Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by user-23911 »

Aaaaaaaah the interweb?

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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by panic »

lighting it off in the cylinder can only occur once some of it's a vapor.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by NewbVetteGuy »

MadBill wrote: Some years ago David Radzus produced some formulae here that correlated air density increase due to the latent heat of the vaporized fuel vs. its charge displacement effects. AIR, in most cases the latter somewhat outweighed the former.
Great points; I'll see if I can find it.

It seems like you get the best of both worlds, if you can get the droplets to the "right" small size such that they're easily and as completely as possible vaporized when they hit the cylinder, but you don't want them fully vaporized in the intake tract and displacing air.

Just like you get more benefit from charge air cooling with an injector higher up the intake track, I imagine the problem of vaporized fuel displacing air become more of a problem as the injector is higher up the intake track. With my application- injector very close to the valve- I'm expecting that fully vaporizing the fuel and displacing air probably isn't a huge concern (which is why getting the best atomization straight out of the injector seems like a good idea).

Also seems like intake heat and length of the intake tract would be at least a minor factor. (Thermal barriers and cool intakes I'd expect to "like" finer atomization as vaporization and displacement of O2 too early is less likely to be a problem, then.)


I'm all of a sudden thinking that electrically heated fuel rails would be a good way to "dial this in" on the dyno. Fuel gets too hot and starts vaporizing early and displacing air and power starts to go down, then dial the fuel temp back a few degrees to stay in the "sweet spot".



I've heard it quoted before that 90% of vaporization occurs in the cylinder anyway, so just getting a "good enough" atomizing injector is probably "good enough". Playing around with fuel pressure at 3 bar, 4 bar, and 5 bar for 3 dyno pulls (self-learning EFI should take care of the pulse width adjustments to hit the right AFRs; right?) would probably as far as I'd ever be willing to test myself although an electric fuel heater would be fun to play with.

Nostrum energy doesn't sell an injector for my purposes and I need about a 500cc injector, so the Injector Dynamics 1050cc seems like massive overkill and possibly nice idle destroying... I'll start calling injector companies; I'm still looking for something better annd newer than a Bosch III, but my lowly SBC and it's TPI style intake definitely isn't the focus of any of these injector companies today and my little 440hp 350 gets no love. Poor little guy!

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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by englertracing »

NewbVetteGuy wrote:
englertracing wrote:How about Dual injectors?

Has anyone ever run efi down nozzles?
This is a 98% street only build and I'm definitely not looking to hack up the intake for dual injectors, although I think I get the theory.
(Traditionally placed, close-to-the-valve injectors for idle and low to mid RPM, then 2nd set of injectors placed up high / further away from the intake valve comes on at WOT and provides higher levels of atomization and increased O2 via cooling effect from fuel vaporization.) -Right?


Adam
i think you may have misread my down nozzle idea
Image
Image

im suggesting you run some little nozzles in the manifold with extra fine atomization
and put some big secondary injectors where they commonly put MFI nozzles

idle run and cruise off the little injectors
wot off the big injectors

and im also asking if anyone has ever seen someone put electronic injectors in the down nozzle position
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by Belgian1979 »

for good atomization :
- four hole injectors
- right fuel pressure
- right injection angle
- right distance from the valve (which varies with rpm)
- right injection timing.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by user-23911 »

Get all your parts from the junk yard.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by Newold1 »

Newbvetteguy Question:

What have you done build wise to your poor little 350 engine? Tell us about your specs and such.

PLEASE EXCUSE MY INPUT HERE, BUT I NEED TO SHARE SOME INFORMATION WITH YOU. :D

One thing I can share with you is that years ago I did some very intense Corvette gm TPI manifold testing with upgrades to your style of intake manifold and injection system. We were trying to get a 383 to make bigger power in a street/ road race Corvette.

