What would it take to make 1.44 lbs-ft per cid ?

[273]

@273 have you learned anything on this thread?

Further ahead than I was before, think I got a few bits of good info to build on.

Seems to me the focus has been on velocities flows etc.
I'm not convinced velocity is an input or an all important variable.

Air flow and it's speed (velocity) obviously plays a big role. But if you look at the acceptable velocities
It does cover a wide range 240-320 fps, If you calculate that out to port cc size for 300 cfm that's about 245-180 cc which is a pretty big range, and Trick Flows are 190 cc putting the on the small side and fairly high velocities 308 fps. If these are correct seems like not enough port cc is generally more of a problem.

I haven't seen much about runner length optimization for a given combo. That's a big deal.

That definitely play a role at particular rpms.

You seem to love your formulas.

When you calculate a lot of these engines aspects out you see a lot of symmetries.

Maybe a tunnel ram should be part of the "equation".

They tend to make torque.

 

[273]

Whats the velocity of a turboed small block running 20 PSI?

Do you have a point?

 

[Hysteric]

I’m well aware of 2 phase flow.

I’m not sure I’ve read everything Bruce has written. What I’ve found I’ve read.

Any links to his stuff that’s not easy to find on Mark’s site would be appreciated.

Holley 950HP 1000HP???? - Page 6 - Don Terrill’s Speed-Talk

The e-bleeds are there to alter the density and viscosity of the fuel above the bleed. They have nothing to do with atomizing the fuel.

And

Troy if your using an annular discharge booster then the fuel is exiting through small holes, not at all the same thing as a dogleg etc. It doesn't matter what you think your doing with atomization in the well. the important point is that the supposed droplet has to go around the internal ring cavity in the booster and then come out through the small hole. In order for that to be a droplet that has survived the path intact it would have to be atomized smaller than the exit hole. Highly unlikely considering that to do that there would have to be considerable more air flowing through the Well than fuel. I think you may agree that that is not the case

Jmarkaudio:
Shrinker, we've had the discussions on the effect of bleeds on viscosity and density, and the fact that excessive emulsion does not help atomization/homogenization, it makes it worse.

Shear Force is what smashes the fuel exiting the booster.

 

[Mean416]

Further ahead than I was before, think I got a few bits of good info to build on.

Air flow and it's speed (velocity) obviously plays a big role. But if you look at the acceptable velocities
It does cover a wide range 240-320 fps, If you calculate that out to port cc size for 300 cfm that's about 245-180 cc which is a pretty big range, and Trick Flows are 190 cc putting the on the small side and fairly high velocities 308 fps. If these are correct seems like not enough port cc is generally more of a problem.

That definitely play a role at particular rpms.

When you calculate a lot of these engines aspects out you see a lot of symmetries.

They tend to make torque.



View attachment 1716282362

I started this post by writing: "To me, airflow obviously affects power and torque. I don't think it's OBVIOUS that velocity - in and of itself - does."

Tuned runner length that is matched to the torque peak will make a huge difference in torque produced.

I'll finish the post by saying...I thought about the velocity thing more. Velocity and momentum are tied together. The faster a ball is moving, the harder it is to bring it to a stop. Same with air. So if average flow velocity is higher in a runner, it will tend to cram into the cylinder more effectively especially at the end of the intake stroke/beginning of the compression stroke.

 

[TT5.9mag]

A little (longwinded) backstory on that 371 because its pertinent to this discussion and sometimes I love to WouldaCouldaShoulda.

I had been using EQ heads since the early 2000's--Ford GTP's, Chevy (which were awesome) there was no Mopar offerings at that time, and then I kinda forgot about them from 2004- until early 2009. A catalog was sent to me and I noticed the CH-318A and CH-318B. I ordered a set for a mild street build 360 with an HR cam, immediately noticed the short stock I.H. and proceeded to bore the guides to 11/32" and use much longer Chev style valves and rockers. That engine made me think the dyno was out of whack as it made what I thought was remarkable power 470+ HP/470+TQ. Over the next couple of years I used them when budget and the customer allowed. Some were tested and some were not, my takeaway was that the dyno results were always impressive. Even the ones that did not get tested I had feedback that implied-WOW.

