Stockishz06

let say i have a torquer v2 which is 232/234 ..595/.598 @112lsa, what would be the differance in that and 112+4 lsa

i know it advances the timing 4 degrees but what does it actually do

pros and cons

fastazzls1

makes your valve events happen sooner

3rdCoastPowerSports

iTrader: (5)

in short when you advance your cam timing it brings the power band in sooner.... so you are essentially moving the power band in tighter, more lower end power at the sacrifice of top end. most go +2 or +4 on n/a application

vettenuts

iTrader: (4)

If you do a search, TSP did some back to back dyno testing of different cams in the same motor a while back (maybe 2 or 3 years ago). One of the things they compared as I recall were cam advance and also LSA of the same cam duration/lift. If the plots aren't up any longer, TSP may be able to provide them to you.

Stockishz06

Would a +4 be less choppy at idle than a +2 or 0 or does it not change that

mark21742

Your overlap gives you the choppy idle.....tighter lsa (like a 110) will have more overlap than the same cam with a 114 lsa, and the 114 lsa cam will have a smoother idle

Stockishz06

Yea I know that , I was askn would a 112+4 be less choppy than just a 112, on old school distributor motors advancing the timing would always make it idle up a touch and clean the idle up just wondering if its the same concept, then thats were the tuning would.come in to tell conputer to idle at a lower rpmwith the cam advance, jist me thinkn out loud tho

SOMbitch

iTrader: (8)

^^^^Ignition timing and the timing of valve events are two distinct things......

Stockishz06

Gotcha

mark21742

Ignition timing will make it run rougher or smoother, but not add or lessen lope

95ONE

iTrader: (1)

I went -2 degrees. NA. More revs please. Helps my gearing (RPM per MPH) and higher average power. Motor is being built for the revs.

3rdCoastPowerSports

iTrader: (5)

what gears are you running?

hammertime

iTrader: (1)

Advancing a cam, whether ground in at the outset, or by using an adjustable timing set, does not change the relationship between the intake and exhaust lobe. The amount of overlap remains constant, so any change in idle quality (chop/lope) would be very minor, if you even noticed at all.

Changing ignition timing thru the tune, though unrelated, can change the idle quality, just like your example with the distributor in an SBC.

You can't change the overlap without grinding a new cam, but you can advance an existing cam to shift the powerband down a touch, or extend it towards the top end a bit by retarding the valve events. If you find you need to move things more than 4 degrees in either direction, its generally accepted that the next cam size should be selected - smaller if you are advancing, larger if you are retarding.

Last thing, with a big cam, advance or retard can effect PTV clearance on both sides. Advancing a given cam will open the intake valve sooner, opening the valve further in relation to TDC and reducing your clearance there, while giving a little more clearance on the exhaust. The exact opposite occurs when you retard, which holds the exhaust valve open later, reducing its clearance at TDC.

Stockishz06

Im running stock gears, 2002 z06 with a m12, hammertime,thanks for clearing that up for me I understand now I was getting confused thingibg the advance on the cam was the same as afjusting the timing on an old sbc but im no mechanic, but ill give it a go haha, im ready for the cam to be in my car wake it up a little

mark21742

Hey man good luck! Just remember even the pros in here had to learn all this stuff at one time