408 Nova wrote: ↑Mon Dec 14, 2020 4:03 am
maxracesoftware wrote: ↑Tue Dec 11, 2018 2:11 pm
gottago wrote: ↑Mon Dec 10, 2018 5:12 pm
In regard ..
But 118 lsa is going quite a ways past the recommendations in DV formula for that aspect.. Not saying the results aren't real nice, just that its not totally explained by the compression ratio /lsa.. 118 lsa installed slightly retarded is so different from most recommendations you usually hear that it makes me wonder. Do you have any dyno numbers from the lower rpm range 3000-5000 ? Does it fall off real fast or drop unusually low anywhere in comparison the usual alternate cam choices?
I have used all the vortecs at one time or another. Currently EQ.. I have been running wider and wider lsa each time with decent results. Never beyond 113 lsa though. The vortecs "seemed" to like that more so than some other heads. Sorry no dyno #s , just curious.
i agree with the previous Post as it was stated,
but i do not agree 100% with DV LSA formula
Do you have any dyno numbers from the lower rpm range 3000-5000 ?
Does it fall off real fast or drop unusually low anywhere in comparison the usual alternate cam choices?
I have used all the vortecs at one time or another. Currently EQ..
I have been running wider and wider lsa each time with decent results.
Never beyond 113 lsa though. The vortecs "seemed" to like that more so than some other heads. Sorry no dyno #s , just curious.
these Dyno tests are the only time we made Dyno Pulls
befow 5000 RPM starting point :
He runs a 5000+ Stall Converter in the Mud Truck
we only started this Dyno Pull this low in RPM
because it had only 10.8:1 CR ( along with Q16 Gas )
so no chance of harming the engine at all
SBC Mud Truck
4.030x3.480=355.2 CID
ProMaxx Vortec Heads 2.055/1.600
Edelbrock Vortec Super Victor
Q16 Race Gas
10.8:1 CR
CompCams 5980/5985 118 251/247 .363/.363 118 Centers 116.5 CL
1.52 Roller Tip Steel Rockers
38 BTDC
LAT 20/50 Breakin Oil
Custom Kickout Oil Pan 10 Qts Oil
unmilled ProMaxx Heads
Peak TQ = 433.3 at 4800 RPM
Peak HP = 476.4 at 6500 RPM
So this is the smallest Cubic Inch Mud Truck engine we ever built/Dyno tested
i think it did really great for only 10.8:1 Compression Ratio , all things considered
476.4 Peak HP / 355.2 CID = 1.341216216 HP/CID Ratio
525.9 Peak HP = best Engine Combo at 361.5 CID
-476.4 Peak HP at 355.2 CID 10.8:1 CR
------------------
49.5 Peak HP difference
Compared to one of our best Engine Combos :
1.341216216 HP/CID Ratio x 361.5 cid = 484.8
so about 484.8 Peak HP if it were 361.5 CID engine size
then Angle-Mill the Heads 0.000-0.085" for almost 12.5:1 CR
12.5 - 10.8 = gain 1.7 points in Compression Ratio
then go from Q16 Race Gas to higher HP C45 Race Gas
then go from 1.52 Rocker Ratios to 1.72 Rocker Ratios
then lighter LAT Race Oil from LAT 20/50 Breakin Oil
and it should end up around 526 Peak HP
Note : CompCams 5980/5985 118 251/247 .363/.363 118 Centers 116.5 CL
Cam was on 116.5 IntCL and had 118.0=LSA
still made a lot of Torque
DV goes into the how's and why's of cam selection in his books, way beyond that formula he was messing with.
I know you're required to have 18" or so of vacuum for your mud truck small block, plus you've been doing this probably longer than I've been alive (I'm 48), so take this with a grain of salt because it's just for for the heck of it.
Let's take your 355 as an example.
One cylinder of 355.2 cubic inches total gives us 44.4 ci.
