Engine Analyzer
Michael F. Sargent
MSargent at gallium.com
Thu Mar 7 18:07:21 GMT 1996
Recently there has been some discussion about the accuracy of commercial
programs like Engine Analyzer. I've been playing with Engine Analyzer, and
I'm fairly impressed. They claim +/- 15% accuaracy between their calculations
and a real dyno test. Here is a list of the inputs available to EA. This
list was something I cribbed up to create a spec sheet for an engine, so there
may be an error or two. You'll note that some inputs seem redundant. That is
because EA allows you to enter a measured value, or if you don't have one it
will estimate from other characteristics. For example, it I have an intake
manifold tested on a flow bench, then I can enter those values directly. If
not, then by entering shape, diameter, length, etc., EA will estimate the
flow rating. Obviously, a measurement is more accurate than an estimate.
---------------------------------- Cut Here ----------------------------------
Engine Specifications
Base Engine
Bore, inches
Stroke, inches
Number of cylinders
Compression ratio
Clearance
Head combustion chamber volume, cc's
Piston dome volume, cc's
Gasket thickness, inches
Deck height, inches
Mill
Inches milled
Percentage of bore area
Accessories
0 - Race engine, no accessories, on dynamometer
1 - Production engine, no accessories, on dynamometer
1 - Race Drag engine, in vehicle
2 - Production engine, min. accessories, in vehicle
2 - Road race engine, in vehicle
3 - '1970s' production engine, in vehicle
4 - 'Pre 1970s' production engine, in vehicle
Intake System
Number of valves per cylinder
Valve diameter, inches
Runner diameter, inches
Runner width, inches
Runner height, inches
Oval/Rectangular shape (O/R)
Runner length, inches
Valve flow coefficient
Flow bench test pressure, "H2O
Number of valves per cylinder
Valve diameter, inches
Valve lift, inches
Flow, standard CFM
Runner flow coefficient
Flow bench test pressure, "H2O
Number of valves per cylinder
Valve diameter, inches
Valve lift, inches
Flow (less runner), standard CFM
Runner diameter, inches
Flow (with runner), standard CFM
Intake Type
1 - Dual plane manifold
2 - Single plane manifold (street)
3 - Single plane manifold (race)
4 - Production 'long runner' injected
5 - Individual runner (IR) carburetors
6 - Individual fuel injector stacks
Intake heat (Yes/No)
Carburetor/Throttle-body flow rating, CFM
Total number of primary barrels
Primary throttle diameter, inches
Total number of secondary barrels
Secondary throttle diameter, inches
Vacuum secondary (Yes/No)
Exhaust System
Number of valves per cylinder
Valve diameter, inches
Runner diameter, inches
Runner width, inches
Runner height, inches
Oval/Rectangular shape (O/R)
Runner length, inches
Valve flow coefficient
Flow bench test pressure, "H2O
Number of valves per cylinder
Valve diameter, inches
Valve lift, inches
Flow, standard CFM
Runner flow coefficient
Flow bench test pressure, "H2O
Number of valves per cylinder
Valve diameter, inches
Valve lift, inches
Flow (less runner), standard CFM
Runner diameter, inches
Flow (with runner), standard CFM
Exhaust system CFM rating, CFM
Original engine HP
Vehicle type (Race/Sport/Quiet)
Cam/Valve Train
Intake cam specifications
Open @ 0.050", degrees BTDC
Centerline
Lobe centerline, crankshaft degrees
Duration @ 0.050", crankshaft degrees
Separation
Lobe separation, camshaft degrees
Duration @ 0.050", crankshaft degrees
Close @ 0.050", degrees ABDC
Centerline
Lobe centerline, crankshaft degrees
