1nastyss

iTrader: (12)

Whats the point for advance ground into the lope sep. for, like 112+2 , or 112+4 ........? Please explain

Steve - Race Eng

iTrader: (1)

Cam companies grind advance in cams for those using stock timing sets with no advance provisions built in. Most aftermarket crank sprockets have multiple key slots to provide advance or retard to dial the cam in.

I generally advance cams about two degrees. The chains will stretch that much pretty quickly. More advance will increase low end torque at the expense of top end power. Heavy cars oft times respond well to more camshaft advance.

Steve

DavidNJ

Advance is sort of an after the fact measurement of valve opening and closing events. It simply means the intake and exhaust are not symmetric around TDC on the exhaust stroke.

Adding advance reflects moving the intake valve closing earlier, adding to dynamic compression. It is typically used to broaden a power curve by increasing low end torque/power (they have a linear relationship) at some expense in higher end power.

By building it into the cam it will install correctly without an offsetting adjustment. Additionally, a billet cam drive pulley usually has 2deg increments, and build in advance can be finer.

delinquent543

doesnt that defeat the purpose of getting a huge cam? y bother getting a cam with huge intake/exhaust periods (and thereby having high high end tq) if you are just going to retard it.. unless you just like the sound?

PREDATOR-Z

Because big cams are not meant for slow driving and moving the trq curve higher is what is best for the racing powerband used.
That is why we do strokers, to get more trq down low and still be able to harness more up high.
Best of both doesn't exist, but aftermarket cam designers are comming up with some pretty good compromises.
I normally like my cams on 0* advance so I can do so at leisure myself.
As mentionned above, for VEs sake, I get advance ground in if and only if I have a non adjustable T-Chain.