44.4/2.055 is 21.60. Rounding this to 22 and plugging this into his LCA chart in his book gives us a 107 LCA. This LCA works with your 10.8:1 compression and 1.52 rockers.
If you use smaller 2.02 intake valves, your LCA would need to be slightly tighter. If you used larger 2.10 intake valves, your LCA would need to be slightly wider.
If I put a 406 ci short block under those heads you're using with 2.055" valves, I would need to tighten the LCA.
If you bumped the compression from 10.8:1 to 12.8:1, the LCA required would need to be slightly wider. DV says .75 LCA wider for each ratio above 10.5:1.
Rocker ratio plays a role in it also. If your cam was optimized with 1.5 rockers, and then you swap to 1.7's, a wider LCA may be called for to restore overlap area back to where it was with the 1.5 rockers.
Comparing the valve events on our cams looks like this:
118/116.5 107/103
IO 9 BTDC IO 22.5 BTDC
IC 62 ABDC IC 48.5 ABDC
EO 63 BBDC EO 54.5 BBDC
EC 4 ATDC EC 12.5 ATDC
Overlap: 13 degrees 35 degrees
As you can see, the intake opens way earlier on the tighter LCA cam, meaning the intake valve is a lot higher off its seat as the piston starts down the bore, thus feeding that cylinder better, earlier on the intake stroke.
Post BDC filling of the cylinder on the intake stroke is not as great with the tighter LCA cam. There should be a good balance of opening and closing of the intake valve before and after the intake stroke, and the 107 LCA certainly looks like it's more balanced than the 118 LCA cam.
There is a lot more overlap with the tighter LCA cam, which will contribute to cylinder filling better before the intake stroke starts.
The exhaust valve on the wider LCA cam opens quite early, cutting into the power stroke more than the narrower LCA cam. This would decrease torque throughout the engine's rev range, with the 118 LCA cam probably only catching up torque wise right at the top of the engine's rev range.
I don't have a dyno, so I rely heavily on what DV has to say about cam selection. I've had very good results on the dragstrip using this cam selection technique. No one else I've seen has ever laid it out like DV to achieve cam selection like this.
Of course, there are more ways than one to skin a cat, and the way DV lays it out here is a way, and it's a very good way in my opinion.
Good info as always Larry! Although you should probably read some of the recent threads and realize a 2.055 intake valve and 1.875" header won't work in a OEM Vortec head
Pete Graves
CPMotorworks,Inc.
Custom Engine Machining
Cylinder Head Fixture for Vertical / Surfacing Mills
" Although you should probably read some of the recent threads and realize a 2.055 intake valve and 1.875" header won't work in a OEM Vortec head "
i love that Quote by Pete !!
i've tested a 2.080" intake valve in #062 castings 3 different engines
1= local Racer ... engine picked up TQ and HP from 2.055/1.600 combo in #062 castings
2= was Harry Clack's ( Lafayette.LA) Sweden DragRace Boat 377cid with 2.080" int valves , came very close to breaking that MPH Record
made more TQ and HP on my Dyno
3= another local Racer #062 castings 2.080/1.600 ... but these lost a few HP from 2.055/1.600 combo
on these #062 castings , they had a lot of core-shift , so i could not maxout the Intake Bowl Short Turn Curve without breaking into water jacket !
so from that point on , i never again attempted to install 2.080" intake valves , just only 2.055/1.600 combo
Cyl Head Core-Shift problems :
original ProAction 14deg cast-iron Heads
1st pair , no bad core-shift , was able to maxout short turn curves
2nd pair, real bad core-shift , one end of Head had combustion chamber really thick wall around exhaust valve,
the other side of Head the chamber was only 0.080" thick in corner around exhaust valve , it eventually cracked there and had to have it welded-up .
