DIY_EFI Digest Thursday, 7 March 1996 Volume 01 : Number 069 In this issue: Has anyone built their own EFI system yet? Re: inductive vs optical Re: Info on MBM27C1028 EPROM for Subaru SVX Re: Equations.. Re: Equations.. Re: Equations.. Re: Equations.. Re: Info on MBM27C1028 EPROM for Subaru SVX Re: Equations.. Volumetric efficiency (Re: Equations..) Re: Equations.. Engine Analyzer Engine Analyzer Re: Volumetric efficiency (Re: Equations..) See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Michael Fawke Date: Thu, 07 Mar 1996 21:19:06 +1000 Subject: Has anyone built their own EFI system yet? Has anyone actually got a working EFI system running yet? By that I mean a self-designed, computer based unit which will run an engine. >From reading the mail so far (only subscribed last week), it sounds like the electronics engineers are trying to develop discrete logic based systems, while the computing types are stuck on sensor design. How about everyone co-operating so we can all benefit? Michael Fawke fawkacs@xxx.au ------------------------------ From: Mark Boxsell Date: Thu, 7 Mar 96 21:17:13 +1000 (EST) Subject: Re: inductive vs optical At 11:43 AM 6/03/96 S, you wrote: >Sensor problems give you the same problems regardless of sensor type >(inductive, optical, ESP). >If a sensor isn't working, you don't know what's happening. Period. Inductive pickups are a bitch to work with. There is "nothing to go wrong" but they are prone to RFI big time. (Although the LM1815 seems to work quite well) > >Car engines run over a relatively wide rpm range, so time-based detection > >is out. I would have to severely disagree big time with this comment. How the hell do you think 90% of the factory systems work !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! >Generally, I'd say an inductive sensor is more reliable than an optical >sensor. A coil of wire is pretty reliable ! >The sensor itself isn't affect by voltage spikes as much as a LED, >although the >supporting analogue circuitry may be. True. > >Unfortunately, it's not easy to design an inductive pickup which will >work from >cranking speed through to red-line. Why ? Everyone (OEM's) does it. >Regards, >Andrew Dalgleish >Axon Research, Pty Ltd >6 Wallace Ave, >Toorak, VIC >3142 >AUSTRALIA >Tel +61-3-9826-5538 >Fax +61-3-9824-0083 > Sorry Andrew but when I see stuff that is a bit strange I have to point it out. regards, Mark Boxsell. ------------------------------ From: "David M Parrish" Date: Thu, 7 Mar 1996 08:38:43 +0000 Subject: Re: Info on MBM27C1028 EPROM for Subaru SVX > How about you find your local FUJITSU seller .. I'll bet ya he has a burner > to program these .. and MAYBE even a few blanks ... > > NEXT .. get the code read ... and disassembled .. > > Now, even if you CANT get any more .. you can always just make a little > daughterboard on a header and use it to translate a regular 27C1024 into > a multiplexed arrangement ... > > No biggie ... (this is where you EE types step in to help ;) Yeah, yeah. But with working full time, driving two hours a day, building an airplane, rewiring an engine and designing an engine mount, following the '332 project and some competitive shooting on weekends, who has time to hassle with an odd ball EPROM? - --- David Parrish Oh, did I mention playing entirely too much Doom? ------------------------------ From: atsakiri@xxx.com Date: Thu, 07 Mar 96 09:21:05 -0500 Subject: Re: Equations.. > I need help with equations for a MAP system. I have this > general equation. > > PV=nRTe > P = pressure [assuming intake from MAP sensor] in KPA > V = Displacement of Cylinder in Liters > N = moles of atmosphere in Moles > R = Universal gas constant : 8.31L/Kpa W/ KPA & Liters > T = Absolute temp !K of intake air [temp sensors job] > > Could you help me nail down the real units on these > things? I'm a second year chemistry student, and I know this > simple Gas law but I don't know the units in this Application!!! Here's one set of units that'll work: P in pascals V in meters^3 n in moles R = 8.3143 joules/(mole*deg Kelvin) T in deg Kelvin > > e = Volumetric Efficiency Unitless > > Could someone provide a formula to just get > a cheap estimate of this term. I can't solve for it since > I have no empirical data, also no staight substitutions work > either: as the e terms will cancel. Yes, e is unitless. A very cheap formula is e(engine speed, manifold pressure) = 0.85. This is a great simplification of course, but is useful in getting started. [snip] Good luck, Anthony Tsakiris - --------------------------------------------------------------------------- The opinions expressed are my own and not necessarily those of my employer. ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Thu, 7 Mar 1996 09:18:02 +0500 Subject: Re: Equations.. Jim Staff, try this instead: PV=mRT, where P=pressure in pascals(not kPa) V=volume in m^3(cubic meters, not liters) m=mass of air in the volume, kg R=287 kJ/(K * kg) for air T=absolute temperature in K This one does away with moles. I'll make a bold assumption that you know what a derivative is(if not, we'll explain). Take the derivative of each side of that equation with respect to time and you get: P(dV/dt)=(dm/dt)RT, where t=time, seconds dV/dt=volume flow rate in m^3/s. A more common unit is CFM, but you can perform the conversion dm/dt=mass flow rate in kg/s. A more common unit is lbs/hr, but... Rearrange to solve for dm/dt, which is what you are really after: dm/dt=P(dV/dt)/(R*T) Now, R is constant, you can measure P with a MAP, T with an air charge temperature(ACT) sensor. Throw in Volumetric Efficiency(called eta, but I can't type in greek, so I'll call it N which looks similar) as a correction factor for dV/dt: dm/dt=P(N*dV/dt)/(R*T) Now dV/dt becomes a constant(it's your engine or cylinder displacement), and you need to predict N(that's you asked in the first place, huh?). That's tough to predict without any measuring equipment at all. You could assume a relatively safe, constant number like 70%, but without measuring SOMETHING, you'll never know how close that is or how it changes with rpm at wide open throttle(WOT). What are you building, kart? Powerplant? Tell us and I'm sure someone can help you figure out a way to qualitatively determine your WOT volumetric efficiency. I'm thinking you could try to monitor exhaust gas temperature(EGT) vs rpm, which can be done without a dyno. Hey, glad to see a high school student trying stuff like this. Life doesn't suck after all! ------------------------------ From: Bruce Bowling Date: Thu, 07 Mar 1996 10:38:13 EST Subject: Re: Equations.. ~ ~ Jim Staff, try this instead: ~ ~ PV=mRT, where ~ ~ P=pressure in pascals(not kPa) ~ V=volume in m^3(cubic meters, not liters) ~ m=mass of air in the volume, kg ~ R=287 kJ/(K * kg) for air ~ T=absolute temperature in K ~ ~ This one does away with moles. I'll make a bold assumption that you ~ know what a derivative is(if not, we'll explain). Take the derivative ~ of each side of that equation with respect to time and you get: ~ ~ P(dV/dt)=(dm/dt)RT, where ~ ~ t=time, seconds ~ dV/dt=volume flow rate in m^3/s. A more common unit is CFM, but you ~ can perform the conversion ~ dm/dt=mass flow rate in kg/s. A more common unit is lbs/hr, but... ~ ~ Rearrange to solve for dm/dt, which is what you are really after: ~ ~ dm/dt=P(dV/dt)/(R*T) ~ ~ Now, R is constant, you can measure P with a MAP, T with an air charge ~ temperature(ACT) sensor. ~ ~ Throw in Volumetric Efficiency(called eta, but I can't type in greek, ~ so I'll call it N which looks similar) as a correction factor for ~ dV/dt: ~ ~ dm/dt=P(N*dV/dt)/(R*T) ~ ~ Now dV/dt becomes a constant(it's your engine or cylinder ~ displacement), and you need to predict N(that's you asked in the first ~ place, huh?). That's tough to predict without any measuring equipment ~ at all. You could assume a relatively safe, constant number like 70%, ~ but without measuring SOMETHING, you'll never know how close that is ~ or how it changes with rpm at wide open throttle(WOT). ~ ~ What are you building, kart? Powerplant? Tell us and I'm sure someone ~ can help you figure out a way to qualitatively determine your WOT ~ volumetric efficiency. I'm thinking you could try to monitor exhaust ~ gas temperature(EGT) vs rpm, which can be done without a dyno. ~ ~ Hey, glad to see a high school student trying stuff like this. Life ~ doesn't suck after all! ~ This explanation is EXCELLENT!!!! This should go on the DIY_EFY WWW page. Good work, Mr. R) (whoever you are.....). - - Bruce - -- - ----------------------------------------------------- <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> - ----------------------------------------------------- Bruce A. Bowling Staff Scientist - Instrumentation and Controls The Continuous Electron Beam Accelerator Facility 12000 Jefferson Ave - Newport News, VA 23602 (804) 249-7240 bowling@xxx.gov http://devserve.cebaf.gov/~bowling - ----------------------------------------------------- <<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> - ----------------------------------------------------- ------------------------------ From: atsakiri@xxx.com