Using Blair to spec a Cam

[maxracesoftware]

Despite the near matching STA's, when all the relevant data is run through EngMod4T and Blair's software, both computed outputs fall way short of the target 900 bhp at the stipulated 7500 rpm.

This is the issue I have with the current "prescribed" STA values, I do not believe the targets for a 2 valve engine should be the same as for a 4 valve engine. And the various 2 valve layouts should each have separate set of target values. As I said before, there are tuners that developed their own values and use it very successfully but do not share. DV probably has the largest database of all by a large percentage but understandably he will not share as he makes his income from it.

Vincenzo :
Intake = 52/86 318 duration 0.972441 Lift 107.0 CL
Exhaust= 88/56 324 duration 1.047244 Lift 106.0 CL
LSA = 106.5 deg
Overlap= 108.0 deg

Despite the near matching STA's, when all the relevant data is run through EngMod4T and Blair's
software, both computed outputs fall way short of the target 900 bhp at the stipulated 7500 rpm.

PipeMax v4.00 calculates an easy 904.9 Peak HP
and can make a lot more HP with Vac-Pump + Lite Oil + Race Oil Pan

Code: Select all

                                  Camshaft = Solid  Roller  Lifter
600 RPM/Sec Dyno Test             Level=10
Peak HorsePower    @  7500 RPM     904.9
Peak Torque Lbs-Ft @  5800 RPM     702.1

i get this from my Time-Area equations ( different equations than Blair )

Intake Time Area TQ Valve Lift = 0.953882      Exhaust Time Area TQ Valve Lift = 0.879506
Intake Time Area HP Valve Lift = 1.047193      Exhaust Time Area HP Valve Lift = 0.940888

for a typical "Race Engine"
Cam Specs might be this instead :

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--------------------------------- Recommended Camshaft Specs at 0.050” inch Lobe Lift -------------
Cam Lobe Separation Angle (LSA)   108.118
Camshaft Intake Valve Lift        0.97629
Camshaft Exhaust Valve Lift       0.88333

Camshaft Intake Duration          272.584
Camshaft Exhaust Duration         292.018
Camshaft Overlap Duration          66.066
* Specs adjusted for ValveTrain Deflection = 0.0000   Intake Lash= 0.0140   Exhaust Lash= 0.0140

This would be for a "Professional Race Engine" type with 11:1 CompRatio
... sort of max-effort with only 11:1 CR and 1 Carb on a Single-Plane Manifold

Code: Select all

535.02108289 Cubic Inches at 7500 RPM with Intake System = 110.62117 % PerCent Volumetric Efficiency
Complete Intake System Flow @28 in. =  428.1298 -to- 458.4661 CFM at 0.97059 Lift (1.00000 % VE Loss)
Cylinder Head  Intake Port Flow @28 in. =  432.0000 -to- 462.6105 CFM at 0.97059 Lift (111.62117 Ve%)
Cylinder Head Exhaust Port Flow @28 in. =  306.0206 -to- 334.9050 CFM at 0.89455 Lift (no Flow Pipe)

Dyno HP Weather Correction Equation = 8•  SAE J607 (June1974) • STP • SuperFlow-FTQ • (Default)
Dyno Correction Factor= 1.0000000     Fuel Type = Gasoline • Race Gas • HP and Torque increase
Fuel BTU=19000.0  Air/Fuel Ratio=12.500000  BSFC=0.519804  Mixture Distribution= 90.0 Quality= 90.0
---------------------------------------------------------------------------------------------------
                                  Camshaft = Solid  Roller  Lifter
600 RPM/Sec Dyno Test             Level=7        Level=8        Level=9       Level=10
Peak HorsePower    @  7500 RPM      871.4          882.5          893.6          904.9
Peak Torque Lbs-Ft @  5800 RPM      670.5          684.7          693.3          702.1

HorsePower per CID                  1.629          1.649          1.670          1.691
Torque per Cubic Inch               1.253          1.280          1.296          1.312
Peak Torque BMEP in psi             189.0          193.0          195.4          197.9
(1) 4-Barrell Carb CFM @ 1.5 inHg.   1296           1442           1515           1588
--------------------------------- Recommended Camshaft Specs at 0.050” inch Lobe Lift -------------
Cam Lobe Separation Angle (LSA)   108.118        108.501        108.982        109.419
Camshaft Intake Valve Lift        0.97629        1.01654        1.05846        1.10210
Camshaft Exhaust Valve Lift       0.88333        0.91975        0.95768        0.99716

