Please refer to the other sticky for links where the credit is due 
. I will list different figures for the STOCK BORE 1JZ engine as that is what most people who have one are using. Information on the bore and stroke of the 1JZ was gathered through a SEARCH that took 10 seconds. The numbers where found in this link and the link to another site provided therein: http://www.supramania.com/forums/showthread.php?t=43289&highlight=bore+stroke+1jz
If you would like an overbore equation made up, please PM me with the bore of the aftermarket piston and link to the info on it to back up the proof.
10psi (1.68027210884)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 1.680272109 ---- 14.472
2500 ---- 87.96296296 ---- 147.8017133 ---- 10.21294315
2750 ---- 96.75925926 ---- 162.5818846 ---- 11.23423747
3000 ---- 105.5555556 ---- 177.3620559 ---- 12.25553178
3250 ---- 114.3518519 ---- 192.1422273 ---- 13.2768261
3500 ---- 123.1481481 ---- 206.9223986 ---- 14.29812041
3750 ---- 131.9444444 ---- 221.7025699 ---- 15.31941473
4000 ---- 140.7407407 ---- 236.4827412 ---- 16.34070904
4250 ---- 149.5370370 ---- 251.2629126 ---- 17.36200336
4500 ---- 158.3333333 ---- 266.0430839 ---- 18.38329767
4750 ---- 167.1296296 ---- 280.8232552 ---- 19.40459199
5000 ---- 175.9259259 ---- 295.6034266 ---- 20.4258863
5250 ---- 184.7222222 ---- 310.3835979 ---- 21.44718062
5500 ---- 193.5185185 ---- 325.1637692 ---- 22.46847493
5750 ---- 202.3148148 ---- 339.9439405 ---- 23.48976925
6000 ---- 211.1111111 ---- 354.7241119 ---- 24.51106356
6250 ---- 219.9074074 ---- 369.5042832 ---- 25.53235788
6500 ---- 228.7037037 ---- 384.2844545 ---- 26.55365219
6750 ---- 237.5000000 ---- 399.0646258 ---- 27.57494651
7000 ---- 246.2962963 ---- 413.8447972 ---- 28.59624082
7250 ---- 255.0925926 ---- 428.6249685 ---- 29.61753514
7500 ---- 263.8888889 ---- 443.4051398 ---- 30.63882945
7750 ---- 272.6851852 ---- 458.1853112 ---- 31.66012377
8000 ---- 281.4814815 ---- 472.9654825 ---- 32.68141808
8250 ---- 290.2777778 ---- 487.7456538 ---- 33.7027124
8500 ---- 299.0740741 ---- 502.5258251 ---- 34.72400671
13psi (1.88435374149)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 1.884353741 ---- 14.472
2500 ---- 87.96296296 ---- 165.7533384 ---- 11.45338159
2750 ---- 96.75925926 ---- 182.3286722 ---- 12.59871975
3000 ---- 105.5555556 ---- 198.9040060 ---- 13.74405791
3250 ---- 114.3518519 ---- 215.4793399 ---- 14.88939607
3500 ---- 123.1481481 ---- 232.0546737 ---- 16.03473423
3750 ---- 131.9444444 ---- 248.6300076 ---- 17.18007239
4000 ---- 140.7407407 ---- 265.2053414 ---- 18.32541054
4250 ---- 149.5370370 ---- 281.7806752 ---- 19.4707487
4500 ---- 158.3333333 ---- 298.3560091 ---- 20.61608686
4750 ---- 167.1296296 ---- 314.9313429 ---- 21.76142502
5000 ---- 175.9259259 ---- 331.5066767 ---- 22.90676318
5250 ---- 184.7222222 ---- 348.0820106 ---- 24.05210134
5500 ---- 193.5185185 ---- 364.6573444 ---- 25.1974395
5750 ---- 202.3148148 ---- 381.2326783 ---- 26.34277766
6000 ---- 211.1111111 ---- 397.8080121 ---- 27.48811582
6250 ---- 219.9074074 ---- 414.3833459 ---- 28.63345398
