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H

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™ — 23

For this example, the current local measured weather conditions 
are 80° F, absolute pressure of 29.15 in Hg, and 53.5% relative 
humidity. Your race car ran best, under these baseline conditions, 
with #78 jets.

Calculate the Air Density Index (ADI).

First, clear the memory on your calculator, including temporary and 
semi-permanent entries.

KEYSTROKES DISPLAY



 

ALL CLEArEd

1. Enter current local measured weather conditions:

  

 

TEMP  S    80. °F



(Absolute Pressure) 

P-ABS  S  29.15 INHG

    

(Moisture/Relative Humidity)    

RH%  S  53.5 %

2. Calculate ADI:

 

ELEV  S  0.

 

 ADI  92.038 %

 

D-ALT 2813.209 F

Notice that the elevation output is 0 feet. This is because the 
example did not include entering an elevation. Elevation is only 
a required input if absolute pressure is not available. Record the 
calculated ADI of 92.038% and density altitude of about 2,813 feet 
in your log, along with your air/fuel settings and jet numbers. In this 
example, these are your baseline settings for this particular track 
location.

You are now at a different track location, and the current weather 
conditions have changed significantly. The air temperature is now 
60° F, absolute pressure is 24.72 in Hg, and relative humidity is 39%.

Calculate the current ADI in order to determine if an adjustment is 
necessary.

Содержание Hot Rod Calc 8703

Страница 1: ...HOT ROD CALC 1...

Страница 2: ...cts of motorsports racing especially those with deep understanding of the relationship between weather conditions and engine performance Calculated Industries gratefully acknowledges Patrick Hale Drag...

Страница 3: ...for predicting elapsed time and trap speed at 1 8 and 1 4 mile intervals The Hot Rod Calc is a powerful cost effective tool for every performance car and truck owner s toolbox Helps you at the track...

Страница 4: ...eed Conversions 13 Engine Displacement Conversions 14 Torque Conversions 14 Weight Conversions 15 Volume Conversions 15 USING THE HOT ROD CALC 16 Important Terms and Definitions 16 Motorsports Standar...

Страница 5: ...metric Efficiency 42 Estimating Flywheel Horsepower at a Known RPM 43 Estimating Flywheel Torque at a Known RPM 44 Calculating Compression Ratio 44 Calculating Mill Amount 48 Calculating Piston Speed...

Страница 6: ...g twice clears all non permanent values Off Turns all power off Clears all non permanent values Arithmetic operation keys and Keys used for entering numbers Convert Used with the dimensional keys to c...

Страница 7: ...gling between linear area and volume units Converts dimensional value to units of inches with repeated presses toggling between inches and feet Feet Identifies entry as feet with repeated presses togg...

Страница 8: ...mber e g 8 0 125 Clear All Returns all stored values to the default settings Does not affect Preference settings Displays value of 3 1415927 Toggle displayed value between minus and plus value Prefere...

Страница 9: ...can enter a value from 0 to 360 Vehicle Weight Enters or calculates the vehicle s weight Vehicle weight typically includes the driver s weight Calculates vehicle weight given ET and HP or MPH and HP...

Страница 10: ...ear ratios adjusted for manual and automatic transmissions New Tire Diameter Enters the new tire size for solving tire and gear ratio problems Engine Displacement Enter or calculate Engine Displacemen...

Страница 11: ...lumetric Efficiency Enter or calculate the volumetric efficiency of an engine Calculate given values for Engine Displacement RPM and Carburetor Size Bore Enter or calculate Bore diameter Use to calcul...

Страница 12: ...Used in calculating Compression Ratio Horsepower Enter or calculate the engine horsepower calculates Horsepower Correction Factor HPc and Motorsport Standard Atmosphere MSA adjusted horsepower when th...

Страница 13: ...Press to exit Preferences Your calculator will keep Preference settings until a Full Reset alters your settings to the default values KEYSTROKES DISPLAY Functional Rounding F RND 0 000 F RND 0 00 F RN...

Страница 14: ...re entered press after each entry DIMENSIONS KEYSTROKE 4 5 inches 95 millimeters 1320 feet 201 meters Square and Cubic Dimensions Examples of how square and cubic dimensions are entered press after ea...