I can share with you that this included even a custom mono-blade throttle body to significantly increase cfm into the engine which was a mild 383 with aluminum fast burn reworked heads, a few camshaft designs, larger diameter intake runner tubes and larger runner custom ported Edlebrock large runner manifold and quite a few injector types all in an attempt to get the GM TPI system to make more power. What can I tell you about all that testing and upgrades and changes?
This, we gave up on the TPI system and manifold altogether. I realize that in a Corvette hood clearance is the BIGGEST problem and that's why GM engineers came up with the TPI type intake to create a mild decent EFI intake that would fit under a Corvette hood! The problem we identified thru lots of work, parts, testing and big dyno hours was that the power limiting characteristic of this intake system is the PLENUM, its SIZE, SHAPE and inability to ultimately flow enough air to meet the requirements of our fairly mild 383 SBC. It's just to small in volume. Do the plenum size calculation math for sizing and you'll see what I am describing.We could not get it to make over 450HP no matter what we changed and did. How did we get this little mild small block 383 to make 525HP and more torque. We took the TPI systme off completely, had Hamburger make us an intake with a single mono-blade throttle body that accepted all the corvette IAC, etc., it had a much larger plenum with straight rectangular tapered runners that crossed over inside the plenum and had bell mouth entrances on them. The runners were only about 6" long. The engine with reprogramming, 45lb Ford Motorsports injectors made 75 more horsepower and about 65pd/ft. more torque and would pull quicker to 7000 rpms than the highly modified TPI intake and all the work we tried with it. Whola! larger plenum volume and straight runners did the trick!
I am sure your new intake is nice but I can assure you its NOT a GIANT increase in air and fuel for your engine, but it does fit under your hood and I am sure its a nice street Vette! The plenum on your intake is a stock volume plenum and the larger throttle body is just bolted via an adaptor to the original plenum intake port. The larger runners are nice and help slightly but I can assure you that the 440HP you are finding is not being capped or held back by injector type or atomization, but by the intake assembly itself. You can spend a lot of money and time flipping injectors in and out of the engine but you will always be limited by that beautiful manifold. Unless you want to change that, be happy and spend the time and money on other car improvements.
Please understand I am not trying to pick apart your build and improvements and I am sure you have a nice running and performing Corvette to be proud of. I am just try to get guys like yourself to understand that an intake system is just that a complete system and the total air flows required for certain increased power levels come from the total intake system efficiencies and not just from things like injector changes
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by turbo2256b »

this guy might be of some help

http://www.mrinjector.us/
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by turbo2256b »

Newold1 wrote:Newbvetteguy Question:

What have you done build wise to your poor little 350 engine? Tell us about your specs and such.

PLEASE EXCUSE MY INPUT HERE, BUT I NEED TO SHARE SOME INFORMATION WITH YOU. :D

One thing I can share with you is that years ago I did some very intense Corvette gm TPI manifold testing with upgrades to your style of intake manifold and injection system. We were trying to get a 383 to make bigger power in a street/ road race Corvette.

I can share with you that this included even a custom mono-blade throttle body to significantly increase cfm into the engine which was a mild 383 with aluminum fast burn reworked heads, a few camshaft designs, larger diameter intake runner tubes and larger runner custom ported Edlebrock large runner manifold and quite a few injector types all in an attempt to get the GM TPI system to make more power. What can I tell you about all that testing and upgrades and changes?
This, we gave up on the TPI system and manifold altogether. I realize that in a Corvette hood clearance is the BIGGEST problem and that's why GM engineers came up with the TPI type intake to create a mild decent EFI intake that would fit under a Corvette hood! The problem we identified thru lots of work, parts, testing and big dyno hours was that the power limiting characteristic of this intake system is the PLENUM, its SIZE, SHAPE and inability to ultimately flow enough air to meet the requirements of our fairly mild 383 SBC. It's just to small in volume. Do the plenum size calculation math for sizing and you'll see what I am describing.We could not get it to make over 450HP no matter what we changed and did. How did we get this little mild small block 383 to make 525HP and more torque. We took the TPI systme off completely, had Hamburger make us an intake with a single mono-blade throttle body that accepted all the corvette IAC, etc., it had a much larger plenum with straight rectangular tapered runners that crossed over inside the plenum and had bell mouth entrances on them. The runners were only about 6" long. The engine with reprogramming, 45lb Ford Motorsports injectors made 75 more horsepower and about 65pd/ft. more torque and would pull quicker to 7000 rpms than the highly modified TPI intake and all the work we tried with it. Whola! larger plenum volume and straight runners did the trick!
I am sure your new intake is nice but I can assure you its NOT a GIANT increase in air and fuel for your engine, but it does fit under your hood and I am sure its a nice street Vette! The plenum on your intake is a stock volume plenum and the larger throttle body is just bolted via an adaptor to the original plenum intake port. The larger runners are nice and help slightly but I can assure you that the 440HP you are finding is not being capped or held back by injector type or atomization, but by the intake assembly itself. You can spend a lot of money and time flipping injectors in and out of the engine but you will always be limited by that beautiful manifold. Unless you want to change that, be happy and spend the time and money on other car improvements.
Please understand I am not trying to pick apart your build and improvements and I am sure you have a nice running and performing Corvette to be proud of. I am just try to get guys like yourself to understand that an intake system is just that a complete system and the total air flows required for certain increased power levels come from the total intake system efficiencies and not just from things like injector changes

