can someone enlighten me as to why a so called computer cam would not always be a better choice than standard cam fare in a non computer car? I was looking over various cams with crane and comp and i see they both market the so called computer cam. it would appear the LSA is greater and max duration about 228. the cam i have picked is at 114 LSA. this should give my map signal at idle a decent vac to work off of and keep ecu happy. why not run this in standard non compyuter car as idle would be bettern andpossible less reversion in intake? what is down side? is down side possible greater stress on valve train?

 

Less midrange torque. Cams with 110* and tighter lobe seperation pull better through the midrange.

 

i fiqured there had to be down side !!!

 

Comp computer cam I installed or had install when ill had 4 degrees advance built into timing, that I did not know of until I asked later. Just a thought as you ask around as comp never told me this when I asked about cam or maybe I did not ask right questions. Good Luck and hope it runs well!

TPI's seem to take a little more duration then TBI's from what I was told anyway!

 

we will install straight up.

 

straight up is uslay the way to do it, that is why comp grinds 4* into their cams, if you notice the LSA will be 114, but the intake centerline will be 110, that is where the 4* come from, the cam in my car right now is on a 112 LSA with a 106 centerline, giving it 6* of advance already ground into it.

 

this probably is not the place to discuss but i thought LSA is the the distance from the center of intake lobe at max lift to the center of exhaust lobe max lift measured in degrees. peak to peak so to speak in degrees. larger LSA means a greater vac as the time one valve is open and the other is closed? tighter LSA means reversion into intake as vac is blead off. is this about right? now if the additional 4 deg is ground into cam how can one determine this to be advance? would this not just be the grind of cam having the greater seperation of the event of valves. i have heard of advancing on install but if you do so what you gain on intake event you lose on exhaust event? i dont really understand the advance comment as built in cam?

 

Ronny, it has to do with the point of the intake at max lift vs crank rotation in degrees. the LSA is the distance between max lift points, as you pointed out.

this chart and article might help

http://compcams.com/Technical/TimingTutorial/

 

Cool, my printer.scanner is down, so I could not done this that well.

I took advance into cam as timing mark when dot to dot on timing marks would be like setting timing marks advance. I use to have this on my GTO 400 with little General Kinetics 292-435 cam, around 3-4 degrees when a friend checked it after blowing head gasket and left it for low end, which was a fun car.

Sorry, I hope his chart helped, thanks! LSA is what it is! I believe most TBI's like a 112 to 114.

Quote Comp Cams: "Most of our street cams have 4 degrees of advance already."

 

one more. so when the 4* adv is "built in" this means the exhaust valve and the intake valve opens earlier in event cycle by 4 deg but LSA remains the same such as 114 LSA ? so in that 720*cycle the events move to earlier in the 720* cycle? so a 110* cam cannot be made to act as a 114* lsa just by advancing on install 4 deg. it would stiil be 110 lsa due to grind. that comment earlier about the 4* confuses me.

 

Advance think of it as timing and when you install a timing chain such as Cloyes Etc true roller, the Crank will have 4 * 4, for 4 advance, straight up, or 4 degrees retarded.

http://www.compcams.com/Technical/Ca...3/HTML/5-7.asp

You can also go to www.compcams.com and look at other technical information etc, but they have used true timing chain setups to advance and retard cams since I am aware of and timing marks are off at times anyway. That's one reason to degree a cam.