Camshaft Intake Duration          272.584        274.552        276.534        278.530
Camshaft Exhaust Duration         292.018        294.124        296.243        298.378
Camshaft Overlap Duration          66.066         67.337         68.426         69.616
* Specs adjusted for ValveTrain Deflection = 0.0000   Intake Lash= 0.0140   Exhaust Lash= 0.0140
---------------------------------------------------------------------------------------------------
* User's current Camshaft Specs :              OverLap Duration =  64.30100
Lobe Separation Angle (LSA)= 112.00000         Camshaft Advanced = 3.88200 degrees     
Intake Lobe CenterLine = 108.11800             Exhaust Lobe CenterLine = 115.88200
Intake Duration at 0.05000” Lobe Lift          Exhaust Duration at 0.05000” Lobe Lift
Intake Duration = 278.58400                    Exhaust Duration = 298.01800
Intake Open =  31.17400 BTDC                   Exhaust Open =  84.89100 BBDC
Intake Close=  67.41000 ABDC                   Exhaust Close=  33.12700 ATDC
Intake Rocker Ratio = 1.90000:1                Exhaust Rocker Ratio = 2.02000:1
Intake Lobe Lift = 0.510837                    Exhaust Lobe Lift = 0.442847
Intake Valve Lift = 0.970590                   Exhaust Valve Lift = 0.894550
---------------------------------------------------------------------------------------------------
Intake System Flow Valve Lift  = 1.087387      Exhaust System Flow Valve Lift  = 0.989642
Intake Port Flow Valve Lift    = 1.096436      Exhaust Port Flow Valve Lift    = 0.982633
Intake Curtain Flow Valve Lift = 1.135719      Exhaust Curtain Flow Valve Lift = 1.013048
Intake Time Area TQ Valve Lift = 0.953882      Exhaust Time Area TQ Valve Lift = 0.879506
Intake Time Area HP Valve Lift = 1.047193      Exhaust Time Area HP Valve Lift = 0.940888
Intake Z-Factor Valve Lift     = 1.060082      Exhaust Z-Factor Valve Lift     = 0.989609

0.250 L/D Ratio Int Valve Lift = 0.557500      0.250 L/D Ratio Exh Valve Lift  = 0.430000
Note : the Valve Curtain Area will equal the Valve Area @ 0.250 Valve Lift/Diameter Ratio

Intake Mach Z-Factor     =  48.5375 % SOS      Exhaust Mach Z-Factor = 68.2787 % SOS
Mach Z-Factor definition = PerCent %  of the Speed of Sound ( SOS ) at the Valve's Curtain Area
Mach Z-Factor Valve Lift = calculated from Speed of Sound velocity thru Valve Curtain Areas
System Flow Valve Lift   = calculated from Intake and Exhaust System Flow and Valve Diameters
Port Flow Valve Lift     = calculated from Intake and Exhaust Port's Flow and Valve Diameters
Curtain Flow Valve Lifts = calculated from Flow thru the Intake and Exhaust Valve Curtain Areas
Time Area Valve Lifts    = calculated from User's Camshaft Durations, Curtain Areas, RPM Range

DCR Cylinder Volume CC   =  838.869367         Dynamic Compression Ratio     = 8.654420:1
DCR Effective Stroke     =  3.4445 inches      Valve Lash Compression Ratio  = 7.701312:1
Static Compression Ratio =  11.000000:1        Ve% + Lash Compression Ratio  = 8.596294:1

Cranking Psi @ 150 RPM = 157.4 Psi -to- 180.9 Psi @ 260 RPM ( depending on Ring seal / Piston Rock )

[Vincenzo]

It would appear that the PipeMax result differs considerably to the Blair computation.

To compare with the PipeMax 'full race' spec, I have again run the Pontiac 535 engine through Blair's software as a single cylinder unit, but fully optimised for maximum output.

The result is given in the output data presented here.

As has been previously stated, the predicted output falls way short of the 900 bhp target.

Stan, you have two very different outputs to consider.
Perhaps one day someone will build such an engine and determine which of the computations comes closest to reality

[maxracesoftware]

Vincenzo :

Despite the near matching STA's, when all the relevant data is run through EngMod4T
and Blair's software, both computed outputs fall way short of the target 900 bhp
at the stipulated 7500 rpm.

It would appear that the PipeMax result differs considerably to the Blair computation.

To compare with the PipeMax 'full race' spec,
I have again run the Pontiac 535 engine through Blair's software as a single cylinder unit,
but fully optimised for maximum output.

The result is given in the output data presented here.

As has been previously stated, the predicted output falls way short of the 900 bhp target.

Stan, you have two very different outputs to consider.

