158kg ballast must be added (to any location)
PWR = 372 / (1.52 + 0.158) = 221.69
This resulted in a 128pt race, not 142 as I had been expecting.
Therefore PWR is not a determining factor in A-spec points.
What about a relation between torque and weight?
At 1520kg, 337hp, and 342 ft lb tq, 142 a-spec pts awarded.
TWR = 342 / 1.52 = 225
At 1520kg, 372hp, and 378ft lb tq, 108 a-spec pts awarded.
TWR = 378 / 1.52 = 248.68
To attain same TWR as previously, 160kg ballast must be added (to any location)
TWR = 378 / (1.52 + 0.160) = 225
This resulted in a 128pt race, not 142 as I had been expecting.
Therefore TWR is not a determining factor in A-spec points.
Vehicle weight is an independent factor in determining A-spec points. It is not combined with power or torque. GT4 does not use PWR or TWR as a basis for determing A-spec points.
So, then how is weight used?
The observations recorded here are specific to the 300zx I was using (quite possibly specific to the field of cars I was entered against as well).
At 1520kg, 337hp, and 342 ft lb tq, 142 a-spec pts awarded.
Added racing chip. At 1520kg (0 ballast), 351hp, 357 ft lb tq, 128pts awarded
With 100kg ballast added on, 141 A spec points awarded.
At 102kg, 141pts
At 103kg, 142pts ***important point.
At 110kg, 142pts
At 111kg, 143pts ***important point.
Therefore, I can predict for every 8kg of ballast installed or removed, I will be awarded or deducted 1 a spec point.
Check: 103kg / (141pts - 128pts) = 7.92kg / a-spec point
This is close enough that I mark my prediction as correct.
Check#2: back to base settings, 337hp, 342ft lb tq. But left on 103kg ballast.
resulted in a 155pt A-spec race. This is good news to me.
With 111kg ballast it was 156pts.
Therefore, 103kg = 13 a spec points at 337hp, 342 ft lb tq or 351hp, 357ft lb tq. 111kg = 14pts.
More proof the weight is independent of Power and Torque!
At 1520kg, 157hp, 361 ft lb tq, 122pts awarded. This represents a 20point deduction from my base settings.
20pts x 8kg/pt = 160kg of ballast should be required for a 142 A-spec pt race.
As it turned out, 160kg of ballast gave 143pts.
20pts x 7.92kg/pt = 158kg of ballast
This did give me 142pts
I should have been able to go lower than 158kg ballast and still recieve 142points... but my notes stop here. Looks like there is still some round off error associated with my calculations. But because this set of calculations is only good for 1 car with a specific field of cars I'm not too concerned with going back to correct them.
By this point I had proved what I had been trying to prove. PWR and TWR are not used to determine a-spec points. Weight is used as a separate and independent factor in whatever equation PD devised to set A-spec point totals.
Some Conclusions:
What can you learn from this?
By following similar calculations you can predict how much ballast will be required to attain a certain amount of A-spec points. It could be used much like reward weight.
By knowing which mods and settings will affect your A-spec points you can tune your cars more successfully. ie. You can modify your cars extensively without affecting your points total. You can take out high powered cars with significantly lower powered cars or heavier cars.
What is still unknown to me?
effects of chassis refreshing and roll cage. (I was restarting all the time to get the same field of cars for my tests - a chassis refresh was never required)
effects of things like AYC's and VCD's to AWD cars.