6500 ---- 228.7037037 ---- 430.9586798 ---- 29.77879213
6750 ---- 237.5000000 ---- 447.5340136 ---- 30.92413029
7000 ---- 246.2962963 ---- 464.1093474 ---- 32.06946845
7250 ---- 255.0925926 ---- 480.6846813 ---- 33.21480661
7500 ---- 263.8888889 ---- 497.2600151 ---- 34.36014477
7750 ---- 272.6851852 ---- 513.8353490 ---- 35.50548293
8000 ---- 281.4814815 ---- 530.4106828 ---- 36.65082109
8250 ---- 290.2777778 ---- 546.9860166 ---- 37.79615925
8500 ---- 299.0740741 ---- 563.5613505 ---- 38.94149741
15psi (2.02040816326)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 2.020408163 ---- 14.472
2500 ---- 87.96296296 ---- 177.7210884 ---- 12.28034055
2750 ---- 96.75925926 ---- 195.4931973 ---- 13.5083746
3000 ---- 105.5555556 ---- 213.2653061 ---- 14.73640866
3250 ---- 114.3518519 ---- 231.0374150 ---- 15.96444271
3500 ---- 123.1481481 ---- 248.8095238 ---- 17.19247677
3750 ---- 131.9444444 ---- 266.5816327 ---- 18.42051082
4000 ---- 140.7407407 ---- 284.3537415 ---- 19.64854488
4250 ---- 149.5370370 ---- 302.1258503 ---- 20.87657893
4500 ---- 158.3333333 ---- 319.8979592 ---- 22.10461299
4750 ---- 167.1296296 ---- 337.6700680 ---- 23.33264704
5000 ---- 175.9259259 ---- 355.4421769 ---- 24.5606811
5250 ---- 184.7222222 ---- 373.2142857 ---- 25.78871515
5500 ---- 193.5185185 ---- 390.9863946 ---- 27.01674921
5750 ---- 202.3148148 ---- 408.7585034 ---- 28.24478326
6000 ---- 211.1111111 ---- 426.5306122 ---- 29.47281732
6250 ---- 219.9074074 ---- 444.3027211 ---- 30.70085137
6500 ---- 228.7037037 ---- 462.0748299 ---- 31.92888543
6750 ---- 237.5000000 ---- 479.8469388 ---- 33.15691948
7000 ---- 246.2962963 ---- 497.6190476 ---- 34.38495354
7250 ---- 255.0925926 ---- 515.3911565 ---- 35.61298759
7500 ---- 263.8888889 ---- 533.1632653 ---- 36.84102165
7750 ---- 272.6851852 ---- 550.9353741 ---- 38.0690557
8000 ---- 281.4814815 ---- 568.7074830 ---- 39.29708976
8250 ---- 290.2777778 ---- 586.4795918 ---- 40.52512381
8500 ---- 299.0740741 ---- 604.2517007 ---- 41.75315787
18psi (2.22448979591)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 2.224489796 ---- 14.472
2500 ---- 87.96296296 ---- 195.6727135 ---- 13.52077899
2750 ---- 96.75925926 ---- 215.2399849 ---- 14.87285689
3000 ---- 105.5555556 ---- 234.8072562 ---- 16.22493479
3250 ---- 114.3518519 ---- 254.3745276 ---- 17.57701269
3500 ---- 123.1481481 ---- 273.9417989 ---- 18.92909058
3750 ---- 131.9444444 ---- 293.5090703 ---- 20.28116848
4000 ---- 140.7407407 ---- 313.0763416 ---- 21.63324638
4250 ---- 149.5370370 ---- 332.6436130 ---- 22.98532428
4500 ---- 158.3333333 ---- 352.2108844 ---- 24.33740218
4750 ---- 167.1296296 ---- 371.7781557 ---- 25.68948008
5000 ---- 175.9259259 ---- 391.3454271 ---- 27.04155798
5250 ---- 184.7222222 ---- 410.9126984 ---- 28.39363588
5500 ---- 193.5185185 ---- 430.4799698 ---- 29.74571378
5750 ---- 202.3148148 ---- 450.0472411 ---- 31.09779167
6000 ---- 211.1111111 ---- 469.6145125 ---- 32.44986957
6250 ---- 219.9074074 ---- 489.1817838 ---- 33.80194747
6500 ---- 228.7037037 ---- 508.7490552 ---- 35.15402537