Date: Thu, 07 Mar 96 10:59:43 -0500 Subject: Re: Equations.. > PV=mRT, where I prefer that form too. Engineers seem to use m (mass), chemists seem to use n (moles). Either works as long as you keep track of the universal gas constant units. The notation I've seen includes a bar over the R for the molar version. _ R = R/M where M is a gases molecular mass (about 29 for air) > R=287 kJ/(K * kg) for air There may be a factor of 1000 problem here. Someone please check the following math! _ R = 8.3 J/(mole*K) _ R = R/M = { 8.3 J/(mole*K) } / { 29 g/mole } = 0.287 J/(g*K) = 0.287 kJ/(kg*K) > Hey, glad to see a high school student trying stuff like this. Yes, me too. Keep at it. Anthony Tsakiris Notation: P = pressure V = cylinder volume R = gas constant for a specific gas _ R = universal gas constant T = absolute temperature M = molecular mass - --------------------------------------------------------------------------- The opinions expressed are my own and not necessarily those of my employer. ------------------------------ From: Johnny Date: Thu, 07 Mar 1996 08:07:17 -0800 Subject: Re: Info on MBM27C1028 EPROM for Subaru SVX David M Parrish wrote: > > > How about you find your local FUJITSU seller .. I'll bet ya he has a burner > > to program these .. and MAYBE even a few blanks ... > > > > NEXT .. get the code read ... and disassembled .. > > > > Now, even if you CANT get any more .. you can always just make a little > > daughterboard on a header and use it to translate a regular 27C1024 into > > a multiplexed arrangement ... > > > > No biggie ... (this is where you EE types step in to help ;) > > Yeah, yeah. But with working full time, driving two hours a day, > building an airplane, rewiring an engine and designing an engine > mount, following the '332 project and some competitive shooting on > weekends, who has time to hassle with an odd ball EPROM? > David, you could eliminate all but the "building an airplane" from the above list and still not have enough time to screw around with an oddball EPROM. Now you can see why I went with the aftermarket system to get the prototype engine ready to fly, and then after that trying to do my own EFI for it. BTW, where are you in the building process now? - -j- ------------------------------ From: orlin steven jared Date: Thu, 7 Mar 1996 11:27:51 -0500 (EST) Subject: Re: Equations.. > PV=nRTe > P = pressure [assuming intake from MAP sensor] in KPA > V = Displacement of Cylinder in Liters > N = moles of atmosphere in Moles > R = Universal gas constant : 8.31L/Kpa W/ KPA & Liters > T = Absolute temp ¡K of intake air [temp sensors job] > > Could you help me nail down the real units on these things? I'm a > second year chemistry student, and I know this simple Gas law but I don't know > the units in this Application!!! You're a second year chemistry student and you don't have a chem book with these units written inside the front cover ? %-) Pressure has dimensions: force/length squared Volume has dimensions: length cubed n has no dimensions (primary dimensions anyways) the units are moles T has secondary dimension, temperature (sometimes a primary dimension). Knowing the above, you can rearrange the equation and get the dimensions and therefor, units, of the universal gas constant (which I always forget myself). I have never seen the ideal gas law used in conjunction with volumetric efficiency like you state above, however. That doesn't mean that it isn't -I just haven't seen it. Maybe someone else can elaborate. There are many ways to calculate volumetric efficiency. I can bring in some formulas later. But typical values for spark ignition engines run about .5-1 (1 being an all out race engine). Steve ------------------------------ From: atsakiri@xxx.com Date: Thu, 07 Mar 96 11:57:00 -0500 Subject: Volumetric efficiency (Re: Equations..) With regard to determining volumetric efficiency ... You need some form of air flow meter to measure the actual amount of air that is inducted by the engine. (This actual measurement is then compared to the displacement of the engine.) The air flow meter doesn't have to be fancy or even electronic. Jim (Staff), the simplest approach I can think of is to use a standard orifice or a laminar flow meter. You can use a simple water manometer to measure the pressure drop across these devices (just make sure that all the air that goes into your engine goes through the device too - buy some duct tape). To convert from pressure drop to mass flow rate, you'll need to know the flow coefficient for the standard orifice or a calibration