hey craig since you knw so much, wanna make me up a turbo cam spec card ??

 

In a round-about way I was trying to say that, but you did a better job explaining it.

A LCA@109 would be a great drag racing cam. An awesome peak power curve at high rmp. A 4k stall and your flying off the line because your immediatley in your powerband, but, the power under 4k really isnt there. Along with idle issues, it would make for a sh*tty street cam.

A LCA@114 however, provides steady power throughout the RPM range making it a way better street cam. You also dont have to rev your motor to 7200rpm to take advantage of the power curve. A 6500 redline with wicked bottom end torque is probably what most people are looking for in a good setup.

Someone correct me if Im wrong.

 

almost there.... the point at which the peak TQ (and thus power) is made is mostly (but not completely) determined by the intake valve closing point, which is influenced mostly by duration, but also by intake centerline (i.e. if the cam is installed straight up, advanced, or retarded) and lastly by LSA. tightening the LSA will actually pull the powerband down a bit since it pulls the intake lobe back 1/2 a degree for every degree of LSA tightened.

So the point here is you could have a tight LSA giving a good TQ peak, but if the duration isn't there or the cam is ground with too much advance, the peak TQ will occur earlier in the RPMs. This would result in way less peak HP then if the TQ peak occured higher in the RPMs by going with more duration.

A great drag racing cam will have the peak TQ roughly halfway between the shifted to RPM (say 4k RPM after you shift into gear) and the desired redline (say 6500 rpm), and will have the biggest TQ peak possible by using a tight LSA - however this will sacrifice low end driveability.

An interesting problem with LS1's is that peak TQ always occurs at 4800 rpm no matter how big the cam - this is due to the intake runner design. Knowing this - why do so many people run massive cams when the high RPM powerband they are trying to achieve cannot happen due to the intake? The simple answer is that they have no idea about cam theory and just shove a big stick in there which hurts their bottom end and does very little for the top. If you look at dyno charts the big cams dont event succeed in easing the TQ rolloff after 4800.

THis means that there really is no reason to go bigger then say a 224/228'ish duration - in fact the fastest C5s from Cartek all run cams about this size - coincidence?

 

Great write up Craig .

 

yeah yeah yeah thats all nice and dandy .. now someone buy my cam

 

I said I was interested..what did Sandeep say? Ball's in your court

 

ok .. i'll give deep another day to decide then

 

SOLD!!!

 

indeed

 

good looks like somebody has some money for me then