Helpful Calculations

FWTQ 294 306 318 326 335 326 318 329 341 353 365 371 376 379 382 388 394 400 406 415 424 424 424 424 424 415 406 403 400 397 394 385 376 371 365 362 359 353 347 341 335 329 324 318 312 306 300

FW VE 1.08 1.12 1.16 1.20 1.23 1.20 1.16 1.21 1.25 1.29 1.34 1.36 1.38 1.39 1.40 1.42 1.44 1.47 1.49 1.52 1.55 1.55 1.55 1.55 1.55 1.52 1.49 1.48 1.47 1.46 1.44 1.41 1.38 1.36 1.34 1.33 1.32 1.29 1.27 1.25 1.23 1.21 1.19 1.16 1.14 1.12 1.10

Runner CFM 54 59 65 70 75 76 76 82 88 95 101 106 112 116 120 126 131 137 143 150 157 161 165 169 173 173 173 175 178 180 182 182 181 182 182 184 186 186 186 186 186 186 186 185 185 184 183

Intake CFM 188 205 223 240 257 261 264 284 305 327 350 367 385 400 415 434 453 473 493 517 541 555 568 582 595 596 597 605 614 622 630 628 626 628 629 636 642 643 643 643 643 642 641 639 638 635 633

249 286 298

375 372 365

1.37 1.36 1.34

121 139 145

417 481 501

Piston Speed 9,840 10,848 11,906 13,013 14,169 15,374 16,629 17,933 19,286 20,688 22,139 23,640 25,189 26,788 28,436 30,134 31,880 33,676 35,521 37,415 39,358 41,351 43,392 45,483 47,623 49,813 52,051 54,339 56,676 59,062 61,497 63,982 66,515 69,098 71,730 74,412 77,142 79,922 82,751 85,629 88,556 91,532 94,558 97,633 100,757 103,930 107,153

Green Field Yellow VE = HP/(displacement*rpm*Com Runner CFM = RPMxFWTQ/1079 Intake CFM = CIDxRPMxVE/3464 based on 28" water VE Calc Data 30.05 302 9.3 650 600 550 500 450 400 350 300 250 200 150 100 50 0

2, 0 0 0 2, 4 0 0 2, 8

FWHP 112 122 133 143 153 155 157 169 182 195 208 219 229 238 248 259 270 282 294 308 323 331 339 347 355 355 355 361 366 370 375 374 373 374 375 379 383 383 383 383 383 383 382 381 380 379 377

HP,TQ,CFM

RPM RWHP RWTQ 2,000 95 250 2,100 104 260 2,200 113 270 2,300 122 278 2,400 130 285 2,500 132 278 2,600 134 270 2,700 144 280 2,800 155 290 2,900 166 300 3,000 177 310 3,100 186 315 3,200 195 320 3,300 203 323 3,400 210 325 3,500 220 330 3,600 230 335 3,700 240 340 3,800 250 345 3,900 262 353 4,000 274 360 4,100 281 360 4,200 288 360 4,300 295 360 4,400 302 360 4,500 302 353 4,600 302 345 4,700 307 343 4,800 311 340 4,900 315 338 5,000 319 335 5,100 318 328 5,200 317 320 5,300 318 315 5,400 319 310 5,500 322 308 5,600 325 305 5,700 326 300 5,800 326 295 5,900 326 290 6,000 326 285 6,100 325 280 6,200 325 275 6,300 324 270 6,400 323 265 6,500 322 260 6,600 320 255 318 AVG 2-4.8k 211 316 AVG 2k-6k 243 310 AVG 2k-6k 254

The above FWHP & FWTQ use 15% correction factor for a T5 car For automatics and to use 25%, type the word "auto" in this box ->

Z = N2 × S (1 + (1 ÷ 2n)) ÷ 2189 100,000 ft/sec/sec is a safe max

650

650

600

600

550

550

500

500

450

450

400

400

350

350

300

300

250

250

200

200

150

150

100

100

50

50

0

0

2, 0 0 0 2, 4 0 0 2, 8 0 0 3, 2 0 0 3, 6 0 0 4, 0 0 0 4, 4 0 0 4, 8 0 0 5, 2 0 0 5, 6 0 0 6, 0 0 0 6, 4 0 0

