[DeTomaso] High Ported Iron Closed Chamber 4V head flow results
Daniel C Jones
daniel.c.jones2 at gmail.com
Sun Feb 9 21:26:00 EST 2014
> What we need is information, which is different. :>)
Number 2: We want information... information... information.
Number 6: You won't get it.
Number 2: By hook or by crook, we will.
> Can you provide some additional context, i.e. compare those numbers with standard 351C heads, CHI, C302B, and any others that are known?
Iron High Ported Pro Stock Style head:
Lift Intake Exhaust
Inch CFM CFM
0.025 15.9 10.2
0.050 33.2 28.5
0.100 65.6 60.0
0.150 100.6 89.0
0.200 137.8 109.8
0.250 167.6 124.1
0.300 195.8 141.4
0.350 224.0 155.4
0.400 245.6 166.8
0.450 261.4 176.7
0.500 278.8 185.3
0.550 289.7 194.7
0.600 300.9 204.2
0.650 312.1 215.2
0.700 322.0 225.8
0.750 325.7 234.4
0.800 307.8 239.7
You can compare to the numbers I previously posted of Brian Hill's
iron 4V heads:
Lift Intake Exhaust
Inch CFM CFM
0.025 13.90 10.90
0.050 33.10 26.50
0.100 66.40 52.20
0.200 140.20 97.90
0.300 201.20 129.90
0.400 251.40 152.30
0.500 290.90 165.50
0.600 313.90 172.70
0.700 301.70 173.30
0.800 303.20 174.70
The exhaust of the high ported heads flow more at 0.450" than Brian's
heads do at 0.800". They also peak at 240 CFM versus 175 CFM so a
huge increase in exhaust flow. You'd certainly want a different cam
profile for those heads compared to Brian's. The Ford Motorsport A3
heads are a direct descendant from the iron high ported 4V heads. The
A3 intake port is similar to a 4V but with a raised floor (similar to
a 4V with a Roush intake port stuffer. Here's a picture of a 4V
gasket on top of an A3 port:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/4V_intake_gasket_on_A3_head.jpg
What's not obvious is the A3 roof is also higher (obscured behind the
gasket). On the exhaust side:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/351C_head_comparison_b_exh_cropped.jpg
On the left above is the iron 4V with an aluminum high port exhaust
port plate that produced the flow numbers above. You can see the lower
edge of the original exhaust port (painted blue).
In the middle is an A3 port which is slightly higher with a more
uniform round shape, instead of the weird area changes of the iron 4V
exhaust port. At the right is a ported C302B. The C302B
ports start out much smaller Here are the flow numbers for the
unported (just a cartridge roll clean up) A3 heads:
Valve M-6049-A3
Lift Intake Exhaust
(inch) 2.19" 1.71"
0.025 15.7 11.7
0.050 34.6 28.1
0.100 65.5 56.7
0.150 95.2 87.5
0.200 129.2 109.8
0.250 161.5 121.9
0.300 188.8 142.4
0.350 216.4 154.5
0.400 242.8 167.0
0.450 265.6 177.7
0.500 287.7 186.7
0.550 305.8 195.9
0.600 321.4 204.4
0.650 331.2 211.7
0.700 337.7 216.3
0.750 317.6 221.8
The evolution of these heads (A3 ==> B351 ==> C302) was towards
smaller higher velocity ports. Here are flow numbers for a C302B
head:
Valve M-6049-C302B
Lift Intake Exhaust
(inch) 2.19 1.65
0.050 51 ---
0.100 81 ---
0.150 120 ---
0.200 157 131
0.300 223 180
0.400 266 210
0.500 306 223
0.600 331 228
0.650 --- 230
You'll notice the ported C302B heads outflow the the unported A3s with
a smaller exhaust valve.
You can also compare Brian's 4V heads to those Pro Comp Chinese copies
of the CHI 3V heads:
Lift Intake Exhaust
(in) CFM CFM
0.025 12.4 10.8
0.050 23.4 26.8
0.100 31.6 53.0
0.150 45.1 64.3
0.200 68.3 85.7
0.250 97.5 109.1
0.300 129.6 123.6
0.350 160.1 139.1
0.400 185.7 151.6
0.450 213.4 162.8
0.500 238.2 169.2
0.550 261.1 177.1
0.600 277.9 184.6
0.650 288.8 189.0
You can see that not only does the intake flow susbstantially less
than Brian's 4V heads, the exhaust outflows the intake all the way up
to 0.350" on the Pro Comps. That is worse than useless and explains
why they were down 30 HP on the dyno on a 400+ HP 351C compared to
unported iron 4V heads and even more (50 HP) compared to the real CHI
3V heads.
> Also, I presume that flow numbers can translate into horsepower, but is there a linear relationship?
The rule of thumb for normally aspirated 2 valve V8 cylinder heads is
2 to 2.2 HP per 1 intake CFM at a 28" pressure drop. This is a very
rough estimate and assumes the rest of the engine can support it
(heads alone don't make the power). In practice, Dave McLain built a
438 cubic inch Clevor with unported CHI 3V heads and intake, Demos
street solid roller and 10.5:1 compression that made 666 HP at 6300
RPM. Those heads flowed around 320 CFM which is in rule of thumb
range.
> Can a head flow TOO well, such that the engine only works at higher rpm? (That was always the armchair criticism of the 351C--that the 4V ports were too large to produce good power results with only 351 inches at moderate rpm levels).
I've never seen a cylinder head that flowed too well but I have seen
heads that flowed too slowly. Volumetric flow rate (CFM) is only part
of what it means to flow well. In addition to speed, the incoming air
has mass. so has momentum. Higher velocity means higher momentum and
more potential power. For a given normally aspirated engine, there is
an ideal minimum port cross-sectional area and associated velocity.
