- 5,603
- England, Warwickshire
- GTP_Sigma
*Warning thread may contain some physics*
Okay so this is thread about physics accuracy, now altitude affects a car in numerous way one of the most noticeable effects is the power output of your engine.
Perhaps you may wonder why does it matter?
Well while many tracks are barely higher than sea level, there are some in-game tracks which are sufficiently high enough to have a noticeable effect. At around 2000 metre's (6500feet) a naturally aspirated engine should experience a powerloss of close to 20%. So your 300bhp car should find itself with around 240bhp.
Clearly Gran Turismo would be more realistic if it took this into account, sadly GT5P doesn't appear to do this currently going by the quick-tune menu at Eiger and then Daytona in which the power remains the same.
If GT where to re-introduce the pike's peak hill climb the effect would be even more noticeable as the rally ranges from 9000-15000feet which would result in a 25-45% powerloss depending on the on what height you are at. It seems too much of an important detail to miss.
Anther reason why I think it is very important aside from accuracy of simulation, is it adds another factor to tuning, a forced induction engine will experience less of a powerloss than a naturally aspirated enigne, this could affect what car you choose for a certain race, how you tune and setup the car. For example you may choose to buy a turbo for your car instead of going down the naturally aspirated root if you planning on racing at a track like eiger.
Now for the physics, you've been warned.
A naturally aspirated looses approximately 3% power for every 1000feet, this is due to a decrease in air density at altitude and thus less oxygen available for combustion. For a forced induction engine its not so simple.
example
Let's say you have a 300bhp turbo charged engine at sea level. The turbo charger supplies 10psi of boost.
Using eiger as an example again, the powerless can be calculated. assuming sea level air pressure to be 14.7psi.
When car produces its peak power of 300bhp at sea level, the intake pressure is 14.7(air pressure) + 10psi provided by turbo charger = 24.7psi to get 300bhp.
at 6500 feet air pressure has decreased by 20% so air pressure is 11.8psi.
11.8psi (air pressure) + 10psi (assuming turbo can spin fast enough to maintain efficiency) = 21.8psi intake pressure.
21.8/24.7 = 89% power
=267bhp
this is an extra 27bhp advantage over a naturally aspirated engine. While this may not seem that huge, the higher the altitude the more power is saved by the turbo, this saving can be increased further by increasing the boost pressure of the turbo.
I think its an interesting factor which to consider when tuning a car, and of course it will add to the accuracy of the simulation so I am certainly hoping we will see the effects of altitude in GT5.
Okay so this is thread about physics accuracy, now altitude affects a car in numerous way one of the most noticeable effects is the power output of your engine.
Perhaps you may wonder why does it matter?
Well while many tracks are barely higher than sea level, there are some in-game tracks which are sufficiently high enough to have a noticeable effect. At around 2000 metre's (6500feet) a naturally aspirated engine should experience a powerloss of close to 20%. So your 300bhp car should find itself with around 240bhp.
Clearly Gran Turismo would be more realistic if it took this into account, sadly GT5P doesn't appear to do this currently going by the quick-tune menu at Eiger and then Daytona in which the power remains the same.
If GT where to re-introduce the pike's peak hill climb the effect would be even more noticeable as the rally ranges from 9000-15000feet which would result in a 25-45% powerloss depending on the on what height you are at. It seems too much of an important detail to miss.
Anther reason why I think it is very important aside from accuracy of simulation, is it adds another factor to tuning, a forced induction engine will experience less of a powerloss than a naturally aspirated enigne, this could affect what car you choose for a certain race, how you tune and setup the car. For example you may choose to buy a turbo for your car instead of going down the naturally aspirated root if you planning on racing at a track like eiger.
Now for the physics, you've been warned.
A naturally aspirated looses approximately 3% power for every 1000feet, this is due to a decrease in air density at altitude and thus less oxygen available for combustion. For a forced induction engine its not so simple.
example
Let's say you have a 300bhp turbo charged engine at sea level. The turbo charger supplies 10psi of boost.
Using eiger as an example again, the powerless can be calculated. assuming sea level air pressure to be 14.7psi.
When car produces its peak power of 300bhp at sea level, the intake pressure is 14.7(air pressure) + 10psi provided by turbo charger = 24.7psi to get 300bhp.
at 6500 feet air pressure has decreased by 20% so air pressure is 11.8psi.
11.8psi (air pressure) + 10psi (assuming turbo can spin fast enough to maintain efficiency) = 21.8psi intake pressure.
21.8/24.7 = 89% power
=267bhp
this is an extra 27bhp advantage over a naturally aspirated engine. While this may not seem that huge, the higher the altitude the more power is saved by the turbo, this saving can be increased further by increasing the boost pressure of the turbo.
I think its an interesting factor which to consider when tuning a car, and of course it will add to the accuracy of the simulation so I am certainly hoping we will see the effects of altitude in GT5.