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Re: 1985 cam specs ?? Posted by Jon [Email]  (#11)  [Profile/Gallery]
(more from Jon) on Tue, 24 Dec 2002 05:48:18
In Reply to: 1985 cam specs ??, wlfbronco, Sat, 21 Dec 2002 08:12:46 Members do not see ads below this line. - Help Keep This Site Online - Signup |
wlfbronco,
How's this, from beaudreau:
Let's Talk Cams
The basic function of a camshaft is to open and close an engine's intake and exhaust valves. When the valves open and how long they stay open is known as duration. How far they open is known as lift. Cam-lobe duration and lift are the result of several variables that must be taken into consideration for optimum performance. Many factors that affect what lift and duration should be:
N/A or forced induction,
type and weight of the vehicle,
vehicle purpose,
rpm range desired for peak performance ,
lifter or tappet type,
engine displacement and more.
In the early days of hot rodding, a .500-inch-lift camshaft was generally considered to be at the limits of street use. In subsequent years, however, increased lift has been a key player in power output without adversely affecting idle and driveability. Valve-to-piston clearances tend to limit lift. High lift with good idle has come as a result of changing the duration and the valve overlap.
Duration is the most overused cam specification. A slight increase in duration over a stock camshaft is good, offering more power and increasing revs while not adversely affecting idle. As duration increases , holding the valves open longer, maximum horsepower is achieved in a higher rpm range, with a loss of
power on the low end. Increasing duration usually means a rough idle and low vacuum, so vacuum operated accessories may suffer.
A good street cam should be a compromise when it comes to duration. The valves should be open long enough to allow adequate cylinder filling and evacuation, yet short enough to maintain adequate vacuum and driveability. Maintaining enough cylinder pressure (or dynamic compression) means keeping the valve open for as short a time as possible.
Lobe separation, or overlap, is the measurement of the time both valves are open simultaneously. This facilitates the scavenging of exhaust gases. As a rule, a wider lobe separation angle (such as 112 to 116 degrees), or decreased overlap, will improve idle vacuum and quality and increase power on the high end. A lower lobe separation angle (such as 106 to 110 degrees), will improve midrange power and promote a choppy idle; however, power fades at the top.
Degreeing a camshaft means altering the valve activation time relative to the crankshaft position. Camshaft degreeing does not affect lift, duration or overlap- but it does affect when these events occur. By opening the valves late in relation to the crankshaft position, or retarding the valve timing, maximum poweris achieved at high rpm. Opening the valves earlier, or advancing the valve timing, results in maximum power at low rpms. Early valve timing works well for low-end torque, such as in a street legal rod.
Lobe Separation Angle Above 114 Deg. Extremely Wide
114-112 Deg Wide
112-110 Deg. Moderately Wide
110-108 Deg. Moderate
108-106 Deg. Moderately Tight
106-104 Deg. Tight
Below 104 Deg. Extremely Tight
Varying Lobe Separation Angle Tighten Widen
Moves Torque to Lower RPM Raise Torque to Higher RPM
Increases Maximum Torque Reduces Maximum Torque
Narrow Powerband Broadens Power Band
Builds Higher Cylinder Pressure Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock Decrease Chance of Engine Knock
Increase Cranking Compression Decrease Cranking Compression
Increase Efective Compression Decrease Efective Compression
Idle Vacuum is Reduced Idle Vacuum is Increased
Idle Quality Suffers Idle Quality Improves
Open Valve-Overlap Increases Open Valve-Overlap Decreases
Closed Valve-Overlap Increases Closed Valve-Overlap Decreases
Natural EGR Efect Increases Natural EGR Efect is Reduced
Decreases Piston-to-Valve Clerance Increases Piston-to-Valve Clerance
Advancing/Retarding Cam Timing Advancing Retarding
Begins Intake Event Sooner Delays Intake Event Closes Intake
Open Intake Valve Sooner Keeps Intake Valve Open Later
Builds More Low-End Torque Builds More High-End Power
Decrease Piston-Intake Valve Clearance Increase Piston-Intake Valve Clearance
Increase Piston-Exhaust Valve Clearance Decrease Piston-Exhaust Valve Clearance
Boost Effect Boost (bar) Effect
0.3-0.5 max low-speed torque, 35% power increase.
0.5-0.7 max low & mid-range power, 40-50% power increase.
0.7-1.7 good mid-range & top-end power withh quick throttle response, up to 250hp / litre.
