MRDAGERUS
Automotive
- May 19, 2009
- 31
Let's consider a
2.5 L, 4cyl, 16v, DOHC,
turbocharged, Max boost = 10psig,
CIS fuel injected engine(Lotus 910),
7500 red line
Where: #1 is a OEM design configuration
#2 is a modified configuration,(exh. cam retarded from 104 MOP to 110 MOP), considered for implementation
#3 for comparison, as an afterthought, just to see how far the overlap can be reduced
.................. .......#1........ . ....#3...............#2
................ ....OEM Turbo...OEred/red....OEgreen/red
Cam ID ..............107/107.....107/107.....107/107
Cam Pulley MOP..104/104.....110/110.....104/110
Int. Total Lift.........0.378"......0.378”.......0.378”
In. Opens, BTDC........22°.........16°...........22°
In. Closes, ABDC.........50°.........56°..........50°
In. MOP ATDC...........104°.......110°.........104°
Int. Duration..............252°.......252°.........252°
Ex. Total Lift..........0.378”....0.378”.......0.378”
Ex Opens, BBDC.........50°........56°...........56°
Ex. Closes, ATDC.......22°........16°...........16°
Ex. MOP, BTDC.........104°.....110°..........110°
Ex. Duration.............252°.....252°..........252°
Overlap...................44°........32°............38°
Lobe separation.......104°.....110°...........107°
Intake C/line offset...0°...........0°...........+3°
Trying to determine:
When it comes to less propensity to detonation, is #2 better? Why? (I was told it would be better, but no explanation was offered.)
What is the effect of advancing Int. cam C/Line?
Less overlap is desirable, but isn't 38° too low?
What would be advantages of #3, if any?
Thank you for your input.
2.5 L, 4cyl, 16v, DOHC,
turbocharged, Max boost = 10psig,
CIS fuel injected engine(Lotus 910),
7500 red line
Where: #1 is a OEM design configuration
#2 is a modified configuration,(exh. cam retarded from 104 MOP to 110 MOP), considered for implementation
#3 for comparison, as an afterthought, just to see how far the overlap can be reduced
.................. .......#1........ . ....#3...............#2
................ ....OEM Turbo...OEred/red....OEgreen/red
Cam ID ..............107/107.....107/107.....107/107
Cam Pulley MOP..104/104.....110/110.....104/110
Int. Total Lift.........0.378"......0.378”.......0.378”
In. Opens, BTDC........22°.........16°...........22°
In. Closes, ABDC.........50°.........56°..........50°
In. MOP ATDC...........104°.......110°.........104°
Int. Duration..............252°.......252°.........252°
Ex. Total Lift..........0.378”....0.378”.......0.378”
Ex Opens, BBDC.........50°........56°...........56°
Ex. Closes, ATDC.......22°........16°...........16°
Ex. MOP, BTDC.........104°.....110°..........110°
Ex. Duration.............252°.....252°..........252°
Overlap...................44°........32°............38°
Lobe separation.......104°.....110°...........107°
Intake C/line offset...0°...........0°...........+3°
Trying to determine:
When it comes to less propensity to detonation, is #2 better? Why? (I was told it would be better, but no explanation was offered.)
What is the effect of advancing Int. cam C/Line?
Less overlap is desirable, but isn't 38° too low?
What would be advantages of #3, if any?
Thank you for your input.