Yeah I get to bloody confused about cams so that one I'll leave to the Eddie's.
cheers
Camshaft change, performance difference
Started by
_rb3torana_
, Jul 26 2014 02:28 PM
58 replies to this topic
#29
_J.A.W._
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Posted 31 July 2014 - 08:33 PM
Have you decided what boost/drivability you want? Charge cooling requirements.. air or liquid intercooler - or ADI?
#30
_sunburst73-xu1_
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Posted 31 July 2014 - 08:38 PM
How it is at the moment I run between 20 and 25 pound boost, its mainly a street car but will see the track from time to time.
Because I run a boost retard on the dizzy I don't run any cooling system other then cold air intake for the carbie and no it doesn't ping.
cheers
#31
_ljxu1torana_
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Posted 31 July 2014 - 10:31 PM
How it is at the moment I run between 20 and 25 pound boost, its mainly a street car but will see the track from time to time.
Because I run a boost retard on the dizzy I don't run any cooling system other then cold air intake for the carbie and no it doesn't ping.
cheersAre you only making about 240 hp with 20-25 psi.there is something wrong.are you only using one su carby?.Just some advice pull the boost back down to about 12-13 psi and you will make more power.This is just my opinion use a carby with a accelerater pump like a dcoe weber 45mm or a holley.
#32
_Bomber Watson_
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Posted 31 July 2014 - 10:35 PM
Im sure an accelerator pump will drastically increase the maximum power output.
Though i agree thats way to much boost for the manifold, and probably the turbo, its most likely just heating the air more as opposed to actually increasing volumetric efficiency.
Cheers.
#33
_sunburst73-xu1_
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Posted 01 August 2014 - 07:03 AM
How it is at the moment I run between 20 and 25 pound boost, its mainly a street car but will see the track from time to time.
Because I run a boost retard on the dizzy I don't run any cooling system other then cold air intake for the carbie and no it doesn't ping.
cheersAre you only making about 240 hp with 20-25 psi.there is something wrong.are you only using one su carby?.Just some advice pull the boost back down to about 12-13 psi and you will make more power.This is just my opinion use a carby with a accelerater pump like a dcoe weber 45mm or a holley.
Thanks for the advise Jason, been thinking about a 650 Holley as I already have the V clamp adaptor plate there.
Don't know about pulling the Boost back that far tho with running about 6 to 1 comp.
When I was running the motor in I had it at 12 pound and I reckon the XU would of gave it a run for its money.
cheers
#34
_rb3torana_
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Posted 02 August 2014 - 07:43 AM
When I was running my turbo 186 I was using a 238/248 camtech, would pull hard to 7000rpm. I also had 6:1 well 5.9:1 in the end. Could run 30psi and 24 degrees timing locked on straight 98 ( ran 123mph 1/4mile ). Cheers
#35
_stretchlc_
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Posted 02 August 2014 - 03:44 PM
The 35666 is a proven turbo cam by many...I've used one myself and can vouch for its performance with a turbo.
Camtech make some even better turbo grind cams that are very well worth checking out........Part Numbers are as follows-CT35
640-113 (a) and the CT35 629-113 (a) which are solid cams.
For something in the hydraulic range go with CT35 536-113 (a).
#36
N/A-PWR
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Posted 29 March 2015 - 02:48 PM
Trying to workout the final Engine capacity.
Does anyone have a calculator to work out the swept volume left in a cylinder,
using the camshaft valve timing duration?
I imagine a big cam duration decreases the engine capacity x 20%.
Edited by NA-PWR, 29 March 2015 - 02:49 PM.
#37
_Bomber Watson_
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Posted 29 March 2015 - 03:40 PM
No, the swept volume stays constant.
#38
_oldjohnno_
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Posted 29 March 2015 - 04:24 PM
I think what Dave is after is a way to calculate the remaining swept volume above the piston when the intake closes. This http://www.torqsoft....n-position.html is designed for two-strokes but it will still give the distance from TDC for any crank angle from TDC.
Once you know this then you can calculate (distance from TDC/stroke) x cylinder volume to find the remaining swept volume.
