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Summary of Contents for Mr. Gasket Hot Rod Calc
- Page 1 Model 8703...
- Page 2 Designing and building the Hot Rod Calc™ could not have been done without the support and input from individuals knowledgeable in all aspects of motorsports racing, especially those with deep understanding of the relationship between weather conditions and engine performance.
- Page 3 Whether you’re into hot rods, street performance, off-road, or drag racing, the Hot Rod Calc can help with its built-in solutions for carburetor size, volumetric efficiency, tire ratios, gear ratios, engine displacement, compression ratio, HP, torque and RPM.
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Page 4: Table Of Contents
Calculating ADI Using a Fuel Correction Index ........24 Calculating Water vapor Content .............27 ELAPSED TIME ..................28 Calibrating your Hot Rod Calc for ET Predictions at the Track ....28 Basic ET Prediction...................29 ET Prediction and HPc................30 ET Prediction and Wind Conditions ............33 vEHICLE WEIGHT AnD HoRSEPoWER ..........35... - Page 5 Estimating Rear Wheel Horsepower — Based on Vehicle Weight and ET .....................37 Estimating Rear Wheel Horsepower — Based on Vehicle Weight, ET and Weather Conditions ..............38 TIRE RATIo ....................39 Calculating Effects of Changing Tire Sizes ..........39 SPEED, RPM, GEAR RATIoS AnD TIRE RELATIonSHIPS ....41 Speed —...
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Page 6: Getting Started
GeTTinG sTarTed you may want to practice getting a feel for your calculator keys by reading through the key definitions and learning how to enter data, how to store values, etc., before proceeding to the exam- ples. key defInItIons basic function Keys On/Clear Key –... -
Page 7: Dimensional Function Keys
dimensional function Keys Millimeters – Identifies entry as Millimeters, with repeated presses toggling between linear, area and volume units. Converts dimensional value to units of Millimeters, with repeated presses toggling between Millimeters and Meters. Meters (m) – Identifies entry as Meters, with ... -
Page 8: Miscellaneous Function Keys
(cont'd) Liters (liters) – Enters or converts to liters. Milliliters (mL) – Enters or converts to milliliters. Pound-foot (lb-ft) – Enters or converts to pound- force foot. Cubic Centimeters (cc) – Enters or converts to cubic centimeters. newton-meters (n-m) –... - Page 9 Pressure – Enters the current local absolute Pressure as reported by a weather meter such as an aircraft altimeter or absolute barometer (not cor- rected by Internet, local radio or Tv news sources). Unitless entries assumed inHg in US mode, mbar in Metric mode.
- Page 10 (cont'd) Wind Direction – Enters the current Head local Wind 0° Direction. A direct 45° headwind is entered as 0°, a 90° direct crosswind is entered as 90°, and a direct tail- wind is entered as 180° 180°. you can Tail enter a value from 0°...
- Page 11 elapsed Time – Enters or calculates the vehicle’s quarter-mile dragstrip Elapsed Time, in seconds. Given entered quarter-mile dragstrip Elapsed Time and speed, calculates the vehicle’s eighth-mile drag- strip Elapsed Time and speed. Given entered HP and vehicle Weight, calculates the vehicle’s Elapsed Time and speed for both the quarter-mile and eighth-mile dragstrips.
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Page 12: Performance Keys
(cont'd) Performance Keys Tire Ratio – Calculates Tire Ratio, effective drive ratio (d-eff), equivalent drive ratio (d-eQV), actu- al speed (SPD►A) and indicated (gauge) speed (G►SPD) given entered old Tire Diameter, new Tire Diameter, Gear Ratio and speed. Old Tire Diameter (Old Tire Dia) – Enters the cur- ... - Page 13 Mill Amount – Enters a new Compression Ratio and calculates the amount to cut out of the cylin- der’s head in order to increase Compression Ratio given entered Stroke length, old Compression Ratio and new Compression Ratio. Piston Speed – Enters or calculates an engine’s ...
- Page 14 (cont'd) gasket Bore (gskt Bore) – Enters Gasket Bore diameter. Unitless entries assumed Inches in US mode, mm in Metric mode. Used in calculating Compression Ratio. Stroke – Enters or calculates Stroke length. Unitless entries assumed Inches in US mode, mm in Metric mode.
