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Some useful info, not sure if it's been posted before but seems relevant here anyway!
Source: http://asia.vtec.net/beystock/honda/civicr/
Highlights of B16B 98 Spec R compared to B16A
Highlights behind the high-RPM, high-output of the B16B 98 SpecR.
In order to increase the power output by 15 hp, and the max RPM by 200RPM, the engine goes through many upgrades. It should be noted that the B18C spec.R's cylinder block is used for its endurance.
The translations for the numbered labels in the diagram are:
1. Cylinder Head - Complete port & polish
2. Exhaust Valve Spring - High-lift, dual-layered spring
3. Sparkplug - High-heat-type #7 platinum plug
4. Pistons - High-compression, low-friction, custom pistons
5. Connecting Rod - High-output, high-durability, lightened, custom conrod
6. Engine Stiffener - Aluminum die-cast, high-durability, one-piece type
7. Crankshaft - Full-balancer, 8-weight, high-output, custom crankshaft
8. Inlet Valves - Lightened inlet valves
9. Inlet Valve Springs - High-lift, flat-surfaced, dual-layered spring
10. Camshaft - Wide-angled, high-lift, high-durability camshaft
11. Intake Manifold - High-RPM type.
Engine Type B16A
Maximum Output: 170ps/7800rpm
Maximum Torque: 16.0kg-m/7300rpm
Bore x Stroke: 81.0x77.4mm <- same
Displacement: 1595cc <- same
Compression: P10.4
Maximum RPM: 8400rpm
Valve Timing at 1mm lift IN Open/Close: BTDC15/ABDC45
Valve Timing at 1mm lift EX Open/Close: BBDC40/ATDC7
Valve Lift: IN 10.7mm, EX 9.4mm
Inlet Valve Diamter: 33mm x 2mm <- same
Spark Plug Type: Heat Rate #6
Throttle Bore Diameter: 60mm <- same
Intake Manifold: Single pipe sideflow
Air Intake Diameter: 65mm <- same
Exhaust Manifold: 4-to-2 <- same
Exhaust Pipe Diameter: 57.2mm
Silencer Flow Capacity: 115liter/sec
Engine Type: B16B 98 Spec.R
Maximum Output: 185ps/8200rpm
Maximum Torque: 16.3kg-m/7500rpm
Bore x Stroke: 81.0x77.4mm <- same
Displacement: 1595cc <- same
Compression: 10.8
Maximum RPM: 8400rpm
Valve Timing at 1mm lift IN Open/Close: BTDC18/ABDC45
Valve Timing at 1mm lift EX Open/Close: BBDC45/ATDC10
Valve Lift: IN 11.5mm, EX 10.5mm
Inlet Valve Diamter: 33mm x 2mm <- same
Spark Plug Type: Heat Rate #7 platinum
Throttle Bore Diameter: 60mm <- same
Intake Manifold: Single pipe sideflow (different manifold)
Air Intake Diameter: 65mm <- same
Exhaust Manifold: 4-to-2 <- same
Exhaust Pipe Diameter: 57.2mm
Silencer Flow Capacity: 115liter/sec
The camshaft profiles (wild cam) change from B16A 160ps to 170ps and finally to B16B are :
Cam Profile: B16A 160ps
Max Lift (IN/EX): 10.4/9.4
Open Timing (IN/EX): BTDC 10/BBDC 40
Close Timing (IN/EX): ABDC 40/ATDC 5
Cam Profile: B16A 170ps
Max Lift (IN/EX): 10.7/9.4
Open Timing (IN/EX): BTDC 15/BBDC 40
Close Timing (IN/EX): ABDC 45/ATDC 7
Cam Profile: B16B 98R
Max Lift (IN/EX): 11.5/10.5
Open Timing (IN/EX): BTDC 18/BBDC 45
Close Timing (IN/EX): BTDC 45/ATDC 10
Different pistons are responsible for the compression ratio increases between 160ps & 170ps B16A and the 10.8 ratio for B16B. Readily apparent is the relatively modest change in piston top between B16A 160ps and B16A 170ps for the 10.2 to 10.4 change. However, the radically different piston top for B16B is very clear from the picture. The increase in compression ratio between B16B from B16A is 0.4.
On B16B, the inlet ports are manually ported to increase air-flow. The exhaust ports are identical to B16A
B16B intake valve seats are at a different angle to B16A, 45 degrees vs 60 degrees. The intake valves are also different, being lighter and having a thinner valve stem.
On the left are the power curves for B16A 170ps versus B16B. Note the big gain in power after 6000rpm, the VTEC switch-over point between mild and wild cam profiles. The gain at extreme high rpms is readily apparent on the curves.
Various individual specifications for B16B can teach us about the feasibility of various modifications to B16A. For eg, the throttle bore diameter for B16B is identical to B16A at 60mm. This means that enlarged throttle bodies for B16A might not be an optimal mod or that a compromise in power delivery might result, eg loss of low-end power in return for gain in high-end power. Note that B16B has identical low and mid range power as B16A.
As with B18C Spec R, the wonder of B16B is the assurance of a 15 to 25ps gain in power on a B16A provided the tuning done by Honda can be completely replicated. Nevertheless even if only a portion can be duplicated, combining with properly designed aftermarket exhaust, headers, and intake could still potentially realize this 15ps gain.