Страница 15: ...Repeated presses of will toggle between meters and millimeters Enter and convert 4 5 inches to millimeters KEYSTROKES DISPLAY 0 4 5 IN 114 3 MM Repeated presses of will toggle between meters and milli...

Страница 16: ...ES DISPLAY 0 450 CU IN LITER 7 3741788 Enter and convert 5 0 liters to CID KEYSTROKES DISPLAY 0 LITER 5 305 11872 CU IN Torque Conversions Enter and convert 42 lb ft to Newton meters KEYSTROKES DISPLA...

Страница 17: ...pounds to kilograms KEYSTROKES DISPLAY 0 LBS 2700 KG 1224 6994 Volume Conversions Enter and convert 5 5 gallons to liters KEYSTROKES DISPLAY 0 GAL 5 5 LITER 20 819765 Enter and convert 15 25 liters t...

Страница 18: ...s performance enabling better ET and MPH predictions To further understand the Hot Rod Calc s outputs and how to use the calculator please get familiar with the following technical and weather related...

Страница 19: ...ly the higher the HPc the slower it will run less horsepower is produced Patrick Hale Motorsports Standard Atmosphere and Weather Correction Methods Arizona DRPro 2008 Density Altitude Density Altitud...

Страница 20: ...uire that much less fuel to maintain the same level of performance Be careful It s safer to be 3 rich than to be 1 lean ADI can tell you a lot about what you need to know for carburetor jetting change...

Страница 21: ...asurement you might get from the local radio station TV station from the Internet or from a corrected barometer It is corrected for sea level and is not suitable for motorsports Do not use Corrected P...

Страница 22: ...r current local measured weather conditions TEMP S 63 2 F Absolute Pressure P ABS S 28 83 INHG Moisture Relative Humidity RH S 58 2 Calculate ADI and density altitude ELEV S 0 ADI 94 641 D ALT 1873 41...

Страница 23: ...Firebird International Raceway are unlikely this example demonstrates an ADI value of over 100 which is certainly a possible situation As stated previously air density is typically over 100 when temp...

Страница 24: ...Using a Fuel Correction Index Note In this example it is assumed that your current air fuel settings and jet numbers are correct for your engine s requirements at wide open throttle This example uses...

Страница 25: ...ADI ELEV S 0 ADI 92 038 D ALT 2813 209 F Notice that the elevation output is 0 feet This is because the example did not include entering an elevation Elevation is only a required input if absolute pre...

Страница 26: ...The fuel correction index is about 89 indicating air density is about 89 of the air density from which you baselined your jet numbers In other words the new air density has gone down about 11 from yo...

Страница 27: ...example density altitude has gone up so it stands to reason that a leaner jet number may be required A conservative change however would be to go from the 78 to the 76 which has a flow of 587 cubic c...

Страница 28: ...ing with the relative humidity input Basic ET Prediction Note Your calculator s ET predictions may vary from other ET prediction sources primarily due to traction The Hot Rod Calc assumes ideal condit...

Страница 29: ...after the previous Basic ET Prediction example Your calculator s ET predictions may vary from other ET prediction sources primarily due to traction The Hot Rod Calc assumes ideal conditions with no t...

Страница 30: ...d weather conditions are 73 F absolute pressure of 25 88 in Hg and 14 relative humidity KEYSTROKES DISPLAY 1 We have already entered the vehicle s weight and HP so we can skip to the next input local...

Страница 31: ...Repeated presses of HP will toggle back through the inputs and outputs starting with absolute pressure Note Recall from the key definitions for Mechanical Efficiency ME that ME is a numeric value repr...

Страница 32: ...and direction were when the ET was recorded Additionally you need to know the race car s frontal area and drag coefficient To determine your race car s frontal area measure the vehicle from head on me...

Страница 33: ...dan style body we will select a value of 45 Enter the Drag Coefficient of our 1970 Ford Mustang Notchback KEYSTROKES DISPLAY Drag Coefficient DRAG S 0 45 Your disappointing ET was 13 85 at 102 304 MPH...