+1
intakes are most often the limiting factor. one reason I like to flow test them bolted to the head they are to be used on.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by Newold1 »

That's why I was posting what we ran into working with the Corvette TPI intake system. Geez, just realized that was almost 30 years ago!!
John Lingenfelter ran into the same problems with his Corvette engine programs and he worked with Accel to develop the Accel TPI Super Ram intake system. The original type TPI plenum was just not big enough, the runners to long and the runner and intake manifold ports were to small and the throttle body to small to allow the Corvette small blocks to make big power especially with stock hoods.
Accel Super Ram intake.jpg
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by user-23911 »

Well of course?

The fuel pump and injectors supply the fuel.

The intake manifold supplies the air.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by 1989TransAm »

I made 420rwhp with my 369" highly modified TPI. This was through a 4L60E. Welded up the Edelbrock TPI base so that we could use a Felpro 1206 intake gasket to match the AFR heads and increase the size of the runners. Hogged out the manifold ports to match the 1 7/8" id of the runners. 2" was the OD of the runners.

Lowered the floor of the TPI plenum. Extended the front and back of the TPI plenum as much as possible and still clear the distributor on the rear. Removed as much material as possible inside the plenum and increase smooth airflow as much as we could with a nice radius into the runners. I also used the AS&M monoblade throttle body. On Joe Shermans flow bench we were around the 320cfm mark for the intake with runners. I don't remember if we had the plenum attached or not. I think we did in order to get the proper inlet radius into the runner opening.

Ran a 11.57 @ 116mph in my fully loaded GTA and my 250 lbs of bulk. Running 45psi fuel pressure with 30 or 32 lb injectors. Don't remember which. Custom tune of course. 11.5 was the limit without a cage so I did not pursue it any further as I did not want to install a cage in the car.

Edit: I have also done a lot of work on the Super Ram to increase the performance of it.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by NewbVetteGuy »

englertracing wrote:
NewbVetteGuy wrote:
englertracing wrote:How about Dual injectors?

Has anyone ever run efi down nozzles?
This is a 98% street only build and I'm definitely not looking to hack up the intake for dual injectors, although I think I get the theory.
(Traditionally placed, close-to-the-valve injectors for idle and low to mid RPM, then 2nd set of injectors placed up high / further away from the intake valve comes on at WOT and provides higher levels of atomization and increased O2 via cooling effect from fuel vaporization.) -Right?


Adam
i think you may have misread my down nozzle idea
Image
Image

im suggesting you run some little nozzles in the manifold with extra fine atomization
and put some big secondary injectors where they commonly put MFI nozzles

idle run and cruise off the little injectors
wot off the big injectors

and im also asking if anyone has ever seen someone put electronic injectors in the down nozzle position
You are most certainly correct. I definitely misread your idea.

Cool concept; probably 20x beyond my capabilities.


Adam
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by NewbVetteGuy »

Newold1 wrote:Newbvetteguy Question:

What have you done build wise to your poor little 350 engine? Tell us about your specs and such.

PLEASE EXCUSE MY INPUT HERE, BUT I NEED TO SHARE SOME INFORMATION WITH YOU. :D

One thing I can share with you is that years ago I did some very intense Corvette gm TPI manifold testing with upgrades to your style of intake manifold and injection system. We were trying to get a 383 to make bigger power in a street/ road race Corvette.