Source: http://asia.vtec.net/beystock/honda/civicr/
Highlights of B16B 98 Spec R compared to B16A
Highlights behind the high-RPM, high-output of the B16B 98 SpecR.
In order to increase the power output by 15 hp, and the max RPM by 200RPM, the engine goes through many upgrades. It should be noted that the B18C spec.R's cylinder block is used for its endurance.
The translations for the numbered labels in the diagram are:
1. Cylinder Head - Complete port & polish
2. Exhaust Valve Spring - High-lift, dual-layered spring
3. Sparkplug - High-heat-type #7 platinum plug
4. Pistons - High-compression, low-friction, custom pistons
5. Connecting Rod - High-output, high-durability, lightened, custom conrod
6. Engine Stiffener - Aluminum die-cast, high-durability, one-piece type
7. Crankshaft - Full-balancer, 8-weight, high-output, custom crankshaft
8. Inlet Valves - Lightened inlet valves
9. Inlet Valve Springs - High-lift, flat-surfaced, dual-layered spring
10. Camshaft - Wide-angled, high-lift, high-durability camshaft
11. Intake Manifold - High-RPM type.
Engine Type B16A
Maximum Output: 170ps/7800rpm
Maximum Torque: 16.0kg-m/7300rpm
Bore x Stroke: 81.0x77.4mm <- same
Displacement: 1595cc <- same
Compression: P10.4
Maximum RPM: 8400rpm
Valve Timing at 1mm lift IN Open/Close: BTDC15/ABDC45
Valve Timing at 1mm lift EX Open/Close: BBDC40/ATDC7
Valve Lift: IN 10.7mm, EX 9.4mm
Inlet Valve Diamter: 33mm x 2mm <- same
Spark Plug Type: Heat Rate #6
Throttle Bore Diameter: 60mm <- same
Intake Manifold: Single pipe sideflow
Air Intake Diameter: 65mm <- same
Exhaust Manifold: 4-to-2 <- same
Exhaust Pipe Diameter: 57.2mm
Silencer Flow Capacity: 115liter/sec
Engine Type: B16B 98 Spec.R
Maximum Output: 185ps/8200rpm
Maximum Torque: 16.3kg-m/7500rpm
Bore x Stroke: 81.0x77.4mm <- same
Displacement: 1595cc <- same
Compression: 10.8
Maximum RPM: 8400rpm
Valve Timing at 1mm lift IN Open/Close: BTDC18/ABDC45
Valve Timing at 1mm lift EX Open/Close: BBDC45/ATDC10
Valve Lift: IN 11.5mm, EX 10.5mm
Inlet Valve Diamter: 33mm x 2mm <- same
Spark Plug Type: Heat Rate #7 platinum
Throttle Bore Diameter: 60mm <- same
Intake Manifold: Single pipe sideflow (different manifold)
Air Intake Diameter: 65mm <- same
Exhaust Manifold: 4-to-2 <- same
Exhaust Pipe Diameter: 57.2mm
Silencer Flow Capacity: 115liter/sec
The camshaft profiles (wild cam) change from B16A 160ps to 170ps and finally to B16B are :
Cam Profile: B16A 160ps
Max Lift (IN/EX): 10.4/9.4
Open Timing (IN/EX): BTDC 10/BBDC 40
Close Timing (IN/EX): ABDC 40/ATDC 5
Cam Profile: B16A 170ps
Max Lift (IN/EX): 10.7/9.4
Open Timing (IN/EX): BTDC 15/BBDC 40
Close Timing (IN/EX): ABDC 45/ATDC 7
Cam Profile: B16B 98R
Max Lift (IN/EX): 11.5/10.5
Open Timing (IN/EX): BTDC 18/BBDC 45
Close Timing (IN/EX): BTDC 45/ATDC 10
Different pistons are responsible for the compression ratio increases between 160ps & 170ps B16A and the 10.8 ratio for B16B. Readily apparent is the relatively modest change in piston top between B16A 160ps and B16A 170ps for the 10.2 to 10.4 change. However, the radically different piston top for B16B is very clear from the picture. The increase in compression ratio between B16B from B16A is 0.4.
On B16B, the inlet ports are manually ported to increase air-flow. The exhaust ports are identical to B16A
B16B intake valve seats are at a different angle to B16A, 45 degrees vs 60 degrees. The intake valves are also different, being lighter and having a thinner valve stem.
On the left are the power curves for B16A 170ps versus B16B. Note the big gain in power after 6000rpm, the VTEC switch-over point between mild and wild cam profiles. The gain at extreme high rpms is readily apparent on the curves.
Various individual specifications for B16B can teach us about the feasibility of various modifications to B16A. For eg, the throttle bore diameter for B16B is identical to B16A at 60mm. This means that enlarged throttle bodies for B16A might not be an optimal mod or that a compromise in power delivery might result, eg loss of low-end power in return for gain in high-end power. Note that B16B has identical low and mid range power as B16A.
As with B18C Spec R, the wonder of B16B is the assurance of a 15 to 25ps gain in power on a B16A provided the tuning done by Honda can be completely replicated. Nevertheless even if only a portion can be duplicated, combining with properly designed aftermarket exhaust, headers, and intake could still potentially realize this 15ps gain.
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