Gm, I made a mistake yesterday. The narrowest part of the port measures 1.28" x 1.33" now this is not the exact port I flowed yesterday but it will be damn close. Now for some wonky stuff, that figures to 1.3 sq" x 147 equals 196cfm. Ok, so it is impossible to flow over 200 cfm? Interesting discussion point. Thanks, Charlie
Ported Chevy 083 heads, the tpi project
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Re: Ported Chevy 083 heads, the tpi project
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Re: Ported Chevy 083 heads, the tpi project
Making chips, "wonky" St has many super genius types that can do calculus in their sleep. They like the "wonky" stuff. They may not even read my threads to be honest.
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Re: Ported Chevy 083 heads, the tpi project
That straight on pic looks like it's even smaller to me...how far down in the bowl did you get the 86%?Carnut1 wrote: ↑Wed Apr 03, 2019 7:23 pmGm, I made a mistake yesterday. The narrowest part of the port measures 1.28" x 1.33" now this is not the exact port I flowed yesterday but it will be damn close. Now for some wonky stuff, that figures to 1.3 sq" x 147 equals 196cfm. Ok, so it is impossible to flow over 200 cfm? Interesting discussion point. Thanks, CharlieResized_20190403_191536_6185.jpeg
Re: Ported Chevy 083 heads, the tpi project
The nice thing with these castings as opposed to some of the others is the spark plug position.
It allows for generous angle milling to set the chamber volume to pretty much any you want.
What was the final chamber volume ? (Before any milling)
It allows for generous angle milling to set the chamber volume to pretty much any you want.
What was the final chamber volume ? (Before any milling)
Re: Ported Chevy 083 heads, the tpi project
Right under the lower cut of valve job. Which gets radiused in. Thanks, Charliegmrocket wrote: ↑Wed Apr 03, 2019 11:40 pmThat straight on pic looks like it's even smaller to me...how far down in the bowl did you get the 86%?Carnut1 wrote: ↑Wed Apr 03, 2019 7:23 pmGm, I made a mistake yesterday. The narrowest part of the port measures 1.28" x 1.33" now this is not the exact port I flowed yesterday but it will be damn close. Now for some wonky stuff, that figures to 1.3 sq" x 147 equals 196cfm. Ok, so it is impossible to flow over 200 cfm? Interesting discussion point. Thanks, CharlieResized_20190403_191536_6185.jpeg
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Re: Ported Chevy 083 heads, the tpi project
Pic of exhaust from flange. If you look you can see the paste ooze line around the bowl. So the exhaust port is not enlarged much from stock. So nobody will call b.s. to this port flowing over 100% efficiency at it's mcsa? So how is this possible? Thanks, Charlie
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Re: Ported Chevy 083 heads, the tpi project
isnt mcsa 1.28"x1.33" is 1.70 sq" ,not 1.3sq" ? why are you averaging the the two measurements and calling it sq inches?Carnut1 wrote: ↑Wed Apr 03, 2019 7:23 pmGm, I made a mistake yesterday. The narrowest part of the port measures 1.28" x 1.33" now this is not the exact port I flowed yesterday but it will be damn close. Now for some wonky stuff, that figures to 1.3 sq" x 147 equals 196cfm. Ok, so it is impossible to flow over 200 cfm? Interesting discussion point. Thanks, CharlieResized_20190403_191536_6185.jpeg
1.3 x 147 equals 191.1 anyway, not 196
so 1.7 x 147 = 249.9
Re: Ported Chevy 083 heads, the tpi project
I averaged two circles. One 1.28" and 1.33" that is 1.3" true the opening is not 100% round that is why I thought of it as two circles. Thanks, Charlie
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Re: Ported Chevy 083 heads, the tpi project
1.3" circle has 1.325 sq in area × 147 = 194.6 cfm.
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Re: Ported Chevy 083 heads, the tpi project
why not do it exact then? plot it out on paper if you have to and add it up. it sure isnt round. ....there are flat areas. or get a piece of solder and do a circumference measurement to get your area. thats what i do to figure area of odd shaped ports
Re: Ported Chevy 083 heads, the tpi project
I was trying to prove a point but I am over it. You stated it looked very small almost stock. Which in reality is true. It just sounds and flows better. Thanks, Charlie
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Re: Ported Chevy 083 heads, the tpi project
I have a question on if the double crossover exhausts on heads like this are that much of a detriment? Exhaust cylinder #1 without crossover vs. Cylinder #3 with crossover.
Cylinder #1. Cylinder #3
.05" 31.2. 31.4
.1" 66.2. 69
.15. 100. 102.2
.2. 124.8. 129
.25. 143. 148
.3. 157.3. 162.3
.35. 169.4. 173
.4. 177.8. 178.3
.5. 185.3. 183.8
.6. 188.1. 187.4
.7. 188.6. 189.1
I should add that the air that actually exits the crossover has an average velocity of 60ft/sec @ .5" lift. 183.8cfm.
This has to do with how I designed the exhaust. I have tested other heads that had very fast air passing through the crossover. This is the first time I measured the air speed. I get that the exhaust will work better if they are filled as far as tuning but is it really worth the effort?
Cylinder #1. Cylinder #3
.05" 31.2. 31.4
.1" 66.2. 69
.15. 100. 102.2
.2. 124.8. 129
.25. 143. 148
.3. 157.3. 162.3
.35. 169.4. 173
.4. 177.8. 178.3
.5. 185.3. 183.8
.6. 188.1. 187.4
.7. 188.6. 189.1
I should add that the air that actually exits the crossover has an average velocity of 60ft/sec @ .5" lift. 183.8cfm.
This has to do with how I designed the exhaust. I have tested other heads that had very fast air passing through the crossover. This is the first time I measured the air speed. I get that the exhaust will work better if they are filled as far as tuning but is it really worth the effort?
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Re: Ported Chevy 083 heads, the tpi project
Charlie,
What about my, stock, 2.02"/1.60" valve, way OLD, -461 heads?
They are '63 or '64 heads.
I know you wanted to get your hands on my new EQ 200 cc intake port 50 cc chambered heads that I am going to run on my 4.155" b x 3.00'" s = "325" engine if I live long enough?
pdq67
What about my, stock, 2.02"/1.60" valve, way OLD, -461 heads?
They are '63 or '64 heads.
I know you wanted to get your hands on my new EQ 200 cc intake port 50 cc chambered heads that I am going to run on my 4.155" b x 3.00'" s = "325" engine if I live long enough?
pdq67
Re: Ported Chevy 083 heads, the tpi project
461's have a single exhaust crossover so two less ports are affected.pdq67 wrote: ↑Sat Apr 13, 2019 9:34 pm Charlie,
What about my, stock, 2.02"/1.60" valve, way OLD, -461 heads?
They are '63 or '64 heads.
I know you wanted to get your hands on my new EQ 200 cc intake port 50 cc chambered heads that I am going to run on my 4.155" b x 3.00'" s = "325" engine if I live long enough?
pdq67
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