Too large or too small relative to that ideal will lose average power
(between RPM points). For most applications, the minimum
cross-sectional area of a 351C-4V head is too large and the flow too
slow. Slow flow is more prone to reversion and has relatively poor
part throttle response and fuel economy. So a more accurate arm chair
criticism is the port velocity is too slow. Also, the taper angle is
too large. You can do various things to try to reduce the intake
tract cross-sectional area (smaller port intakes, intake and exhaust
port stuffers, etc.) and the 351C seems to respond. One of the
reasons why the 351C-4V responds so well to stroking is it increases
the intake velocity for a given port size.
> For the amateur engine builder, what are shear vanes?
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/351C_head_comparison_b_int.jpg
In the 4V head on the left, they are the fins put in the bottoms of
the intake ports. They look like turning vanes but I believe their
function was to break up fuel droplets that fall out of the air-fuel
mixture due to
poor intake velocity.
Dan "I am not a number" Jones
On Sun, Feb 9, 2014 at 6:38 PM, mark skwarek <ehpantera at yahoo.com> wrote:
> Are there any pictures of the vanes that are being discussed?
> Mark
>
>
>
> On Sunday, February 9, 2014 7:23 PM, Stephen Nelson <steve at snclocks.com>
> wrote:
> I believe flow vanes act to reduce turbulence in a flow stream. The
> Reynolds number, a dimensionless quantity that is used to help predict
> similar flow patterns in different fluid flow situations, is directly
> proportionate to the diameter of the flow channel. Putting in a vane
> reduces the flow diameter, thereby reducing turbulence and increasing flow.
>
> Stephen Nelson
>
> SNClocks.com
> Click here to join one of our mailing lists Contact Lists
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> From: DeTomaso [mailto:detomaso-bounces at poca.com] On Behalf Of Charles
> Engles
> Sent: Sunday, February 09, 2014 4:16 PM
> To: michael at michaelshortt.com; 'Sean Korb'
> Cc: 'POCA list'
> Subject: Re: [DeTomaso] High Ported Iron Closed Chamber 4V head flow results
>
> Dear Michael,
>
>
> I *think* the example was that the vanes act to minimize
> the air flow from layering out into laminar flow and turbulent flow. I
> *think* it keeps the boundary layer from becoming laminar.
>
>
> FWIW, Chuck Engles
>
>
>
> From: DeTomaso [mailto:detomaso-bounces at poca.com] On Behalf Of
> michael at michaelshortt.com
> Sent: Sunday, February 09, 2014 5:57 PM
> To: Sean Korb
> Cc: POCA list
> Subject: Re: [DeTomaso] High Ported Iron Closed Chamber 4V head flow results
>
> Not sure why the Jet engine was used as an example, those S shaped port
> directors in those engines are designed to slow the air down by several
> hundred miles per hour before it enters the jet engine.
> SST and SR71 did too.
> Why would you want to slow down your fuel air mix? Performance items like
> Blowers and Superchargers are used to increase the speed and pressure to
> attain greater performance.
> I don't get why that was an example.
> Michael
> On Feb 9, 2014 6:47 PM, "Sean Korb" <spkorb at gmail.com> wrote:
> I'm not sure if this is germane but I am utterly fascinated.
>
> http://speedtalk.com/forum/viewtopic.php?t=4785
>
>
> On Sun, Feb 9, 2014 at 5:55 PM, Charles Engles <cengles at cox.net> wrote:
>> Dear Dan,
>>
>>
>> You wrote: "....and shear vanes screwed into the intake
>> port
>> floors."
>>
>> For the amateur engine builder, what are shear vanes?
>>
>> Very curious, Chuck Engles
>>
>> -----Original Message-----
>> From: DeTomaso [mailto:detomaso-bounces at poca.com] On Behalf Of Daniel C
>> Jones
>> Sent: Sunday, February 09, 2014 4:24 PM
>> To: POCA list
>> Subject: [DeTomaso] High Ported Iron Closed Chamber 4V head flow results
>>
>> A while back, Dave McLain flowed a set of old iron closed chamber 4V heads
>> with the 1970's Pro Stock style high port exhaust plate and shear vanes
>> screwed into the intake port floors. I thought I'd share the results.
>> Flowed on a Super Flow bench. Tested at 10" and converted to 28". 2.19"
>> intake valve and 1.71" exhaust. Completely stock combustion chambers.
>>
>> Lift Intake Exhaust
>>
>> Inch CFM CFM
>>
>> 0.025 15.9 10.2
>>
>> 0.050 33.2 28.5
>>
>> 0.100 65.6 60.0
>>
>> 0.150 100.6 89.0
>>
>> 0.200 137.8 109.8
>>
>> 0.250 167.6 124.1
>>
>> 0.300 195.8 141.4
>>
>> 0.350 224.0 155.4
>>
>> 0.400 245.6 166.8
>>
>> 0.450 261.4 176.7
>>
>> 0.500 278.8 185.3
>>
>> 0.550 289.7 194.7
>>
>> 0.600 300.9 204.2
>>
>> 0.650 312.1 215.2
>>
>> 0.700 322.0 225.8
>>
>> 0.750 325.7 234.4
>>
>> 0.800 307.8 239.7
>>
>> Not too bad for 1970's small block cylinder heads.
>>
>> Dan Jones
>>
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>
>
>
> --
> Sean Korb spkorb at spkorb.org http://www.spkorb.org/
>
> '65,'68 Mustangs,'68 Cougar,'78 R100/7,'60 Metro,'59 A35,'71 Pantera #1382
> "The more you drive, the less intelligent you get" --Miller
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