Quote:
Originally Posted by Cyanfall
Excepet warming up, i cannot make sense of why the car wanna close one exhaust even, or especially at eco pro mode. More exhausts means Less back pressure means better fuel economy right?
|
Back pressure increases torque at low revs..makes the car more driveable which would also reduce MPG because you use less throtle to get going. But closed flap is bad for BHP at higher revs so you want to open the flap to reduce back-pressure to get better high end performance and free reving engine, thats why they have a valve. Its a bit like vanous on the camshafts which gives better torque at low revs and more BHP/higher rpm. Simples