same thing with end-cylinder still had 0.200" thick walls after i maxed out the Short Turn Curves
the other end of that same Head , i could not maxout that Intake Short Turn Curve, so that Intake Port ended up not Flowing that well
so Craig A/ND Heads ended up with basically 2 cylinders on each Head that were great, and other 2 cylinders that weren't
so on a V8 it was like 4 great cylinders and 4 other not so great cylinders
still managed to make 960's HP on then was a 403cid engine @ 9300 to 9400 RPM
in PipeMax v4.50 it has a choice : " Plenum Vacuum Rule • MotorSports Classes"
so it will predict Cam Specs for those applications
but if you just use the Default choice : " Race Engine • Mid-Range Peak TQ • Hi RPM Peak HP"
or choose the type : " Hi-Perf Engine • Low-to-Mid-Range RPM Torque + HP"
it will probably come very close to predicting Cam Specs David Vizard 's LSA
one of included example file in the PipeMax v4.50 installation is :
350_Vortec_Vizards_Sledgehammer_6200RPM_447HP__4400RPM_445TQ__355cid.PMW
Application Type : " Hi-Perf Engine • Low-to-Mid-Range RPM Torque + HP"
the Vizard File almost exact match to Cam Specs he used in that Engine !
Code: Select all
Bore=4.03000 Stroke=3.48000 355.11515321 Cubic Inches @ 6200 RPM Intake System= 101.63413 VE%
Complete Intake System Flow @28in.= 195.9021 -to- 209.7833 CFM @ 0.563200 Lift (17.69000 VE% Loss)
Cylinder Head Intake Port Flow @28in.= 230.0000 -to- 246.2973 CFM @ 0.563200 Lift (119.32413 VE%)
Cylinder Head Exhaust Port Flow @28in.= 165.5000 -to- 177.2270 CFM @ 0.563200 Lift (no Flow Pipe)
Dyno HP Weather Correction Equation = 8• SAE J607 (June1974) • STP • SuperFlow-FTQ • (Default)
Air Correction=0.90768188 Station Barometer=29.48000000 Air DegF=96.00 Vapor Pressure=0.442
HP Correction Factor= 1.083533596 Fuel Type= Gasoline • Pump Gas • ( 91 to 93 Octane Premium )
Fuel BTU=19000.0 Air/Fuel Ratio=12.532835 BSFC=0.520393 Mixture Distribution= 90.0 Quality= 90.0
Step Oil Pan • Regular Oil • 0.0 inHg • 0.0 kPa Vacuum • Harmonic Damper Efficiency= 90.0 %
Engine Application = Hi-Perf Engine • Low-to-Mid-Range RPM Torque and HP
-----------------------------------------------------------------------------------------------------
Camshaft = Hydraulic Roller Lifter
300 RPM/Sec Dyno Test Level=4 Level=5 Level=6 Level=7 Piston FPM
Peak HorsePower @ 6200 RPM 430.4 435.9 441.4 447.0 3596.00
Peak Torque Lbs-Ft @ 4400 RPM 416.3 421.6 426.9 432.3 2552.00
HorsePower per CID 1.212 1.227 1.243 1.259 Peak HP Fuel
Torque per Cubic Inch 1.172 1.187 1.202 1.217 consumed in
Peak Torque BMEP in psi 176.8 179.0 181.3 183.6 Lbs./ Hour
Throttle Plate CFM @ 1.5 inHg. 760 846 888 931 214.7
--------------------------------- Recommended Camshaft Specs at 0.050” inch Lobe Lift ---------------
Cam Lobe Separation Angle (LSA) 107.173 107.173 107.173 107.173
Intake Minimum Valve Lift 0.48947 0.50965 0.53067 0.55255
Exhaust Minimum Valve Lift 0.47621 0.49585 0.51629 0.53758
Intake Minimum Duration 217.757 219.292 220.838 222.395