Fastforward to spring of 2011 and although I had entered and was accepted @ EMC 2011, I had thoughts of not really building anything serious or even anything at all. Time and $$$ were always an issue and I had done the EMC twice already and I knew my chances at a win were zero and I thought my chances at a third consecutive feature magazine article were zero-hence my lackluster attitude. So in the background I had built a nice 360 circletrack engine for a good friend of mine with W2 heads and a SFT cam, W2 intake, and 500cfm 4412 as per the rules...(447hp/440tq). He runs it for the season May-1st week of Sep. <<<We'll come back to this.

So during that summer I have no idea what I'm going to build for the EMC which is always the 1st week of October. I didn't know what displacement, bore size, stroke etc...I didn't even really have a decent smallblock core to use and the idea of using the EQ heads hadn't really been cemented either--but they were there in the back of my mind.

I had been working on another 360 build for a customer and he wanted ported EQ's. As I began shaping a bowl I realized how much better quality the iron was and how much time this was going to take and my wheels started turning. Enter the CNC idea. I took a head and mounted it on our 3axis CNC because I didn't really want to get too crazy and just wanted to knock some material out of the bowls with a simple interpolation program. So a small program was written with a custom venturi style shape and some ovality. Chips were made and off to the flowbench. A 2.02" valve size and ZERO blending=272cfm!!! Keep in mind there was a huge ledge where the CNC machining left off. I thought this was going to be so easy to get these into the 290's--was I wrong, but still even blending the ledge out only netted about 275-277cfm. Anyways this was in July 2011 and thats when I thought about using them on the the 371 shortblock in my buddys CT car. So I found the T&D shaft rockers on Moparts, and proceeded to make the heads the best I could for the month of August while I patiently waited for the CT season to be over. It was an excruciating wait because that engine could have expired while in the car or even on the dyno just weeks or days before the EMC.

Back to the heads--So like I said in an earlier post I had time to really scrutinize every port and exactly half of them needed substantial rework. 4 of them flowed the same at all lifts and 4 of them were as much as 10cfm behind at all lift ranges and turbulent as well. Anyways I sourced an old Weiand 7545 (awesome intake) and took my best shot at a custom roller cam from Comp. My friend pulled his engine the first week of September--I re-ringed it and changed the cam and top end which took me into the third week of September as I had to wait for different length pushrods. So here we are basically one week away from having to leave for the EMC and testing begins. I was shocked when it outscored 2010's 367 w/W2's on account of the incredible TQ. Like I said a bit of tuning and 513 ft/lbs on test 6 or 7 and off comes the manifold. I cut some runner extension ears out of .187" aluminum and tack welded them in thinking I'd pick up 5 pts. Nope--lost something like 11 ft/lbs. Off comes the manifold and I hack about half of the extensions off. Nope still down but coming back a bit. Off comes the manifold again and I wind up breaking 2 of the extensions off right at the weld. Oh well it worth a shot right? I try it again and have to live with it as we have to leave the next evening.

Anyways we get to Ohio and Johnny Hunkins spots the heads right away as he is good friends with Eric Haughland @ EQ--he is all excited and films some of the dyno footage himself and sends it Eric's way. That engine was so strong at the bottom it never wavered or faultered or fell in rpm. At full load on the brake before the engine is "released" for its acceleration run you will often see and hear the TQ and RPM drop a bit--Not that engine. From our prior 2 years experience at EMC the dyno operator liked to F@#$ with the newer teams and would deliberately hold us @ 2300-2400 rpm for as much as 10-20 seconds--which is a lifetime. That engine was different--It did not fall off or go into detontation at all, it just sat there and sat there and sat there making 400+ ft/lbs @ 2500rpm. The dyno operator made a comment and even the tech director Wes did as well. I still wonder what that engine could have done being fresh and with a trick set of pistons with a better ring pack and more time--always more time. LOL. That engine was thee best bang for the buck EMC engine I ever did. Sorry for the longwinded story.