1.0-3.0 as much power as posible using special fuel blends, 350hp / litre.
5.5 more than 866hp / litre.
Cam Data for Stock SAAB Camshafts
Info in bold was calculated by me and may be wrong.
All Calculated Data Is At Stock Installed Settings. Motor & yr inlet lift (mm) opens (BTDC) closes (ABDC) intake centerline
(ATDC) duration exhaust lift (mm) opens (BBDC) closes (ATDC) exhaust
centerline (BTDC) duration lobe center overlap
B202t '85 8.65/6.65** 10 56 113 246 8.65 56 10 113 246 113 20
B202t cat '86 8.65/6.65** 10 56 113 246 8.65 56 10 113 246 113 20
B202t '86- 8.65 16 56 110 252 8.65 61 13 114 254 112 29
B202t cat '87 8.65 16 56 110 252 8.65 61 13 114 254 112 29
B202i '86- 8.65 16 44 104 240 8.65 61 13 114 254 109 29
B212i '91- 8.65 16 44 104 240 8.65 61 13 114 254 109 29
B234i '91-93 8.65 13 53 110 246 8.65 50 16 107 246 108.5 29
B234t '91-93 8.65 13 53 110 246 8.65 50 16 107 246 108.5 29
B204 all 8.65 14 46 106 240 8.65 44 16 104 240 105 30
B234t '94- 8.65 14 46 106 240 8.65 44 16 104 240 105 30
B234i 30'94- 8.65 13 53 110 246 8.65 48 18 105 246 107.5 31
'86T- int
'85T exh 8.65 16 56 110 252 8.65 56 10 113 246 111.5 26
'86I- int
'85T exh 8.65 16 44 104 240 8.65 56 10 113 246 108.5 26
** - the difference in the height of the two lobes is for swirl in the combustion chamber
BTDC - Before Top Dead Center
ATDC - After " " "
BBDC - Before Bottom Dead Center
ABDC - After " " "
B202i:
B = Gasoline (Bransle in Swedish)
20 = displacement in deciliters 20=2l, 21 = 2.1l, etc.
2 = # of cam (or other) shafts 2 = slant block, 4 = balance shaft block
i = injection, t=turbo, all=all variants (i thru t)
cat = means with catalyst
Auto Speed- Cam Talk
0 280 150 001 265 cm3/min
0 280 150 002 265 cm3/min
0 280 150 003 380 cm3/min
0 280 150 009 265 cm3/min
0 280 155 009 346 cm3/min Saab Turbo
0 280 150 015 380 cm3/min
0 280 150 024 380 cm3/min Volvo B30E
0 280 150 026 380 cm3/min
0 280 150 036 380 cm3/min MB 4.5l
0 280 150 041 480 cm3/min MB 6.9l V8 / Cadillac
0 280 150 043 380 cm3/min BMW
0 280 150 100 185 cm3/min
0 280 150 121 178 cm3/min
B 280 410 144 434 cm3/min Bosch R-SPORT
0 280 150 200 300 cm3/min BMW
0 280 150 201 236 cm3/min
0 280 150 203 185 cm3/min
0 280 150 208 133 cm3/min
0 280 150 209 176 cm3/min Volvo B200-B230
0 280 150 211 146 cm3/min
0 280 150 335 300 cm3/min Volvo B230 turbo
0 280 150 400 437 cm3/min Ford 4.5l
0 280 150 401 437 cm3/min Ford
0 280 150 402 338 cm3/min Ford
0 280 150 403 503 cm3/min Ford
0 280 150 614 189 cm3/min
0 280 150 704 170 cm3/min
0 280 150 706 214 cm3/min 250kPa
0 180 150 712 214 cm3/min 250kPa Saab Turbo 2.3l
0 280 150 715 149 cm3/min
0 280 150 716 134 cm3/min
0 280 150 762 214 cm3/min Volvo B230F
0 280 150 802 284 cm3/min Volvo B200 turbo, Renault J7R turbo
0 280 150 803 384 cm3/min
0 280 150 804 337 cm3/min Peugeot 505T
0 180 150 811 298 cm3/min 3.5kPa Porsche Turbo 944
0 280 150 814 384 cm3/min
0 280 150 834 397 cm3/min
0 280 150 835 397 cm3/min Chrysler
0 180 150 951 346 cm3/min Porsche Turbo
posted by 24.51.228...
http://beaudreau.50megs.com/SAAB/camdata.html
, Tue, 24 Dec 2002 05:48:18 <-- Viewing This Message
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