Calculating CFM used from Dyno sheet ?

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Warp Speed
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Re: Calculating CFM used from Dyno sheet ?

Post by Warp Speed »

DrillDawg wrote: Sat May 19, 2018 1:32 pm 2nd pulse is the strongest, but the longest, 4th the weakest, but the sbortest, each time it gets weaker.
Yes, the third is typically the e easiest to work with in most all architectures. I am guessing the old Chrysler cross ram was aimed at the second?
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Re: Calculating CFM used from Dyno sheet ?

Post by pastry_chef »

groberts101 wrote: Sat May 19, 2018 10:23 am What I don't understand is how someone could be so well versed in engine theory and design yet not believe in wave tuning?
Has anyone listened to this interview and his comments on wave tuning?
So experienced doubters exist.
https://www.speed-talk.com/shows/012_jere_stahl.html

I DO believe in wave tuning.
Mike R
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Re: Calculating CFM used from Dyno sheet ?

Post by DrillDawg »

BORN RIGHT THE FIRST TIME
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Re: Calculating CFM used from Dyno sheet ?

Post by user-23911 »

Warp Speed wrote: Sat May 19, 2018 2:19 pm
DrillDawg wrote: Sat May 19, 2018 1:32 pm 2nd pulse is the strongest, but the longest, 4th the weakest, but the sbortest, each time it gets weaker.
Yes, the third is typically the e easiest to work with in most all architectures. I am guessing the old Chrysler cross ram was aimed at the second?

The first pulse or reflected wave is the strongest.
The second will reduce power as do all the even ones.
The 3rd is next strongest followed by the 5th, 7th 9th etc all progressively diminishing in amplitude.


Nobody uses the first (or 3rd) due to the excessive pipe length required but it would be easy to demonstrate on a dyno.


The Chrysler cross ram works out at about the 7th harmonic, or as the 4th (wave) to those who don't understand harmonics.
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Re: Calculating CFM used from Dyno sheet ?

Post by DrillDawg »

I was just referring to the three examples in my post, and which cross ram are you talking about. I just know that the wave bounces around in the intake tract from the valve closing and hope that the wave makes it back to the valve when it opens again.
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Re: Calculating CFM used from Dyno sheet ?

Post by user-23911 »

The wave keeps on bouncing back and forth due to it's stored energy. The energy is gradually lost as heat due to friction etc.
Exactly as demonstrated in one of the above videos.
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Re: Calculating CFM used from Dyno sheet ?

Post by Firedome8 »

n2xlr8n wrote: Sat May 19, 2018 10:38 am
groberts101 wrote: Sat May 19, 2018 10:23 am
n2xlr8n wrote: Sat May 19, 2018 6:50 am
Rhetorical statement, I know.

But to the OP, pressure waves are certainly not a joke.

Most of my career has been focused on waves of some sort.

I used to show these vids to students having trouble with the function:

https://www.youtube.com/watch?v=BWraEDaVXZM
What I don't understand is how someone could be so well versed in engine theory and design yet not believe in wave tuning? Seems highly counter-intuitive in the scheme of what goes on inside a constantly moving uni-directional mass and exploding combustion engine.

Ever see fuel standoff above a carb or injector trumpet? The power of multi-directional waves combining to create standing waves can easily levitate those small droplets of fuel.

So even testing same tube diameter headers.. subtle changes in bend radius and number of bends along with slight length variations can cause different reflected wave tuned results that Randy is pointing towards here. Very real phenomena and extremely well studied for the last hundred years or so.

Tons of vid's out there showing sound wave levitation capabilities over solid objects much heavier than air. I had a few good ones saved on my other downed hard drive but I will see if I can recollect their names and post them up here.
Or the pulses exiting the zoomies on a TF FC at night....the pulsed RF waves (with E and H fields) accelerating an electron to 99.997% of the speed of light...two sound sources out of phase, algebraically cancelling or adding a phase shift to the sound our brains register, etc.

Waves are cool :wink:
I too think waves are kool , I have often tried to visualize the goings on in an engine. I like to see it modeled like an electronic circuit to help in the understanding.
A good test is worth a thousand opinions.
Smokey
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Re: Calculating CFM used from Dyno sheet ?

Post by DrillDawg »

Thanks joe 90, you have been a lot of help.
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Re: Calculating CFM used from Dyno sheet ?

Post by Warp Speed »

joe 90 wrote: Sat May 19, 2018 6:06 pm
Warp Speed wrote: Sat May 19, 2018 2:19 pm
DrillDawg wrote: Sat May 19, 2018 1:32 pm 2nd pulse is the strongest, but the longest, 4th the weakest, but the sbortest, each time it gets weaker.
Yes, the third is typically the e easiest to work with in most all architectures. I am guessing the old Chrysler cross ram was aimed at the second?

The first pulse or reflected wave is the strongest.
The second will reduce power as do all the even ones.
The 3rd is next strongest followed by the 5th, 7th 9th etc all progressively diminishing in amplitude.


Nobody uses the first (or 3rd) due to the excessive pipe length required but it would be easy to demonstrate on a dyno.