6750 ---- 237.5000000 ---- 528.3163265 ---- 36.50610327
7000 ---- 246.2962963 ---- 547.8835979 ---- 37.85818117
7250 ---- 255.0925926 ---- 567.4508692 ---- 39.21025907
7500 ---- 263.8888889 ---- 587.0181406 ---- 40.56233697
7750 ---- 272.6851852 ---- 606.5854119 ---- 41.91441487
8000 ---- 281.4814815 ---- 626.1526833 ---- 43.26649276
8250 ---- 290.2777778 ---- 645.7199546 ---- 44.61857066
8500 ---- 299.0740741 ---- 665.2872260 ---- 45.97064856
20psi (2.36054421768)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 2.360544218 ---- 14.472
2500 ---- 87.96296296 ---- 207.6404636 ---- 14.34773795
2750 ---- 96.75925926 ---- 228.4045100 ---- 15.78251174
3000 ---- 105.5555556 ---- 249.1685563 ---- 17.21728554
3250 ---- 114.3518519 ---- 269.9326027 ---- 18.65205933
3500 ---- 123.1481481 ---- 290.6966490 ---- 20.08683313
3750 ---- 131.9444444 ---- 311.4606954 ---- 21.52160692
4000 ---- 140.7407407 ---- 332.2247417 ---- 22.95638072
4250 ---- 149.5370370 ---- 352.9887881 ---- 24.39115451
4500 ---- 158.3333333 ---- 373.7528345 ---- 25.82592831
4750 ---- 167.1296296 ---- 394.5168808 ---- 27.2607021
5000 ---- 175.9259259 ---- 415.2809272 ---- 28.6954759
5250 ---- 184.7222222 ---- 436.0449735 ---- 30.13024969
5500 ---- 193.5185185 ---- 456.8090199 ---- 31.56502349
5750 ---- 202.3148148 ---- 477.5730663 ---- 32.99979728
6000 ---- 211.1111111 ---- 498.3371126 ---- 34.43457108
6250 ---- 219.9074074 ---- 519.1011590 ---- 35.86934487
6500 ---- 228.7037037 ---- 539.8652053 ---- 37.30411867
6750 ---- 237.5000000 ---- 560.6292517 ---- 38.73889246
7000 ---- 246.2962963 ---- 581.3932981 ---- 40.17366626
7250 ---- 255.0925926 ---- 602.1573444 ---- 41.60844005
7500 ---- 263.8888889 ---- 622.9213908 ---- 43.04321385
7750 ---- 272.6851852 ---- 643.6854371 ---- 44.47798764
8000 ---- 281.4814815 ---- 664.4494835 ---- 45.91276144
8250 ---- 290.2777778 ---- 685.2135299 ---- 47.34753523
8500 ---- 299.0740741 ---- 705.9775762 ---- 48.78230903
23psi (2.56462585034)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 2.56462585 ---- 14.472
2500 ---- 87.96296296 ---- 225.5920887 ---- 15.58817639
2750 ---- 96.75925926 ---- 248.1512976 ---- 17.14699403
3000 ---- 105.5555556 ---- 270.7105064 ---- 18.70581167
3250 ---- 114.3518519 ---- 293.2697153 ---- 20.2646293
3500 ---- 123.1481481 ---- 315.8289242 ---- 21.82344694
3750 ---- 131.9444444 ---- 338.3881330 ---- 23.38226458
4000 ---- 140.7407407 ---- 360.9473419 ---- 24.94108222
4250 ---- 149.5370370 ---- 383.5065508 ---- 26.49989986
4500 ---- 158.3333333 ---- 406.0657596 ---- 28.0587175
4750 ---- 167.1296296 ---- 428.6249685 ---- 29.61753514
5000 ---- 175.9259259 ---- 451.1841774 ---- 31.17635278
5250 ---- 184.7222222 ---- 473.7433862 ---- 32.73517041
5500 ---- 193.5185185 ---- 496.3025951 ---- 34.29398805
5750 ---- 202.3148148 ---- 518.8618040 ---- 35.85280569
6000 ---- 211.1111111 ---- 541.4210128 ---- 37.41162333
6250 ---- 219.9074074 ---- 563.9802217 ---- 38.97044097
6500 ---- 228.7037037 ---- 586.5394306 ---- 40.52925861
6750 ---- 237.5000000 ---- 609.0986395 ---- 42.08807625
