Analysis of H22 Crower Cam Specs
fritz_269
12-05-2001, 03:12 PM
Old PH post (written by fritz_269):
OK - here we go:
Crower Stage 1 H22A cam #63421
CAM ad int/ex @05 int/ex lift int/ex
Stock SH 275/275 225/227 448/415
Stage 1 275/278 231/230 457/426
Diff 000/003 006/003 009/011
% 2.0%/2.7%
ad = advertised duration. @05 = duration at 0.050" gross lift
lift = gross lift (in thousandths)
Diff = difference
Analysis: The exhaust side has 3 degrees more advertised and @05 duration; this generally means that the lobe has been evenly widened three degrees, allowing 2.7% more peak lift with a similar ramp rate. The intake side shows equal advertised duration but a jump to 6 degrees more duration @05 as well as 2% more lift; this indicates that the ramp rate has been steepened such that the valve will not open any sooner, but it will open faster.
Result: A mild improvement over the stock cam - good for NA applications with no or mild bolt-ons. Also good for FI applications as valve overlap is less than 2 degrees greater than stock. The one drawback is that the increased ramp rate will result in intake valve float at an earlier RPM than the stock cam (with stock valve springs) - I would not recommend raising the redline past the stock point with this cam and stock intake valvesprings.
Crower Stage 2 H22A cam #63422
CAM ad int/ex @05 int/ex lift int/ex
Stock SH 275/275 225/227 448/415
Stage 2 297/287 248/240 466/465
Diff 022/012 023/013 018/050
% 4.0%/12%
ad = advertised duration. @05 = duration at 0.050" gross lift
lift = gross lift (in thousandths)
Diff = difference, % = percentange increase from stock
Analysis: Intake lobe ad and @05 are both widened considerably but equally, and lift is up a mild 4%, this indicates a overall wider lobe with a wide peak; ramp rates are near stock. Exhaust lobe ad and @50 are widened equally, but lift is up a large 12%. This indicates a steep ramp and a sharp peak. As indicated by crower, stronger springs than stock must be used to prevent exhaust valve float. Overlap is increased about 18 degrees over stock.
Result: A good NA cam, should make good power in the upper RPMs. Will definitely make good use of a long 4-1 header and free-flowing exhaust system, pipe diameter should probably be increased slightly. May lose a bit of torque at the VTEC switchover point - use a VTEC controller to tune. Wear on the exhaust rockers will increase, valve adjustments should be done more often. The increased overlap will hurt FI applications; with adjustable cam gears they might still be useable in low-pressure systems. Might also be possible to use the Stage 1 intake cam and the Stage 2 exhaust cam for bigger FI systems.
Crower Stage 3 H22A cam #63423
CAM ad int/ex @05 int/ex lift int/ex
Stock SH 275/275 225/227 448/415
Stage 3 295/297 260/250 472/466
Diff 020/022 035/023 024/051
% 5.4%/12.3%
ad = advertised duration. @05 = duration at 0.050" gross lift
lift = gross lift (in thousandths)
Diff = difference, % = percentange increase from stock
Analysis: Intake lobe ad is somewhat wider, but the @05 mark is pushed way out. This indicates a radically steep ramp, and a smooth, wide peak near maximum lift. Exhaust lobe ad and @05 are expanded greatly but equally, but the lift increase is large as well, resulting in a mild ramp increase. Very stong springs must be used on the intake to prevent valve float. Overlap is increased about 21 degrees over stock.
Result: A BIG NA cam, should make big power in the top RPMs. With the proper valvetrain setup, this should make big power well past the stock redline, but intake valve float could be a serious problem. Power at lower RPMs (on the wild lobe) will fall dramatically, a programmable ECU may be neccesary to ensure that a lean burn and stumble does not happen at those RPMs. The power band will probably start around 6-6.5kRPM. This cam will really benefit from some quality headwork - flow rates should increase dramatically. And, of course, properly ported intake and exhaust manifolds will be highly useful. The extreme stress on the intake valves will cause premature wear and misalignment - adjustments will be needed often. Forced induction would probably not work well at all due to the overlap and steep intake ramp.
Personal Comment: It looks to me like the intake lift on this cam was limited, and will not match the exhaust lift well. If the H22A head could be modified to allow more than 0.500" gross lift, I would suggest a custom cam of these approximate proportions (A "Stage 4" cam, if you will): 300/300 250/255 510/475
I think it would be better suited for big NA power and cause less valvetrain stress.