HP,TQ,CFM

= Fields to "enter" values = Calculation (No Entries!) Piston Speed = = HP/(displacement*rpm*Comp Ratio/53888.54868) nner CFM = RPMxFWTQ/10798 ake CFM = CIDxRPMxVE/3464 sed on 28" water Piston Speed Data Atmos. Press. Stroke (Inches)(N) 3.00 CID Rod Length (inches)(S) 5.09 CR Rod-Stroke Ratio (n) 1.7

rpm Column D

Column E

Column H

650 600 550 500 450 400 350 300 250 200 150 100 50 0 6, 0 0 0 6, 4 0 0

0

Fuel _ HP Calcs

Green Field

= Fields to "enter" values

Yellow

= Calculation (No Entries!)

NOTE:

HP Calculator

All HP values are Flywheel

Brake Specific Fuel Consumption (BSFC)

Curb weight of car = Added Weight = Weight Driver/Passenger = Gallons of gas = Weight of Gas =

3327 20 210 10 62

Total Car Weight = 1/4 mile Elapsed Time = 1/4 mile MPH =

3619 13.30 102.5

(88 Vert 5spd) (subs,cage,etc) (5.8-6.5#/gal)

Note: Fuel requirements must be based upon flywheel horsepower. Drivetrain losses must be made up for by engine horsepower.

HP Formulas

(5.82)cubed x (car weight) ET based HP = (E.T.) cubed = Speed based HP = (.00426 x mph)cubed x weight = ET for a HP = cube root(5.825 cubed) x (weight)/(HP) Enter HP (weight used from above) = Est.ET=cube root((5.825cubed)xweight/RWHP) (Assumes some tire spin & clutch slip)

304 301

350 12.69

Stick car drivetrain losses normally 11-13% 250-350HP, 15-18% 350-500HP Automatics vary depending on trans and converter

Pete Jackson Gear Drive ET Calculator Enter 1/4 MPH Traction = 103 (Between 90-125)

100%

96%

93%

ET = 12.35 12.86 13.38 (traction = tire spin & clutch/converter slippage)

Calculating EFI Injector and Fuel Requirements Injector Size = ( FWHP 303 X 0.500 BSFC) / Every 10°F coolant temp below 190°F (to 170°F) the EEC increases pulse width 2% Change Flow Rating by Altering Fuel Pressure = Square root (new pressure (Stock 19# injectors can support up to 300 HP at 39# pressure and up to 330 HP at 60#) Maximum Obtainable Horsepower = 24.0 Inj. Flow X Fuel Pump Test Summary (Lph) Pump (Lph) Type Weldon inline Walbro 255 in-tank Bosch 216 inline Airtex inline Walbro 155 inline Walbro 190 in-tank Walbro 155 in-tank

12v 296 212 171 144 129 N/A N/A

(5.0 Mustang Sept. 2001 "Fuel Stream Ahead) 13.5v 17.5v -- (Boost-a-pump volts) 353 441 232 307 207 280 182 244 159 219 143 205 136 199

100% = No gain attainable (Possibly too much gear)

96% = Nominal ET (About right) 93% = Power loss (More gear, traction loss,etc)

(number of injectors) 8 X 0.9 (Injector Duty Cycle) = BSFC - .5 N/A, .6 turbo,.65 supercharge,.70 Nitrous (Normal Range =.8 to .9 ) 42 / 39 old pressure) X 19 Inject rating = (Stock 19# injectors are rated at 39 psi) 8 # Injctr's X 0.8 / 0.56 BSFC = Current

HP 250 270 302

Boosted HP Estimator Boost

New HP

New ET

MPH

6 6 6

352 380 425

12.7 12.3 11.9

108 110 115

This is a rough estimate of the potential power gain from supercharging or turbocharging and uses the weight entered above in the "HP Calculator" column.

