![](/assets/images/picto-drapeau-france-3a76576a5d60a512053b4612ab58dae5.png)
8. Current trends
8.1 Effect of a displacement change
If you increase the stroke of a car engine without modifying its intake or timing, you'll generally see a gain in torque at low and medium engine speeds, without maximum power increasing in the same ratio as displacement. The reason for this is that permeability has not increased in line with displacement, whereas air flow should be greater, thus increasing pressure losses and limiting refuelling at high revs.
At intermediate engine speeds, filling variations will be small as relative permeability varies: the mass of fresh air will increase in proportion to engine displacement.
At low revs, the fuel tank will be fuller, so torque will increase faster than displacement.
This will...
Exclusive to subscribers. 97% yet to be discovered!
You do not have access to this resource.
Click here to request your free trial access!
Already subscribed? Log in!
![](/assets/images/logo-eti-286623ed91fa802ce039246e516e5852.png)
The Ultimate Scientific and Technical Reference
This article is included in
Hydraulic, aerodynamic and thermal machines
This offer includes:
Knowledge Base
Updated and enriched with articles validated by our scientific committees
Services
A set of exclusive tools to complement the resources
Practical Path
Operational and didactic, to guarantee the acquisition of transversal skills
Doc & Quiz
Interactive articles with quizzes, for constructive reading
Current trends
Bibliography
Exclusive to subscribers. 97% yet to be discovered!
You do not have access to this resource.
Click here to request your free trial access!
Already subscribed? Log in!
![](/assets/images/logo-eti-286623ed91fa802ce039246e516e5852.png)
The Ultimate Scientific and Technical Reference