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Page 15: Preference Settings
Horsepower – Enters or calculates the engine Horsepower. Calculates engine Horsepower given entered speed and vehicle Weight. Calculates rear wheel Horsepower given entered ET and vehicle Weight. Calculates flywheel Horsepower given entered RPM and Torque. When the appropriate environmental conditions are entered, all methods calculate the vehicle’s Horsepower correction factor (HPc) and provide the Motorsport Standard Atmosphere (MSA) adjusted Horsepower. -
Page 16: Entering Dimensions
(cont'd) KeysTroKe disPlay MeTrC Units Us Units (repeats options) Third press of MeTer 0.000 (Meter Rounding) MeTer float MeTer 0.000 (repeats options) enteRInG dImensIons distance/length dimensions Examples of how linear dimensions are entered (press after each entry): diMensions KeysTroKe 4.5 inches... -
Page 17: Conversions
ConveRsIons distance/length Conversions Enter and convert 1,320 feet to meters. KeysTroKe disPlay 1320 (Feet) 402.336 * Repeated presses of will toggle between meters and millimeters. Enter and convert 4.5 inches to millimeters. KeysTroKe disPlay ... -
Page 18: Torque Conversions
(cont'd) KeysTroKe disPlay CU in liTer 7.3741788 (liters) Enter and convert 5.0 liters to cubic inches (CID). KeysTroKe disPlay liTer 5 (liters) 305.11872 CU in Torque Conversions Enter and convert 42 lb-ft to Newton-meters. KeysTroKe disPlay ... -
Page 19: Volume Conversions
Volume Conversions Enter and convert 5.5 gallons to liters. KeysTroKe disPlay Gal 5.5 (gal) liTer 20.819765 (liters) Enter and convert 15.25 liters to gallons. KeysTroKe disPlay liTer 15.25 (liters) Gal 4.0286238 ... -
Page 20: Using M
ET and speed 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 terms used throughout this section of the user’s guide. -
Page 21: Important Terms And Definitions
ImPoRtAnt teRms And defInItIons Motorsports Standard Atmosphere (MSA)* Motorsports Standard Atmosphere, MSA, is a term defined by Drag Racing Pro’s Patrick Hale, and is a methodology implemented in this calculator. Simply stated, it is a standard, reference set of ambient weather conditions. Engine and race car performance can be corrected back to MSA in order to understand the effects of environmental changes. -
Page 22: Density Altitude
(cont'd) density altitude Density Altitude is an MSA Elevation that has the same air density as the current local measured weather conditions. Meaning, your physical Elevation might be 4,000 feet above sea level, but the current air conditions are like a “theoreti- cal”... -
Page 23: Pressure
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 Pressure on the Hot Rod Calc. (cont'd) — 21 Uide... -
Page 24: Elapsed Time
ET predictions may vary from other ET prediction sources pri- marily due to traction. The Hot Rod Calc assumes ideal con- ditions with no tire slippage and 100% converter lockup, and the predictions are for estimation purposes only. - Page 25 * Recall that ADI is a ratio, expressed as a percentage, of the current air’s density to that of MSA. At the Auto Club Raceway under the afore- mentioned weather conditions, the air’s density is about 94.6% of that of MSA.
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Page 26: Calculating Adi And Density Altitude Using Elevation
Calculating adi and density altitude Using elevation For this example, you are at Top Gun Raceway in Fallon, nev., and only have access to air temperature and humidity data. However, you know the track’s Elevation is about 3,963 feet above sea level. With these three variables — Air Temperature, humidity and Elevation —... - Page 27 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 a basic Holley carburetor with squared jetting and identical primary and secondary main metering circuits.
- Page 28 (cont'd) KeysTroKe disPlay 3. Enter current weather conditions: TeMP 60. °f P-abs 24.72 inHG (Pressure) 4. Calculate ADI and Density Altitude: eleV adi 81.94 d-alT 6662.18 Record the calculated ADI of 81.94% and Density Altitude of 6,662 feet in your log.