21.0 19.7 274

CID =

302

VE (Decimal) =

0.80

Determining Runner Length

L = Runner Length EVCD = Effective Valve Closed Duration

L = ((EVCD x .025 x V x 2) / (RPM x RV)) - ½D

EVCD = 720 - (advertides duration @ .006" - 30 or 20) (use 30 for a race orineted cam and 20 for street cams) RV = Refelctive Wave Value (Use RV = 3 and if runner length is too short use 4, this selects which reflected wave harmonic to tune for) RV = 3

Street Cam Runner Length = Race Cam Runner Length = Other Methods of determination Chrysler 50s mild Flat tappet = Chrysler Update street roller = Boden/Shector Peak TQ @rpm =

V = Pressure Wave Speed (1,300 fps) D = Runner Diameter RPM = Max usable rpm = 6,500 VE (Vol Efficiency) =

Recommended TB Runner Size

To calculate the average diameter for a square runner, input the runner ID dimensions below: Runner Height 2.00

Plenum Volume

Runner Width Square Runner Area = Radius of Equivalent Circle = Equivalent Runner Diameter =

of total cylinder displacement. For higher rpm ranges closer to 7,000-7,500 rpm, the plenum will need to be 10-15% larger. CI Volume 5,000-6,000 rpm = 136 Cubic Centimeters (cc) = 2226 CI Volume 7,000-7,500 rpm = 156 Cubic Centimeters (cc) = 2560

12.9 12.4 14.9

D = Sqrt (CID x VE x RPM) / (V x 1130) TB Runner Inch Diameter = 2.78 TB Runner mm Diameter = 70.6 For engines operating in the 5,000-6,000 rpm range, plenum volume should be about 40-50%

1.20 2.40 0.874 1.75

Advertised Cam Duration @ .006" EVCD Race Cam = EVCD Street Cam = Runner Inside Diameter (from above)

15.1 14.7

272 478 468 1.75

Intake runner Taper To be effective, there should be between 2% and 5% increase in runner area over the runner length. This is often not feasible outside the lower intake in some cases does not help that much as other design variables far out-weigh it.

EFI

PM x RV)) - ½D

Performer RPMI RPMII Victor 5.0 Victor 351-W Holley SM I TF Street Heat TF Track Heat TFS - R TF 351-W

1.02" x 1.85" 1.16" x 2.00" 2.58sqin section 1.16" x 1.96" 1.20" x 2.00" 2.94sqin section 1.14" x 2.11" 1.20" x 2.00" 1.20" x 2.00" 1.20" x 2.00" (1.38" x 2.38" @ upper) 1.20" x 2.00" (1.38" x 2.38" @ upper)

Carb

000-6,000 rpm e about 40-50%

For higher rpm m, the plenum

between 2%

feasible outside does not help that far out-weigh it.

Performer 302 Performer 351-W RPM 302 RPM 351-W RPM Air Gap 302 RPM 351-W Air Gap Victor Jr 302 Victor Jr 351-W Super Victor 302 Super Victor 351-W

.90" x 1.90" 1.10" x 1.80" 1.05" x 1.86" 1.12" x 1.86" 1.04" x 1.85" 1.07" x 1.88" 1.08" x 1.90" (1.25 x 2.10 max port) 1.10" x 1.90" 2.70sqin section 1.18" x 2.00" 3.1sqin section 1.18" x 2.00" 3.2sqin section

1250 - 1.20"x2.00" 1250 - 1.20"x2.00" 1250 - 1.20"x2.00" 1262 - 1.28x2.100 1262 - 1.28x2.100

14.5" 13.25" 13.25" 11.5" 12.5" 15" 14" gen1, 13" gen2 12.2" 13.3"

idle - 5,500 1,500 - 6,500 7,500 7,500 idle - 6,200 1,500 - 6,700 2,500 - 7,250 1,000-6,200 idle - 5,500 idle - 5,500 1.500 - 6,500 1.500 - 6,500 1.500 - 6,500 1.500 - 6,500 3,500 - 8,000 3,500 - 7,500 4,500 - 9,000 4,500 - 8,500

