How about cfm per sqin at the maximum velocity that will allow the intake charge to move cleanly through said port and it's changes in CSA and direction without causing choke, separation or turbulence.
Can we agree on that and move on with the discussion? I think most here know it's not just the CFM number.
I do try to move on but some guys get very hung up on any other way of doing things but there way .... the idea that this forum was to discuss like adults what we each believe without being attacked or bullied seems to be lost in egos that have to be right at all cost and the shame of it is that there are big names that would share with the rest of us more of what they know but don't because they get attacked ... even when I don't agree with a post I am interested in why they think what they do and how they make it work as you never know what others have learned that can make you think about something new.........
You'll never win, best to just put in your 2cents and hope for the best. Even the best don't agree and a lot of the rest are just parrots, but it can't be a forum without the freedom to say what you want to say.
DrillDawg wrote: ↑Fri Jun 08, 2018 11:40 am
You'll never win, best to just put in your 2cents and hope for the best. Even the best don't agree and a lot of the rest are just parrots, but it can't be a forum without the freedom to say what you want to say.
Right on target and great altruistic post.
IMO, there are guys here wanting to better understand everything from lawnmower to F1 engines and everything in between that's ever been invented to turn a wheel or shaft, but far too many guys get too caught up thinking that this place is called.. mypersonalracespace.com. So over time speedtalk has become a completely subjective and personally relative experience for some posters. Live and let live.. learn or don't learn.. freedom is a great thing if you can enjoy it without hurting others in the process.
Everyone that has pulled heads and ported them to gain power is doing so to up the cfm flow not to change some wave characteristic .... when you add high ratio rockers and gain power why is it helping? More flow from peak lift? Changing cam specs? Or did it change the waveform?
You guys are so hung up on the cool idea of how to refine a engine you have forgotten the bread and butter of how it works most of the time .....
Not really, you start with the basics (bread and butter as you mention) then add the rest to over achieve!
Scott, most of your views are based purely on the data supplied in the Superflow manual and inertia-supercharging effect. Being as you do not believe in the resonant pulses /waves and their effects on the intake tract, did you skip page 31 9.0, or just don't believe it?
Scotthatch wrote: ↑Fri Jun 08, 2018 12:33 pm
15267463087920.jpg
I'm assuming that your are talking about this page ....
Sorry about the link I will see if I can fix it ...
Yes. It appears you base most of your math and such off of the following page, but discredit pressure waves in the intake tract having an effect on performance?
Scotthatch wrote: ↑Fri Jun 08, 2018 12:33 pm
15267463087920.jpg
I'm assuming that your are talking about this page ....
Sorry about the link I will see if I can fix it ...
Yes. It appears you base most of your math and such off of the following page, but discredit pressure waves in the intake tract having an effect on performance?
New link works ... little disjointed in that thread because there are several subjects running but faster then me typing it .... I do have a problem with acoustical wave propagation in the intake tract as being the primary reason for horsepower being made .... I do agree on the exhaust side it can be a help though not huge help ...
One thing being overlooked on SBC wave tuning is that most modern as cast parts have been designed with that factored in within the constraints of fitment, to fine tune that you would have to go to custom fabricated intake which is not legal in many racing bodies because of the possibility of dominating the class and there not cheap!
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
Scotthatch wrote: ↑Fri Jun 08, 2018 12:33 pm
15267463087920.jpg
I'm assuming that your are talking about this page ....
Sorry about the link I will see if I can fix it ...
Yes. It appears you base most of your math and such off of the following page, but discredit pressure waves in the intake tract having an effect on performance?
[/quote
New link works ... little disjointed in that thread because there are several subjects running but faster then me typing it .... I do have a problem with acoustical wave propagation in the intake tract as being the primary reason for horsepower being made .... I do agree on the exhaust side it can be a help though not huge help ...
If I'm tracking this thread correctly (and I may not be) it would seem a simple understanding of two stoke function actually proves wave tuning.
Early two strokes had little or no expansion chamber. As the expansion chamber developed, the two strokes specific output jumped ahead of four stroke specific output by leaps and bounds.
Scotthatch wrote: ↑Fri Jun 08, 2018 12:33 pm
15267463087920.jpg
I'm assuming that your are talking about this page ....
Sorry about the link I will see if I can fix it ...
Yes. It appears you base most of your math and such off of the following page, but discredit pressure waves in the intake tract having an effect on performance?
New link works ... little disjointed in that thread because there are several subjects running but faster then me typing it .... I do have a problem with acoustical wave propagation in the intake tract as being the primary reason for horsepower being made .... I do agree on the exhaust side it can be a help though not huge help ...
