Posted:
Sun Jan 20, 2008 2:07 pmby bruce
We'll try and keep all the Pipemax Program discussion in this area.
The program can be found at
Edited By bruce on 1200852721
Posted:
Sun Jan 20, 2008 3:23 pmby 200cfm
Thanks Bruce. I'll start the ball.
1.What do intake and exhaust margin cc's mean?
2. Why do tunnel ram intake plenums always have the same displacement as the engine?
3. What is camshaft intake and exhaust Lobe rpm? Is that the speed of the cam? And why a range?
4. Why isn't runner volume and port length required information to predict a csa?
5. Do you adjust % efficiency to agree to head port flow only or do you add the losses from the intake/carb manifold (once installed) to set up the net cfm flow to the program?
6. What are others selecting as their fps target. Default is 300. Is that a target for only high lift, very high rpm race motors only?
7. If you exceed the 100% eff are you simulating boost?
Posted:
Thu Jan 24, 2008 2:49 amby maxracesoftware
1.What do intake and exhaust margin cc's mean?
i Port Heads for various NHRA SuperStock Engines
and i'm always wanting to know how many
thousandsths of an inch of Valve Margin equals 1 CC.
i need to know these values in order to sometimes
juggle Combustion Chamber CC's to as close as possible
to NHRA Legal minimum for maximum Compression Ratio
possible for the greatest Torque/HP Curve.
Under NHRA Rules up until recently,
you were not allowed to grind or port anything in the
Combustion Chamber....so instead you could grind
the Valve Face angle reducing the margin's width
which increased the CC's by so many tenths CC per .001"
Normally you would use PipeMax's data to tell how much
you needed to grind off valves to increase chamber CC's
if you were just slightly illegal on a few Chambers
2. Why do tunnel ram intake plenums always have the same displacement as the engine?
This is the largest BallPark "Plenum Volume" you would
attempt to use ,...and the Single-Plane Plenum Volumes
are real and calculated for you.
However in this version , the Tunnel-Ram Plenum Volumes
are fixed...and in future versions the Tunnel-Ram plenum
volumes will be calculated for you as the case with
the Single-Plane Manifolds.
3. What is camshaft intake and exhaust Lobe rpm? Is that the speed of the cam? And why a range?
Lobe RPM estimations are equivalent to how much
"Area Under the Curve" they represent from a
combination of Valve Lift and Duration @.050"
From these "Lobe RPMs" estimations the User can see
at what RPM Range those particular Cam Specs will give
you the greatest Power
in current version of PipeMax, these Lobe RPM estimations
are based on OEM Cam Journal sizes.
in future versions of PipeMax,
there will be new Input to model Cams and ValveTrains that are stiffer and reduce losses and ValveTrain flex/float.
Example, going from OEM BBC Core to 60MM Cam Core
can reduce the Duration @ .050" from 4 to as much as 9 deg
to achieve the same peak RPM or RPM Range
4. Why isn't runner volume and port length required information to predict a csa?
PipeMax calculates CSA ..then from CSA you can
calculate either or both Runner Volume and Runner Length.
in addition PipeMax calculates Total Intake System Lengths
at various Harmonics...from these Total Lengths you can
simply subtract your Intake Manifold Runner Length to get
Cylinder Head Length or Vice/Versa to get Head Port Length.
in future version PipeMax will have Cyl Head's Intake Port
length input and a Length and/or Volume Calculator built in.
5. Do you adjust % efficiency to agree to head port flow only or do you add the losses from the intake/carb manifold (once installed) to set up the net cfm flow to the program?
here's the most accurate method to use PipeMax=>
you are already on the Dyno,
and have made 3 or 4 Pulls and know for sure the
RPM point of Peak HP.......at this point you Input
all your Engine specs into PipeMax, and calculate Hp and TQ,
you keep changine VE% Input a little at a time
until HP and TQ correlate to your Dyno as closely as possible ,
after that, then you Calculate Header Specs.