75mm 75mm 75mm 75mm

Figuring Cross-Sectional Area Needed Bore 4.0300 Stroke 3.2500 RPM 6250 CA required

2.400

Figuring FPS based on RPM and CA Bore 4.030 Stroke 3.250 RPM 6250 CA 2.400 Feet per Second 485

Figuring RPM based on CA and FPS Bore 4.030 Stroke 3.250 FPS 485 CA 1.710

Calculated area based on FPS and RPM Bore 4.030 Stroke 3.250 RPM 6250 FPS 485

RPM limit

Calculated Area

4453

Calculate FPS based on Pitot reading Pitot tube reading in "H20 28 Calculate FPS

350

2.400

Calculate FPS with Flow CFM and CSA CFM at 28"H20 500 Cross-Sectional Area 1.71 F.P.S. 701.75

Valve Diameter Test Pressure " H2O

200 190 180

1.850 28.0 146

Measured Flow

58 121 159 186 190 195 195 0 0 157.7

Discharge coefficient

Effective flow area

Actual flow area

0.342 0.476 0.469 0.439 0.373 0.329 0.287 0.000 0.000 0.388

0.397 0.829 1.089 1.274 1.302 1.336 1.336 0.000 0.000 2.253

1.162 1.743 2.324 2.905 3.485 4.066 4.647 0.000 0.000 2.905

140 130 120 flow

Lift 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000 avg

170 160 150

110 100 90 80 70 60 50 40 30 20 10 0

200 190 180

1.4

170 160 150

1.2

flow

140 130 120 110 100 90 80 70

1.3

1.1 1 0.9 0.8

Column B

0.7

Column C Column E

0.6 0.5

60 50 40

0.4

30 20 10

0.2

0

0.3

0.1 0

Column B

Column C Column E

V8 Compression Calculation Cylinder Bore Gasket Bore Stroke Head Gasket Thickness (compressed) Deck Height (Distance piston "in hole" - neg values mean piston is out-of-the-bore) Head Volume (cc) Variable Volume = Piston Dish (cc) Variable Volume = Piston Valve Reliefs (add all - cc) Variable Volume = Piston Dome (cc) Variable Volume = Valve Pocket (cc) Variable Volume Total = (cc) Gasket Volume (GV in cc) = Bore (in) x Bore (in) x 12.7 x Head Gasket Thickness (in) Below Deck Volume in cc = Bore (in) x Bore (in) x 12.7 x Deck Height (in) Piston Displaced Volume = Bore (in) x Bore (in) x Stroke (in) x 12.7 Compression Ratio = (GV+DV+HV+VV+PV)/(GV+DV+HV+VV) Green Field = Fields to "enter" values Yellow = Calculation (No Entries!)

HV = VV = VV = VV = VV = GV = DV = PV =

4.00 4.10 3.00 0.047 0.000 58.5 0 6 0 0 6 10.03 0 609.6 9.18

Green = enter value in cell

Gear Shift RPM Trans RWTQ RWHP Gear Ratios Final Ratios Reduction 1st-2nd 250 95 1st 3.35 11.89 4,000 256 107 2nd 1.93 6.85 1.74 4,200 265 121 3rd 1.29 4.58 1.496 4,400 274 136 4th 1 3.55 1.290 4,600 285 152 5th 0.68 2.41 1.471 4,800 289 165 5,000 292 178 Axle Ratio 5,200 300 194 3.55 5,400 302 207 The axle gear does not change the trans gear 5,600 299 216 reduction at shifts - it is a constant in all gears. 5,800 296 225 Higher ratios multiply the the final ratio and 6,000 293 234 enable the faster application of torque. 6,200 286 240 6,400 280 245 6,600 271 248 261 248 340 251 249 238 245 320 224 239 210 232 300 200 228 190 224 280 180 219 170 214 260

Resultant RPM 2,304 2,420 2,535 2,650 2,765 2,881 2,996 3,111 3,226 3,341 3,457 3,572 3,687 3,802