Have you ever done any testing in this area?
So you carve in stone pages 32-33, but page 31 is incorrect? That's what seems a little weird?
Yes. It appears you base most of your math and such off of the following page, but discredit pressure waves in the intake tract having an effect on performance?
New link works ... little disjointed in that thread because there are several subjects running but faster then me typing it .... I do have a problem with acoustical wave propagation in the intake tract as being the primary reason for horsepower being made .... I do agree on the exhaust side it can be a help though not huge help ...
Have you ever done any testing in this area?
So you carve in stone pages 32-33, but page 31 is incorrect? That's what seems a little weird?
I go with the part I see working .... I have looked for years for something that shows that page works .... and like I said before some of it conflicts with the ram effect calculation which does work .... I am well aware that the steady state flow model is not what happens in the running motor ... never said it was .... but the goal was to make better use of the cfm flow data from my bench to build better motors and to let those I port for know what to expect .... once I figured out it went along with the ram calculation in the superflow manual I started looking at what happened on engines not up to the number .... then with peak figured out the question was low end torque ...
This is not something I figured out yesterday I have been using it for almost 20 years ....
New link works ... little disjointed in that thread because there are several subjects running but faster then me typing it .... I do have a problem with acoustical wave propagation in the intake tract as being the primary reason for horsepower being made .... I do agree on the exhaust side it can be a help though not huge help ...
Have you ever done any testing in this area?
So you carve in stone pages 32-33, but page 31 is incorrect? That's what seems a little weird?
I go with the part I see working .... I have looked for years for something that shows that page works .... and like I said before some of it conflicts with the ram effect calculation which does work .... I am well aware that the steady state flow model is not what happens in the running motor ... never said it was .... but the goal was to make better use of the cfm flow data from my bench to build better motors and to let those I port for know what to expect .... once I figured out it went along with the ram calculation in the superflow manual I started looking at what happened on engines not up to the number .... then with peak figured out the question was low end torque ...
This is not something I figured out yesterday I have been using it for almost 20 years ....
I understand, but how can you expect others to believe your theories, when you totally discount the basic physics of engine dynamics?
I've done enough pressure analysis to know it is Very real.
And this isn't something we figured out yesterday! Lol
Warp Speed wrote: ↑Fri Jun 08, 2018 12:36 pm
Yes. It appears you base most of your math and such off of the following page, but discredit pressure waves in the intake tract having an effect on performance?
[/quote
New link works ... little disjointed in that thread because there are several subjects running but faster then me typing it .... I do have a problem with acoustical wave propagation in the intake tract as being the primary reason for horsepower being made .... I do agree on the exhaust side it can be a help though not huge help ...
If I'm tracking this thread correctly (and I may not be) it would seem a simple understanding of two stoke function actually proves wave tuning.
Early two strokes had little or no expansion chamber. As the expansion chamber developed, the two strokes specific output jumped ahead of four stroke specific output by leaps and bounds.
This would easily prove acoustical tuning.
Right, aside from various amounts of heat and unburned/hydrocarbon particulate %'s between the designs, an exhaust system knows not what type of combustion engine is generating those various amplitudes and multitudes of waves.. it only knows what temps, mass, and wave patterns(primary or residual) that needs to be moved within the constraints of its design.
Case in point. When I was living in Madison, WI many years ago there was a shop called Kelly Moss racing which specialized in Porsche's for many different road racing categories from mild to experimental classes. They did some flow bench testing and helped me with a few custom exhaust designs because at the time I was heavier into 2 strokes/snowmobile racing(even grass drags) that used differing yardsticks in design comparison to more familiar 4 stroke stuff. After seeing many of those cars up on lifts I was astounded to find out they were implementing many different shapes and sized expansion chambers into some, maybe even all?, of those cars. After having a few discussions with their custom exhaust designer(with mechanical engineering PHD) I was told that even the lower class club racers n such(some being heavily class limited 924's generating around 240'ish whp) would lose a consistent 8-12 ft/lbs off the corners without them. That really opened my eyes about what potentially happens acoustically within the exhaust systems of 2 AND 4 strokes and how it can affect the exhaust pulse tuning characteristics in both positive and negative ways.
The original research is not mine .....I found these Pages here on speed talk that I'm guessing are the data that the super flow tech manual was taken from ..... but the bottom line is that it works and it's simple enough to use and for you to test on engines you have built that you have accurate information on .... when I first figured it out I tried it on everything I had info on because it seemed a little to simple .... but it does work
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