VVT

[HF1]

Sorry if this has been discussed before.

Was variable valve timing ever allowed in F1 and when did they ban it? (any specific reasons?)

Since F1 engines are high reving machines with narrow power bands, would VVT be as beneficial as in a road car engine?

[DaveKillens]

VVT would definitely help any GP engine. But it would add complexity, and of course, the research and development would make the engine more expensive. We have seen the FIA impose a lot of restrictions on development. variable length intake and exhausts are banned, the engine is fixed to a 90 degree V-8, and a lot more stuff like materials. According to Mad max, it's in the interests of controlling costs.

[Guest]

I thought VVT was still used...
I am off on this?

-T

[DaveKillens]

http://www.fia.com/resources/documents/ ... ATIONS.pdf
Regulation 5.6 Variable geometry systems:
5.6.1 Variable geometry inlet systems are not permitted.
5.6.2 Variable geometry exhaust systems are not permitted.
5.6.3 Variable valve timing and variable valve lift systems are not permitted.

[Guest]

5.6.4 Variation in Engine Design is not permitted

[HF1]

VVT would definitely help any GP engine...

I kind of doubt it would. The drivetrain losses would increase significantly, while the benefits may not be big enough. In a road car engine the useful powerband is 2000-8000rpm, 4 times difference. In F1 it is 15000-19000 - less than 30% increase.

[Sawtooth-spike]

in f1 a 1% increse is worth the effort, so it would be. but its not allowed so it doesnt matter

[DaveKillens]

With a fixed geometry valvetrain, engineers can design an engine for it's optimum at only one fixed RPM. Go outside of that RPM, and the engine is not running at it's peak efficiency. A VVT allows engineers to dynamically change the valve timing, which can result in more power or torque at different RPM. For example, modern GP angines are difficult to start, and have trouble idling at lower RPM. By altering the valve timing, you can get an engine that not only idles well, but can deliver lots of power at peak RPM. VVT expands the torque and power throughout the RPM band. Thus, you can get increased torque as a car is exiting the coorners, or you can use that extra torque to run less gears.
http://www.streetracersonline.com/artic ... afts/3.php

[HF1]

I am aware of all this. What I'm saying is the improved "breathability" of the engine over the entire range may not be enough to compensate the increase of drivetrain losses and the revability will probably go down due to increased complexity.
Under hard acceleration a VTEC engine doesen't use the low-profile cam at all (you don't go bellow the 5500rpm) so effectively it doesen't use VVT!