240 220 200 180 160 140 120 Row 9

Row 8

Row 7

Row 6

Row 5

Row 4

100 Row 3

Resultant Torque

RPM 2,000 2,200 2,400 2,600 2,800 3,000 3,200 3,400 3,600 3,800 4,000 4,200 4,400 4,600 4,800 5,000 5,200 5,400 5,600 5,800 6,000 6,200 6,400 6,600

Shift RPM Column J

Column M

Column J

Row 9

Row 8

Row 7

Row 6

Row 5

Row 4

Row 3

120

100

Shift RPM

Column M

Shift RPM 2nd-3rd 4,000 4,200 4,400 4,600 4,800 5,000 5,200 5,400 5,600 5,800 6,000 6,200 6,400 6,600

Resultant RPM 2,674 2,807 2,941 3,075 3,208 3,342 3,476 3,609 3,743 3,877 4,010 4,144 4,278 4,411

Resultant HP 145 152 164 168 178 190 200 207 212 220 225 230 235 240

Shift RPM 3rd-4th 4,000 4,200 4,400 4,600 4,800 5,000 5,200 5,400 5,600 5,800 6,000 6,200 6,400 6,600

Resultant RPM 3,101 3,256 3,411 3,566 3,721 3,876 4,031 4,186 4,341 4,496 4,651 4,806 4,961 5,116

Resultant HP 171 186 195 204 211 220 225 232 238 243 246 248 248 249

INSTRUCTIONS: Use your dyno curve to p fields in the far left colum transmission and axle da The "Shift RPM" and "Re will then populate to sho be at after the shift. Now data and insert the HP y after shift rpm in the "Re The graph will show the curve after the shift and experimenting with shift higher than your peak H to maximize average HP If you cannot rpm 10% o maximize the average H

Shift RPM Column J

Column M

Column P

Row 16

Row 15

Row 14

Row 13

Row 12

Row 11

Row 10

Row 9

The best shift point is a b want to wind the engine hit maximum average HP want to shift too short an HP curve.

Row 8

Row 7

Resultant HP 110 121 132 138 150 158 165 171 178 186 200 205 212 216

Shift RPM

Column J Column M Column P

Row 16

Row 15

Row 14

Row 13

Row 12

Row 11

Row 10

Row 9

Row 8

Row 7

INSTRUCTIONS: Use your dyno curve to populate the green fields in the far left column. Then enter your transmission and axle data in the next column. The "Shift RPM" and "Resultant HP" fields will then populate to show what rpm you will be at after the shift. Now, go to your dyno data and insert the HP you made at that after shift rpm in the "Resultant HP" column. The graph will show the shape of your HP curve after the shift and you want to start experimenting with shift points that are ~10% higher than your peak HP point. You want to maximize average HP over the usable rpm range. If you cannot rpm 10% over the HP peak, then maximize the average HP. The best shift point is a balancing act. You don't want to wind the engine too far beyond peak HP to hit maximum average HP, but you also do not want to shift too short and fall too far down the HP curve.

Ideal Header Sizing Area of Primary Pipe = RPM × Motor Size ÷ 705,600 (assumes 18ga walls - .049") Pipe ID2 = RPM × Motor Size ÷ 705,600 ÷ .7854 ID = (RPM × Motor Size ÷ 554,177).5 Pipe ID2 = RPM × Motor Size ÷ 554,177 ID = (RPM × Motor Size ÷ 554,177).5 OD = (RPM × Motor Size ÷ 554,177).5 + .098” Calculate Header Primary Length Ideal Primary Length 46" 42.5" 39.2" 36.4" 34" 39.5" 36.2" 33.4" 31" 29" 34" 31.2" 28.8" 26.75" 25" 26" 23.9" 22" 20.5" 19.1" 50.8" 46.6" 43" 39.9" 37.3"

CID

RPM

Tube OD

302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 331 331 331 331 331

5,500 6,000 6,500 7,000 7,500 5,500 6,000 6,500 7,000 7,500 5,500 6,000 6,500 7,000 7,500 5,500 6,000 6,500 7,000 7,500 5,500 6,000 6,500 7,000 7,500