Страница 34: ...rrected Speed SPDc 105 85 MPH Repeated presses of will toggle back through the inputs and outputs starting with the Wind Speed input So if you were to re do your run everything being the same except t...

Страница 35: ...has a 2005 Ford Mustang GT with an estimated horsepower of 520 HP and ran a 1 4 mile at 121 6 MPH Calculate the estimated Vehicle Weight KEYSTROKES DISPLAY 4 Clear the memory first 0 5 Enter the esti...

Страница 36: ...d 14 relative humidity then calculate the estimated Horsepower again KEYSTROKES DISPLAY 4 Enter current local measured weather conditions TEMP S 73 F Absolute Pressure P ABS S 25 88 INHG RH S 14 5 The...

Страница 37: ...diameter of 28 9 inches whereas the mud tires you are looking to upgrade to have a tire diameter of 33 inches Your four wheeler currently has a final drive ratio of 3 08 Calculate the equivalent drive...

Страница 38: ...ed will be with an indicated gauge speed of 65 MPH Don t clear the memory on your calculator we can use your inputs from the previous example which are currently in memory 4 Enter a target indicated g...

Страница 39: ...99 for 2nd 1 32 for 3rd direct drive 1 00 in 4th and an overdrive 0 68 in 5th The final drive ratio is 3 08 Lastly the tires have a diameter of 26 inches In this example calculate your top speed in 2...

Страница 40: ...RATIO 5 Enter your cruising speed of 65 MPH SPEED S 65 MPH 6 Calculate the RPM RPM 1760 004 Repeated presses of will toggle through the inputs and outputs starting with the gear ratio input From the...

Страница 41: ...00 RPM in 4th gear at 65 MPH the LX will need a final drive ratio of 3 57 And for the users who have experience with the Larry Shepard correction method your calculator also shows a manual transmissio...

Страница 42: ...ng Effects of Changing Tire Sizes for more information Calculating Carburetor Size The Hot Rod Calc can calculate carburetor sizes in four configurations based on different volumetric efficiency VE va...

Страница 43: ...RPM S 5400 ENG S SIZE 400 CU IN 2 Calculate the carburetor sizes THEOR CARB SIZE 625 CFM STREET CARB SIZE 531 25 CFM RACE CARB SIZE 687 5 CFM The theoretical carburetor size of about 625 cfm was calc...

Страница 44: ...B SIZE 625 CFM STREET CARB SIZE 531 25 CFM RACE CARB SIZE 687 5 CFM Notice within the outputs the User carburetor size appears first in the output This carburetor size is calculated using the entered...

Страница 45: ...actual measured airflow capacity at 7000 RPM RPM S 7000 ENG S SIZE 400 CU IN USER S CARB SIZE 625 CFM 2 Calculate your engine s VE EFF 77 143 VOL The calculated VE of your GTO at 7000 RPM is about 77...

Страница 46: ...is example your 400 CID engine produces 366 HP at 5400 RPM Calculate the torque for the same RPM KEYSTROKES DISPLAY 0 1 Enter your HP and RPM HP S MSA 366 RPM S 5400 2 Calculate the Torque at 5400 RPM...

Страница 47: ...r amount of air fuel mix that is compressed the greater the combustion power will be The greater the combustion power is the hotter the combustion is which can lead to detonation Detonation pinging an...

Страница 48: ...uld be entered as a positive number they add to the chamber volume and have a lowering effect on compression Cylinder Head Combustion Chamber Volume You will need to measure this manually Note Your Ho...

Страница 49: ...ore The calculated compression ratio is about 8 81 1 At this point if you were not satisfied with this ratio you can use your Hot Rod Calc to play out some other scenarios For this example to raise yo...

Страница 50: ...nt to determine how much material to remove from your engine s heads Note Your Hot Rod Calc user s guide does not go into details on the milling process Your local engine building shop will likely hav...

Страница 51: ...g racing Piston speed is the speed typically in feet per minute at which the piston moves up and down within a cylinder As your engine s crankshaft rotates once your cylinder s piston travels two stro...

Страница 52: ...at about at 5000 RPM 3 Enter the RPM for which you want to determine piston speed RPM S 5000 4 Calculate the Piston Speed at 5000 RPM FPM 2900 M MIN 883 92 At 5000 RPM your piston speed is 2 900 feet...