The 4 takeaways here are:

1. I should have left the ridge and tested with a 2.02" valve. ( I got greedy chasing #'s)
2. I should have committed to a plan and built a slightly smaller cubic inch before September
3. I should have recognized I would likely not exceed 1.38 ft/lbs/ci and leave well enough alone.
4. I should have ordered a pallet of EQ heads and waited...Or bought bitcoin--LOL.

J.Rob

You should tell more stories. That was a good read. Thanks.

 

[273]

I started this post by writing: "To me, airflow obviously affects power and torque. I don't think it's OBVIOUS that velocity - in and of itself - does."

Velocity is the speed of the air mass without speed (movement) you got no air flow.

Tuned runner length that is matched to the torque peak will make a huge difference in torque produced.

The runner is part of the port it's size and shape is gonna aid in velocity and the mass of air, a 360 gonna need about 600-800 cc of air for each power stroke and got less than a millisecond to do it.

The runner length is gonna give extra assistance at certain rpms every runner is technically tuned for a certain rpm ranges. It might not be the ranges you want.

I'll finish the post by saying...I thought about the velocity thing more. Velocity and momentum are tied together. The faster a ball is moving, the harder it is to bring it to a stop. Same with air. So if average flow velocity is higher in a runner, it will tend to cram into the cylinder more effectively especially at the end of the intake stroke/beginning of the compression stroke.

Yes, momentum is velocity x mass.

Also if velocity is too slow reversion is easier and get less filling for the first bit compression stroke and less filling overall. Higher velocity can fill the cylinder quicker and easier needing less cam duration and overlap but too much velocity and the port chokes. Like everything in life it's about finding the right balance.

But if you look at the chart mid velocities seem like the Ideal, I'm guessing cause an engine has to operate over a fairly wide range of rpms and those mid velocities which dictates port size for a given cfm probably gives the best overall powerband.

 

[273]

Wonder what the Ideal ratio of exhaust port volume, flow and velocity is to achieving higher lbs-ft per cid, I feel it's one of the reasons LS heads do so well, even why I think magnum heads respond well to cams.

 

[Newbomb Turk]

Wonder what the Ideal ratio of exhaust port volume, flow and velocity is to achieving higher lbs-ft per cid, I feel it's one of the reasons LS heads do so well, even why I think magnum heads respond well to cams.

There is no real ideal anything. Especially building engines. There are plenty of rules of thumb ****. But that gets you close.

The general rule (NA) is get the biggest intake you can, fit the exhaust valve and then deal with it.

You can spend time, effort and an assload of money to try and develop a formula of those ratios, but it will only matter in that specific application.

This is what I know. It is settled unless arguing is what you do. Not YOU specifically. You in general. I think you can figure that out.

I know the exhaust port on most of the stuff we deal with is way too big. So is the valve. You’re kinda stuck because shrinking a valve for a Chrysler Pcar head is near impossible. It’s certainly impractical.

So you deal with it.

It’s hard to change cam timing to help the big port and valve, especially when the engine wants more exhaust duration but if you give it more you’ll kill a bunch in the middle of the torque curve for a minimal gain in hp.

The W2 has a port on the big size, but I think using a 50 degree seat I can shrink the valve down to 1.500 and have a better shape. Because shape is more important than flow.

 

[273]

There is no real ideal anything. Especially building engines. There are plenty of rules of thumb ****. But that gets you close.

The general rule (NA) is get the biggest intake you can, fit the exhaust valve and then deal with it.

You can spend time, effort and an assload of money to try and develop a formula of those ratios, but it will only matter in that specific application.

This is what I know. It is settled unless arguing is what you do. Not YOU specifically. You in general. I think you can figure that out.

I get there's no overall ideal, it's all a series of compromises, I guess by Ideal I mean more in the general sense.

I know the exhaust port on most of the stuff we deal with is way too big. So is the valve. You’re kinda stuck because shrinking a valve for a Chrysler Pcar head is near impossible. It’s certainly impractical.

So you deal with it.

