The HP modifiers are:
-5.0% = dirty oil
-3.0% = not broken in
-2.0% = old engine
So, when you get a car, it has a -5% dirty oil modifier and a -3% not broken in modifier. These are compounded, not added. The final number is calculated as:
(base HP) / 1.03 / 1.05
A small problem is that base HP isn't an integer. What you see displayed is rounded off, so it's hard to tell what the exact HP is. You also have to remember that the numbers the car dealer shows are often wrong and you have to buy it and check your garage to make sure. For example:
Mazda MX-5 Miata LS: 168.3 base HP (listed as 157 in dealer)
168 HP broken in with oil change
163 HP new with oil change (168.3 / 1.03 = 163.4)
160 HP broken in with dirty oil (168.3 / 1.05 = 160.3)
156 HP new with dirty oil (168.3 / 1.03 / 1.05 = 155.6)
F094/S: 829.1 base HP
829 HP broken in with oil change (peak)
813 HP with old engine & clean oil (829.1 / 1.02 = 812.8)
790 HP broken in with dirty oil (829.1 / 1.05 = 789.6)
774 HP
After finding a good thread on GranTurmo.com, I think I've figured out how milage works. Apparently GT3 uses km * 0.630 to determine miles (which is a bit inaccurate, but oh well).
oil mileage:
0 - 200km (126mi): no modifier for dirty oil
300km (189mi): oil light comes on, -5.0% dirty oil modifier
The presumable HP modifier % for oil milage between 200km - 300km is:
(km - 200) * 0.05
or
(mi / 0.630 - 200) * 0.05
break in (purchased cars only):
300km (189mi)
The presumable HP modifier % for car milage between 0km - 300km is:
km * 0.01
or
mi / 0.630 * 0.01
old engine (purchased cars):
0 - 800km (504mi): no modifier
900km (567mi): -2.0% old engine modifier
old engine (prize cars):
0 - 500km (315mi): no modifier
600km (378mi): -2.0% old engine modifier
The presumable HP modifier % for car milage between 800km - 900km is:
(km - 800) * 0.02
(km - 500) * 0.02 for prize cars
or
(mi / 0.630 - 800) * 0.02
(mi / 0.630 - 500) * 0.02 for prize cars
So, let's say you entered Formula GT with a brand new F094/S or F094/H (same HP) with an oil change.
Race 1: Midfield, 0mi elapsed, 829 HP
Race 2: Seattle, 67mi elapsed, 829 HP
Race 3: Grand Valley, 163mi elapsed, partially dirty oil, 805 HP (829.1 / 1.0294 = 805.4)
Race 4: Super Speedway, 247mi elapsed, dirty oil, 790 HP (829.1 / 1.05 = 789.6)
Race 5: Rome, 322mi elapsed, aging engine, dirty oil, 788 HP (829.1 / 1.0022 / 1.05 = 787.9)
Race 6: Test Course, 391mi elapsed, old engine, dirty oil, 774 HP (829.1 / 1.02 / 1.05 = 774.1)
Race 7: Laguna Seca, 552mi elapsed, 774 HP
Race 8: Apricot Hill, 627mi elapsed, 774 HP
Race 9: Tokyo Rt. 246, 691mi elapsed, 774 HP
Race 10: Monaco, 771mi elapsed, 774 HP
final: 934mi elapsed (946 actual with pit stops), 774 HP
change oil: old engine, clean oil, 813 HP (829.1 / 1.02 = 812.8)
The important figures here are the partially dirty oil formula for Race 3:
(163mi / 0.630 - 200) * 0.05 = 2.94%
and the aging engine formula for Race 5:
(322mi / 0.630 - 500) * 0.02 = 0.22%
As you can see, these numbers match exactly the per-race figures reported in Der Alta's Compendium
-5.0% = dirty oil
-3.0% = not broken in
-2.0% = old engine
So, when you get a car, it has a -5% dirty oil modifier and a -3% not broken in modifier. These are compounded, not added. The final number is calculated as:
(base HP) / 1.03 / 1.05
A small problem is that base HP isn't an integer. What you see displayed is rounded off, so it's hard to tell what the exact HP is. You also have to remember that the numbers the car dealer shows are often wrong and you have to buy it and check your garage to make sure. For example:
Mazda MX-5 Miata LS: 168.3 base HP (listed as 157 in dealer)
168 HP broken in with oil change
163 HP new with oil change (168.3 / 1.03 = 163.4)
160 HP broken in with dirty oil (168.3 / 1.05 = 160.3)
156 HP new with dirty oil (168.3 / 1.03 / 1.05 = 155.6)
F094/S: 829.1 base HP
829 HP broken in with oil change (peak)
813 HP with old engine & clean oil (829.1 / 1.02 = 812.8)
790 HP broken in with dirty oil (829.1 / 1.05 = 789.6)
774 HP
After finding a good thread on GranTurmo.com, I think I've figured out how milage works. Apparently GT3 uses km * 0.630 to determine miles (which is a bit inaccurate, but oh well).
oil mileage:
0 - 200km (126mi): no modifier for dirty oil
300km (189mi): oil light comes on, -5.0% dirty oil modifier
The presumable HP modifier % for oil milage between 200km - 300km is:
(km - 200) * 0.05
or
(mi / 0.630 - 200) * 0.05
break in (purchased cars only):
300km (189mi)
The presumable HP modifier % for car milage between 0km - 300km is:
km * 0.01
or
mi / 0.630 * 0.01
old engine (purchased cars):
0 - 800km (504mi): no modifier
900km (567mi): -2.0% old engine modifier
old engine (prize cars):
0 - 500km (315mi): no modifier
600km (378mi): -2.0% old engine modifier
The presumable HP modifier % for car milage between 800km - 900km is:
(km - 800) * 0.02
(km - 500) * 0.02 for prize cars
or
(mi / 0.630 - 800) * 0.02
(mi / 0.630 - 500) * 0.02 for prize cars
So, let's say you entered Formula GT with a brand new F094/S or F094/H (same HP) with an oil change.
Race 1: Midfield, 0mi elapsed, 829 HP
Race 2: Seattle, 67mi elapsed, 829 HP
Race 3: Grand Valley, 163mi elapsed, partially dirty oil, 805 HP (829.1 / 1.0294 = 805.4)
Race 4: Super Speedway, 247mi elapsed, dirty oil, 790 HP (829.1 / 1.05 = 789.6)
Race 5: Rome, 322mi elapsed, aging engine, dirty oil, 788 HP (829.1 / 1.0022 / 1.05 = 787.9)
Race 6: Test Course, 391mi elapsed, old engine, dirty oil, 774 HP (829.1 / 1.02 / 1.05 = 774.1)
Race 7: Laguna Seca, 552mi elapsed, 774 HP
Race 8: Apricot Hill, 627mi elapsed, 774 HP
Race 9: Tokyo Rt. 246, 691mi elapsed, 774 HP
Race 10: Monaco, 771mi elapsed, 774 HP
final: 934mi elapsed (946 actual with pit stops), 774 HP
change oil: old engine, clean oil, 813 HP (829.1 / 1.02 = 812.8)
The important figures here are the partially dirty oil formula for Race 3:
(163mi / 0.630 - 200) * 0.05 = 2.94%
and the aging engine formula for Race 5:
(322mi / 0.630 - 500) * 0.02 = 0.22%
As you can see, these numbers match exactly the per-race figures reported in Der Alta's Compendium