Страница 53: ...ication or modifying one and want to know the effects on displacement by changing bore and or stroke the Hot Rod Calc can do it In this example your 1968 Pontiac GTO s Ram Air II engine has a publishe...

Страница 54: ...layed in cubic inches In this example your 1962 Ford Falcon straight 6 engine has a published engine displacement of 169 95 CID The spec Bore and Stroke are 3 5 inches and 2 94 inches respectively Cal...

Страница 55: ...respectively Keeping the stock Stroke length calculate a new Bore size First clear the memory on your calculator including temporary and semi permanent entries KEYSTROKES DISPLAY ALL CLEArEd 1 Enter...

Страница 56: ...roke length STROK 3 797 IN Notice you can also meet your goals by keeping the stock bore and going to a longer stroke of 3 797 In terms of cost it will be more cost effective to go over bore to reach...

Страница 57: ...Convertible 0 5 0 7 Station Wagon and Van Body 0 5 0 6 Notchback or Sedan 0 4 0 55 Fastback 0 3 0 4 Fairings all around streamlined shape 0 2 0 25 K shape 0 23 Optimum streamliner 0 15 0 2 Motorcycle...

Страница 58: ...er Drill Size and Flow JET NO DRILL SIZE FLOW 40 040 117 41 041 122 42 042 129 43 043 135 44 044 142 45 045 149 46 046 156 47 047 163 48 048 170 49 049 178 50 049 185 51 050 194 52 052 203 53 052 212...

Страница 59: ...92 68 069 411 69 070 429 70 073 448 71 076 470 72 079 492 73 079 517 74 081 542 75 082 566 76 084 587 77 086 615 78 089 645 79 091 677 80 093 703 81 093 731 82 093 765 83 094 795 84 099 824 85 100 858...

Страница 60: ...58 HOT ROD CALC 92 105 1150 93 105 1200 94 108 1260 95 118 1320 96 118 1375 97 125 1440 98 125 1500 99 125 1570 100 128 1640...

Страница 61: ...01697 0 175 0 02405 0 032 0 0008 0 061 0 00292 0 09 0 00636 0 119 0 01112 0 148 0 0172 0 176 0 02433 0 033 0 00086 0 062 0 00302 0 091 0 0065 0 12 0 01131 0 149 0 01744 0 177 0 02461 0 034 0 00091 0 0...

Страница 62: ...EET Drag Coefficient 0 35 Mechanical Efficiency 85 Cylinders 8 Volumetric Efficiency 100 If you replace your batteries or perform a Full Reset press hold down and press your calculator will return to...

Страница 63: ...t following the instructions listed below may result in damage not covered by your warranty Refer to the Repair and Return section on page 44 for more details Do not expose calculator to temperatures...

Страница 64: ...re key the problem ERROR CODES DISPLAY ERROR TYPE OFLO Overflow too large MATH Error Divide by 0 DIM Error Dimension error ENT Error Invalid entry error Auto Range If an overflow is created because o...

Страница 65: ...me very dim or erratic replace the batteries Note Please use caution when disposing of your old battery as it contains hazardous chemicals Replacement batteries are available at most discount or elect...

Страница 66: ...Toll Free 1 800 854 8075 Outside USA 1 775 885 4900 www calculated com warranty WARRANTY Warranty Repair Service U S A Calculated Industries CI warrants this product against defects in materials and w...

Страница 67: ...ht and duties Disclaimer CI MAKES NO WARRANTY OR REPRESENTATION EITHER EXPRESS OR IMPLIED WITH RESPECT TO THE PRODUCT S QUALITY PERFORMANCE MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE AS A RES...

Страница 68: ...66 HOT ROD CALC...

Страница 69: ...registered trademark of Calculated Industries Inc ALL RIGHTS RESERVED Designed in the U S A Looking For New Ideas Calculated Industries a leading manufacturer of special function calculators and digi...

Страница 70: ...registered trademark of Calculated Industries Inc ALL RIGHTS RESERVED Designed in the U S A Looking For New Ideas Calculated Industries a leading manufacturer of special function calculators and digit...

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