I've heard many say they'd sacrifice exhaust valve for intake valve, and hear of making the exhaust side of the cam smaller cause too much of the intake charge is going out the exhaust.

It’s hard to change cam timing to help the big port and valve, especially when the engine wants more exhaust duration but if you give it more you’ll kill a bunch in the middle of the torque curve for a minimal gain in hp.

The W2 has a port on the big size, but I think using a 50 degree seat I can shrink the valve down to 1.500 and have a better shape. Because shape is more important than flow.

Your generally thinking W2 or better, I'm generally thinking under that

 

[Newbomb Turk]

I get there's no overall ideal, it's all a series of compromises, I guess by Ideal I mean more in the general sense.

I've heard many say they'd sacrifice exhaust valve for intake valve, and hear of making the exhaust side of the cam smaller cause too much of the intake charge is going out the exhaust.

Your generally thinking W2 or better, I'm generally thinking under that

LOL I try and think both but if you can tell I shade (more like run to) the performance side of things.

That’s probably blatantly obvious though.

 

[273]

Anyone hear of this formula for tuning (sizing ave. csa of intake and header) for peak torque rpm?
Supposedly base on that an engine torque peaks at 240 fps. (obviously there's other factors that influence where it peaks).

csa = cid of one cylinder x rpm / 88,200

https://www.motortrend.com/how-to/ctrp-1101-intake-exhaust-size/

 

[273]

I wonder if velocity is around 240 fps at peak torque what would it be at peak hp?

 

[Spudmaster]

The simplest way is to put a TorqStorm supercharger on it. I have one on my 8.5 to 1 slant six and it’s putting out 400 hp and a ton of torque. It does cost because of the fuel and ignition systems needed to run it, but the grunt at any RPM in any gear is a joy to drive

 

[TT5.9mag]

The simplest way is to put a TorqStorm supercharger on it. I have one on my 8.5 to 1 slant six and it’s putting out 400 hp and a ton of torque. It does cost because of the fuel and ignition systems needed to run it, but the grunt at any RPM in any gear is a joy to drive

How much boost did it take to make 400? What fuel are you on? do you have any track times or dyno results?

 

[273]

Maybe the real question people should be asking is why too much velocity is a problem. What's the velocity in a supercharged or turboed engine?

I came across this, might be your answer.

"You'd test it the same as you would any other head. Flow it at 28" and see what kind of results you get. The airspeed in the ports on the running engine will be the same regardless of boost since the airspeed is a product of the ratio of bore area to port area and the piston speed of the engine. The boost is only a measure of the density of the input charge as it relates to atmospheric. The density of the air will have virtually no effect on how the port flows, if you have a troublesome head on the bench you will see the same problems on the running engine. I had a chance to discuss this topic with Ken Sperry at the PRI show a couple years ago and he said basically the same thing."

 

[Mean416]

I came across this, might be your answer.

"You'd test it the same as you would any other head. Flow it at 28" and see what kind of results you get. The airspeed in the ports on the running engine will be the same regardless of boost since the airspeed is a product of the ratio of bore area to port area and the piston speed of the engine. The boost is only a measure of the density of the input charge as it relates to atmospheric. The density of the air will have virtually no effect on how the port flows, if you have a troublesome head on the bench you will see the same problems on the running engine. I had a chance to discuss this topic with Ken Sperry at the PRI show a couple years ago and he said basically the same thing."

Air velocity through a given cross section area is going to be proportional to the mass flow. Increase the mass flow, the speed is going to go up.

 

[273]

Air velocity through a given cross section area is going to be proportional to the mass flow. Increase the mass flow, the speed is going to go up.

Why ? Aren't we talking volume cfm = velocity x csa ? the cfm should be the same no matter the mass or am I missing something ?

 

[Mean416]

Comparing NA to forced induction, what's varying?

1. Air density is going up from air being compressed.
2. Mass flow rate is also going up because you're pumping more air mass through the system with the turbo or supercharger.

