Charles Servedio just posted a video porting SBM cast iron intake with Thermoquad

[StreetSleeper]

At .500” lift together they only flow 217.6 cfm.

.1” 70 cfm
.15” 95.5
.2” 124
.2.5” 147
.3” 167.2
.3.5” 184.2
.4” 198.1
.4.5” ?
.5” 217.6

222.56

My question is: if this induction setup is a choke point,

why would it matter if someone ran mildly (or full ported for 920/302) ported 318 heads heads on their small block mopar if stock induction is limiting? **

Basically 220 cfm being the choke point stock? Which is a hair above 2.02 j head flow, maybe right at X head flow (stock)

Does the ported 318 equal the other two heads in performance with the thermoquad & cast iron intake induction, or would the j/x head pull/flow more air through the ‘choke point’?

Thank you for your answers !

** (Which has been instructed against on this Fabo SBM focus threads since I have been here)
His 920 heads fully ported at 222cfm & 302 heads slightly less, plus if I remember correctly that is what one wild crazy guy about had for his 920 head flow when he ported 920’s as well.

 

[273]

It seems to me intakes can make more hp per cfm than heads, what I mean is the rule of thumb is an engine can make at least 2 hp per cfm (apparently max is 2.5 hp per cfm) but you generally don't see that I use 1.8 hp per cfm. But a lot of intakes will bring the overall flow down but still be able to make 400-500+ hp stock unported even though there flow would suggests otherwise. Like to see more intake flow data and dyno results but seems like you can get pretty far with an unported intake.

 

[273]

Don't forget there's two main parts to this equation, flow is only one and velocity is the other, which both is made up from shape and size.

 

[StreetSleeper]

Don't forget there's two main parts to this equation, flow is only one and velocity is the other, which both is made up from shape and size.

Velocity is the speed of the flow??
And flow is the volume of movement of air???
I don’t see how the two terms can be seperate.

Please explain to me, thank you!

(Margin Call movie):
“Please, speak as you might to a young child. Or a golden retriever. It wasn't brains that brought me here; I assure you that.”

 

[273]

Say a head flows 200 cfm, cubic feet per minute, a smaller port would have to move air faster (fps feet per second) to still be able to move the same overall cfm as a larger port.

 

[ch1ll]

There's alot more to the rest of the engine in reaching 2.5 hp per 1cfm just like there is more to power producing flow than cfm and velocity.

 

[fishmens67]

Ideally an intake should flow 20-30% more than a cylinder head

 

[ch1ll]

The most concerning thing about that combo is the lack of mid lift swirl.

 

[ch1ll]

Ideally an intake should flow 20-30% more than a cylinder head

I don't believe you will find any single 4 barrel intakes for a small block mopar that's going to do that. That's tunnel ram territory.

 

[fishmens67]

That's tunnel ram territory.

It usually is or a fabricated sheet metal intake.
Indy and Victor can get real close.

 

[273]

There's alot more to the rest of the engine in reaching 2.5 hp per 1cfm just like there is more to power producing flow than cfm and velocity.

No one said there wasn't, I even stated I feel 1.8 hp per cfm is a more likely achievable goal for most compared to the 2 hp rule of thumb (obviously with the right combo).

 

[273]

(Margin Call movie):
“Please, speak as you might to a young child. Or a golden retriever. It wasn't brains that brought me here; I assure you that.”

Or think of it this way, you got a bridge that Max a 1,000 cars can cross per hour at 80 mph, but you want the same car capacity but cut speed in half to 40 mph, you would need to double the width of the bridge.

 

[ch1ll]

No one said there wasn't, I even stated I feel 1.8 hp per cfm is a more likely achievable goal for most compared to the 2 hp rule of thumb (obviously with the right combo).

I would believe 1.8 would be pushing it with stock aftermarket parts and common builds.

 

[273]

I would believe 1.8 would be pushing it with stock aftermarket parts and common builds.

I don't understand what that's got to do with my point, I believe the OP is asking is there a point to use heads that flow more than the intake and I'd say yes.

 

[273]

Ideally an intake should flow 20-30% more than a cylinder head

I'm just curious where you got that from ?

Not saying/implying your wrong (just never heard of that).

 

[fishmens67]

I'm just curious where you got that from ?

Not saying/implying your wrong (just never heard of that).

It's common knowledge

 

[ch1ll]

It's common knowledge

Ron white called it a known fact.

 

[ch1ll]

I don't understand what that's got to do with my point, I believe the OP is asking is there a point to use heads that flow more than the intake and I'd say yes.

I'm not disagreeing with you, actually I agree with you.
I just believe 1.8 is a little generous, but my saying so is a butt dyno thing, it carries no weight.

 

[ch1ll]

It would be interesting to know the dyno results of the build. What would be really be interesting is the rest of the build be done by Brian Salter who is spec' ing the cam, that way you'd know the true potential of all the porting work that was done.

 

[MOPAROFFICIAL]

At .500” lift together they only flow 217.6 cfm.

.1” 70 cfm
.15” 95.5
.2” 124
.2.5” 147
.3” 167.2
.3.5” 184.2
.4” 198.1
.4.5” ?
.5” 217.6

222.56

My question is: if this induction setup is a choke point,

why would it matter if someone ran mildly (or full ported for 920/302) ported 318 heads heads on their small block mopar if stock induction is limiting? **

Basically 220 cfm being the choke point stock? Which is a hair above 2.02 j head flow, maybe right at X head flow (stock)

Does the ported 318 equal the other two heads in performance with the thermoquad & cast iron intake induction, or would the j/x head pull/flow more air through the ‘choke point’?

Thank you for your answers !

** (Which has been instructed against on this Fabo SBM focus threads since I have been here)
His 920 heads fully ported at 222cfm & 302 heads slightly less, plus if I remember correctly that is what one wild crazy guy about had for his 920 head flow when he ported 920’s as well.

Yes. Done this already before severed'labido did his.

Click bait borrowed idea, as usual.

 

[fishmens67]

 

[ch1ll]

Yes. Done this already before severed'labido did his.

Click bait borrowed idea, as usual.

Exactly what are you saying?

 

[rumblefish360]

Click bait borrowed idea, as usual.

Exactly what are you saying?

Yes, please clear that up.

 

[furrystump]

I’m just a ham fisted monkey, but this is how I think about it. The force creating the flow starts in the cylinder and is first seen at the bowl. Then onward back through the intake tract. You “want” to create the greatest pressure differential you can and transmit that back through the head then the intake then the carb. Say the head flows more than the intake. The velocity of the charge will increase in the intake. At some point, the velocity gets so high, problems occur. Fuel separation etc. I’m not sure at what point it goes bad. What I’m absolutely sure about is the thermoquad intake and carb when massaged can support 275+ CFM of head flow to the tune of 420 CI’s at 130+ mph. So you aren’t probably aren’t going to be out flowing it at 222 cfm. I believe the aftermarket intakes improve the quality of the charge more than the gross air flow, but remember ham fisted monkey!

 

[ch1ll]

Yes. Done this already before severed'labido did his.

Click bait borrowed idea, as usual.

Still waiting for your reply.