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Is this correct thinking:
(example)
210/230 (in/ex duration) 110 lsa VS 220/230 (duration) 115 lsa.
The 210/230 110 lsa cam should have more overlap than the 220/230 115 lsa cam, correct? Reason being that the tips of the lobes (halfway point of the cycle) in the second are farther apart even though the duration of the intake on the first is smaller.
Also, what is the largest amount of overlap anyone has tried? If my thinking is correct in the above examples, I am looking at possibly getting a cam with 97.5 to 109 degrees of overlap. The stock overlap (by my calcs) is roughly 79 degrees. Would a cam with 97.5 to 109 degrees of overlap trigger an SES?
With all the searches I have done, it seems everyone has agreed that anymore than 0.500" total lift is pointless with stock heads as after 0.500" lift the heads begin to flow worse. So by going with say 0.496" intake lift and 0.512" exhaust lift, would this be a good combo? I currently have a 3" exhaust with a high flow cat and a post-cat O2 sim, the 01's have the tubular manifolds as well.
Bah, basically, the cams I am considering right now look like this - all will be using the stock 1.6 rockers:
#1:
210/216 115 LSA .310/.320
#2:
210/220 115 LSA .310/.320
#3:
206/225 118 LSA .310/.320
#4:
220/230 116 LSA .310/.320
#5:
220/230 120 LSA .310/.320
I realize that with more overlap, I will get a less responsive bottom end and I will need a torque converter to make up the difference. I do plan to advance the timing a bit in the grind to help lower my powerband back into something a little more reasonable (I do plan to run simulations on all these once the software arrives but I want experienced opinions too). How much overlap is considered as being too much though? I am hoping that by increasing the exhaust duration that I can increase the vacuum effect overall using my 3" exhaust which should hopefully yeild more fresh mix in the cylinder which should give more HP. I plan to use my car for Auto-X and as a daily driver still, so a bit of responsiveness at the bottom end will be necessary.
Sorry about the editorial, but I figured I might as well dump everything I was thinking down and let everyone pick it apart so I can learn more.
Any and all thoughts/comments are welcomed [img]smile.gif[/img]
(example)
210/230 (in/ex duration) 110 lsa VS 220/230 (duration) 115 lsa.
The 210/230 110 lsa cam should have more overlap than the 220/230 115 lsa cam, correct? Reason being that the tips of the lobes (halfway point of the cycle) in the second are farther apart even though the duration of the intake on the first is smaller.
Also, what is the largest amount of overlap anyone has tried? If my thinking is correct in the above examples, I am looking at possibly getting a cam with 97.5 to 109 degrees of overlap. The stock overlap (by my calcs) is roughly 79 degrees. Would a cam with 97.5 to 109 degrees of overlap trigger an SES?
With all the searches I have done, it seems everyone has agreed that anymore than 0.500" total lift is pointless with stock heads as after 0.500" lift the heads begin to flow worse. So by going with say 0.496" intake lift and 0.512" exhaust lift, would this be a good combo? I currently have a 3" exhaust with a high flow cat and a post-cat O2 sim, the 01's have the tubular manifolds as well.
Bah, basically, the cams I am considering right now look like this - all will be using the stock 1.6 rockers:
#1:
210/216 115 LSA .310/.320
#2:
210/220 115 LSA .310/.320
#3:
206/225 118 LSA .310/.320
#4:
220/230 116 LSA .310/.320
#5:
220/230 120 LSA .310/.320
I realize that with more overlap, I will get a less responsive bottom end and I will need a torque converter to make up the difference. I do plan to advance the timing a bit in the grind to help lower my powerband back into something a little more reasonable (I do plan to run simulations on all these once the software arrives but I want experienced opinions too). How much overlap is considered as being too much though? I am hoping that by increasing the exhaust duration that I can increase the vacuum effect overall using my 3" exhaust which should hopefully yeild more fresh mix in the cylinder which should give more HP. I plan to use my car for Auto-X and as a daily driver still, so a bit of responsiveness at the bottom end will be necessary.
Sorry about the editorial, but I figured I might as well dump everything I was thinking down and let everyone pick it apart so I can learn more.
Any and all thoughts/comments are welcomed [img]smile.gif[/img]
