I did a search and could not find enough info. Can someone explain to me the importance of cam lift and duration. There are so many cams on the market and they have different specs for each. What lift and duration is better for what. Drag race or road race.
Thanks

 

Anybody?

 

Lift and duration are both ways to get air into the combustion chamber. Duration keeps the valve open longer, lift opens the valve more. If you desire a high rpm engine, extreme lift can cause problems with valve float unless the valvetrain is built up for it because there is more movement, however lift will build much more torque with lower durations. Lift will also make a more 'streetable' power band.
Duration, on the other hand gets more air into the chamber by keeping the valve open for a longer period. A naturally asperated engine responds to extreme duration/overlap in a favorable way, it uses the exiting exhaust charge to pull air into the combustion chamber. With a blower or turbo, less overlap is desired, so generally, the valves need to open slightly before TDC in the intake as the piston movement stalls, to prevent blow-back and seal slightly after BDC at the moment the piston starts to travel up...and slightly before BDC on exhaust et al. As the piston speeds increase, the optimum moment will travel, thus moving the power curve. More duration seems to work better with higher rpm.
Hopefully this all came out right and is understandable. Bottom line is; more lift will give a wider power band with a lower usable rpm range, more duration will give you +/_ equal peak hp and higher rpm range with more of a spike in power.

 

Thanks Bman!!!