7000 ---- 246.2962963 ---- 631.6578483 ---- 43.64689389
7250 ---- 255.0925926 ---- 654.2170572 ---- 45.20571153
7500 ---- 263.8888889 ---- 676.7762661 ---- 46.76452916
7750 ---- 272.6851852 ---- 699.3354749 ---- 48.3233468
8000 ---- 281.4814815 ---- 721.8946838 ---- 49.88216444
8250 ---- 290.2777778 ---- 744.4538927 ---- 51.44098208
8500 ---- 299.0740741 ---- 767.0131015 ---- 52.99979972
25psi (2.7006802721)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 2.700680272 ---- 14.472
2500 ---- 87.96296296 ---- 237.5598387 ---- 16.41513535
2750 ---- 96.75925926 ---- 261.3158226 ---- 18.05664888
3000 ---- 105.5555556 ---- 285.0718065 ---- 19.69816242
3250 ---- 114.3518519 ---- 308.8277904 ---- 21.33967595
3500 ---- 123.1481481 ---- 332.5837742 ---- 22.98118949
3750 ---- 131.9444444 ---- 356.3397581 ---- 24.62270302
4000 ---- 140.7407407 ---- 380.0957420 ---- 26.26421656
4250 ---- 149.5370370 ---- 403.8517259 ---- 27.90573009
4500 ---- 158.3333333 ---- 427.6077097 ---- 29.54724363
4750 ---- 167.1296296 ---- 451.3636936 ---- 31.18875716
5000 ---- 175.9259259 ---- 475.1196775 ---- 32.8302707
5250 ---- 184.7222222 ---- 498.8756614 ---- 34.47178423
5500 ---- 193.5185185 ---- 522.6316452 ---- 36.11329776
5750 ---- 202.3148148 ---- 546.3876291 ---- 37.7548113
6000 ---- 211.1111111 ---- 570.1436130 ---- 39.39632483
6250 ---- 219.9074074 ---- 593.8995969 ---- 41.03783837
6500 ---- 228.7037037 ---- 617.6555807 ---- 42.6793519
6750 ---- 237.5000000 ---- 641.4115646 ---- 44.32086544
7000 ---- 246.2962963 ---- 665.1675485 ---- 45.96237897
7250 ---- 255.0925926 ---- 688.9235324 ---- 47.60389251
7500 ---- 263.8888889 ---- 712.6795162 ---- 49.24540604
7750 ---- 272.6851852 ---- 736.4355001 ---- 50.88691958
8000 ---- 281.4814815 ---- 760.1914840 ---- 52.52843311
8250 ---- 290.2777778 ---- 783.9474679 ---- 54.16994665
8500 ---- 299.0740741 ---- 807.7034517 ---- 55.81146018
To calculate what diameter piping is best for your setup, plug in these numbers for the specific RPMs that you are curious about in this link: http://not2fast.com/gasflow/velocity.shtml
For example: Let's say that the peak power of this specific 1JZ is around 6500 RPMs at 20 psi. Using an intake temp of 75 degrees and 2.5" piping, that will give you 263.9 ft/sec velocity with a psig of 0.57. You are reving the engin to 7250 RPM's in this specific setup so velocity is 294.3 ft/sec and psig is 0.72 with the 2.5" piping. A tip from a well respected member on here is to have a throttle body that is typically .5" larger than you intake piping since they do not flow the same as straight through piping. This is all assuming that 2.5" is the smallest piping comming of your turbo (s). There is still more room to grow with on the 2.5" piping in the 1JZ. Bumping boost up to 23psi will yeild 286.7 ft/sec at 6500 RPM with a psig of 0.68, and the same sized piping, and 319.8 ft/sec at 7250 RPM. The threshold of critical velocity has been breached, but not by much. Notice that the psig is 0.84? Not bad, but it was starting to climb fast after passing 300 ft/sec.
