Albert Widmann with the car engine running. He had nearly died of carbon monoxide poisoning from the exhaust fumes. This engine exhaust testing inspired the development of gas vans. Back in Berlin, Reinhard Heydrich immediately set to work within the RSHA for the development of, in the words of Heydrich's subordinate Walter Rauff, a "more humane method of execution" than the "Einsatzgruppen" firing squads which had been used. When a prototype gas van was driven to KTI, Widmann explained to his young chemists that by adjusting the timing of the ignition, one could maximize the amount of poisonous carbon monoxide in the
Exhaust manifold exhaust gas to expand and slow down, decreasing the scavenging effect. Tubes that are too small will create exhaust flow resistance which the engine must work to expel the exhaust gas from the chamber, reducing power and leaving exhaust in the chamber to dilute the incoming intake charge. Since engines produce more exhaust gas at higher speeds, the header(s) are tuned to a particular engine speed range according to the intended application. Typically, wide primary tubes offer the best gains in power and torque at higher engine speeds, while narrow tubes offer the best gains at lower speeds. Many headers