Flow balancing

Tobin said:
30KSI on a CR injector??


Tobin
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PSI....you could ask for that but most cannot hold that rail presure with a big nozzle. shut off pre and post injection and you may be surprised the numbers you see on the rail
 
lenahan05 said:
PSI....you could ask for that but most cannot hold that rail presure with a big nozzle. shut off pre and post injection and you may be surprised the numbers you see on the rail
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30KSI = 30,000PSI (same thing)

I think you would blow the injector bodies apart with that much pressure. I thought the safest limit was in the 25KSI range?


Tobin
 
lenahan05 said:
i think you look way to hard into things and think to hard about a lot of things. all you need to do is get air in and out of the motor and begin to work on ways to lower timing to get effiency up. that is the easiest way to build big horsepower (effiency). a motor being blown or not really doesnt have a lot of effect on flow ratio if im understanding what your talkin about.
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I do agree with you, sometimes I do think a little deep, but sometimes you need to view as much as possible and then come to a simple or mildly detailed conclusion. I guess I get headaches more than others.

If we get the best flow per side, the volumetric efficiency should go up, port pressures should reduce due to improved flow. Reducing the timing is what every gearhead should have in mind from the start. Mass flow could be used with air itself or fuel/air mixture with such things as TBI/carbs/ multiport injector layouts. Ford used MAF sensor at the beginning of the intake plenum that was only measuring airflow, I believe in the early 90s.

Flowing a mass of air will be different from an emulsified fuel mixture. The densities are different especially with a fuel that is absorbing the heat from the air that was transfered from the engine's components. Not to mention weather and altitude. If we look at cams, the LSA/LCA is more or less a by product of cam designing itself.

24vriviera, I have about 10 460 heads I haven't touched for atleast 2.5 years, and which I can't build my 460 gasser yet, its a bummer at the moment! If you want some help with those, I know just who you could contact too, not just rely on mag articles or forums all the time.
 
Fahlin Racing said:
24vriviera, I have about 10 460 heads I haven't touched for atleast 2.5 years, and which I can't build my 460 gasser yet, its a bummer at the moment! If you want some help with those, I know just who you could contact too, not just rely on mag articles or forums all the time.
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I agree with you with the information gathering..
Though a lot of information had been through these eyes, i think that magazines like car craft do the least biased testing they are allowed, and only take what i believe is the best info... Same from here, and i don't take crap from cf!
But of course when i do something, i read up and ask for more help.
That being said, the best thinking and brainstorming happen in threads just like this, info is out there and i think it all needs to be looked at. So let's keep it going!

Ps you can keep the Ford stuff, not a fan!
 
I enjoy any American auto engine Riv, Ford tends to be my favorite brand, I have Chevy's, Mopars too but not Olds, Pon or Buick yet. Don't really play with AMC/Jeep though, maybe some day.

Any ways, Burgess & Gollan mention valve sizing is dependant on cylinder pressure upon exhaust valve opening point, now I am not sure how much more is involved for forced induction flow. I am contuing to read their writings to see how things have become apparent.
 
They, burgess & Gollan go to mention
the flow rate is based upon the square root of the pressure difference across the valve.
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Our valve curtain, the area created by our lift at the valve and the size of the valve itself will have a direct effect on the flow in or out of the cylinder. Now I guess you can take different valve designs and rpm range they may operate best in.
 
Tobin said:
30KSI = 30,000PSI (same thing)

I think you would blow the injector bodies apart with that much pressure. I thought the safest limit was in the 25KSI range?


Tobin
Click to expand...

We run 26KSI on 5.9 injectors, and I know of someone running 32+KSI on 6.7 injectors.
 
Looking into some of what Phillip H. Smith & John C. Morrison in their Scientific design of Exhaust & Intake systems.

Pg 75, Chapter 5. Exhaust pressure
....When the exhaust valve opens, there is a high-pressure release of the gas into the port and pipe. This imparts kinetic energy to the column in front of it; as the 'bung' or slug of pressure reaches the end of the pipe, the energy is transferred to the region of the exhaust port, causing a rarefraction which pulls out the residuals concurrently with a rise in port pressure as the kinetic effect decreases.
It is by no means inferred that this proposition is incorrect; its forms an essential part of the process. But superimposed as it were on the flow as a whole is the presence of the pulsating wave motion, in consequence of having an elastic medium to deal with. Whereas the gas column as a whole may be moving in the pipe at an average speed of 200-300fps, amuch higher speed is obviously attained at the wave pressure peaks....
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As they speak of the flow slowing up at the end of the port, its brings to mind that when our flowing portion of exhaust mass has hit the entrance of the exiting side of the turbo, there is something of this action occurring once our flow has come into contact with the turbocharger waiting to proceed through the turbine and out to the piping system.