. I will list different figures for the STOCK BORE 1JZ engine as that is what most people who have one are using. Information on the bore and stroke of the 1JZ was gathered through a SEARCH that took 10 seconds. The numbers where found in this link and the link to another site provided therein: http://www.supramania.com/forums/showthread.php?t=43289&highlight=bore+stroke+1jz If you would like an overbore equation made up, please PM me with the bore of the aftermarket piston and link to the info on it to back up the proof
.10psi (1.68027210884)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 1.680272109 ---- 14.472
2500 ---- 87.96296296 ---- 147.8017133 ---- 10.21294315
2750 ---- 96.75925926 ---- 162.5818846 ---- 11.23423747
3000 ---- 105.5555556 ---- 177.3620559 ---- 12.25553178
3250 ---- 114.3518519 ---- 192.1422273 ---- 13.2768261
3500 ---- 123.1481481 ---- 206.9223986 ---- 14.29812041
3750 ---- 131.9444444 ---- 221.7025699 ---- 15.31941473
4000 ---- 140.7407407 ---- 236.4827412 ---- 16.34070904
4250 ---- 149.5370370 ---- 251.2629126 ---- 17.36200336
4500 ---- 158.3333333 ---- 266.0430839 ---- 18.38329767
4750 ---- 167.1296296 ---- 280.8232552 ---- 19.40459199
5000 ---- 175.9259259 ---- 295.6034266 ---- 20.4258863
5250 ---- 184.7222222 ---- 310.3835979 ---- 21.44718062
5500 ---- 193.5185185 ---- 325.1637692 ---- 22.46847493
5750 ---- 202.3148148 ---- 339.9439405 ---- 23.48976925
6000 ---- 211.1111111 ---- 354.7241119 ---- 24.51106356
6250 ---- 219.9074074 ---- 369.5042832 ---- 25.53235788
6500 ---- 228.7037037 ---- 384.2844545 ---- 26.55365219
6750 ---- 237.5000000 ---- 399.0646258 ---- 27.57494651
7000 ---- 246.2962963 ---- 413.8447972 ---- 28.59624082
7250 ---- 255.0925926 ---- 428.6249685 ---- 29.61753514
7500 ---- 263.8888889 ---- 443.4051398 ---- 30.63882945
7750 ---- 272.6851852 ---- 458.1853112 ---- 31.66012377
8000 ---- 281.4814815 ---- 472.9654825 ---- 32.68141808
8250 ---- 290.2777778 ---- 487.7456538 ---- 33.7027124
8500 ---- 299.0740741 ---- 502.5258251 ---- 34.72400671
13psi (1.88435374149)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 1.884353741 ---- 14.472
2500 ---- 87.96296296 ---- 165.7533384 ---- 11.45338159
2750 ---- 96.75925926 ---- 182.3286722 ---- 12.59871975
3000 ---- 105.5555556 ---- 198.9040060 ---- 13.74405791
3250 ---- 114.3518519 ---- 215.4793399 ---- 14.88939607
3500 ---- 123.1481481 ---- 232.0546737 ---- 16.03473423
3750 ---- 131.9444444 ---- 248.6300076 ---- 17.18007239
4000 ---- 140.7407407 ---- 265.2053414 ---- 18.32541054
4250 ---- 149.5370370 ---- 281.7806752 ---- 19.4707487
4500 ---- 158.3333333 ---- 298.3560091 ---- 20.61608686
4750 ---- 167.1296296 ---- 314.9313429 ---- 21.76142502
5000 ---- 175.9259259 ---- 331.5066767 ---- 22.90676318
5250 ---- 184.7222222 ---- 348.0820106 ---- 24.05210134
5500 ---- 193.5185185 ---- 364.6573444 ---- 25.1974395
5750 ---- 202.3148148 ---- 381.2326783 ---- 26.34277766
6000 ---- 211.1111111 ---- 397.8080121 ---- 27.48811582
6250 ---- 219.9074074 ---- 414.3833459 ---- 28.63345398
6500 ---- 228.7037037 ---- 430.9586798 ---- 29.77879213