If you don't mind spending a little bit of money check out CARFOR http://users.erols.com/srweiss/ . It's not pretty but it'll work out damn near anything for you, like the swiss army knife of car calculators. Here's what it can do:
A Computer Program designed for the motor sports enthusiast. Performance software that does the math for YOU. Handy Car Formulas for high performance math that will help you to analyze your (Street / Drag Racing, Circle Track, Oval Track, Road Racing, Off-Road) Car / Motorcycle / Kart / Engine and chassis needs, and improve performance. American or Metric Input (This is some what Limited). The menus are straightforward and "fill-in-the-blanks" data entry will get your answer. The most important thing to remember is that the more accurate your input to the program, the more accurate the answer will be. Although some examples may show only one or two decimal places the program will accept however many you key in, but any more then seven will not hold accuracy. Calculates engine displacement, Bore Stroke ratio, Rod Stroke ratio, Piston Speed, compression ratio, air and fuel flow, rear end gear ratio, shift RPM, 1/4 mile et and MPH, 60 foot MPH and G's, a change in Horsepower from a change in weather, or altitude, or adding blower pressure, Carburetor size in CFM, Carburetor size in CFM for blown engine, Blower Drive Ratio and RPM, Pressure Ratio, Intercooler Efficiency, Intercooler Density Ratio, Compressed Air Temperature, Blower Density Ratio, Compressor Inlet Flow in CFM, Drive Wheel Torque, Aerodynamic drag / HP Loss, Acceleration and Top Speed Prediction, Horse power Prediction from MPH's and Times, rollout distance, tire growth, trans power loss, shift rpm, shift time, % rear end power loss, % converter slippage, coefficient of drag (CD), launch rpm, Horse power Prediction from RPM's and Times, Est. Frontal Area, Carburetor jet size or bypass jet size change based on change in weather, Air filter size, Vapor Pressure, Dew Point, Saturation Vapor Pressure, Density Altitude, Dyno Air Correction Factor, Air Density Percent, Air Density, Lap Speed (MPH) over measured distance from distance and time, Lap time over measured distance from distance and Lap Speed, skid pad G's, Coil Spring Stiffness / Rate, Wire Diameter, Number of Active Coils, Mean Diameter of Coils, Modulus of Rigidity, Number of Coils, Solid Height, Torsion Bar Stiffness / Rate, Torsion Bar Diameter, Sway Bar Stiffness / Rate, Leaf Spring Rate, Camshaft duration needed from compression ratio, Exhaust/Muffler(s) Airflow for no Horsepower lose, Piston Travel, Crank Rod angle, Rod Bore angle and Cylinder volume over piston vs. Crank Rotation, Crankshaft revs per Second Crankshaft Degrees at which rod and crank are 90 Degrees, bearing speed, Rotation Time of crankshaft per degree in Milliseconds, crankpin load, Rotation Time of crankshaft per rev in Milliseconds, crankpin force, Max RPM from Piston Speed, Needed Combustion Chamber Volume, Needed Chamber (Total) Volume, Needed Dome Volume, piston deck height, Block Deck Height, Piston Compression Height, BMEP from Horsepower and RPM, BMEP from Torque, EFI injector size in lbs/hr / Fuel pump flow - from Horsepower, Change in EFI rating from fuel pressure change, duty cycle, fuel pump flow, Compression Gauge reading for a given engine size, Compression ratio from Compression Gauge reading, adjusted/effective compression ratio, Dynamic Compression Ratio, Est. Gasoline Octane Needed, a number of these let you use wrist pin offset, Average rate of acceleration from rest to X MPH, Cam duration centerline lobe separation angle from cam events, Cam timing events from duration and centerline, New valve lift from change in rocker arm ratio, Advance or Retard Timing, Read and display information from *.cam files, or 'C1' files from Cam Doctor or exported from Cam Pro Plus. Convert Airflow to a different depression, weight transfer, center of gravity, ballast placement position and amount, corner weights, percent of weight on each corner/front/rear/left/right, cross weight, cross percentage, lateral acceleration, spring rates, spring movement, spring wheel rates, suspension frequency / cpm / hz, sway bar rates, sway bar movement, sway bar rates, roll stiffness, roll center, roll axis height, roll axis to CG height, roll moment, roll angle, header collector sizing, primary drive, final drive, front sprocket, rear sprocket, converter slippage, 2-stroke port timing, distance, degrees ATDC, duration, boost, transfer, blowdown, dynamic compression ratio, corrected compression ratio, two-stroke, max squish velocity m/s, max squish velocity degrees, squish ratio, squish area, quench / squish clearance, squish volume, bowl diameter, time port open in milliseconds, total port area, port time area, 2-stroke exhaust, single stage diffuser, two (2) stage diffuser, three (3) stage diffuser, expansion chamber, speed of sound, exhaust gas temperature, nitrous jetting, timing retard (degrees), plug heat range change (colder), fuel (gas) jet size, methanol jet size, ethanol jet size, nitrous pressure, specific gravity of gas, analyze flow data, bowl csa, velocity @ bowl, discharge coefficient, Read and display information from *.flw files, and much more. Unit/Metric Conversion. Equivalence Charts.
