I need to make a small correction. At minute 21 in the video I say that the larger flow benches that can draw 28” water test depression are more accurate than my smaller 10 inch unit but with a conversion factor of 1.67 the two flow benches would read the same. That is only mostly true. Higher test pressure will create higher air velocities and if there is an inefficient short side radius the air will detach from the port floor. Harley’s are known For this and even my flow bench can pick this up on the twin cam and evolution heads pretty easily. The 28” test pressure will find this symptoms earlier and easier. Also, my little flow bench is good to about 190cfm at 10” total flow. That equals 320cfm off of a 28” test pressure out of a bigger flow bench. Beyond that my flow bench struggles. So far all the Harley heads I have tested were no problem as well as small block and oval port big block heads. Big block heads flowing 400 cfm are way out of my test range. That is where the bigger flow benches are a necessity.
I know this is a long one at 39 minutes. Normally I would keep these types of videos 15-30 minutes, but I encourage you to watch to the end. The end of this video teases a few upcoming projects I plan to film and post on RUclips. Also, I tell of more things I plan to do with this channel beyond the classroom style teaching videos I have posted so far. In short, I plan to expand this channel into many areas of automotive interests.
Watch for the next video, Racing Physics Class #6 which will go into an introduction into Volumetric Efficiency, how to increase it, and what the benefits are.
If you have a modern high flowing cylinder head this formula might be a little more accurate: 1150 / displacement x CFM These are just estimates. Intake runner length. Header length and many other things will effect actual peak power rpm but this will get you in the ballpark for an optimized race engine with optimum cam, compression, carb, ect….
Eric definitely does great work from the videos I’ve seen. He has way better equipment and more knowledge on that stuff than me. I hope you like my channel. I’ll eventually get to MOPAR stuff. I’m a big fan of everything MOPAR. I’ve got a 413 I plan to build. I’ve got a couple 318’s sitting around I want to make into a high rpm screamer. I’ve got a couple 360’s. And of course the 1956 Hemi in the dragster. Thank you for your comments.
Nice job ... There is more in your flow bench manual ...look at inertia ram theory ..... I explain more about this on my RUclips channel and how to Factor in the camshaft into hp .... Plus what all effects rpm with of course more math which i think you would like .... My channel is my name plus Cadillac because i do the Cadillac engine ..then look at playlist marked chalkboard videos..... Keep up the good work ...Scott Hatch
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I need to make a small correction. At minute 21 in the video I say that the larger flow benches that can draw 28” water test depression are more accurate than my smaller 10 inch unit but with a conversion factor of 1.67 the two flow benches would read the same. That is only mostly true. Higher test pressure will create higher air velocities and if there is an inefficient short side radius the air will detach from the port floor. Harley’s are known For this and even my flow bench can pick this up on the twin cam and evolution heads pretty easily. The 28” test pressure will find this symptoms earlier and easier. Also, my little flow bench is good to about 190cfm at 10” total flow. That equals 320cfm off of a 28” test pressure out of a bigger flow bench. Beyond that my flow bench struggles. So far all the Harley heads I have tested were no problem as well as small block and oval port big block heads. Big block heads flowing 400 cfm are way out of my test range. That is where the bigger flow benches are a necessity.
I know this is a long one at 39 minutes. Normally I would keep these types of videos 15-30 minutes, but I encourage you to watch to the end. The end of this video teases a few upcoming projects I plan to film and post on RUclips. Also, I tell of more things I plan to do with this channel beyond the classroom style teaching videos I have posted so far. In short, I plan to expand this channel into many areas of automotive interests.
Cool
Watch for the next video, Racing Physics Class #6 which will go into an introduction into Volumetric Efficiency, how to increase it, and what the benefits are.
Awesome info, I'm just getting back into the sport. What is the rpm formula for 28 inches, thank you.
1200 / displacement x CFM
If you have a modern high flowing cylinder head this formula might be a little more accurate:
1150 / displacement x CFM
These are just estimates. Intake runner length. Header length and many other things will effect actual peak power rpm but this will get you in the ballpark for an optimized race engine with optimum cam, compression, carb, ect….
Thanks, it's a 440 with 452 heads. I'm restoring a 71 challenger. Eric weingarner flow these years ago.
That is awesome!
Eric definitely does great work from the videos I’ve seen. He has way better equipment and more knowledge on that stuff than me. I hope you like my channel. I’ll eventually get to MOPAR stuff. I’m a big fan of everything MOPAR. I’ve got a 413 I plan to build. I’ve got a couple 318’s sitting around I want to make into a high rpm screamer. I’ve got a couple 360’s. And of course the 1956 Hemi in the dragster. Thank you for your comments.
Nice job ... There is more in your flow bench manual ...look at inertia ram theory ..... I explain more about this on my RUclips channel and how to Factor in the camshaft into hp .... Plus what all effects rpm with of course more math which i think you would like .... My channel is my name plus Cadillac because i do the Cadillac engine ..then look at playlist marked chalkboard videos..... Keep up the good work ...Scott Hatch
Thank you. I appreciate it. I will cover more of all that stuff once I get into volumetric efficiency. I’ll check out your channel.
Quit smacking 😮
You should learn how to do your videos with voice over far superior and you can edit