6750 ---- 237.5000000 ---- 447.5340136 ---- 30.92413029
7000 ---- 246.2962963 ---- 464.1093474 ---- 32.06946845
7250 ---- 255.0925926 ---- 480.6846813 ---- 33.21480661
7500 ---- 263.8888889 ---- 497.2600151 ---- 34.36014477
7750 ---- 272.6851852 ---- 513.8353490 ---- 35.50548293
8000 ---- 281.4814815 ---- 530.4106828 ---- 36.65082109
8250 ---- 290.2777778 ---- 546.9860166 ---- 37.79615925
8500 ---- 299.0740741 ---- 563.5613505 ---- 38.94149741
15psi (2.02040816326)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 2.020408163 ---- 14.472
2500 ---- 87.96296296 ---- 177.7210884 ---- 12.28034055
2750 ---- 96.75925926 ---- 195.4931973 ---- 13.5083746
3000 ---- 105.5555556 ---- 213.2653061 ---- 14.73640866
3250 ---- 114.3518519 ---- 231.0374150 ---- 15.96444271
3500 ---- 123.1481481 ---- 248.8095238 ---- 17.19247677
3750 ---- 131.9444444 ---- 266.5816327 ---- 18.42051082
4000 ---- 140.7407407 ---- 284.3537415 ---- 19.64854488
4250 ---- 149.5370370 ---- 302.1258503 ---- 20.87657893
4500 ---- 158.3333333 ---- 319.8979592 ---- 22.10461299
4750 ---- 167.1296296 ---- 337.6700680 ---- 23.33264704
5000 ---- 175.9259259 ---- 355.4421769 ---- 24.5606811
5250 ---- 184.7222222 ---- 373.2142857 ---- 25.78871515
5500 ---- 193.5185185 ---- 390.9863946 ---- 27.01674921
5750 ---- 202.3148148 ---- 408.7585034 ---- 28.24478326
6000 ---- 211.1111111 ---- 426.5306122 ---- 29.47281732
6250 ---- 219.9074074 ---- 444.3027211 ---- 30.70085137
6500 ---- 228.7037037 ---- 462.0748299 ---- 31.92888543
6750 ---- 237.5000000 ---- 479.8469388 ---- 33.15691948
7000 ---- 246.2962963 ---- 497.6190476 ---- 34.38495354
7250 ---- 255.0925926 ---- 515.3911565 ---- 35.61298759
7500 ---- 263.8888889 ---- 533.1632653 ---- 36.84102165
7750 ---- 272.6851852 ---- 550.9353741 ---- 38.0690557
8000 ---- 281.4814815 ---- 568.7074830 ---- 39.29708976
8250 ---- 290.2777778 ---- 586.4795918 ---- 40.52512381
8500 ---- 299.0740741 ---- 604.2517007 ---- 41.75315787
18psi (2.22448979591)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 2.224489796 ---- 14.472
2500 ---- 87.96296296 ---- 195.6727135 ---- 13.52077899
2750 ---- 96.75925926 ---- 215.2399849 ---- 14.87285689
3000 ---- 105.5555556 ---- 234.8072562 ---- 16.22493479
3250 ---- 114.3518519 ---- 254.3745276 ---- 17.57701269
3500 ---- 123.1481481 ---- 273.9417989 ---- 18.92909058
3750 ---- 131.9444444 ---- 293.5090703 ---- 20.28116848
4000 ---- 140.7407407 ---- 313.0763416 ---- 21.63324638
4250 ---- 149.5370370 ---- 332.6436130 ---- 22.98532428
4500 ---- 158.3333333 ---- 352.2108844 ---- 24.33740218
4750 ---- 167.1296296 ---- 371.7781557 ---- 25.68948008
5000 ---- 175.9259259 ---- 391.3454271 ---- 27.04155798
5250 ---- 184.7222222 ---- 410.9126984 ---- 28.39363588
5500 ---- 193.5185185 ---- 430.4799698 ---- 29.74571378
5750 ---- 202.3148148 ---- 450.0472411 ---- 31.09779167
6000 ---- 211.1111111 ---- 469.6145125 ---- 32.44986957
6250 ---- 219.9074074 ---- 489.1817838 ---- 33.80194747
6500 ---- 228.7037037 ---- 508.7490552 ---- 35.15402537
6750 ---- 237.5000000 ---- 528.3163265 ---- 36.50610327
