Cam timing events: when is there enough overlap???

[dsm-onster]

I must admit I am still rather new to DSMs but i have heard of retarding the exhaust cam timing to increase overlap and thus give the turbo a quicker spool up and consequently more midrange power. But how much is too much cam retard? I am sure 7+ degrees retard is too much, right?

I ask this question because i've just gotten back from changing my cam timing? I couldn't stop my knocking issues so i thought my ignition timing was off... sure enough it was about 15 degrees advanced instead of 5* (+/- 2*).I checked my cam timing and my Exhaust cam was retarded one tooth and my intake was advanced one tooth... the later explained why i was at 15 degrees base timing... but anyway, my car has great toend but the mid has dropped off a little and now i have to keep my foot in it to spool up my 16G. to get more midrange power should i retard the exhaust cam 1 degree, or 7 degrees, or somewhere in between? what has been anyone's experience? I know tuning my car will be different from another but i don't know where the median is.

thanx

 

[dsm-onster]

No replies?!? I know that it helps my old 85 T-bird Turbo coup to retard the cam a bit... But that is a single over head cam... what do you all think? wouldn't increasing overlap help "push" the exhaust gas out of the cylinder?

 

[15psi88]

i would think this should help
http://www.dsmtuners.com/forums/showthread.php?p=1333023#post1333023

 

[MNGSX]

I must admit I am still rather new to DSMs but i have heard of retarding the exhaust cam timing to increase overlap and thus give the turbo a quicker spool up and consequently more midrange power. But how much is too much cam retard? I am sure 7+ degrees retard is too much, right?

I ask this question because i've just gotten back from changing my cam timing? I couldn't stop my knocking issues so i thought my ignition timing was off... sure enough it was about 15 degrees advanced instead of 5* (+/- 2*).I checked my cam timing and my Exhaust cam was retarded one tooth and my intake was advanced one tooth... the later explained why i was at 15 degrees base timing... but anyway, my car has great toend but the mid has dropped off a little and now i have to keep my foot in it to spool up my 16G. to get more midrange power should i retard the exhaust cam 1 degree, or 7 degrees, or somewhere in between? what has been anyone's experience? I know tuning my car will be different from another but i don't know where the median is.

thanx

Dont do 7 degrees....

are they stock cams?

 

[dsm-onster]

i would think this should help
http://www.dsmtuners.com/forums/showthread.php?p=1333023#post1333023

Man, I searched and never found this thread But that clears alot up. . .

MNGSX, yes they are stock cams. I figure 7 degrees retarded is just retarded because there would be idle issues. I'll start at two degrees and work from there...