2000Z28M6

iTrader: (13)

Ok I understand the basic specs like intake and exhaust dur., lift, but why do you have to usually order some advance ground into the cam? How does it coincide with ICL and a given power range? What kind of advance are X1 people running? Is advance required in any aftermarket cam? Any comments are encouraged.

LOnSLO

iTrader: (15)

Intake valve closing point determines rpm range. Let's use the X1 as an example. It has a 112 LSA, 108 ICL, and 230 degrees intake duration. To figure intake valve closing point:
(duration @.05" /2)-(180-ICL) = closing point ABDC.
So, if you plug in the numbers, you get 43 degrees ABDC. In an LS1, this corresponds to about a 6400 rpm power peak. Decrease the advance to 2 degrees, and you have an intake closing point of 45 degrees ABDC. This will raise your peak power up to around 6600rpm. With 0 degrees advance, well you get the picture. You should use this formula when designing your own custom cam. That will help in picking an rpm range that is suitable for your combo. If you need more info, let me know.

2000Z28M6

iTrader: (13)

WOW!!Let me chew on that for a lil bit LOsSLO... Thanks I will have more questions!

soundengineer

iTrader: (16)

with the x1 cam its typically ground 3* advance...which nets your torque down in the 4000-5500 range...and HP keeps climbing until about 6500...gives you a pretty big powerband...
I have nearly 300tq at the rearwheels at 1500 rpm!!! and 364 at its peak around 5000rpm....If I shift at 5500-6000rpm it keeps me in this good torque area....and power is really good..if I didnt have any advance it would all be way too high to be useable....I would have no down low power at all my hp starts to flatten out at about 6000rpm...and with no advance It would probably be in the 7000-7500 range...way to high to spin up to on a stock bottom end....maybe way to high for most of the parts.

Phil99vette

iTrader: (11)

I think that grinding in advance will result in more cranking compression. This will make more HP and is easier than milling the heads or using different headgaskets.
Phillip

someday

not to flame anyone and their cam choices, but isn't advance used as a "crutch" because everyone uses a cam thats too big and it pushes the hp peak up too high, so they add advance to bring the peak back down??

SSactionLs1

im no cam expert...but that statement means one thing to me...more useable power..

eallanboggs

iTrader: (1)

I think this is the cam manurfacturers way of outsmarting the buying public. You have the option of buying a adjustable timing set. The RollMaster has ZERO plus 2,4,6 and 8 degrees of Advance or Retard to allow you to either OVERRIDE or ADD to what is ground in.

sbrown99TA

Yeah, a big cam with advance just shifts the power down back to the usable range for your rotating assembly, from what I know. It's not really a "crutch"

LOnSLO

iTrader: (15)

True, but when a cam is ground with 4 degrees advance, that means only the intake lobe has been ground with 4 degrees advance. Retarding a cam 4 degrees, on a cam that has 4 degrees ground in, is not the same as having that cam ground with 0 advance.

2000Z28M6

iTrader: (13)

Oh ok, I like the simple terms everyone else used. Dont get me wrong I still wanna really understand the formula posted. So I'm still chewing....Thanks guys appreciate the info.

MyLS1Hauls

iTrader: (2)

This is not correct. If you only advance the ICL, you just tightened up the LSA. Whether you adjust the ICL by "grinding" or by a timing chain setup, it still adjusts it. By moving the ICL and keeping the LSA the same, you also adjust ECL. Its just the way the calculations work. ICL+ECL/2=LSA.

As for advance adjusting peak power RPM. The intake manifold has more control over this than a few degrees of advance from a cam does. Advancing a cam should add a little more low rpm torque and thats what most people want.

LOnSLO

iTrader: (15)

You are correct. All this cam tech talk throws me for a loop at times.

2000Z28M6

iTrader: (13)

Since were talkin specs and tech where does valve overlap come in place?, how does it affect the cam's duration or performance?

MyLS1Hauls

iTrader: (2)

LOL..yeah it does get confusing sometimes doesnt it? I always have to double check what I type when it comes to this stuff to make sure I got it right

ChiTownSS

I have a 226/224 112 lsa compcam with no advance ground into it. I have an M6 w/stock 3.42 gears in it and basically, it seems like the power kicks in at around 3,000 rpms.

Do you think I will feel more of a difference DOWN LOW if I add 4.10 gears or if I advance my cam 4 degrees with a timing set?

MyLS1Hauls

iTrader: (2)

4.10 without a doubt would be the thing to do. I'd leave the cam straight up and call it good. 4.10 gears really help out a cammed 6spd car feel faster around town.