Perhaps one day someone will build such an engine and determine
which of the computations comes closest to reality

Vincenzo :
Intake = 52/86 318 duration 0.972441 Lift 107.0 CL
Exhaust= 88/56 324 duration 1.047244 Lift 106.0 CL
LSA = 106.5 deg
Overlap= 108.0 deg

Vincenzo ,
If i'm reading your Output Data correctly ?? ( Imperial Units )
88.77 x 8 Cyl = 710.16 Peak HP @ 7500 RPM

710.2 HP with a Cam that has 0.972441 Intake Lift and 1.047244 Exhaust Lift ??

Here's a BigBlockChevy Engine 4.600x4.000=531.9 CID
so 531.9cid is super close to Stan's 535cid Pontiac engine

Peak TQ = 670.8 at 6400 RPM
Peak HP = 878.5 at 7500 RPM

it also has only 10.2:1 CompRatio and is using AV-Gas 0.690 SPG

it's using a 4-Vane Vac Pump that makes 12.0 inches Hg Vacuum at 7500 RPM

the Cyl Heads are relatively small at 325cc Ported to about 335 CC
2.350/1.880 Valves 50.0 deg Valve Job

could have made more Peak HP with higher Lift Cam
but all he had were 1.70/1.70 Rocker Ratios
plus it was a Nitrous Cam for additional 300+ NOS adder later on at the Dragstrip

at 0.800 Valve Lift on my Flowbench the Dart Pro 1 325 CC Heads 2.350/1.880 50.0 deg Valve Job
Cyl#3 BPD = 0.800Lift__ 367.8 Int__300.9 Exh__no Flow Pipe 4.500 Fixture
Cyl#1 GPD =0.800Lift__403.1Int__300.9 Exh__no Flow Pipe 4.500 Fixture

add the Bad and the Good Ports = 367.8 + 403.1 = 770.9 / 2 = 385.45 CFM average at 0.800 Lift

.... Stan was using 432.0 CFM as his baseline
385.45 CFM is considerably less than 432.0 CFM , yet it made almost 900 HP @ 7500 RPM

or could easily make 900 HP with :

Water temp was 150.0 DegF ... we could have made more HP at colder temp

used relatively heavy 20/50 Amsoil ... could have made more HP with lite-Oil

better Cam Specs specifically for only Motor HP , no NOS Cam

( click on the Image to see larger ScreenShot )

[maxracesoftware]

532cid Simulation :

[maxracesoftware]

Header Specs :

[maxracesoftware]

Fuel Data :

[maxracesoftware]

Dart Pro 1 325CC Flow Sheet Data :

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Monday , February 26, 2007  Chris - Leon Marks - Ray wilde
Dart Pro 1 325CC Cyl #3 BPD 50 deg seats
4.500 Fixture No-pipe 17.5/23.0

Intake  Valve OD= 2.350	    Valve Area= 4.3374	  .25 L/D Ratio= 0.5875
Exhaust Valve OD= 1.880	    Valve Area= 2.7759	  .25 L/D Ratio= 0.4700

	Intake	Exhaust	Intake	Exhaust		Intake	Exhaust	Intake	Exhaust
Valve	L/D	L/D	Valve	Valve		Curtain	Curtain	Curtain	Curtain
Lift	Ratio	Ratio	CFM/In	CFM/In		Area	Area	CFM/In	CFM/In
0.200	0.0851	0.1064	33.81	50.74		1.477	1.181	99.32	119.25
0.300	0.1277	0.1596	47.26	68.04		2.215	1.772	92.55	106.60
0.400	0.1702	0.2128	61.17	81.50		2.953	2.362	89.84	95.76
0.450	0.1915	0.2394	67.80			3.322		88.52	
0.500	0.2128	0.2660	73.80	91.65		3.691	2.953	86.72	86.15
0.550	0.2340	0.2926	77.71			4.061		83.01	
0.600	0.2553	0.3191	79.80	99.33		4.430	3.544	78.14	77.81
0.650	0.2766	0.3457	82.16			4.799		74.26	
0.700	0.2979	0.3723	84.80	104.56		5.168	4.134	71.17	70.21
0.750	0.3191	0.3989	84.80			5.537		66.43	
0.800	0.3404	0.4255	84.80	108.41		5.906	4.725	62.27	63.69
0.850	0.3617	0.4521	85.80			6.275		59.30	
0.900	0.3830	0.4787	86.98	111.33		6.644	5.316	56.78	58.14
0.950	0.4043	0.5053	88.25			7.014		54.58	
1.000	0.4255	0.5319	0.00	0.00		0.000	0.000	0.00	0.00

