Advanced Guru's Only Please Respond! Copied From Nitrous Section
03-06-2007, 08:50 PM
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Advanced Guru's Only Please Respond! Copied From Nitrous Section in the motor section i notice alot of talk that goes on about DCR ratios and how important it is to get to 8.5 to keep running pump gas. and everyone should select a cam and heads setup to get you to this mark. but what i dont see is anyone talking about how nitrous will affect this ratio. if im going to get a cam and head setup for nitrous, then what should i shot for in a DCR ratio? how much does a 100 shot affect that DCR ratio? what will a 200 shot do to it? how much will more or less valve overlap change this with lower or higher lobe seperation? if i have less lift with more duration, will my DCR rise less or more than it would if i had high lift and long durartion? alot of questions i know, but what bothers me is that i cant find where anyone has ask these questions. and lastly, piano, can you come up with a chart that you could input a nitrous shot and compute what the DCR would rise too?
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03-07-2007, 07:04 PM
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DCR should not be the End-all number... infact.. it seems to be QUITE overrated on this forum.
DCR is a basic calculation that has NOTHING to do with rpm. The DCR is only calculated by intake valve closing and basic geometric calculations for piston location.
Your DCR vs SCR will tell you what type of engine you have... if your SCR is 15:1 and your DCR is 7:1, you will have a high rpm engine... likewise if you have a 8:1 SCR and a 7.9 DCR.. you will have a low rpm engine.
Your IVC is critical for rpm selection, espeially NA because your trying to capture all the momentum of the air charge, the higher the target rpm, usually you will want a later IVC.
If you put to much empahsis on the DCR number you will not get the big picture!!
DCR is a basic calculation that has NOTHING to do with rpm. The DCR is only calculated by intake valve closing and basic geometric calculations for piston location.
Your DCR vs SCR will tell you what type of engine you have... if your SCR is 15:1 and your DCR is 7:1, you will have a high rpm engine... likewise if you have a 8:1 SCR and a 7.9 DCR.. you will have a low rpm engine.
Your IVC is critical for rpm selection, espeially NA because your trying to capture all the momentum of the air charge, the higher the target rpm, usually you will want a later IVC.
If you put to much empahsis on the DCR number you will not get the big picture!!
03-08-2007, 09:18 AM
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Originally Posted by XBR24
DCR should not be the End-all number... infact.. it seems to be QUITE overrated on this forum.
DCR is a basic calculation that has NOTHING to do with rpm. The DCR is only calculated by intake valve closing and basic geometric calculations for piston location.
Your DCR vs SCR will tell you what type of engine you have... if your SCR is 15:1 and your DCR is 7:1, you will have a high rpm engine... likewise if you have a 8:1 SCR and a 7.9 DCR.. you will have a low rpm engine.
Your IVC is critical for rpm selection, espeially NA because your trying to capture all the momentum of the air charge, the higher the target rpm, usually you will want a later IVC.
If you put to much empahsis on the DCR number you will not get the big picture!!
DCR is a basic calculation that has NOTHING to do with rpm. The DCR is only calculated by intake valve closing and basic geometric calculations for piston location.
Your DCR vs SCR will tell you what type of engine you have... if your SCR is 15:1 and your DCR is 7:1, you will have a high rpm engine... likewise if you have a 8:1 SCR and a 7.9 DCR.. you will have a low rpm engine.
Your IVC is critical for rpm selection, espeially NA because your trying to capture all the momentum of the air charge, the higher the target rpm, usually you will want a later IVC.
If you put to much empahsis on the DCR number you will not get the big picture!!
