School me on Cam differences
School me on Cam differences Ok guys, trying to make a call on a cam, and I got two different recommendations, and having a hard time deciding which will be better, or if the differences are enough that I'll notice them at all.
School me please!
Cam recommendation was requested for a 402 procharged ls2 running stock 243's. Daily driver with weekend strip use, BTR 0.660 springs.
Cam 1: 235/251 0.638/0.632 117+4
Cam 2 239/251 0.624/0.632 115
So im wondering, What is the change in intake duration going to do, and the change in lift specs?
Also, would 117+4 mean installing it advanced 4 degrees, so it would theoretically be 113?
Im a bit lost, any help is greatly appreciated.
School me please!
Cam recommendation was requested for a 402 procharged ls2 running stock 243's. Daily driver with weekend strip use, BTR 0.660 springs.
Cam 1: 235/251 0.638/0.632 117+4
Cam 2 239/251 0.624/0.632 115
So im wondering, What is the change in intake duration going to do, and the change in lift specs?
Also, would 117+4 mean installing it advanced 4 degrees, so it would theoretically be 113?
Im a bit lost, any help is greatly appreciated.
Cam1, has a IVC of 50.5 with 9* of overlap.
Cam2, has a IVC of 54.5 with 15* of overlap.
IMO, for a daily driver with weekend strip use I'd go with Cam1 since it will have a lower more useable powerband and a lot less overlap which you want with a SC so it doesn't bleed off boost. With you having stock 243 heads I'd go with a lot less lift(under .620"), unless you plan on having them thoroughly cnc ported to take advantage of the high lift.
IMO, 4* difference in IVC, and 6* difference in valve overlap @ .05" lift seems like noticeable differences to me.
Cam2, has a IVC of 54.5 with 15* of overlap.
IMO, for a daily driver with weekend strip use I'd go with Cam1 since it will have a lower more useable powerband and a lot less overlap which you want with a SC so it doesn't bleed off boost. With you having stock 243 heads I'd go with a lot less lift(under .620"), unless you plan on having them thoroughly cnc ported to take advantage of the high lift.
IMO, 4* difference in IVC, and 6* difference in valve overlap @ .05" lift seems like noticeable differences to me.
Last edited by 99Bluz28; Jan 24, 2015 at 07:26 PM.
Cam1, has a IVC of 50.5 with 9* of overlap.
Cam2, has a IVC of 54.5 with 15* of overlap.
IMO, for a daily driver with weekend strip use I'd go with Cam1 since it will have a lower more useable powerband and a lot less overlap which you want with a SC so it doesn't bleed off boost. With you having stock 243 heads I'd go with a lot less lift(under .620"), unless you plan on having them thoroughly cnc ported to take advantage of the high lift.
IMO, 4* difference in IVC, and 6* difference in valve overlap @ .05" lift seems like noticeable differences to me.
Cam2, has a IVC of 54.5 with 15* of overlap.
IMO, for a daily driver with weekend strip use I'd go with Cam1 since it will have a lower more useable powerband and a lot less overlap which you want with a SC so it doesn't bleed off boost. With you having stock 243 heads I'd go with a lot less lift(under .620"), unless you plan on having them thoroughly cnc ported to take advantage of the high lift.
IMO, 4* difference in IVC, and 6* difference in valve overlap @ .05" lift seems like noticeable differences to me.
Just so im understanding correctly, if Cam1 is installed at 4degrees advanced (+4?) would that theoretically make the overlap 17 degrees? So the 117 Cam should be installed at 117 to minimize overlap?
The heads will get changed out eventually, would having the extra lift necessarily be bad though?
Edit: Im also running a pretty high CR ( ~10.5:1) so would having a little extra overlap be beneficial in that regard?
Last edited by BigBadWhitey; Jan 24, 2015 at 08:27 PM.
The +4 advance changes the intake centerline (ICL) to 113 with having a 117 lobe separation angle(LSA). Advancing or retarding the cam has nothing to do with intake and exhaust valve overlap, the overlap can't be changed. Advancing the cam gives better low-end power and moves the whole power band down lower in the rpm range, and the DCR will go up some. Retarding the cam giver better top-end power and moves the whole power band up higher in the rpm range and the DCR goes down some. IMO, 9* of valve overlap is still a good amount of overlap in SC 402ci engine, I wouldn't want any more than that for a daily driver with weekend strip use.