curve for the laminar flow meter. Ask your physics teacher if your school has such equipment. Anthony Tsakiris ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Thu, 7 Mar 1996 12:24:00 +0500 Subject: Re: Equations.. > There may be a factor of 1000 problem here. Someone please > check the following math! > _ > R = 8.3 J/(mole*K) > _ > R = R/M = { 8.3 J/(mole*K) } / { 29 g/mole } = 0.287 J/(g*K) > = 0.287 kJ/(kg*K) Your math is correct, but I posted the wrong units in the formula. R is actually in units of J/(kg*K), not kJ/(kg*K) as I first posted. Substitue "R=287 J/(kg*K)" instead of "R=287 kJ/(kg*K)" and the units will work out in the formula as originally posted. Gee, you guys are sharp! Ed Hernandez Ford Motor Company ehernan3@xxx.com ------------------------------ From: MSargent@xxx. Sargent) Date: Thu, 7 Mar 1996 12:51:58 -0500 Subject: Engine Analyzer 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 @xxx.050", degrees BTDC Centerline Lobe centerline, crankshaft degrees Duration @xxx.050", crankshaft degrees Separation Lobe separation, camshaft degrees Duration @xxx.050", crankshaft degrees Close @xxx.050", degrees ABDC Centerline Lobe centerline, crankshaft degrees Duration @xxx.050", crankshaft degrees Separation Lobe separation, camshaft degrees Duration @xxx.050", crankshaft degrees Maximum lobe lift at tappet, inches Lash at valve, inches Rocker arm ratio Exhaust cam specifications Open @xxx.050", degrees BBDC Centerline Lobe centerline, crankshaft degrees Duration @xxx.050", crankshaft degrees Separation Lobe separation, camshaft degrees Duration @xxx.050", crankshaft degrees Close @xxx.050", degrees ATDC Centerline Lobe centerline, crankshaft degrees Duration @xxx.050", crankshaft degrees Separation Lobe separation, camshaft degrees Duration @xxx.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@xxx.com | Phone: 1(613)721-0902 | | Gallium Software Inc.| | FAX: 1(613)721-1278 | +--------------------------------------------------------------------------+ ------------------------------ From: MSargent@xxx. Sargent) Date: Thu, 7 Mar 1996 13:04:51 -0500 Subject: Engine Analyzer 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 @xxx.050", degrees BTDC Centerline Lobe centerline, crankshaft degrees Duration @xxx.050", crankshaft degrees Separation Lobe separation, camshaft degrees Duration @xxx.050", crankshaft degrees Close @xxx.050", degrees ABDC Centerline Lobe centerline, crankshaft degrees Duration @xxx.050", crankshaft degrees Separation Lobe separation, camshaft degrees Duration @xxx.050", crankshaft degrees Maximum lobe lift at tappet, inches Lash at valve, inches Rocker arm ratio Exhaust cam specifications Open @xxx.050", degrees BBDC Centerline Lobe centerline, crankshaft degrees Duration @xxx.050", crankshaft degrees Separation Lobe separation, camshaft degrees Duration @xxx.050", crankshaft degrees Close @xxx.050", degrees ATDC Centerline Lobe centerline, crankshaft degrees Duration @xxx.050", crankshaft degrees Separation Lobe separation, camshaft degrees Duration @xxx.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@xxx.com | Phone: 1(613)721-0902 | | Gallium Software Inc.| | FAX: 1(613)721-1278 | +--------------------------------------------------------------------------+ ------------------------------ From: ehernan3@xxx.com (Edward Hernandez (R)) Date: Thu, 7 Mar 1996 13:34:55 +0500 Subject: Re: Volumetric efficiency (Re: Equations..) > With regard to determining volumetric efficiency ... > > You need some form of air flow meter to measure the actual > amount of air that is inducted by the engine. (This actual > measurement is then compared to the displacement of the engine.) > The air flow meter doesn't have to be fancy or even electronic. > Jim (Staff), the simplest approach I can think of is to use > a standard orifice or a laminar flow meter. You can use a > simple water manometer to measure the pressure drop across > these devices (just make sure that all the air that goes > into your engine goes through the device too - buy some duct > tape). To convert from pressure drop to mass flow rate, you'll > need to know the flow coefficient for the standard orifice or > a calibration curve for the laminar flow meter. Ask your physics > teacher if your school has such equipment. Remember that one of Jim Staff's problems is that he has no dyno. This method requires steady state loading at WOT. I'd like to know what he's building first. ------------------------------ End of DIY_EFI Digest V1 #69 **************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".