Neither of these things are constants in real life so bear that in mind. Also.... very importantly.... remember that at the flow rates in real life, vs on a Flow bench, are much higher and therefore velocities are going to be higher. The flows are going to be much more chaotic (non laminar). And there's a bunch of pressure waves all around in there. The formulas are useful for gaining insight and understanding but they aren't always good predictors.

 

[273]

View attachment 1716283253

Comparing NA to forced induction, what's varying?

1. Air density is going up from air being compressed.
2. Mass flow rate is also going up because you're pumping more air mass through the system with the turbo or supercharger.

Were measuring cfm but ok mass flow rate, M = r x v x a right ?

So and NA engines Air density varies but say it's static for a moment at atmosphere psi 14.7 & we add a turbo and double it to 29.4 psi overall so the density is twice that of an NA engine so per cubic foot it's got about twice the oxygen and fuel molecules why makes about double the power.

So density is r in the formula so in the turbo r would be twice the amount than in an NA engine in this example so doubling the density would double the mass flow rate with Velocity and Area still being the same turbo vs boosted, NA 100r x 1v x 1a = 100m, Boosted 200r x 1v x 1a = 200m.

Is this wrong ? Seems right.

Neither of these things are constants in real life so bear that in mind. Also.... very importantly.... remember that at the flow rates in real life, vs on a Flow bench, are much higher and therefore velocities are going to be higher. The flows are going to be much more chaotic (non laminar). And there's a bunch of pressure waves all around in there. The formulas are useful for gaining insight and understanding but they aren't always good predictors.

I totally agree, the velocity in the engine probably way higher and same with overall air flow, but we see some correlations between the bench and what works in the engine.

 

[Mean416]

Were measuring cfm but ok mass flow rate, M = r x v x a right ?

So and NA engines Air density varies but say it's static for a moment at atmosphere psi 14.7 & we add a turbo and double it to 29.4 psi overall so the density is twice that of an NA engine so per cubic foot it's got about twice the oxygen and fuel molecules why makes about double the power.

So density is r in the formula so in the turbo r would be twice the amount than in an NA engine in this example so doubling the density would double the mass flow rate with Velocity and Area still being the same turbo vs boosted, NA 100r x 1v x 1a = 100m, Boosted 200r x 1v x 1a = 200m.

Is this wrong ? Seems right.


I totally agree, the velocity in the engine probably way higher and same with overall air flow, but we see some correlations between the bench and what works in the engine.

Trust me I understand the concept. You squeeze more air in a given volume, now move it along at a fixed velocity. You're flowing more air but the velocity is constant.

But pressure and velocity arent constant--at all-- so the formulas break down. I'm trying to explain that it's not as simple as plugging it into a formula. Those formulas also assume a laminar flow which is absolutely not the case.

I also think it's helpful to remember...

1. Power production is a result of burn rate of air/fuel (mass flow)

2. Pressure is a result of flow restriction

Anyway, I still understand the need to have a certain amount of flow velocity. I can see how it's helpful for increasing volumetric efficiency.

 

[Newbomb Turk]

Trust me I understand the concept. You squeeze more air in a given volume, now move it along at a fixed velocity. You're flowing more air but the velocity is constant.

But pressure and velocity arent constant--at all-- so the formulas break down. I'm trying to explain that it's not as simple as plugging it into a formula. Those formulas also assume a laminar flow which is absolutely not the case.

I also think it's helpful to remember...

1. Power production is a result of burn rate of air/fuel (mass flow)

2. Pressure is a result of flow restriction

Anyway, I still understand the need to have a certain amount of flow velocity. I can see how it's helpful for increasing volumetric efficiency.

Velocity is great until you can't control it. A head port developer is a velocity manager.

 

[Hysteric]

Velocity is great until you can't control it. A head port developer is a velocity manager.

So why does he need to manage the velocity?

 

[Newbomb Turk]

So why does he need to manage the velocity?

You explain why you don't have to manage velocity.

 

[Hysteric]

You explain why you don't have to manage velocity.

C'mon Tim

 

[273]

C'mon Tim

Nothing productive is ever accomplished by conversing with ya, just an endless stream of questions that go nowhere. Your always looking for a gotcha instead of an honest conversation.