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Page 29: Calculating Water Vapor Content
To translate a fuel correction index to a new jet number, recall your baseline was recorded with #78 jets, which according to the Holley Jet Chart (see Appendix B), have a flow of 645 cubic centimeters per minute. Recall your fuel correction index is about 89%. -
Page 30: Elapsed Time
Your calculator’s ET predictions may vary from other ET predic- tion sources primarily due to traction. The Hot Rod Calc assumes ideal conditions with no tire slippage and 100% converter lockup, and the predictions are for estimation purposes only. -
Page 31: Basic Et Prediction
1. Enter your dial-in ET. 2. Enter vehicle Weight. 3. Enter track Elevation. 4. Enter Temperature at the time of your dial-in. 5. Enter Moisture at the time of your dial-in. 6. Press the HP key, and record the HP value associated to the aforementioned track conditions (not the HP MSA value, which is a value calculated under sea level condi- tions). -
Page 32: Et Prediction And Hpc
The inputs demonstrated in this example are not required for an ET prediction, however, this example will demonstrate the Hot Rod Calc’s ability to calculate a Horsepower correction factor (HPc) and output for current weather conditions as well as MSA conditions. - Page 33 KeysTroKe disPlay 4. We have already entered the vehicle’s weight and HP, so we can skip to the next input – local measured weather condi- tions: TeMP 73. °f P-abs 25.88 inHG (Pressure) 5.
- Page 34 (cont'd) KeysTroKe disPlay 6. Display the entered MSA HP, corrected HP and the calculat- ed Horsepower correction factor (HPc): 411. HP 341.92 HPc 1.202 * Repeated presses of will toggle through the inputs and outputs, starting with the entered absolute Pressure. —...
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Page 35: Et Prediction And Wind Conditions
eT Prediction and Wind Conditions now let’s say you ran your 3,840-pound 1970 Ford Mustang notchback at Top Gun Raceway in Fallon, nev., where there are often raging winds. you can use your actual ET and determine what your ET would have been without the windy conditions. you will need several new pieces of information. - Page 36 (cont'd) Based on Appendix A, we will use a Drag Coefficient of 0.45. your disappointing ET was 13.85 at 102.304 MPH and the vehicle Weight is 3,840 pounds. Use a Wind Speed of 30 MPH and a Wind Direction of 5°. KeysTroKe disPlay 3.
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Page 37: Vehicle Weight And Horsepower
veHICle WeIGHt And HoRsePoWeR often, a racer (or a fan, or a friend of a racer) will try to figure out what a particular race car’s weight is, what Horsepower is required to achieve a recorded ET, what speed a race car can run, or how much Horsepower a race car has. -
Page 38: Vehicle Speed - Based On Hp And Vehicle Weight
(cont'd) KeysTroKe disPlay 1. Enter the estimated HP: 520. 2. Enter the speed at 1/4 mile: sPeed 121.6 3. Solve for the vehicle’s weight: lbs 3705.529 * Repeated presses of will toggle through the inputs and outputs, starting with the HP correction factor. -
Page 39: Horsepower - Based On Speed And Vehicle Weight
Horsepower — Based on Speed and Vehicle Weight In this example, you want to calculate the Horsepower for the 1970 Chevelle SS, knowing it weighs 4,100 pounds and had a 107.723 1/4-mile speed. Calculate the estimated Horsepower. KeysTroKe disPlay 1. -
Page 40: Estimating Rear Wheel Horsepower - Based On Vehicle Weight, Et And Weather Conditions
(cont'd) KeysTroKe disPlay 3. Solve for the vehicle’s estimated rear wheel HP: 332.17 * Repeated presses of will toggle through the inputs and outputs, starting with the HP correction factor. — do noT Clear CalCUlaTor — estimating rear Wheel Horsepower — Based on Vehicle Weight, eT and Weather Conditions Building from the prior example, let’s correct the estimated rear wheel HP based on current local measured weather conditions... -
Page 41: Tire Ratio
tIRe RAtIo Calculating effects of Changing Tire sizes your daily commuter has four-wheel drive, and you want some extra ground clearance for those occasional off-highway excur- sions on the way home from work. However, before you make the switch to a taller tire, you want to know what the effects will be to your final-drive ratio and even more importantly, to your speedometer as you don’t want to draw any unnecessary atten- tion while you are cruising down the highway. - Page 42 (cont'd) * Repeated presses of will toggle through the inputs and outputs, starting with the current final-drive ratio input. — do noT Clear CalCUlaTor — ** The effect to the final-drive (d-eff) of going from a tire diameter of 28.9 to 33 inches is an estimated ratio of 2.697, which will create a fair- ly noticeable loss in your four-wheeler pickup from a stop or while roll- ing down the highway.