1.5" 1.5" 1.5" 1.5" 1.5" 1.625" 1.625" 1.625" 1.625" 1.625" 1.75" 1.75" 1.75" 1.75" 1.75" 2.00" 2.00" 2.00" 2.00" 2.00" 1.5" 1.5" 1.5" 1.5" 1.5"

Ideal Primary Length 43.3" 39.7" 36.6" 34" 31.8" 37.3" 34.2" 31.6" 29.3" 27.3" 28.6" 26.2" 24.2" 22.5" 21" 39.1" 35.9" 33.1' 30.8" 28.7" 30" 27.5" 25.4" 23.5" 22"

walls - .049")

302

Motor CID

6500

Max RPM

Race

1.98

O.D.

Street

1.78

Race

1.88

I.D.

Street

1.69

r Primary Length -

http://www.thedirtforum.com/headercalc.htm

rimary Length

CID

RPM

Tube OD

331 331 331 331 331 331 331 331 331 331 331 331 331 331 331 347 347 347 347 347 347 347 347 347 347

5,500 6,000 6,500 7,000 7,500 5,500 6,000 6,500 7,000 7,500 5,500 6,000 6,500 7,000 7,500 5,500 6,000 6,500 7,000 7,500 5,500 6,000 6,500 7,000 7,500

1.625" 1.625" 1.625" 1.625" 1.625" 1.75" 1.75" 1.75" 1.75" 1.75" 2.00" 2.00" 2.00" 2.00" 2.00" 1.75 1.75 1.75 1.75 1.75 2.00" 2.00" 2.00" 2.00" 2.00"

Calculating Piston Speed Z = N2 × S (1 + (1 ÷ 2n)) ÷ 2189 RPM Stroke (Inches)(N) Rod Length (inches)(S) Rod-Stroke Ratio (n)

6,250 3.00 5.09 1.7

Z = Piston Speed in Ft/Sec/Sec Z= 96,089

A safe limit for “Z” is about 100,000 f/s squ

this will cause ring flutter with 1/16” compres

Long-rod motors (“n” = 1.75 to 2.1-1) will have the piston closer to TDC than the short-rod motor at any point between 90° BT will have the piston closer to BDC than the long-rod motor at any point between 90° BBDC & 90° ABDC

Short-rod motors have slower piston movement upwards away from BDC on the compression stroke, and will capture This makes them more tolerant of extended (late intake closure) cam timing.

ston Speed in Ft/Sec/Sec

mit for “Z” is about 100,000 f/s squared, although .

ause ring flutter with 1/16” compression rings.

motor at any point between 90° BTDC & 90° ATDC. Short-rod motors (“n” = 1.4 to 1.75-1)

n stroke, and will capture more mixture at the same point of intake valve closure.

Use .006" or .050" Lift Data in the Duration Cells ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) = IVC (ABDC) = EVO (BBDC) = EVC (ATDC) = Overlap = ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) = IVC (ABDC) = EVO (BBDC) = EVC (ATDC) = Overlap = ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) = IVC (ABDC) = EVO (BBDC) = EVC (ATDC) = Overlap = ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) = IVC (ABDC) = EVO (BBDC) = EVC (ATDC) = Overlap =

115 Stock 85-88 cam 115 .444/.444 lift 0 266 266 115 (ICL - (Dur/2)) + (Installed Advance) = 18 ((Dur - IVO) - 180) = 68 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 68 ((Dur - EVO)) - 180) = 18 36.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) 113 112.5

My 88 Cam

.050" events 267 219 262 212.5 112.5 (ICL - (Dur/2)) + (Installed Advance) = 20.5 ((Dur - IVO) - 180) = 66.5 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 63.5 ((Dur - EVO)) - 180) = 18.5 39.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) 110 118

270H-R14 (35-310-8) (4° advance ground in) .533/.544 lift

270 276 114 (ICL - (Dur/2)) + (Installed Advance) = 25 ((Dur - IVO) - 180) = 65 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 76 ((Dur - EVO)) - 180) = 20 45.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) 110 118

