351W Fuel Injection

[broncodan]

For those of you I have not chatted with yet, I just bought back an old Bronco that I built in high school. I am tackling a couple of projects that I never got to back then, and one of those is the desire to add fuel injection. What is the easiest and most cost effecient way to add fuel injection to my currently carb'ed 351w?

 

[mbryson]

Easiest: Probably out of an FI pickup that came with a 351W?

Can you use the 5.0L Mustang stuff? I know they are both Windsor blocks, but do parts interchange above the heads? (stinkin' F*rds and their plants of origin).

http://www.edelbrock.com/automotive_new/mc/manifolds/ford_sb_fuel-inject.shtml
{that doesn't really help, but kinda adds to the truck vs. Mustang motor differences}

http://www.edelbrock.com/automotive_new/mc/efi/pro-flo_ford.shtml

{and this link kinda adds to the evidence that there are differences in the 351-302}


...OH, and congrats on buying back your old rig. I've always wanted a couple of mine back.

 

[Milner]

Best to use an carbed 351w (cheaper) and source the mustang injection set up from either a JY or ford motorsport.
The injection setup on the late model 351W truck motors is to tall to fit under a EB hood, even with a body lift.

You can also use a carbed 351W and either a chev/holley/howell throttle body, or the holley or edelbrock sefi....
There are also custom setups out there but $$$$ get out of hand.

I run a holley tbi on my 351w, but it limits my power a little, I am gathering parts for a custom set up and mega squirt computer....

Check out www.broncofix.com www.broncos.com www.broncodriver.com
Bronco Driver did an excellent multi part article on the this exact subject.

HTH

Marc

PS are you the Dan that had an EB at Highland YEARS ago?

 

[broncodan]

I live in Draper, and lived in Draper when I had it prior. I sold it about 4 years ago.

 

[broncodan]

I have definately decided against throttle body injection, I would just stick with a carb. I am trying to find someone, somewhere how has gotten tuned port injection onto an early bronco. You think even with a 2" body lift and a hood scoop (wild horses fiberglass front clip) it would not fit? I don't have a body in it now, so I have nothing to measure off of.

 

[Milner]

Nope, I know that the truck injection won't fit even with a 3" body lift. Seen people try....The other problem is the tallest part is off center, so even if the scoop was tall enough, it would have to be off center....

 

[mbryson]

I have definately decided against throttle body injection, I would just stick with a carb. .............

It's not the coolest, but it runs at almost ANY angle. Works for me.

 

[broncodan]

I actually believe I have found a way to do this, and fit it under the factory hood. I ran into a guy on broncofix.com that has pulled this off. He combined the intake plenums (the lower is the tall part). He used the lower that was designed by edelbrock for a 5.0 mustang, and then all the other componants from the truck. He says it works great, it fits under a pro flow hood with a 2" body lift. I will let you know what happens. I am not the best with electronics, so if anyone has any advice I would really appreciate it. THANKS, and wish me luck! :greg:

 

[dungbeetle]

I have definately decided against throttle body injection, I would just stick with a carb. .

I'm curious as to why you would be against throttle body injection for a rock crawling application. I am currently running a holley 950 commander throttle body injection on a street engine, and I have run (for a while, just long enough to verify that I could tune it) a megasquirt unit on a port injection BMW.

The thing I would probably avoid for rock crawling would be a mass air flow injection.... think I'd rather stay with speed density.

I guess I don't really understand the issues related to rock crawling.

 

[broncodan]

At this point it looks like I can run EFI for less $$$ than I can get a TBI kit, and it is more efficient. TBI is nice, but in my opinion it is not worth the money. EFI will run at ANY angle, well TBI may struggle (only at extreme angles mind you).

 

[mbryson]

At this point it looks like I can run EFI for less $$$ than I can get a TBI kit, and it is more efficient. TBI is nice, but in my opinion it is not worth the money. EFI will run at ANY angle, well TBI may struggle (only at extreme angles mind you).

I don't think I follow (or agree) on your EFI statement. Maybe I'll learn sumthin. Just curious on your logic here. The GM TBI is two injectors in a carb type configuration. Making a 'wet' fuel system similar to a carb. I believe the aftermarket (Holley, etc.) to be very similar.

A port-injected system will usually be 8 injectors (one per cylinder anyway). Making a 'dry' fuel system as the injectors spray right on the open intake valve in the cylinder head. Port-injection is more efficient due to many factors, but can be attributed directly to time of delivery, spray pattern and optimized valves/heads, etc.

BOTH are EFI systems and I believe both will run at the same angles. The only time either will quit running is if you lose your ability to pick up fuel out of the tank to keep the pressure up. With the port injection, they typically run higher fuel pressures 40-90 psi while a GM TBI system will run around 10-15 psi. All things being equal (which we all know is never the case), it would seem logical to me the port-injected EFI would run out of fuel sooner due to the drop in pressure, while the TBI might get enough 'slosh' to keep it's pressure within accepted range longer.

Don't get me wrong, I think you're doing the exact right thing for your 351 by going to port injection. Esp. if the cost is actually less than a TBI system that would work with your F*rd. I LOVE to use as many factory type parts as possible just in case you have issues with your rig, you can find parts easily.