Duration @ 0.050", crankshaft degrees
Separation
Lobe separation, camshaft degrees
Duration @ 0.050", crankshaft degrees
Maximum lobe lift at tappet, inches
Lash at valve, inches
Rocker arm ratio
Exhaust cam specifications
Open @ 0.050", degrees BBDC
Centerline
Lobe centerline, crankshaft degrees
Duration @ 0.050", crankshaft degrees
Separation
Lobe separation, camshaft degrees
Duration @ 0.050", crankshaft degrees
Close @ 0.050", degrees ATDC
Centerline
Lobe centerline, crankshaft degrees
Duration @ 0.050", crankshaft degrees
Separation
Lobe separation, camshaft degrees
Duration @ 0.050", crankshaft degrees
Maximum lobe lift at tappet, inches
Lash at valve, inches
Rocker arm ratio
Cam advance, degrees
Supercharger
Supercharger present (Yes/No)
Supercharger type (Centrifugal/Racing roots/Street roots/Turbo)
Boost limit, "Hg
Intercooler efficiency, %
0 - No intercooler
50 -Typical intercooler
100 - 'Perfect' intercooler
150 - 'Cooled' intercooler
Centrifugal/Roots belt ratio
Supercharger pulley diameter, inches
Crank pulley diameter, inches
Roots volume per revolution, cubic inches
Relative turbo size (Small/Medium/Large/Xtra large)
Calculate Performance
Environmental conditions
Barometric pressure, "Hg
Intake air temperature, degrees Fahrenheit
Relative humidity, %
Relative humidity temperature, degrees Fahrenheit
Elevation, feet
Coolant temperature, degrees Fahrenheit
Nitrous oxide specifications
Nitrous oxide system rating, HP
RPM to start nitrous
RPM for full nitrous
Gas/Alcohol (G/A)
Rpm's to Run
Starting RPM
Number of Rpm's
RPM increment
Recommended runner dimensions
For this RPM
Specified intake runner length, inches
---------------------------------- Cut Here ----------------------------------
With all those inputs, EA also puts out a fairly complete "dyno sheet" as
well as graphing torque and HP vs RPM (including overplotting two runs so
you can see the differences.
---------------------------------- Cut Here ----------------------------------
------ ENGINE COMMENTS ---------------------------------------------------
Mercruiser MC470 Stock
Rated at 170 HP; Suggested peak RPM is 4400 RPM
------ PROJECTED PERFORMANCE ---------------------------------------------
RPM 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
BRK TQ 190 208 218 220 222 222 207 187 164 139
BRK HP 21.8 47.6 74.8 101 127 152 166 171 169 159
EX PRS .1 .3 .8 1.5 2.4 3.5 4.4 5.1 5.7 6.1
IN VAC 0.0 0.0 .1 .2 .3 .4 .5 .6 .7 .7
VE % 67.7 74.5 78.9 81.4 83.8 85.8 83.0 79.5 75.3 70.2
CFM 28.3 62.3 99.0 136 175 215 243 266 283 293
FL FLW 10.4 22.9 36.3 49.9 64.3 78.9 89.0 97.6 104 108
BSFC .477 .480 .485 .496 .507 .518 .537 .571 .615 .678
BSAC 5.966 6.006 6.068 6.206 6.340 6.477 6.710 7.135 7.686 8.471
FRN HP 2 5 9 14 21 29 39 49 61 73
MACH # .063 .127 .190 .253 .317 .380 .443 .507 .570 .633
PSN SP 375 750 1125 1500 1875 2250 2625 3000 3375 3750
PSN GS 25 98 221 392 613 882 1201 1568 1985 2450
OV %VE -.4 -.4 -.4 -.4 -.3 -.3 -.3 -.3 -.2 -.2
IN VEL 23 47 70 93 116 140 163 186 209 233
IN TNP 0.0 0.0 .2 .5 1.0 1.5 1.8 2.1 2.3 2.4
IN OVP 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
EX VEL 38 77 115 153 192 230 268 307 345 384
EX OVP 0.0 0.0 0.0 0.0 0.0 -.1 -.3 -.7 -1.2 -1.5
OCTANE 130+ 120 110 105 100 100 95 90 85 85
------ VALVE FLOW & CAM CALCULATIONS ------------------- --INT-- --EXH--
OVERLAP AREA, SQ IN*DEG 2.3 VALVE AVG FLOW COEF .284 .321
VALVE EXH/INT % 73.7 TOTAL AVG FLOW COEF .278 .312
TOTAL EXH/INT % 73.3 LOBE AREA, INCH*DEG 20.47 22.40