The Chrysler cross ram works out at about the 7th harmonic, or as the 4th (wave) to those who don't understand harmonics.
Kinda as I mentioned, they all deminish after the first, but trying to use the second comes at a big compromise, as the tract needs to be excesivly long, hurting it in other ares.
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Re: Calculating CFM used from Dyno sheet ?

Post by hoffman900 »

Stan Weiss wrote: Sat May 19, 2018 11:10 am
hoffman900 wrote: Sat May 19, 2018 10:44 am
swampbuggy wrote: Sat May 19, 2018 10:36 am Uni-directional-----i can not for the life of me believe other than, at 9000 RPM's the air/fuel mixture is moving "MOSTLY" one direction----towards the cylinder. ???????? Mark H. :D
I'll post lots of graphs later on at both peak hp and peak torque. Have stuff to do..

In the meantime..

Jon Kaase's clear manifold:
https://www.youtube.com/watch?v=7Iq1B-2paCs

Renault Formula One engine dyno (circa 2006):
https://www.youtube.com/watch?v=y2iBbwocYZw

Harley horsepower shootout winner:
https://www.youtube.com/watch?v=pvECwI7ODwE
Stan Weiss wrote: Sat May 19, 2018 10:41 am

Bob,
Thanks. If it is not a lot of work can you produce another one of those at what will be the RPM you shift at?

Stan
Stan, I accidentally overwrote that file, but I produced a new file (slightly different exhaust) while eating breakfast this morning. Does peak hp and peak torque work? I have most of them saved, just need some time to post them up and type a key.
Bob,
Yes, that should work.

You need a better data back up system. I have an external hard drive that I can hookup and use about once a month. But I always have a USB thumb drive plugged in and back what I am working on to there at least one a day.

Stan
Stan, here you go:

Power in hp/torque units.
Image

Pressures at peak torque. This would be the cylinder, and at each valve:
Image
Pressures at peak horsepower. Same as above.
Image

Mass flow at peak torque. Again, for simplicity sake, I kept this at the valve:
Image
Mass flow at peak horsepower.
Image

Mach Index at peak torque. InPMach(1) and ExPMach(1) are located 3.93" (100mm) from the valve seats in their respective ports. InVMach(1) and ExVMach(1) are through the valve seat.
Image
Mach Index at peak horsepower. Same key as above.
Image

I'm pretty good about backing things up, I just sometimes rename things as something I already did previously. #-o
-Bob
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Re: Calculating CFM used from Dyno sheet ?

Post by swampbuggy »

Hoffman900, please do not get the idea that i don't believe that there are pulses and waves or what ever you wish to call them going on. I had seen the John K. lexan manifolded engine on the dyno and that was a very cool video. In your opinion do you think the quite long intake manifold runners on the NASCAR engines are that long to work WITH the pulses going on ? :?: Mark H
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Re: Calculating CFM used from Dyno sheet ?

Post by hoffman900 »

swampbuggy wrote: Sun May 20, 2018 4:19 pm Hoffman900, please do not get the idea that i don't believe that there are pulses and waves or what ever you wish to call them going on. I had seen the John K. lexan manifolded engine on the dyno and that was a very cool video. In your opinion do you think the quite long intake manifold runners on the NASCAR engines are that long to work WITH the pulses going on ? :?: Mark H
A NASCAR manifold (any single carburetor V8 manifold) is a series of compromises. The designer has so many competing interests:
Runner length to hit a certain harmonic
The valve angle is dictated by a lot (combustion chamber shape, valve train limitations) which effect the angle the port leaves the head, which effects everything.
Taper
Plenum volume
Equalizing air/fuel ratio
Hood clearance
etc.

All this still exists with the EFI they currently have. It would be nice if they could just come off the head in a straight line to an individual throttle body type manifold.

Clint Grey (nitro2) posted one time on the effects of harmonic tuning vs. inertia. He did say if you want to test this, have runner long enough that the intake valve will be closed by the time the wave returns. Let me see if I can dig some posts up.
-Bob
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Re: Calculating CFM used from Dyno sheet ?

Post by swampbuggy »

VERY VERY interesting Bob, would appreciate anything you can add, Mark H. =D>
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Re: Calculating CFM used from Dyno sheet ?

Post by hoffman900 »

swampbuggy wrote: Sun May 20, 2018 6:58 pm VERY VERY interesting Bob, would appreciate anything you can add, Mark H. =D>
Well, this is pretty typical of what is (was?) used in Australian V8 Supercars:
Image

Here is similar to what NASCAR uses:
Image


One of the EMC teams used this one year:
Image

a tunnel ram is essentially that, except with the carburetors sitting over the runners and the bellmouths flush to the floor. Plenum volume on this manifolds are too big for circuit racing. I don't know what the insides look like, but I believe they're a bit like this:
Image
Basically a tunnel ram with lid.


In regards to Acoustic Wave Action vs Mass Inertia, This is one of the all time great threads here:
https://www.speed-talk.com/forum/viewtopic.php?f=15&t=28901
Vannik, Schmidtmotorworks, and Nitro2 are the posters to pay attention to (not that others don't add anything, they certainly do!).
-Bob
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Re: Calculating CFM used from Dyno sheet ?

Post by Scotthatch »

15267463087920.jpg

So am I to assume that the people that posted fully agree with this page on acoustical wave and how it works to make power?
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