I can share with you that this included even a custom mono-blade throttle body to significantly increase cfm into the engine which was a mild 383 with aluminum fast burn reworked heads, a few camshaft designs, larger diameter intake runner tubes and larger runner custom ported Edlebrock large runner manifold and quite a few injector types all in an attempt to get the GM TPI system to make more power. What can I tell you about all that testing and upgrades and changes?
This, we gave up on the TPI system and manifold altogether. I realize that in a Corvette hood clearance is the BIGGEST problem and that's why GM engineers came up with the TPI type intake to create a mild decent EFI intake that would fit under a Corvette hood! The problem we identified thru lots of work, parts, testing and big dyno hours was that the power limiting characteristic of this intake system is the PLENUM, its SIZE, SHAPE and inability to ultimately flow enough air to meet the requirements of our fairly mild 383 SBC. It's just to small in volume. Do the plenum size calculation math for sizing and you'll see what I am describing.We could not get it to make over 450HP no matter what we changed and did. How did we get this little mild small block 383 to make 525HP and more torque. We took the TPI systme off completely, had Hamburger make us an intake with a single mono-blade throttle body that accepted all the corvette IAC, etc., it had a much larger plenum with straight rectangular tapered runners that crossed over inside the plenum and had bell mouth entrances on them. The runners were only about 6" long. The engine with reprogramming, 45lb Ford Motorsports injectors made 75 more horsepower and about 65pd/ft. more torque and would pull quicker to 7000 rpms than the highly modified TPI intake and all the work we tried with it. Whola! larger plenum volume and straight runners did the trick!
I am sure your new intake is nice but I can assure you its NOT a GIANT increase in air and fuel for your engine, but it does fit under your hood and I am sure its a nice street Vette! The plenum on your intake is a stock volume plenum and the larger throttle body is just bolted via an adaptor to the original plenum intake port. The larger runners are nice and help slightly but I can assure you that the 440HP you are finding is not being capped or held back by injector type or atomization, but by the intake assembly itself. You can spend a lot of money and time flipping injectors in and out of the engine but you will always be limited by that beautiful manifold. Unless you want to change that, be happy and spend the time and money on other car improvements.
Please understand I am not trying to pick apart your build and improvements and I am sure you have a nice running and performing Corvette to be proud of. I am just try to get guys like yourself to understand that an intake system is just that a complete system and the total air flows required for certain increased power levels come from the total intake system efficiencies and not just from things like injector changes

I appreciate all the time it took to write this and all the effort that clearly went into it, but I think there might be some sort of misunderstanding in what I'm asking for and why.

To be clear, I'm NOT looking for more peak HP. I'm more than happy with 440hp; I'm looking for improved fuel economy, idle quality, and fattening up that torque curve in the low to mid RPM. My goal was really 400HP and as much fuel economy and torque as possible. I'm looking for an injector that provides best atomization for these reasons; I'm not chasing more max power, I'm chasing more max MPG, street manners, and throttle response.


SBC 350
Profiler 64cc / 195cc heads (10.2:1 static CR with 0.015" felpro head gasket) $999 via Jegs on BlackFriday Sale
Mike Jones aggressive Roller Cam HR70375 227/230 @ 0.050" -0.600" lift on intake with 1.6:1 comp ultra pro magnums, slightly less on exhaust; 110LSA
First Fuel Injection Intake gasket matched to Felpro 1206 to match Profiler 195cc intake (as pointed out by another poster, flows 301 CFM on the crappy runner) The first intake might have a very similar runner length vs a GM TPI intake but the plenum, runners, throttle body, and intake base are significantly different; this thing looks like the monster that ate the TPI intake $1,050 all-in except for fuel pressure regulator: Image
Holley EFI doing sequential multiport injection via crank trigger
(Peak Torque RPM @ 4,500; Peak HP @ 5,800 (or 6,000 depending upon the simulations)- hp peak flat from 5,800 - 6,200)

This is a simple "buy it and bolt it on" (except for gasket matching the intake, which Ken for FIRST is doing for free) long runner SBC build for a cool 440HP. The FIRST intake makes a good HP, monster torque TPI build pretty dang easy and reasonably priced. It's "not your father's TPI intake."


Adam
Last edited by NewbVetteGuy on Tue Sep 19, 2017 1:06 pm, edited 2 times in total.
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Re: Fuel injectors & fuel pressure for best atomization, MPG and low to mid RPM power?

Post by englertracing »

Yea that manifold is a wee bit bigger
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