vader99

iTrader: (4)

A quick question about cams for the guys with more knowledge/expertise than me...

What would happen if you took a tr 224 224 563 563 114+4 and compared to the same cam except with +6 degrees of advance?

Any problems with adding the additional 2 degress of advance?
Would the powerband move lower?
Would it affect the idle quality any compared to the +4 cam?

thanks...

Orange Juice

iTrader: (3)

Not an expert, but I think that you would have to consider P/V clearance. What is your lift?

GuitsBoy

iTrader: (4)

You are correct about the P/V clearance issues, but lift will tell you little. Duration at .050 and .006 will heml more, but in the end, you have to measure it to be sure, since there's no accurate calculations.

s346k

iTrader: (4)

what you would accomplish by grinding in more advance is this:

theoretically you'd move the powerband lower in the rpm range, making a flatter curve. however, you would push the actual hp peak up a bit. also you'd make less peak hp..

idle is unaffected by ground in advance.

SideStep

SMonty

iTrader: (8)

that sentence definitly needs an explanation

cantdrv65

iTrader: (3)

P/V definitely might be an issue. It would also raise the DCR some, and yes lower the powerband slightly.... Wouldnt make a whole hell of alot of difference in power IMHO...

s346k

iTrader: (4)

you'd push the peak RPM for hp up, but the actual peak NUMBER down..

ie +0 = 400 hp peaked at 6500 - "peaky curve"

+4 = 395 hp peaked at 6700 - "not-so-peaky curve"

basically by grinding in advance you are giving up some hp on top, and pushing your peak rpm up in the band...this is done to provide more power lower in the rpm band, but at the expense of a few hp up top.

my theory - ground in advance is for street cars.

s346k

iTrader: (4)

since no one else could check out the cam guide STICKY..

here it is straught from the source...

"- Most off the shelf cams have 2 or 4 degrees of advance ground in. This lowers the power band slightly and offers more low end and midrange at the sacrifice of a bit more top end power

- For cams used primarily on the street the advance is best appreciated. For a strip or racing setup 2 or 0 degrees advance will net you more peak power in the upper ranges of the power band"

SideStep

That is what I thought meant; you actually have it backwards... Every cam I have added advance to peaked earlier and with slightly less HP.... but had a better (fatter) TQ curve through the TQ curve... mainly because you are closing the intake valve earlier and building more cylinder pressure.

All of this is speculative though, you cannot just arbitrarily shove advance in and expect optimum results for the street. My current cam has only 1 degree advance (111 ICL) and is the best STREET/strip cam I have used.. 346 LS1s like an IVC between 44 & 46 degrees (@ .050) and the IVO and EVC at equal distances from TDC. Not to say deviations from these specs will make for a "bad" cam, these are just good guide lines for street driven cars. I am currently at an IVC of 44 degrees and the IVO and EVC are equal distances from TDC. Patrick and Tony helped me pick this cam to meet my goals, mostly street very little strip.

s346k

iTrader: (4)

i have yet to deal with advance & cams with these particular motors. i am old school, i've dealt a lot with bbc and gen 1 sbc..adjustable timing chains, etc. for the most part what i stated is true, but as you said...it is speculation, each engine is different, regardless of its mechanical specs.

i've always installed cams straight up with no advance and went from there. but it's a little more difficult to reveal this timing chain than that of a gen 1 sbc, so i think i'll install my cam +0 and leave it.

ArcticZ28

iTrader: (14)

advance - move power band down (earlier in the rpm), less peak hp (earlier) but more area under curve
retard - move power band up (later in the rpm), more peak hp (later) and less area under the curve