You can also estimate Ve% by choosing one of the choices
in [ Estimate Ve% ] Menu .... , and the greatest accuracy is when all 3 agree closely .
if all 3 do not agree closely....then most likely trying
to estimate VE will not be accurate enough using
these 3 methods. i would only trust these 3 methods if
all 3 agreed pretty close.
And you should always account for Carb and Manifold
Flow CFM Losses for greatest accuracy.
in next version..there will be Input for this as well !!
6. What are others selecting as their fps target. Default is 300. Is that a target for only high lift, very high rpm race motors only?
You can change the Default of 300 FPS to anywhere
between 170fps to 350fps in the drop down Menu
[Velocity FPS] in Menu Bar at top.
300fps was simply chosen as Default ,
as its half way between 250fps and 350fps,
which are normal FPS Ranges encountered.
most of the NHRA small block style Heads i Port like
SBC and Chrysler...have as an average around 311 FPS
and for Methanol Engines 260fps is good starting point
and 260 to 285fps on gasoline engines are good starting points.
to begin to handle 285fps and faster speeds in intake ports,
the Shapes, Valve Job, and Bowl to Chamber transitions
must begin to be perfect.
these are all "Theoretical Average FPS" as calculated by
PipeMax. These FPS are for Users who do not have
a Pitot Probe. Pitot Probe FPS's or Pressures are much more
accurate than PipeMax.
Pitot Probe measurements relect the effects the Port's Shape
has on the Velocity Profile .
7. If you exceed the 100% eff are you simulating boost?
Simulating Boost ???...in a manner so to speak from the
combined effects of mixture inertia and wave action.
but not as Boost Psi to try to simulate
a SuperCharger or TurboCharger.
Many Engines in Naturally-Aspirated form i Dyno test
exceed 100.0 VE %.
---------------------------------------------------
You can use PipeMax 2 ways=>
1-the most accurate method=>.....you are already on the Dyno,
and have made 3 or 4 Pulls and know for sure the
RPM point of Peak HP.......at this point you Input
all your Engine specs into PipeMax, and calculate Hp and TQ,
you keep changine VE% Input a little at a time
until HP and TQ correlate to your Dyno as closely as possible ,
after that, then you Calculate Header Specs.
Then you go make Header/Exhaust changes
according to PipeMax
2-You choose or design to a certain RPM.
in PipeMax you Input the RPM you want Peak HP to occur at,
then PipeMax calculates all Specs you need to achieve that goal.
Posted:
Thu Jan 24, 2008 10:21 pmby gofaster
Is pipemax applicable to small engines, one or two cylinders? How would it benefit a tuner of small engines?
Posted:
Fri Jan 25, 2008 10:17 amby wfolarry
I work on Harleys. Have you compared any data from these motors in Pipemax? I have Pipemax & think it is an excellent program.
Posted:
Fri Jan 25, 2008 5:42 pmby stevenford
I tried to work out a VE by looking at cyl head and piston demand table but I seem to have too much flow, my head flows 290cfm but he table says I need 282cfm for 135VE
I don't think this engine could have that much VE, 4cyl Toyota
Posted:
Fri Jan 25, 2008 11:00 pmby wfolarry
I can give you flow #'s & dyno charts but they are all chassis dynos. I don't know anybody around here that is setup to run the motor alone. I also sponsor a friend's bike that races in hot street. Last year he ran consistent 9.95's with a best of 9.79 here in Joliet. That bike is a 113 ci. Dyno'd at 170hp last year [ don't know how reliable that was]. This year we bumped the cubes up to 124. If you want I could send you the slips from the track after each race. If you'd be interested in this or if there is some other info I can help you with let me know. The dealer show is coming up in Cincinatti Feb.1. I'll talk to my rep there & see if I can get you that info. from them or maybe arrange for you to contact them. never hurts to ask.
Larry