XE264HR (35-308-8) (4° advance ground in) .533/.533 lift

266 270 114 (ICL - (Dur/2)) + (Installed Advance) = 23 ((Dur - IVO) - 180) = 63 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 73 ((Dur - EVO)) - 180) = 17 40.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

ICL = Intake Center Line,ECL = Exhaust Center Line ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) = IVC (ABDC) = EVO (BBDC) = EVC (ATDC) = Overlap = ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) = IVC (ABDC) = EVO (BBDC) = EVC (ATDC) = Overlap = ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) = IVC (ABDC) = EVO (BBDC) = EVC (ATDC) = Overlap = ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) = IVC (ABDC) = EVO (BBDC) = EVC (ATDC) = Overlap =

116 Stock 89-93 cam 115 .444/.444 lift 0 276 266 115 (ICL - (Dur/2)) + (Installed Advance) = 22 ((Dur - IVO) - 180) = 74 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 68 ((Dur - EVO)) - 180) = 18 40.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) 110 118

Crower 15511 (4° advance ground in) .468/.486 lift 218 224

278 282 114 (ICL - (Dur/2)) + (Installed Advance) = 29 ((Dur - IVO) - 180) = 69 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 79 ((Dur - EVO)) - 180) = 23 52.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) 110 118

270AH-R14 (35-304-8) (4° advance ground in) .533/.533 lift

270 284 114 (ICL - (Dur/2)) + (Installed Advance) = 25 ((Dur - IVO) - 180) = 65 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 80 ((Dur - EVO)) - 180) = 24 49.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) 110 118

XE264HR (35-349-8) (4° advance ground in) .512/.512 lift

264 270 114 (ICL - (Dur/2)) + (Installed Advance) = 22 ((Dur - IVO) - 180) = 62 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 73 ((Dur - EVO)) - 180) = 17 39.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

haust Center Line

Yellow = Calculation (No Entries!)

Stock 89-93 cam

ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) =

)) + (Installed Advance)

115 121.5 0 270 270

Green Field = Fields to "enter" values Cobra cam .479/.479 (1.7 RR)

(ICL - (Dur/2)) + (Installed Advance) 20 ((Dur - IVO) - 180) = 70 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 76.5 ((Dur - EVO)) - 180) = 13.5 33.5 ((I Dur/2)-ICL)+((E Dur/2)-ECL) =

IVC (ABDC) =

r/2)) - 180) + (Installed Advance)

EVO (BBDC) = EVC (ATDC) =

((I Dur/2)-ICL)+((E Dur/2)-ECL)

Overlap =

Crower 15511 (4° advance ground in)

ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) =

)) + (Installed Advance)

IVC (ABDC) =

r/2)) - 180) + (Installed Advance)

EVO (BBDC) = EVC (ATDC) =

((I Dur/2)-ICL)+((E Dur/2)-ECL)

Overlap =

270AH-R14 (35-304-8) (4° advance ground in)

ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) =

)) + (Installed Advance)

IVC (ABDC) =

r/2)) - 180) + (Installed Advance)

EVO (BBDC) = EVC (ATDC) =

((I Dur/2)-ICL)+((E Dur/2)-ECL)

Overlap =

XE264HR (35-349-8) (4° advance ground in)

ICL = ECL = Installed Advance Intake Duration Exhaust Duration Lobe Seperation IVO (BTDC) =

)) + (Installed Advance)

IVC (ABDC) =

r/2)) - 180) + (Installed Advance)

EVO (BBDC) = EVC (ATDC) =

((I Dur/2)-ICL)+((E Dur/2)-ECL)

Overlap =

108 Crower 15510 116 (4° advance ground in) 0 .531/.531 lift 275 212 @ .050" 275 212 @ .050" 112 (ICL - (Dur/2)) + (Installed Advance) = 29.5 ((Dur - IVO) - 180) = 65.5 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 73.5 ((Dur - EVO)) - 180) = 21.5 51.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) 110 118