	Intake	Effect	Valve	Curtain	Curt	Exhaust	Effect	Valve	Curtain	Curt
Valve	Flow	CSA	Area	Area	Area	Flow	CSA	Area	Area	Area
Lift	Coeff.	Area	FPS	FPS	Coeff.	Coeff.	Area	FPS	FPS	Coeff.
0.200	0.232	1.005	81.15	238.36	0.680	0.348	0.965	121.78	286.19	0.817
0.300	0.324	1.404	113.43	222.13	0.634	0.466	1.294	163.30	255.84	0.730
0.400	0.419	1.818	146.80	215.62	0.616	0.558	1.550	195.59	229.82	0.656
0.450	0.465	2.015	162.73	212.45	0.606
0.500	0.506	2.193	177.12	208.12	0.594	0.628	1.743	219.95	206.75	0.590
0.550	0.532	2.309	186.50	199.22	0.569
0.600	0.547	2.371	191.52	187.53	0.535	0.681	1.889	238.40	186.75	0.533
0.650	0.563	2.442	197.19	178.23	0.509
0.700	0.581	2.520	203.52	170.81	0.488	0.716	1.989	250.95	168.49	0.481
0.750	0.581	2.520	203.52	159.42	0.455
0.800	0.581	2.520	203.52	149.46	0.427	0.743	2.062	260.18	152.85	0.436
0.850	0.588	2.550	205.92	142.32	0.406
0.900	0.596	2.585	208.75	136.27	0.389	0.763	2.117	267.19	139.53	0.398
0.950	0.605	2.623	211.81	130.99	0.374
1.000	0.000	0.000	0.00	0.00	0.000	0.000	0.000	0.00	0.00	0.000

	Intake	Exhaust	Exh/Int	Exh/Int	Minimum	Normal	Maximum	Minimum	Normal	Maximum
Valve	Flow	Flow	Flow %	Curtain	HP for	HP for	HP for	HP per	HP per	HP per
Lift	CFM@28	CFM@28	Ratio	FPS Rat	8 Cyl.	8 Cyl.	8 Cyl.	Cyl.	Cyl.	Cyl.
0.200	146.6	140.9	96.1	120.1	301.5	340.2	375.4	37.7	42.5	46.9
0.300	205.0	188.9	92.1	115.2	421.5	475.6	524.8	52.7	59.4	65.6
0.400	265.3	226.2	85.3	106.6	545.5	615.5	679.2	68.2	76.9	84.9
0.450	294.1				604.6	682.3	752.9	75.6	85.3	94.1
0.500	320.1	254.4	79.5	99.3	658.1	742.6	819.5	82.3	92.8	102.4
0.550	337.1				693.0	782.0	862.9	86.6	97.7	107.9
0.600	346.1	275.7	79.7	99.6	711.6	803.0	886.1	89.0	100.4	110.8
0.650	356.4				732.7	826.8	912.3	91.6	103.3	114.0
0.700	367.8	290.3	78.9	98.6	756.2	853.3	941.6	94.5	106.7	117.7
0.750	367.8				756.2	853.3	941.6	94.5	106.7	117.7
0.800	367.8	300.9	81.8	102.3	756.2	853.3	941.6	94.5	106.7	117.7
0.850	372.1				765.1	863.4	952.7	95.6	107.9	119.1
0.900	377.3	309.0	81.9	102.4	775.7	875.3	965.8	97.0	109.4	120.7
0.950	382.8				787.0	888.1	979.9	98.4	111.0	122.5
======================================================================================


Monday , February 26, 2007  Chris - Leon Marks - Ray wilde
Dart Pro 1 325CC Cyl #1 GPD 50 deg seats
4.500 Fixture No-pipe 17.5/23.0

Intake  Valve OD= 2.350	    Valve Area= 4.3374	  .25 L/D Ratio= 0.5875
Exhaust Valve OD= 1.880	    Valve Area= 2.7759	  .25 L/D Ratio= 0.4700

	Intake	Exhaust	Intake	Exhaust		Intake	Exhaust	Intake	Exhaust
Valve	L/D	L/D	Valve	Valve		Curtain	Curtain	Curtain	Curtain
Lift	Ratio	Ratio	CFM/In	CFM/In		Area	Area	CFM/In	CFM/In
0.200	0.0851	0.1064	33.81	50.74		1.477	1.181	99.32	119.25
0.300	0.1277	0.1596	48.63	67.66		2.215	1.772	95.22	106.00
0.400	0.1702	0.2128	62.26	80.27		2.953	2.362	91.44	94.31
0.450	0.1915	0.2394	68.62			3.322		89.59	
0.500	0.2128	0.2660	74.89	91.18		3.691	2.953	88.00	85.71
0.550	0.2340	0.2926	80.71			4.061		86.21	
0.600	0.2553	0.3191	85.62	99.33		4.430	3.544	83.83	77.81
0.650	0.2766	0.3457	89.34			4.799		80.75	
0.700	0.2979	0.3723	91.20	104.87		5.168	4.134	76.54	70.41
0.750	0.3191	0.3989	92.26			5.537		72.27	
0.800	0.3404	0.4255	92.93	108.41		5.906	4.725	68.25	63.69
0.850	0.3617	0.4521	90.42			6.275		62.50	
0.900	0.3830	0.4787	90.42	111.48		6.644	5.316	59.03	58.22
0.950	0.4043	0.5053	91.39			7.014		56.52	
1.000	0.4255	0.5319	0.00	0.00		0.000	0.000	0.00	0.00