As I said it isn't pretty - it looks like it was done in Visual Basic in 1990 - but it works, and Stan Weiss, the guy that wrote it and incidentally maintains that head flow database, will help with any problems and offers free updates, seemingly forever.
#39
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Posted 29 March 2015 - 04:52 PM
Great Man Old Johnno,
now I got my work cut-out. 
thank-you DJ too, I was wondering if there was a difference.
#40
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Posted 29 March 2015 - 05:21 PM
after first calculation, using TorqSoft,
Cam spec sheet say's - inlet center-line is 104° atdc:-
Volume Calculation.jpg 39.78K
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3400cc ( 208ci ) down to 2349cc ( 144ci )
not sure if this is right yet. 
#41
_coupe202_
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Posted 29 March 2015 - 05:23 PM
I've used a Wade 259a and a Crow 5651 with success with both cams on a draw through with a quadrajet carby on Holden 6
#42
_oldjohnno_
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Posted 29 March 2015 - 05:55 PM
after first calculation, using TorqSoft,
Cam spec sheet say's - inlet center-line is 104° atdc:-
3400cc ( 208ci ) down to 2349cc ( 144ci )
not sure if this is right yet.
Not quite Dave, instead of 104 use the intake closing figure which I'm guessing will be somewhere around 80 degrees.
#43
EunUCh
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Posted 29 March 2015 - 05:59 PM
Don't worry about the displacement,i had a 3inch stroke turned into 100th over a 2 inch stroke using measured dcr,the cam does the rest,probably one thing i not sure about is the cranking pressures with above stock cams?
#44
_Bomber Watson_
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Posted 29 March 2015 - 06:02 PM
Looks like $70 well spent to me for that computer program type thing OJ mentioned, might grab that one.
Edited by Bomber Watson, 29 March 2015 - 06:04 PM.
#45
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Posted 29 March 2015 - 06:10 PM
Oh OK Old Johnno,
as you can see, there is no atdc in the inlet closing timing:-
Don't worry about the displacement,i had a 3inch stroke turned into 100th over a 2 inch stroke using measured dcr,the cam does the rest,probably one thing i not sure about is the cranking pressures with above stock cams?
Realize we get the Cam etc, to do the work,
but was an interesting figure to work out,
as this is what we are making power from.
Not quite Dave, instead of 104 use the intake closing figure which I'm guessing will be somewhere around 80 degrees.
#46
_oldjohnno_
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Posted 29 March 2015 - 06:27 PM
The distance is the same whether it's BTDC or ATDC. Using 1.5 rockers and the suggested lash gives an actual closing figure of approximately 83 degrees, so use that.
#47
_oldjohnno_
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Posted 29 March 2015 - 06:31 PM
Looks like $70 well spent to me for that computer program type thing OJ mentioned, might grab that one.
It's handy, though I must admit I only use maybe 5% of its capabilities.
#48
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Posted 29 March 2015 - 06:43 PM
Got it:-
Volume = π x radius squared x height
= 3.142 x 2190.19 x 42.151
= 290065.4³mm x 6 pistons / 1000
= 1740.4³cc
that is half the combustion gone, gees.
Volume Calculation 2.jpg 42.72K
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Edited by NA-PWR, 29 March 2015 - 06:45 PM.
#49
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Posted 29 March 2015 - 06:50 PM
she be right 
it will be made up through improved cylinder filling,intertia filling/air speed vol. etc.?
all we we doing i believe is shifting the ve up the range a bit with a cam?
Edited by EunUCh, 29 March 2015 - 06:50 PM.
#50
_Bomber Watson_
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Posted 29 March 2015 - 06:57 PM
93.37ABDC + 180ATDC =173.37 ATDC?
What am i missing OJ?
Edited by Bomber Watson, 29 March 2015 - 06:58 PM.
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