 

[broncodan]

I really appreciate your feedback. I do not feel that I am in a position where I can argue with you, because I am certain you have a better understanding than me. I will however, explain my thoughts. Like you said TBI is injection in a carb type application. The TBI (to my understanding) basically is carburation, but more controlled. The fuel still gets dumped into a cylinder and then is taken down through the intake manifold and distributed to the cylinders. To my knowledge, the fuel going the right direction (down to the motor) inside that "carb type application" is left to gravity. At extreme angles, I could see how TBI could not deliver the fuel properly. Also, as far as I know and understand, in an EFI setup the tank is pressurized, and so loss of fuel or PSI in the fuel system should not occur until there is not fuel left in the tank. I could be wrong, as I said I do not feel I know enough to put up a good arguement, that is just my thoughts given my limited understanding of how TBI fuel delivery actually works. On another note, do you think I should start a thread and post pics of my progress? I am in the middle of my frame off, I was just wondering if seeing the progress is something people might find interesting, and maybe a little helpful. I am also certain there will be several times when I need your guys' help, and if you are following it then it could make it easier. Again, I appreciate your feedback and your thoughts. :greg:

 

[mbryson]

I really appreciate your feedback. I do not feel that I am in a position where I can argue with you, because I am certain you have a better understanding than me. I will however, explain my thoughts. Like you said TBI is injection in a carb type application. The TBI (to my understanding) basically is carburation, but more controlled. The fuel still gets dumped into a cylinder and then is taken down through the intake manifold and distributed to the cylinders.

correct

To my knowledge, the fuel going the right direction (down to the motor) inside that "carb type application" is left to gravity. At extreme angles, I could see how TBI could not deliver the fuel properly.

Vacuum from the cylinders is what will pull the fuel/air mixture into the cylinder MUCH more than gravity. You would be correct if there was no or very little compression. (at least as far as I know) At extreme angles, you'll still have the engine vacuum to pull air into the cylinders. Even on port injected EFI, you still need air and fuel to create combustion.

Also, as far as I know and understand, in an EFI setup the tank is pressurized, and so loss of fuel or PSI in the fuel system should not occur until there is not fuel left in the tank. I could be wrong, as I said I do not feel I know enough to put up a good arguement, that is just my thoughts given my limited understanding of how TBI fuel delivery actually works.

I don't know of a pressurized tank (at least to the degree the line is pressurized) type of system. From everything I've seen (and I'm not a professional mechanic or anything so I'm sure I could be wrong), the pressure starts at the pump. The fuel in the tank could be somewhat pressurized, but it's definitely not pressurized to the degree it is in the line and the rest of the system. TBI motors have the same gas cap that the port injected motors have. If there was a significant difference, I'm sure there would be much more elaborate fuel tanks/filler necks/gas caps. (Just a little 'mbryson' logic there......again, could be proven wrong. Most of my experience/research has been in late '80s F-cars {Firebirds/Camaros} that come with both systems, TBI/TPI---almost a F*rd vs. Chev debate---the TPI is more efficient and builds power more easily, but a TBI system is very simple, cheap and effective and 'almost' as good in most circumstances)

On another note, do you think I should start a thread and post pics of my progress? I am in the middle of my frame off, I was just wondering if seeing the progress is something people might find interesting, and maybe a little helpful. I am also certain there will be several times when I need your guys' help, and if you are following it then it could make it easier. Again, I appreciate your feedback and your thoughts. :greg:

Build threads are KEWL..... Put it up. I even like to see F*rd builds (sometimes I learn something )

 

[Milner]

Yep, vacum....I can personally attest to a throttle body that runs upsidedown If it were gravity fed, NASCARs would starve in a corner

No pressurized fuel tanks....It would be HIGHLY unsafe, and is not allowed by many gov't agencies....

Only readily available motors that have direct injection into the cyl. that I know of are diesel. And they use high pressure oil to fire the injector, due to the combustion forces....I normal gas inj would be blown apart by the combustion forces!!
And not all tune port are individually time inj. fire....most are batch fire....meaning certain inj are all fired at the same time slightly before the intake stroke and the fuel is held in the manifold until it is drawn in by the stroke. Ford sefi is and sequential setup....fires each inj individually, needs much more comp control and sensors....Jeep renix is a batch fire and fires 3 inj and then the other 3....just 2 firing cycles per rotation....

Megasquirt can be set up for either....in most the research I have done, dynos seem to show little or no improvement for SEFI unless you are at WOT or have a very high horse/high rpm motor....

 

[broncodan]

No pressurized fuel tanks....It would be HIGHLY unsafe, and is not allowed by many gov't agencies....

I did not mean to state the fuel tank is pressurized, but in this application the fuel pump is INSIDE the tank, therefore the whole system (short of the tank) is pressurized.

 

[mbryson]

I did not mean to state the fuel tank is pressurized, but in this application the fuel pump is INSIDE the tank, therefore the whole system (short of the tank) is pressurized.

Both my port injected 4.0L Jeep motor and my TBI motors have an in-tank fuel pump. I think that's pretty common to an OEM injection system.

 

[Milner]

Both my port injected 4.0L Jeep motor and my TBI motors have an in-tank fuel pump. I think that's pretty common to an OEM injection system.

Yep and even some after market upgrade pumps go in the tank....mostly for cooling reasons....and pumps, pump....they don't suck