	Intake	Effect	Valve	Curtain	Curt	Exhaust	Effect	Valve	Curtain	Curt
Valve	Flow	CSA	Area	Area	Area	Flow	CSA	Area	Area	Area
Lift	Coeff.	Area	FPS	FPS	Coeff.	Coeff.	Area	FPS	FPS	Coeff.
0.200	0.232	1.005	81.15	238.36	0.680	0.348	0.965	121.78	286.19	0.817
0.300	0.333	1.445	116.70	228.54	0.652	0.464	1.287	162.38	254.39	0.726
0.400	0.427	1.850	149.42	219.46	0.626	0.550	1.527	192.64	226.35	0.646
0.450	0.470	2.039	164.69	215.01	0.614
0.500	0.513	2.226	179.74	211.20	0.603	0.625	1.734	218.84	205.71	0.587
0.550	0.553	2.398	193.70	206.91	0.591
0.600	0.587	2.544	205.48	201.20	0.574	0.681	1.889	238.40	186.75	0.533
0.650	0.612	2.655	214.42	193.81	0.553
0.700	0.625	2.710	218.87	183.69	0.524	0.718	1.994	251.69	168.99	0.482
0.750	0.632	2.742	221.42	173.44	0.495
0.800	0.637	2.762	223.04	163.79	0.468	0.743	2.062	260.18	152.85	0.436
0.850	0.620	2.687	217.02	150.00	0.428
0.900	0.620	2.687	217.02	141.67	0.404	0.764	2.120	267.56	139.72	0.399
0.950	0.626	2.716	219.33	135.64	0.387
1.000	0.000	0.000	0.00	0.00	0.000	0.000	0.000	0.00	0.00	0.000

	Intake	Exhaust	Exh/Int	Exh/Int	Minimum	Normal	Maximum	Minimum	Normal	Maximum
Valve	Flow	Flow	Flow %	Curtain	HP for	HP for	HP for	HP per	HP per	HP per
Lift	CFM@28	CFM@28	Ratio	FPS Rat	8 Cyl.	8 Cyl.	8 Cyl.	Cyl.	Cyl.	Cyl.
0.200	146.6	140.9	96.1	120.1	301.5	340.2	375.4	37.7	42.5	46.9
0.300	210.9	187.8	89.1	111.3	433.6	489.3	539.9	54.2	61.2	67.5
0.400	270.0	222.8	82.5	103.1	555.2	626.5	691.3	69.4	78.3	86.4
0.450	297.6				611.9	690.5	761.9	76.5	86.3	95.2
0.500	324.8	253.1	77.9	97.4	667.9	753.6	831.6	83.5	94.2	103.9
0.550	350.1				719.7	812.1	896.2	90.0	101.5	112.0
0.600	371.4	275.7	74.3	92.8	763.5	861.5	950.7	95.4	107.7	118.8
0.650	387.5				796.7	899.0	992.0	99.6	112.4	124.0
0.700	395.6	291.1	73.6	92.0	813.3	917.7	1012.6	101.7	114.7	126.6
0.750	400.2				822.7	928.3	1024.4	102.8	116.0	128.0
0.800	403.1	300.9	74.7	93.3	828.7	935.1	1031.9	103.6	116.9	129.0
0.850	392.2				806.4	909.9	1004.0	100.8	113.7	125.5
0.900	392.2	309.5	78.9	98.6	806.4	909.9	1004.0	100.8	113.7	125.5
0.950	396.4				815.0	919.6	1014.8	101.9	115.0	126.8

Dyno Test Description :

Code: Select all

Chris___Ray_Wilde_BBC531.9cid_7500RPM_878.5HP_6400RPM_670.8TQ_June_19_2007

Chris - Ray Wilde  June 19, 2007  4.600x4.000=531.9 CID
Dart Pro 1 Alum Heads 325 CC ported by Meaux
403 CFM @.800 Lift  300CFM@.800 Lift on Exh
Edelbrock Super Victor + (2) 1 inch open spacers
ProSystems 1300 w/PowerValve
4-Vane Vac-Pump
2.250x32 4.000x16 Headers
Jesel Belt Drive 
Cam Motion solid roller R2869/3005-112 on 108CL  .487/.457
Jesel 1.70 Rockers
10.2:1 CR Ross pistons 32 CC Domes
Moroso steel oil pan 7 qts of Amsoil 20/50
ATI Balancer
.025/.025
36 BTDC
change=82 from 85 in front
change=81/93 from 82/96
change=94 from 93 rear
change=av-100 gas  .690 SPG
change=38 from 36

change=40.5 from 38


 COLUMN AVERAGES
 Test: JUN19009
 Corrected Torque and HorsePower
 Range: 5500 RPM - 7700 RPM
 EngSpd:   6600 RPM
 STPTrq:  644.5 Clb-ft
 STPPwr:  807.4 CHp
 BSFC  :  0.445 lb/hph
 Fuel A:  165.1 lb/hr
 Fuel B:  162.8 lb/hr
 Oil P :   68.1 psig
 WtrOut:    150 degF
 ManPrs:     -1 inHg