:cool:
OK - here we go:
Crower Stage 1 H22A cam #63421
CAM ad int/ex @05 int/ex lift int/ex
Stock SH 275/275 225/227 448/415
Stage 1 275/278 231/230 457/426
Diff 000/003 006/003 009/011
% 2.0%/2.7%
ad = advertised duration. @05 = duration at 0.050" gross lift
lift = gross lift (in thousandths)
Diff = difference
Analysis: The exhaust side has 3 degrees more advertised and @05 duration; this generally means that the lobe has been evenly widened three degrees, allowing 2.7% more peak lift with a similar ramp rate. The intake side shows equal advertised duration but a jump to 6 degrees more duration @05 as well as 2% more lift; this indicates that the ramp rate has been steepened such that the valve will not open any sooner, but it will open faster.
Result: A mild improvement over the stock cam - good for NA applications with no or mild bolt-ons. Also good for FI applications as valve overlap is less than 2 degrees greater than stock. The one drawback is that the increased ramp rate will result in intake valve float at an earlier RPM than the stock cam (with stock valve springs) - I would not recommend raising the redline past the stock point with this cam and stock intake valvesprings.
Crower Stage 2 H22A cam #63422
CAM ad int/ex @05 int/ex lift int/ex
Stock SH 275/275 225/227 448/415
Stage 2 297/287 248/240 466/465
Diff 022/012 023/013 018/050
% 4.0%/12%
ad = advertised duration. @05 = duration at 0.050" gross lift
lift = gross lift (in thousandths)
Diff = difference, % = percentange increase from stock
Analysis: Intake lobe ad and @05 are both widened considerably but equally, and lift is up a mild 4%, this indicates a overall wider lobe with a wide peak; ramp rates are near stock. Exhaust lobe ad and @50 are widened equally, but lift is up a large 12%. This indicates a steep ramp and a sharp peak. As indicated by crower, stronger springs than stock must be used to prevent exhaust valve float. Overlap is increased about 18 degrees over stock.
Result: A good NA cam, should make good power in the upper RPMs. Will definitely make good use of a long 4-1 header and free-flowing exhaust system, pipe diameter should probably be increased slightly. May lose a bit of torque at the VTEC switchover point - use a VTEC controller to tune. Wear on the exhaust rockers will increase, valve adjustments should be done more often. The increased overlap will hurt FI applications; with adjustable cam gears they might still be useable in low-pressure systems. Might also be possible to use the Stage 1 intake cam and the Stage 2 exhaust cam for bigger FI systems.
Crower Stage 3 H22A cam #63423
CAM ad int/ex @05 int/ex lift int/ex
Stock SH 275/275 225/227 448/415
Stage 3 295/297 260/250 472/466
Diff 020/022 035/023 024/051
% 5.4%/12.3%
ad = advertised duration. @05 = duration at 0.050" gross lift
lift = gross lift (in thousandths)
Diff = difference, % = percentange increase from stock
Analysis: Intake lobe ad is somewhat wider, but the @05 mark is pushed way out. This indicates a radically steep ramp, and a smooth, wide peak near maximum lift. Exhaust lobe ad and @05 are expanded greatly but equally, but the lift increase is large as well, resulting in a mild ramp increase. Very stong springs must be used on the intake to prevent valve float. Overlap is increased about 21 degrees over stock.
Result: A BIG NA cam, should make big power in the top RPMs. With the proper valvetrain setup, this should make big power well past the stock redline, but intake valve float could be a serious problem. Power at lower RPMs (on the wild lobe) will fall dramatically, a programmable ECU may be neccesary to ensure that a lean burn and stumble does not happen at those RPMs. The power band will probably start around 6-6.5kRPM. This cam will really benefit from some quality headwork - flow rates should increase dramatically. And, of course, properly ported intake and exhaust manifolds will be highly useful. The extreme stress on the intake valves will cause premature wear and misalignment - adjustments will be needed often. Forced induction would probably not work well at all due to the overlap and steep intake ramp.
Personal Comment: It looks to me like the intake lift on this cam was limited, and will not match the exhaust lift well. If the H22A head could be modified to allow more than 0.500" gross lift, I would suggest a custom cam of these approximate proportions (A "Stage 4" cam, if you will): 300/300 250/255 510/475
I think it would be better suited for big NA power and cause less valvetrain stress.
:cool:
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