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Page 43: Speed, Rpm, Gear Ratios And Tire Relationships
sPeed, RPm, GeAR RAtIos And tIRe RelAtIonsHIPs Speed, RPM, Gear Ratios and tire sizes are interrelated, and with any three values, the fourth value can be solved on your calculator. Getting these four areas set up properly on your road or dragstrip vehicle can have very positive performance effects. -
Page 44: Rpm - Based On Gear Ratio, Speed And Tire Diameter
(cont'd) — do noT Clear CalCUlaTor — rPM — Based on gear Ratio, Speed and Tire Diameter From the above calculation, it is estimated that the mighty 5.0 LX will be going about 70 MPH at 5,500 RPM in 2nd gear. In this example, calculate your RPM at 65 MPH in 5th gear. -
Page 45: Tire Diameter - Based On Rpm, Speed And Gear Ratio
KeysTroKe disPlay 8. Enter your RPM and cruising speed of 65 MPH: 3000. sPeed 9. Calculate the final-drive ratio: Gear 3.57** raTio (Final-drive ratio) Gr-M 3.529 raTio (Manual trans final-drive ratio) GR-a 3.582 RatIo (Auto trans final-drive ratio) ... -
Page 46: Carburetor Size
(see Calculating effects of Changing Tire sizes section on page 39 for more information). CARbuRetoR sIze The Hot Rod Calc can calculate Carburetor Sizes in four config- urations based on different volumetric Efficiency (vE) values: User, Theoretical, Street and Race. See Volumetric efficiency section on page 46 for more about vE. -
Page 47: Carburetor Size - Based On Rpm And Engine Displacement
Carburetor size — Based on RPM and engine Displacement In this example, you want to upgrade your 1968 Pontiac GTo’s carburetor. With all the engine and accessory modifications you have made, your Ram Air II 400-CID engine makes its peak Horsepower RPM at about 5,400 RPM. -
Page 48: Carburetor Size - Based On Rpm, Engine Displacement And Volumetric Efficiency
(cont'd) Carburetor size — Based on RPM, engine Displacement and Volumetric Efficiency Building off of the previous example, you want to calculate your user-defined Carburetor Size based on a known vE value. Suppose through your experience and knowledge of your 1968 Pontiac GTo’s engine specs and modifications, you know you can reach a vE of 95%. -
Page 49: Volumetric Efficiency - Based On Rpm, Engine Displacement And
Volumetric Efficiency — Based on RPM, engine Displacement and Carburetor Size In this example, your 1968 Pontiac GTo has a Ram Air II 400-CID engine and you want to calculate the engine’s vE at 7,000 RPM, which is the RPM at your maximum speed. your measured airflow capacity at 7,000 RPM is said to be 625 cfm. -
Page 50: Estimating Flywheel Torque - Based On Hp And Rpm
(cont'd) KeysTroKe disPlay 1. Enter your Torque and RPM: lb-fT 445. 3800. 2. Calculate the HP at 3,800 RPM: 321.966** * Repeated presses of will toggle through the inputs and outputs, starting with the HP correction factor. ** At 3,800 RPM, when your 400-CID engine is producing 445 pounds- feet of Torque, it is also producing about 322 HP at the flywheel. -
Page 51: Compression Ratio And Mill Amount
So, to get big power, you need big Compression Ratios to get more powerful combustion, which requires higher octane fuels. your Hot Rod Calc needs several inputs to calculate a Com- pression Ratio, which you may need to track down and in some... -
Page 52: Calculating Compression Ratio
• Cylinder Head Combustion Chamber Volume – you will need to measure this manually. note: Your Hot Rod Calc User’s Guide does not go into details on measuring Piston Dome Volume or Combustion Chamber Volume. You will need to consult an auto repair or engine building resource for that procedure. - Page 53 Bore. — do noT Clear CalCUlaTor — ** 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 your Compression Ratio, you could en- ter a thinner Head Gasket Thickness of 0.015.
