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Discussion Starter #1
Alright, now that I've gotten off my lazy ass and done some research, instead of bugging others for it, I've come to the decision that I'm going with a VEX1. Part of my problem now is that info on other sites I've seen conflicts. (92 302/E4OD)

I read that the -HB (vex1) is strictly for 4.10 gears... and there is a -GB model that is made for the 3.55 gears. True? Does the computer even care?

And as for the harness, I should just be able to hack one off a 94-95 Bronco/F150 and tear it apart to get the good stuff right? I dont really care if it's showroom look under the hood, just as long as it works right. You can't even tell under all that damn mud. :toothless

I should just be able to go to a 94-95 B/150 and hack all the neccessary parts off right? I mean, it can't be that extremely difficult, right?

Tuning, is it possible? With the stock computer, is it that big of a deal, I read that the timing and other stuff is nothing compared to the stang computer with the baum, but what kind of a difference does it make? ... Its a daily driver with 31's, and I only do light mudding, and take her on the beach once in a while. I'm a normal driver, but every so often I like to beat up the skinny pedal.

Second O2? Should the first one be the same distance off the manifolds? What's the tolerance on this?
 

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Discussion Starter #2
After some more reading over at the NLOC, now I'm teetering on the idea...

Its just that I have this picture in my head of a running engine, and of how inefficient SD is at fuel use. If its fired in two banks, would 3 of the 4 injectors on each side eventually waste a substantial amount of fuel if only 1 of the 4 cylinders is on the intake stroke? And being that it happens on 3 cylinders of all 8 pistons' intake stroke... it just seems obvious. Maybe my idea of the exact inner workings of an engine is off, but hey, does anyone else see my point?

It just seems like with this upgrade to SEFI, I'd gain a decent little amount of MPG back. Not to mention the other benefits...hugely improved reaction time of the engine, second o2 sensor, and then other upgrades in the future that arent SD friendly.
 

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Ex Navy Nuke
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I doubt you'll see the slightest increase in mileage by switching to MAF. The injectors put the fuel as close to the head as it can get. It's not like 3 other cylinders are stealing fuel from the last one before it fires. When an intake valve opens air is being drawn through the intake manifold to the combustion chamber picking up the fuel on the way in. It can't rob any fuel from any of the other cylinders because there isn't any air being let in over there to cause it to flow. BTW with bank injection 2 inner injectors on one side and 2 outer injectors on the other side fire at a time.
Besides no path for flow(for one cylinder to steal fuel from another's injector) this is all happening so fast I doubt there is much difference between it(SD) and SEFI(MAF).
 

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Discussion Starter #4
No, I know that a cylinder can't steal from another. I've seen what the inside of a intake manifold/heads looks like. But either way, do you see my point that when 1 cylinder is on its intake stroke, that injector fires, as does 3 other injectors. So that cylinder gets its mix, and the fuel that was sprayed into the other 3 cylinders just sits there. right? Now its onto the intake stroke of another piston. Repeat. Again, I know the cylinders can't steal from each other, but it just seems like if every cylinder only got a fuel shot when it needed it, a whole lot less gas would be wasted.

With MAF, one complete cycle of every cylinder means that 8 shots of fuel were fired.

With SD, you have 32 shots of fuel being fired. Only 8 of them being used for one complete cycle. So with the extra gas that sits in there, it obviously gets burned because it can't just fill up the intake manifold, so what does that do to the fuel mix if the computer is accounting for extra fuel in there, because wouldnt the hego see a rich mix? At WOT maybe it wouldn't make a whole lot of difference if the engine is spinning fast... but at cruise (1900rpm)?

Again, maybe I don't know what the hell I'm talking about and I'm just rambling, but this makes sense to me, does anyone else see my point? :confused:
 

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Bronco4Life said:
No, I know that a cylinder can't steal from another. I've seen what the inside of a intake manifold/heads looks like. But either way, do you see my point that when 1 cylinder is on its intake stroke, that injector fires, as does 3 other injectors. So that cylinder gets its mix, and the fuel that was sprayed into the other 3 cylinders just sits there. right? Now its onto the intake stroke of another piston. Repeat. Again, I know the cylinders can't steal from each other, but it just seems like if every cylinder only got a fuel shot when it needed it, a whole lot less gas would be wasted.

With MAF, one complete cycle of every cylinder means that 8 shots of fuel were fired.

With SD, you have 32 shots of fuel being fired. Only 8 of them being used for one complete cycle. So with the extra gas that sits in there, it obviously gets burned because it can't just fill up the intake manifold, so what does that do to the fuel mix if the computer is accounting for extra fuel in there, because wouldnt the hego see a rich mix? At WOT maybe it wouldn't make a whole lot of difference if the engine is spinning fast... but at cruise (1900rpm)?

Again, maybe I don't know what the hell I'm talking about and I'm just rambling, but this makes sense to me, does anyone else see my point? :confused:

I think that you're just rambling. You definitely don't need to switch to MAF for better gas mileage. You would only want to make this change if you are doing MAJOR engine modifications.
 

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Ex Navy Nuke
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No gas is gonna just "sit there" and none of the fuel from the bank injection is gonna be used by any other cylinders except the ones it's injected by(meant for). Even at idle(appox. 750 RPM) the engine is spinning too fast for any of what you're talking about to happen. It would probably have operate at less than 50 RPM for any of that to even be a legit concern. If you're looking mainly for mileage then don't waste your money on a MAF conversion. If you want more power there's plenty you can do and still stick with SD(like what I did, and a few others).

Why don't you let us know exactly what you want to accomplish and see how we can help from there.
 

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Discussion Starter #8
RLKBOB said:
No gas is gonna just "sit there" and none of the fuel from the bank injection is gonna be used by any other cylinders except the ones it's injected by(meant for). Even at idle(appox. 750 RPM) the engine is spinning too fast for any of what you're talking about to happen. It would probably have operate at less than 50 RPM for any of that to even be a legit concern. If you're looking mainly for mileage then don't waste your money on a MAF conversion. If you want more power there's plenty you can do and still stick with SD(like what I did, and a few others).

Why don't you let us know exactly what you want to accomplish and see how we can help from there.
I never said that the cylinders could "steal" fuel from each other... said that twice now. Reguardless, you're missing my point of the fuel still being put into a place where it's not being used at that point...which happens 32 times when it really only needs to happen 8 times. Obviously it doesnt sound like much... but the fuel gets used eventually... it does add up... And the performance of the engine changes dramatically, according to a couple of guys that did an article of it with their f-150.

I know there's a lot that can be done without upgrading to SEFI/MassAir, the main thing I'm trying to get at right now is fuel economy, other upgrades are coming down the road. Its not a big thing that I'm going after, its just that I dont understand why I only average 9-10mpg with no lift, nothing extra heavy on my truck, and only 31's, where guys that have 35+ tires, lifts, and tons of extra weight average the same. I've greased, replaced, and tweaked out pretty much everything except for the engine, and I just don't understand where I'm losing 3-7mpg at when I compare to guys that have basically the same setup as me. At this point, it's really starting to irk me.

I know I'm driving a bronco, and again, I'm not looking for 20+ mpg, I know I'm sure as hell not going to get it, but 10? There's gotta be some decent ineffieciency with my engine to only get 10mpg.
 
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