 COLUMN AVERAGES
 Test: JUN19009
 Corrected  Torque  and  HorsePower
 Range: 5500 RPM - 7700 RPM
 EngSpd:   6600 RPM
 STPTrq:  644.5 Clb-ft
 STPPwr:  807.4 CHp
 FulA+B:  327.9 lb/hr
 BSFC  :  0.445 lb/hph
 A/F   :  15.59 Ratio
 Air1+2: 1120.9 scfm
 VolEff:  122.3 %
 BSAC  :   6.95 lb/hph

EngSpd	STPTrq	STPPwr	FulA+B	 BSFC 	ManPrs	WtrOut	BaroP 	VapPrs	AirTmp	EngPwr	FulA+B
 RPM  	Clb-ft	 CHp  	 lb/hr	lb/hph	 inHg 	 degF 	inHg  	 InHg 	 degF 	  Hp  	 lb/hr
5500	653.5	684.4	282.6	0.450	-0.6	149	30.05	1.17	97	627.8	282.6
5600	649.9	692.9	284.2	0.447	-0.6	149	30.05	1.17	97	635.4	284.2
5700	657.4	713.4	287.9	0.441	-0.7	149	30.05	1.17	98	653.3	287.9
5800	662.3	731.4	299.8	0.448	-0.7	149	30.05	1.17	98	669.7	299.8
5900	660.6	742.1	292.5	0.431	-0.6	149	30.05	1.17	98	679.2	292.5
6000	662.3	756.6	310.6	0.449	-0.8	150	30.05	1.17	98	692.2	310.6
6100	666.4	774.0	318.2	0.449	-0.8	150	30.05	1.17	98	707.9	318.2
6200	667.3	787.7	317.3	0.441	-1.0	150	30.05	1.17	98	720.1	317.3
6300	668.1	801.5	328.9	0.449	-0.9	149	30.05	1.17	98	732.3	328.9
6400	670.8	817.4	322.1	0.431	-0.9	149	30.05	1.17	98	746.6	322.1
6500	659.1	815.7	321.6	0.432	-1.0	150	30.05	1.17	98	744.4	321.6
6600	658.3	827.3	326.1	0.432	-1.0	150	30.05	1.17	98	754.6	326.1
6700	658.9	840.5	341.7	0.446	-1.1	150	30.05	1.17	98	766.3	341.7
6800	650.1	841.7	349.5	0.456	-1.0	150	30.05	1.17	98	766.7	349.5
6900	643.3	845.2	339.9	0.441	-1.1	150	30.05	1.17	97	770.3	339.9
7000	639.8	852.7	348.7	0.449	-1.1	150	30.05	1.17	97	776.6	348.7
7100	635.6	859.3	347.4	0.444	-1.2	150	30.05	1.17	97	782.0	347.4
7200	634.7	870.1	356.0	0.450	-1.3	150	30.05	1.17	97	791.4	356
7300	622.1	864.7	340.6	0.433	-1.2	150	30.05	1.17	97	785.7	340.6
7400	614.6	866.0	351.0	0.446	-1.3	150	30.05	1.17	97	786.2	351
7500	615.2	878.5	356.2	0.447	-1.1	150	30.05	1.17	97	797.1	356.2
7600	593.6	858.9	356.2	0.458	-1.2	150	30.05	1.17	97	778.1	356.2
7700	578.5	848.1	362.8	0.473	-1.2	150	30.05	1.17	97	767.2	362.8

Dragstrip Run Data :

Code: Select all

1991 Firebird 
2500 lbs w/Chris driving
300 HP with NOS
Best Run = 7.190 ET at  181 mph

1221.5 - 878.5 = 343.0 HO from NOS 300 HP Kit
Peak HP=1221.5  Torque=932.3    (600 RPM/SEC-Acceleration)
  60= 1.140  57.131
 330= 3.324  107.963
 660= 5.131  137.441
1000= 6.653  164.184
1320= 7.910  180.867

Fa = 21.0 SqFeet
Cd = 0.3200
DA Feet = 1500.0
HoodScoop % = 100.0

Width 	72.4 in (1,839 mm)
Height 	49.7 in (1,262 mm)
3598.28 = 24.98789563 sqft * 0.85 = 21.23971129 SqFeet

[Stan Weiss]

First I would like to thank everyone who has posted and made this thread at least for me very interesting.