Exhaust Minimum Duration 218.161 219.699 221.247 222.807
Overlap Minimum Duration 3.613 5.150 6.697 8.255
Intake Maximum Valve Lift 0.50965 0.53067 0.55255 0.57533
Exhaust Maximum Valve Lift 0.49585 0.51629 0.53758 0.55975
Intake Maximum Duration 219.292 220.838 222.395 223.963
Exhaust Maximum Duration 219.699 221.247 222.807 224.378
Overlap Maximum Duration 5.150 6.697 8.255 9.824
-----------------------------------------------------------------------------------------------------
* above Specs adjusted for ValveTrain Deflection= 0.0000 Intake Lash= 0.0000 Exhaust Lash= 0.0000
* User's current Camshaft Specs : OverLap Duration = 8.00000
Lobe Separation Angle (LSA)= 108.00000 Camshaft Advanced = 4.00000 degrees
Intake Lobe CenterLine = 104.00000 Exhaust Lobe CenterLine = 112.00000
Intake Duration = 224.00000 @ 0.05000” Exhaust Duration = 224.00000 @ 0.05000”
Intake Open = 8.00000 BTDC Exhaust Open = 44.00000 BBDC
Intake Close= 36.00000 ABDC Exhaust Close= 0.00000 TDC
Intake Rocker Ratio = 1.60000:1 Exhaust Rocker Ratio = 1.60000:1
Intake Lobe Lift = 0.352000 Exhaust Lobe Lift = 0.352000
Intake Valve Lift = 0.563200 Exhaust Valve Lift = 0.563200
-----------------------------------------------------------------------------------------------------
Intake Pumping Choke Valve Lift= 0.612163 Exhaust Pumping Choke Valve Lift= 0.602085
Intake Time Area TQ Valve Lift = 0.718969 Exhaust Time Area TQ Valve Lift = 0.704015
Intake Time Area HP Valve Lift = 0.821423 Exhaust Time Area HP Valve Lift = 0.787587
Intake System Flow Valve Lift = 0.631459 Exhaust System Flow Valve Lift = 0.640686
Intake Port Flow Valve Lift = 0.667920 Exhaust Port Flow Valve Lift = 0.621592
Intake Curtain Flow Valve Lift = 0.705231 Exhaust Curtain Flow Valve Lift = 0.661756
Intake Z-Factor Valve Lift = 0.668607 Exhaust Z-Factor Valve Lift = 0.622630
0.250 L/D Ratio Int Valve Lift = 0.485000 0.250 L/D Ratio Exh Valve Lift = 0.375000
Note : the Valve Curtain Area will equal the Valve Area @ 0.250 Valve Lift/Diameter Ratio
Intake Mach Z-Factor = 52.7573 % SOS Exhaust Mach Z-Factor = 68.2328 % SOS
Mach Z-Factor definition = PerCent % of the Speed of Sound ( SOS ) at the Valve's Curtain Area
Mach Z-Factor Valve Lift = Level=10 Cam calculated Speed of Sound velocity thru Valve Curtain Areas
Pumping Choke Valve Lift = Level=10 Cam calculated Intake and Exhaust Valve Diameters and RPM Range
Time Area Valve Lifts = Level=10 Cam calculated User's Camshaft Durations, Curtain Areas, RPM Range
System Flow Valve Lift = Level=10 Cam calculated Intake and Exhaust System Flow and Valve Diameters
Port Flow Valve Lift = Level=10 Cam calculated Intake and Exhaust Port's Flow and Valve Diameters
Curtain Flow Valve Lifts = Level=10 Cam calculated Flow thru Intake and Exhaust Valve Curtain Areas
DCR Cylinder Volume CC = 677.286370 Dynamic Compression Ratio = 9.379816:1
DCR Effective Stroke = 3.2402 inches Valve Lash Compression Ratio = 7.987053:1