XE270HR-14 (35-351-8) (4° advance ground in) .512/.512 lift

270 276 114 (ICL - (Dur/2)) + (Installed Advance) = 25 ((Dur - IVO) - 180) = 65 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 76 ((Dur - EVO)) - 180) = 20 45.0 ((I Dur/2)-ICL)+((E Dur/2)-ECL) 113 my 88 cam .050" events 112 4 219 212.5 112.5 (ICL - (Dur/2)) + (Installed Advance) = 0.5 ((Dur - IVO) - 180) = 38.5 ((ECL + (Dur/2)) - 180) + (Installed Advance) = 43.5 ((Dur - EVO)) - 180) = -11 -9.3 ((I Dur/2)-ICL)+((E Dur/2)-ECL)

Volume - Pressure Index Calculations

Description Limit of engine speed based on the stress of the reciprocating components P = piston speed in fpm, S = stroke in inches, R = engine rpm Method of calculating max RPM based on the point of fastest piston acceleration - takes into account rod length (longer rods improve the safe RPM slightly) Z = piston speed in fps/s, N = rpm, S = stroke inches, n = rod-to-stroke ratio Calculate piston positions SE = effecctive stroke, S = Full Stroke, R = rod length, A = crankshaft angle degrees ABDC 0-90 degrees Nominal cylinder volume VN = nominal cylinder volume, B = bore, S = stroke Effective cylinder volume VE = effective cylinder volume, B = bore, SE = effecctive stroke Nominal compression ratio CRN = nominal compresion ratio, VN = nominal cylinder volume, VC = chamber volume Effective compression ratio CRE = effective compression ratio, VE = effective cylinder volume, VC = chamber volume Chamber volume VC = chamber volume, VN = nominal cylinder volume, CRN = nominal compression ratio Absolute cranking pressure CP = cranking pressure, CRE = effecctive compression ratio, AP = atmosheric pressure Gauge pressure GP = guage pressure, CRE = effective compression ratio, AP = atmospheric pressure Volume pressure index V/P = volume pressure index, CP = cranking pressure, VE = effective cylinder volume, N = number of cylinders

Bore Stroke Rod/stroke ratio Rod length Atmospheric pressure # cylinders Max rpm

Formula P=S×R÷6

nches, R = engine rpm Z = N2 × S (1 + (1 ÷ 2n)) ÷ 2189

stroke inches, n = rod-to-stroke ratio SE = (S ÷ 2) + R + ((S ÷ 2) × cosA) - SQRT ((R 2) - ((S ÷ 2) × sinA)2) R = rod length, A = crankshaft angle degrees ABDC 0-90 degrees VN = B2 × S × .7854 e, S = stroke VE = B2 × SE × .7854 e, SE = effecctive stroke CRN = (VN + VC) ÷ VC nominal cylinder volume, VC = chamber volume CRE = (VE + VC) ÷ VC = effective cylinder volume, VC = chamber volume VC = VN ÷ (CRN - 1) ylinder volume, CRN = nominal compression ratio CP = (CRE1.2 × AP) ive compression ratio, AP = atmosheric pressure GP = (CRE1.2 × AP) - AP compression ratio, AP = atmospheric pressure V/P = CP × VE × N × .3% nking pressure, VE = effective cylinder volume, N = number of cylinders

4.00 3.00 1.70 5.09 14.70 8 6250

Total VN 301.59 Total VE 277.50 P

S

3,125

3.00

Z

N

69,280

6250

SE 2.76 VN 37.70 VE 34.69 CRN 9.99 CRE 9.27 VC 4.19 CP 212.85 GP 198.15 V/P 354.40

S 3.00 B 4.000 B 4.000 VN 37.70 VE 34.69 VN 37.70 CRE 9.27 CRE 9.27 CP 212.85

Enter data in these fields Cylinder VN 37.70 Cylinder VE 34.69 effective swept volume, i.e. intake valve closing event @ A below R 6250 S

n

3.00

1.70

R 5.09 S 3.00 SE 2.76 VC 4.19 VC 4.19 CRN 9.99 AP 14.70 AP 14.70 VE 34.69

A 38.50

(piston position ABDC)

(find this two rows above to the left)

N 8