I use a bastardized set of formulas that I worked out with one of my customers some year ago for calculation of curtain area. This what I get for 2.23" valve, 45 degree seat angle, .113 seat width, 7500 RPM. Do they look in the ballpark?

Stan


Lift -- cm^2 (Curtain Area)

0 -- 0
0.05 -- 1.53484309175489
0.1 -- 3.10551581296457
0.15 -- 4.81141960088513
0.2 -- 6.79205885830198
0.25 -- 8.87790267154114
0.3 -- 11.009315851039
0.35 -- 13.1641825618753
0.4 -- 15.3326174180629
0.45 -- 17.509580195049
0.5 -- 19.6922428300304
0.55 -- 21.8788995175437
0.6 -- 24.0684616847967
0.65 -- 26.2602025696327
0.7 -- 28.4536187061614
0.75 -- 30.6483504173546
0.8 -- 32.8441339737579
0.85 -- 35.0407716384674
0.9 -- 37.2381122628974
0.95 -- 39.4360383423708
1 -- 41.634457156658

Lift -- TA cm^2/sec.

0 -- 0
0.05 -- 3.33644532918769E-02
0.1 -- 6.75251205716377E-02
0.15 -- 0.102482001839283
0.2 -- 0.139693319585475
0.25 -- 0.181994224121895
0.3 -- 0.226757002866351
0.35 -- 0.272772333168906
0.4 -- 0.319499483245538
0.45 -- 0.366666415838976
0.5 -- 0.414122889819575
0.55 -- 0.461779646475576
0.6 -- 0.509580496667582
0.65 -- 0.557488376495089
0.7 -- 0.605477880626996
0.75 -- 0.653531028022592
0.8 -- 0.701634742516541
0.85 -- 0.749779291446835
0.9 -- 0.797957283641838
0.95 -- 0.846163006642268
1 -- 0.89439197657458

[Stan Weiss]

Sorry used the wrong parameter file to calculate the cm^2 numbers.

0 -- 0
0.05 -- 1.50140039813446
0.1 -- 3.0386304257237
0.15 -- 4.61169008276771
0.2 -- 6.28619938134637
0.25 -- 8.18974008548529
0.3 -- 10.2040651289858
0.35 -- 12.2747549926008
0.4 -- 14.3774767460492
0.45 -- 16.4999887127539
0.5 -- 18.6355300418809
0.55 -- 20.7800840914009
0.6 -- 22.9311223500412
0.65 -- 25.086976942279
0.7 -- 27.2465046282148
0.75 -- 29.4088962610167
0.8 -- 31.5735634132443
0.85 -- 33.7400681151076
0.9 -- 35.9080777638827
0.95 -- 38.0773352989021
1 -- 40.2476389458561

From - INTAKE_PORT_FLOW_STUDY_ON_VARIOUS_CYLINDER_HEAD_USING_FLOWBENCH.pdf

1. First stage
For low valve lifts, the minimum flow area corresponds to a frustrum of a right circular cone where the conical face between the valve and the seat, which is perpendicular to the seat, defines the flow area.
The minimum area is;
Am = πLv cos β (Dv – 2w + (Lv/2) sin 2β)
Where: β = Valve seat angle [º]
Lv = Valve lift [mm]
Dv = Valve head diameter (the outer diameter of the Seat) [mm}
w = Seat width (difference between the inner and outer seat radii) [mm]

2. Second stage
For the second stage, the minimum area still the slant surface of a frustrum of a right circular cone, but his surface is no longer perpendicular to the valve seat. The base angle of the cone increases from (90-β)º toward that of a cylinder, 90º.
The minimum area is;
Am = π Dm [ (Lv – w tan β)² + w²]½
Where: Dm = Mean seat diameter (Dv – w) [mm]

Stan

[Vincenzo]

The PipeMax computations for the drag race engine, interesting as they are, do not compare with the Pontiac target engine, simply because bore, stroke, conrod length and valve sizes all differ.
In any case, Stan's original post was questioning the possibility of in some was using Blair STA values as realistic targets when designing cam events for the engine, and my responses were concerned solely with the validity of these targets.

[pastry_chef]

The PipeMax computations for the drag race engine, interesting as they are, do not compare with the Pontiac target engine, simply because bore, stroke, conrod length and valve sizes all differ.