Static Compression Ratio = 10.000000:1 Ve% + Lash Compression Ratio = 9.530482:1
Cranking Psi @ 150 RPM = 164.2 Psi -to- 187.7 Psi @ 260 RPM (depending on Ring seal + Piston Rock)
Station Barometer NOAA= 29.48885898 Pressure Altitude Feet= 410.5 Z•Elevation Feet= 0.0
Density Altitude Feet = 3025.3 Relative Humidity % = 25.81 Dew Point DegF = 55.40
Virtual Temperature DegF = 99.17 Water Grains = 66.27 Wet Bulb DegF = 69.84
Bore=4.03000 Stroke=3.48000 355.11515321 Cubic Inches @ 6200 RPM Intake System= 101.63413 VE%
Complete Intake System Flow @28in.= 195.9021 -to- 209.7833 CFM @ 0.563200 Lift (17.69000 VE% Loss)
Cylinder Head Intake Port Flow @28in.= 230.0000 -to- 246.2973 CFM @ 0.563200 Lift (119.32413 VE%)
Cylinder Head Exhaust Port Flow @28in.= 165.5000 -to- 177.2270 CFM @ 0.563200 Lift (no Flow Pipe)
Dyno HP Weather Correction Equation = 8• SAE J607 (June1974) • STP • SuperFlow-FTQ • (Default)
Dyno Air Correction=0.90768188 Fuel Type= Gasoline • Pump Gas • ( 91 to 93 Octane Premium )
Station Barometer=29.48000000 Air DegF=96.00 Vapor Pressure=0.442 Density Altitude Feet=3025.3
Pressure Altitude Feet= 410.5 Relative Humidity % = 25.81 Dew Point DegF = 55.40
Virtual Temperature DegF = 99.17 Water Grains = 66.27 Wet Bulb DegF = 69.84
Step Oil Pan • Regular Oil • 0.0 inHg • 0.0 kPa Vacuum • Harmonic Damper Efficiency= 90.0 %
Engine Application = Hi-Perf Engine • Low-to-Mid-Range RPM Torque and HP
FlowVe% Plenum Front Rear Total BTU Intake UnCorr Engine Piston Frequency
Engine 101.634 Vacuum Fuel Fuel Fuel Heat Flow Peak HP/CID Speed per second
RPM SCFM In.Hg. Lbs/Hr Lbs/Hr Lbs/Hr HP CFM HP Ratio FPM Hertz
6200 587.7 1.042 107.3 107.3 214.7 1602.7 195.9 412.5 1.162 3596.0 51.7
-------------------------------------------------------------------------------------------------------
Camshaft = Hydraulic Roller Lifter
300 RPM/Sec Dyno Test Level=4 Level=5 Level=6 Level=7
Peak HorsePower @ 6200 RPM 430.4 435.9 441.4 447.0 Peak HP CBHP
Brake Specific Fuel Consumption 0.5404 0.5337 0.5270 0.5204 BSFC Lbs/HP-hour
Brake Specific Air Consumption 6.7728 6.6882 6.6046 6.5220 BSAC Lbs/HP-hour
Brake Thermal Efficiency PerCent 24.786 25.100 25.418 25.740 BTE percent %
Brake Mean Effective Pressure 154.8 156.8 158.8 160.8 BMEP Psi
Peak Horsepower per Cubic Inch 1.212 1.227 1.243 1.259 HP/CID Ratio
Throttle Plate CFM @ 1.5 inHg. 760 846 888 931 CFM @ 1.5 inHg
-------------------------------------------------------------------------------------------------------
Peak Torque Lbs-Ft @ 4400 RPM 416.3 421.6 426.9 432.3 Peak TQ CBTQ
Brake Specific Fuel Consumption 0.4733 0.4674 0.4616 0.4558 BSFC Lbs/HP-hour
Brake Specific Air Consumption 5.9323 5.8581 5.7849 5.7126 BSAC Lbs/HP-hour
Brake Thermal Efficiency PerCent 28.298 28.657 29.019 29.387 BTE percent %
Brake Mean Effective Pressure 176.8 179.0 181.3 183.6 BMEP Psi
Peak Torque per Cubic Inch 1.172 1.187 1.202 1.217 TQ/CID Ratio
-------------------------------------------------------------------------------------------------------