7000 ---- 246.2962963 ---- 547.8835979 ---- 37.85818117
7250 ---- 255.0925926 ---- 567.4508692 ---- 39.21025907
7500 ---- 263.8888889 ---- 587.0181406 ---- 40.56233697
7750 ---- 272.6851852 ---- 606.5854119 ---- 41.91441487
8000 ---- 281.4814815 ---- 626.1526833 ---- 43.26649276
8250 ---- 290.2777778 ---- 645.7199546 ---- 44.61857066
8500 ---- 299.0740741 ---- 665.2872260 ---- 45.97064856
20psi (2.36054421768)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 2.360544218 ---- 14.472
2500 ---- 87.96296296 ---- 207.6404636 ---- 14.34773795
2750 ---- 96.75925926 ---- 228.4045100 ---- 15.78251174
3000 ---- 105.5555556 ---- 249.1685563 ---- 17.21728554
3250 ---- 114.3518519 ---- 269.9326027 ---- 18.65205933
3500 ---- 123.1481481 ---- 290.6966490 ---- 20.08683313
3750 ---- 131.9444444 ---- 311.4606954 ---- 21.52160692
4000 ---- 140.7407407 ---- 332.2247417 ---- 22.95638072
4250 ---- 149.5370370 ---- 352.9887881 ---- 24.39115451
4500 ---- 158.3333333 ---- 373.7528345 ---- 25.82592831
4750 ---- 167.1296296 ---- 394.5168808 ---- 27.2607021
5000 ---- 175.9259259 ---- 415.2809272 ---- 28.6954759
5250 ---- 184.7222222 ---- 436.0449735 ---- 30.13024969
5500 ---- 193.5185185 ---- 456.8090199 ---- 31.56502349
5750 ---- 202.3148148 ---- 477.5730663 ---- 32.99979728
6000 ---- 211.1111111 ---- 498.3371126 ---- 34.43457108
6250 ---- 219.9074074 ---- 519.1011590 ---- 35.86934487
6500 ---- 228.7037037 ---- 539.8652053 ---- 37.30411867
6750 ---- 237.5000000 ---- 560.6292517 ---- 38.73889246
7000 ---- 246.2962963 ---- 581.3932981 ---- 40.17366626
7250 ---- 255.0925926 ---- 602.1573444 ---- 41.60844005
7500 ---- 263.8888889 ---- 622.9213908 ---- 43.04321385
7750 ---- 272.6851852 ---- 643.6854371 ---- 44.47798764
8000 ---- 281.4814815 ---- 664.4494835 ---- 45.91276144
8250 ---- 290.2777778 ---- 685.2135299 ---- 47.34753523
8500 ---- 299.0740741 ---- 705.9775762 ---- 48.78230903
23psi (2.56462585034)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 2.56462585 ---- 14.472
2500 ---- 87.96296296 ---- 225.5920887 ---- 15.58817639
2750 ---- 96.75925926 ---- 248.1512976 ---- 17.14699403
3000 ---- 105.5555556 ---- 270.7105064 ---- 18.70581167
3250 ---- 114.3518519 ---- 293.2697153 ---- 20.2646293
3500 ---- 123.1481481 ---- 315.8289242 ---- 21.82344694
3750 ---- 131.9444444 ---- 338.3881330 ---- 23.38226458
4000 ---- 140.7407407 ---- 360.9473419 ---- 24.94108222
4250 ---- 149.5370370 ---- 383.5065508 ---- 26.49989986
4500 ---- 158.3333333 ---- 406.0657596 ---- 28.0587175
4750 ---- 167.1296296 ---- 428.6249685 ---- 29.61753514
5000 ---- 175.9259259 ---- 451.1841774 ---- 31.17635278
5250 ---- 184.7222222 ---- 473.7433862 ---- 32.73517041
5500 ---- 193.5185185 ---- 496.3025951 ---- 34.29398805
5750 ---- 202.3148148 ---- 518.8618040 ---- 35.85280569
6000 ---- 211.1111111 ---- 541.4210128 ---- 37.41162333
6250 ---- 219.9074074 ---- 563.9802217 ---- 38.97044097
6500 ---- 228.7037037 ---- 586.5394306 ---- 40.52925861
6750 ---- 237.5000000 ---- 609.0986395 ---- 42.08807625
7000 ---- 246.2962963 ---- 631.6578483 ---- 43.64689389