Pg 76 Wave propagation
....The pressure waves in the outflowing gas are formed by sound waves and move at the speed of sound.....In order to start such a wave, however, a sudden impulse is necessary....
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Sound not only tells us if our port is turbulent on a flowbench, its also saying sounds effect the flow as well. Hmmm and once the exhaust valve opens, we must include the cylinder itself as a part of the exhausting path too for full consideration of the exhaust evacuation quality and time which it is desired to be done in.
 
If we have a turbocharger that utilizes pressure to turn the compressor, wouldn't it be sensible to tune waves enough to deliver a slug of exhaust to the inlet and relfect back, or rarefraction wave if you prefer, to proceed another exhaust cycle to keep the turbine moving more consistantly and maybe reduce a sudden load effect on the turbo and keep the engine speed up?
 
Sorry, correction, rarefaction*

With a little more reading & investigating looks like we are more concerned on pressure pulse tuning and trying to avoid the overlapping phase of the camshaft to keep our charge free of contaminants to keep the power level consistent.
 
But 6 cylinders churning at desired operating speed(3000-5000 rpm) pushing on a turbine with quite a lot of load behind it....I think the exhaust pulses would be so frequent and the turbine with so much inertia/friction/drag that trying to tune them would be a moot point.

BTW the 5x.014 sac injectors came in, probably get them installed within 2-3 weeks.
 
That could be, however there is always something that can be minutely tuned of course the dyno/track would be the prover. Its been interesting, some say you can't tune the turbo and there are others saying yes. Maybe its an amount of work some want to put in? Does the competition want it more than what you want it is the question.

Nice, I am still pretty intregued about your venture as I am sure others are as well! Hope things are going well for you, isn't too bad over here.
 
Any thoughts on the possibility of tuning flow by way of rocker ratio mixing like you can do in N/A engines?
 
Tossed in the 5x.014's, they run considerably stronger than the old 7x.012's. They also seem to fuel harder, with the same AFC settings I had more low end smoke, tries to spool up the turbo sooner at the same pedal. Run about 75* cooler. I've only taken the truck up to 35 psi with a #10 plate in, I'm optimistic that with moderate DVs and about 50 psi this thing could definitely make good power.

I'll eat my words in that changing from the 7 to 5 hole nozzle makes a noticeable difference. I'm just guessing with the fluid dynamics but a thicker fuel jet really seems to combust aggressively with what we're pushing these trucks to.
 
straight 6 roar said:
Tossed in the 5x.014's, they run considerably stronger than the old 7x.012's. They also seem to fuel harder, with the same AFC settings I had more low end smoke, tries to spool up the turbo sooner at the same pedal. Run about 75* cooler. I've only taken the truck up to 35 psi with a #10 plate in, I'm optimistic that with moderate DVs and about 50 psi this thing could definitely make good power.

I'll eat my words in that changing from the 7 to 5 hole nozzle makes a noticeable difference. I'm just guessing with the fluid dynamics but a thicker fuel jet really seems to combust aggressively with what we're pushing these trucks to.
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I was less than impressed with my 7 hole injectors. Went back to a 5 hole injector and egts dropped, spooled faster, and ran much stronger.

Sent from my DROID RAZR using Tapatalk 2
 
What was the injection starting point and ending. Also, did you observe at the point where the burn ended too?

Could the large jet stream be penetrating more allowing more oxygen molecules to be around once our fuel charge has reached a stoichiometric situation sooner and more homogenous across the chamber area?
 
Fahlin Racing said:
What was the injection starting point and ending. Also, did you observe at the point where the burn ended too?

Could the large jet stream be penetrating more allowing more oxygen molecules to be around once our fuel charge has reached a stoichiometric situation sooner and more homogenous across the chamber area?
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With higher jet penetration the fuel slugs tend to reach a cooler part of the burn zone and so do not oxidise fully. This results in higher HC emission and lower specific torque output for a given fuel mass.
 
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