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Page 54: Calculating Mill Amount
Your Hot Rod Calc User’s Guide does not go into details on the milling process. Your local engine building shop will likely have the nec- essary knowledge and tools for milling your heads to your specs. -
Page 55: Piston Speed
PIston sPeed Piston Speed is an important factor when building an engine, es- pecially if that engine is being built to run short distances at wide open throttle, such as drag racing. Piston Speed is the speed, typically in feet per minute, at which the piston moves up and down within a cylinder. -
Page 56: Rpm - Based On Piston Speed And Stroke
— Based on Piston Speed and Stroke your Hot Rod Calc can also calculate an RPM limit should you want to calculate a limit based on a particular Piston Speed. Cal- culate an RPM with a Piston Speed of 3,500 feet per minute and a Stroke of 3.48 inches. -
Page 57: Engine Displacement, Bore And Stroke
If you are building an engine to your specifi- cation, or modifying one and want to know the effects on dis- placement by changing Bore and/or Stroke, the Hot Rod Calc can do it. engine displacement — Based on Bore and Stroke In this example, your 1968 Pontiac GTo’s Ram Air II engine has... -
Page 58: Bore - Based On Engine Displacement And Stroke
(cont'd) 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 inches and 2.94 inches, respectively. Calcu- late the exact cubic-inch displacement by going to a larger Bore of 3.75. -
Page 59: Stroke - Based On Engine Displacement And Bore
KeysTroKe disPlay 1. Clear all stored values: all Cleared (Clear All) 2. Enter the target displacement of 405 CID and current Stroke length: 405. siZe CU in sTroK 3.75 3. Calculate the new Bore: bore 4.146 ... -
Page 60: Appendix A - Body Style And Drag Coefficients
aPPendiX a – BODy STyLe AnD DRAg COeffiCienTS* body sTyle draG CoeffeCienT open 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 –... -
Page 61: Appendix B - Reference Charts
aPPendiX b – RefeRenCe CHARTS Holley Jet CHARt JeT no. drill siZe floW .040 .041 .042 .043 .044 .045 .046 .047 .048 .049 .049 .050 .052 .052 .053 .054 .055 .056 .057 .058 .060 .060 .061 (cont'd) — 59 Uide... - Page 62 (cont'd) JeT no. drill siZe floW .062 .064 .065 .066 .068 .069 .070 .073 .076 .079 .079 .081 .082 .084 .086 .089 .091 .093 .093 .093 .094 .099 .100 .101 .103 .104 60 — H ™...
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Page 63: Jet Orifice Area Conversion Chart
JeT no. drill siZe floW .104 .104 1014 .105 1080 .105 1150 .105 1200 .108 1260 .118 1320 .118 1375 .125 1440 .125 1500 .125 1570 .128 1640 Jet oRIfICe AReA ConveRsIon CHARt size size size size size size size size size size... - Page 64 (cont'd) size size size size size size size size size size size size dia. area dia. area dia. area dia. area dia. area dia. area (") (sq. ") (") (sq. ") (") (sq. ") (") (sq. ") (") (sq. ") (") (sq.
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Page 65: Appendix C - Default Settings
Full Reset aPPendiX d – PRefeRenCe SeTTingS The Hot Rod Calc has Preference Settings that allow you to customize or set desired unit formats and calculations. If you replace your batteries or perform a Full Reset* (press , hold down ... - Page 66 (cont'd) PreferenCe oPTions – 0.000: calculation results obtained using the 1) Functional Result motor, performance and environmental functions Rounding are always displayed to three decimal places. – 0.00: calculation results obtained using the motor, performance and environmental functions are always displayed to two decimal places. –...
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Page 67: Appendix E - Care Instructions
aPPendiX e – CARe inSTRUCTiOnS Please follow the guidelines listed in this section for proper care and operation of your calculator. not following the instruc- tions listed below may result in damage not covered by your warranty. Refer to the WARRAnTy section on page 67 for more details. -
Page 68: Auto Shut-Off
8-12 minutes of non-use. bAtteRIes The Hot Rod Calc uses two LR-44 batteries. Should your calculator display become very dim or erratic, replace the batteries. note: Please use caution when disposing of your old batteries, as they contain hazardous chemicals. -
Page 69: Repair And Return
(1) year from the date of origi- nal consumer purchase in the U.s. If a defect exists during the warranty period, Mr. Gasket at its option will either repair (using new or remanufactured parts) or replace (with a new or remanufac- tured calculator) the product at no charge. - Page 70 Contact Mr. Gasket at the number listed on the previous page to obtain current product repair information and charges. Repairs are guaranteed for 90 days.
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Page 71: Legal Notes
Specialty Calculator Technologies, LLC, 2010. User’s Guide copyrighted by Calculated Industries, Inc., 2010. Hot rod Calc™ is a trademark and Calculated Industries® is a reg- istered trademark of Calculated Industries, Inc. © 2010. Licensed to Mr. Gasket by Calculated Industries, Inc. 2010. - Page 72 Designed in the United States of America. Printed in China. 3/10 10601 Memphis Ave. #12, Cleveland, OH 44144 U.S.A. www.mr-gasket.com UG8703E-B...
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