LOBE SEPARATION, CAM DEG 112.0 VLV AREA, SQ IN*DEG 252.2 185.9
LOBE CENTERLINES 107.0 117.0
------ GENERAL ENGINE CALCULATIONS ---------------------------------------
DISPLACEMENT, ccs 3670.6 DISPLACEMENT, cu in 223.95
STATIC VOL EFF, % 79.0 COMPRESSION RATIO 8.80
THEO. CRANK COMPRSSN, PSI 190 CLEARANCE VOLUME, ccs 117.6
CARB MINIMUM WOT RPM 870 EST INT CLOSING, DEG ABC 61.9
------ RECOMMENDED RUNNER DIMENSIONS @ 5000 RPM ------- --AREA-- --DIA--
INTAKE DIMENSIONS ( FOR 1 RUNNER/CYLINDER ):
REC INERTIA LEN, IN 11.7 REC AREA, SQ IN/IN 3.17 2.01
SPEC INERTIA LEN, IN 11.0 REC AREA, SQ IN/IN 2.98 1.95
REC LEN, 2ND PULSE 28.9 REC AREA, SQ IN/IN 7.82 3.16
REC LEN, 3RD PULSE 20.8 REC AREA, SQ IN/IN 5.63 2.68
EXHAUST DIMENSIONS ( FOR 1750 FT/SEC & 1 RUNNER/CYLINDER ):
REC LEN, 1ST PULSE 59.3 REC AREA, 300 FT/SEC 2.59 1.817
REC LEN, 2ND PULSE 27.0 PRIMARY TUBE O.D. 2.000
---------------------------------- Cut Here ----------------------------------
Engine Analyzer comes with a 166 page manual explaining all of this, but I'll
just repeat the explainations for the rows under PROJECTED PERFORMANCE to
make the above example easier to understand.
RPM Engines rotational speed in Revolutions Per Minute
BRK TQ Brake Torque in foot pounds - usable net torque at flywheel
BRK HP Brake Horse Power - usable net power at flywheel
EX PRS Exhaust Pressuse in inches of mercury measured after manifold
IN VAC Intake Vaccum in inches of mercury after the throttle body
VE % Volumetric Efficiency as a percentage - % cylinder fills and remains
CFM Flow rating of air into the engine in Cubic Feet per Minute
FL FLW Fuel Flow in pounds per hour (gasoline or methanol)
BSFC Brake Specific Fuel Consumption in pounds per horsepower hour
BSAC Brake Specific Air Consumption in pounds per horsepower hour
FRN HP Friction HorsePower - power lost in internal friction and accesories
MACH # Mean or Average Mach Number - see paper SAE 790484
PSN SP Piston Speed in feet per minute
PSN GS Piston Acceleration in Gs at TDC - helps establish a red-line
OV %VE Overlap Contribution to Volumetric Efficiency- due to overlap scavenging
IN VEL Average Intake Runner Velocity in feet per second
IN TNP Intake Inertia Tuning Pressure in inches of mercury
IN OVP Intake Overlap Pressure from Resonance Tuning in inches of mercury
EX VEL Average Exhaust Runner Velocity in feet per second
EX OVP Exhaust Overlap Pressure from Resonance and Inertia Tuning - ft/sec
OCTANE Fuel Octane Required - estimated RM required for peak performance
And finally:
Engine Analyzer, v2.1
Performance Trends, Inc.
PO Box 573
Dearborn Heights, MI
48127
1(810)473-9230
Summit Racing sells EA for about $80US.
There is an Engine Analyzer Pro version which sells for around $500US and
includes the following:
- Valve train dynamics
- Sophisticated detonation predictions
- Full 4-cycle calculations for modeling of unusual or complex engine designs.
(This feature significantly increases execution time.)
Engine Analyzer is an MS-DOS program (runs under Windows 95). Requirements
are minimal (IBM PC, XT, AT, PS/2 or 100% compatible; 512K of RAM, MS-DOS 2.0
or higher). Graphs are EGA resolution (or CGA if mono), but are acceptable.
+--------------------------------------------------------------------------+
| Michael F. Sargent | Net: msargent at gallium.com | Phone: 1(613)721-0902 |
| Gallium Software Inc.| | FAX: 1(613)721-1278 |
+--------------------------------------------------------------------------+
More information about the Diy_efi
mailing list