7250 ---- 255.0925926 ---- 654.2170572 ---- 45.20571153
7500 ---- 263.8888889 ---- 676.7762661 ---- 46.76452916
7750 ---- 272.6851852 ---- 699.3354749 ---- 48.3233468
8000 ---- 281.4814815 ---- 721.8946838 ---- 49.88216444
8250 ---- 290.2777778 ---- 744.4538927 ---- 51.44098208
8500 ---- 299.0740741 ---- 767.0131015 ---- 52.99979972
25psi (2.7006802721)
RPM -------- NA ---------- TURBO CFM ------- lb/min
---------------- STOCK BORE 1JZ
---------- 152 Cid -------- 2.700680272 ---- 14.472
2500 ---- 87.96296296 ---- 237.5598387 ---- 16.41513535
2750 ---- 96.75925926 ---- 261.3158226 ---- 18.05664888
3000 ---- 105.5555556 ---- 285.0718065 ---- 19.69816242
3250 ---- 114.3518519 ---- 308.8277904 ---- 21.33967595
3500 ---- 123.1481481 ---- 332.5837742 ---- 22.98118949
3750 ---- 131.9444444 ---- 356.3397581 ---- 24.62270302
4000 ---- 140.7407407 ---- 380.0957420 ---- 26.26421656
4250 ---- 149.5370370 ---- 403.8517259 ---- 27.90573009
4500 ---- 158.3333333 ---- 427.6077097 ---- 29.54724363
4750 ---- 167.1296296 ---- 451.3636936 ---- 31.18875716
5000 ---- 175.9259259 ---- 475.1196775 ---- 32.8302707
5250 ---- 184.7222222 ---- 498.8756614 ---- 34.47178423
5500 ---- 193.5185185 ---- 522.6316452 ---- 36.11329776
5750 ---- 202.3148148 ---- 546.3876291 ---- 37.7548113
6000 ---- 211.1111111 ---- 570.1436130 ---- 39.39632483
6250 ---- 219.9074074 ---- 593.8995969 ---- 41.03783837
6500 ---- 228.7037037 ---- 617.6555807 ---- 42.6793519
6750 ---- 237.5000000 ---- 641.4115646 ---- 44.32086544
7000 ---- 246.2962963 ---- 665.1675485 ---- 45.96237897
7250 ---- 255.0925926 ---- 688.9235324 ---- 47.60389251
7500 ---- 263.8888889 ---- 712.6795162 ---- 49.24540604
7750 ---- 272.6851852 ---- 736.4355001 ---- 50.88691958
8000 ---- 281.4814815 ---- 760.1914840 ---- 52.52843311
8250 ---- 290.2777778 ---- 783.9474679 ---- 54.16994665
8500 ---- 299.0740741 ---- 807.7034517 ---- 55.81146018
To calculate what diameter piping is best for your setup, plug in these numbers for the specific RPMs that you are curious about in this link: http://not2fast.com/gasflow/velocity.shtml
For example: Let's say that the peak power of this specific 1JZ is around 6500 RPMs at 20 psi. Using an intake temp of 75 degrees and 2.5" piping, that will give you 263.9 ft/sec velocity with a psig of 0.57. You are reving the engin to 7250 RPM's in this specific setup so velocity is 294.3 ft/sec and psig is 0.72 with the 2.5" piping. A tip from a well respected member on here is to have a throttle body that is typically .5" larger than you intake piping since they do not flow the same as straight through piping. This is all assuming that 2.5" is the smallest piping comming of your turbo (s). There is still more room to grow with on the 2.5" piping in the 1JZ. Bumping boost up to 23psi will yeild 286.7 ft/sec at 6500 RPM with a psig of 0.68, and the same sized piping, and 319.8 ft/sec at 7250 RPM. The threshold of critical velocity has been breached, but not by much. Notice that the psig is 0.84? Not bad, but it was starting to climb fast after passing 300 ft/sec.
Last edited: