Engine Problem?

[Deanslug]

When I accelerate hard, the engine seems to surge and pick up speed quicker at 4500rpm. Almost feels like there is a turbo. What could cause this?

[steve2006]

Probably the VVTI kicking in.

[BenIS]

Yup VVT-i my friend. Wish it was a turbo though!

[noby76]

VVT-i is always on guys as its continously varying the valves in all driving conditions and not fixed to a specific rpm like Hondas VTEC or VVTL-i which comes in at 6000rpm on the celicas. what you are feeling is when you hit 4500rpm is the second intake opening to suck in huge amount of air into the cylinders of the engine and this effect feels like something just kicked in had this on my previus ford cougar v6 aswell. Lexus calls it Acoustic Control Induction System which has the effect of a super charger but not quite like a super charger it just helps your engine breath better at higher speeds which results in better performance. see link below about this and other Lexus technologies they use in thier cars.

http://www.lexus.com.bh/technology_explorer/acoustic_control_induction_system_ACIS.asp?model=All