A few years ago another member shared this
https://www.youtube.com/watch?v=rbaGcUJVBeE

496 Pontiac with 11:1 compression - nearly 900 HP.
http://pontiaczone.com/forum/attachment ... 1257719369

Bore 4.31 Diamond pistons dished for 11:1 compression
Stroke 4.25
6.800 rods
KRE HP heads ported by Dan Barton flow 430cfm
Edelbrock Victor intake flowed 413cfm when bolted onto the head, ported by Dan Barton
1250 carb that we could never get enough jetting into it.
Comp Cam 276-286 .749-.726 lift on a 112 L/S installed at 111.5.
T&D 1.65 shaft rockers

[GARY C]

The PipeMax computations for the drag race engine, interesting as they are, do not compare with the Pontiac target engine, simply because bore, stroke, conrod length and valve sizes all differ.

A few years ago another member shared this
https://www.youtube.com/watch?v=rbaGcUJVBeE

496 Pontiac with 11:1 compression - nearly 900 HP.
http://pontiaczone.com/forum/attachment ... 1257719369

Bore 4.31 Diamond pistons dished for 11:1 compression
Stroke 4.25
6.800 rods
KRE HP heads ported by Dan Barton flow 430cfm
Edelbrock Victor intake flowed 413cfm when bolted onto the head, ported by Dan Barton
1250 carb that we could never get enough jetting into it.
Comp Cam 276-286 .749-.726 lift on a 112 L/S installed at 111.5.
T&D 1.65 shaft rockers

Do you know valve size?
Kasse did a 2.23 on his EMC 507 at 850+ hp and rumored a 30* seat... unless he did another Pontiac that I am not aware of.
It seems the valve size for Stan's engine is border line limited for the application?

[Stan Weiss]

The PipeMax computations for the drag race engine, interesting as they are, do not compare with the Pontiac target engine, simply because bore, stroke, conrod length and valve sizes all differ.

A few years ago another member shared this
https://www.youtube.com/watch?v=rbaGcUJVBeE

496 Pontiac with 11:1 compression - nearly 900 HP.
http://pontiaczone.com/forum/attachment ... 1257719369

Bore 4.31 Diamond pistons dished for 11:1 compression
Stroke 4.25
6.800 rods
KRE HP heads ported by Dan Barton flow 430cfm
Edelbrock Victor intake flowed 413cfm when bolted onto the head, ported by Dan Barton
1250 carb that we could never get enough jetting into it.
Comp Cam 276-286 .749-.726 lift on a 112 L/S installed at 111.5.
T&D 1.65 shaft rockers

Do you know valve size?
Kasse did a 2.23 on his EMC 507 at 850+ hp and rumored a 30* seat... unless he did another Pontiac that I am not aware of.
It seems the valve size for Stan's engine is border line limited for the application?

Gary,
If not that set of heads then ones very close is the numbers that I used.

Stan

In case anyone wants to do a simulation save the lines between ==== as a flw file.
=====
3.08
Bore Size=4.31-KRE High-Port Ported Dan Barton Pushrod Moved
0
9
1 2.230000
1 28.000000
1 0.200000
1 0.300000
1 0.400000
1 0.500000
1 0.600000
1 0.700000
1 0.800000
1 0.900000
1 1.000000
1 166.000000
1 227.000000
1 294.000000
1 357.000000
1 400.000000
1 426.000000
1 432.000000
1 434.000000
1 433.000000
1 1.720000
1 28.000000
1 0.200000
1 0.300000
1 0.400000
1 0.500000
1 0.600000
1 0.700000
1 0.800000
1 0.900000
1 1.000000
1 114.000000
1 168.000000
1 215.000000
1 238.000000
1 254.000000
1 267.000000
1 281.000000
1 285.000000
1 290.000000
======

[GARY C]

A few years ago another member shared this
https://www.youtube.com/watch?v=rbaGcUJVBeE

496 Pontiac with 11:1 compression - nearly 900 HP.
http://pontiaczone.com/forum/attachment ... 1257719369

Bore 4.31 Diamond pistons dished for 11:1 compression
Stroke 4.25
6.800 rods
KRE HP heads ported by Dan Barton flow 430cfm
Edelbrock Victor intake flowed 413cfm when bolted onto the head, ported by Dan Barton
1250 carb that we could never get enough jetting into it.
Comp Cam 276-286 .749-.726 lift on a 112 L/S installed at 111.5.
T&D 1.65 shaft rockers

Do you know valve size?
Kasse did a 2.23 on his EMC 507 at 850+ hp and rumored a 30* seat... unless he did another Pontiac that I am not aware of.
It seems the valve size for Stan's engine is border line limited for the application?

Gary,
If that that set of heads then ones very close is the number that I used.

Stan

Thats why I was curious if they changed them on the 496 build posted, I was wondering if the 2.23 was good for the 496" but becoming a restriction as the engine got bigger.

[pastry_chef]

Do you know valve size?

2.28/1.70 valves and 48cc chambers.

http://forums.maxperformanceinc.com/for ... ostcount=2