Will I Need Bigger Injectors

Diabolic

Diabolic

Active member
Hey guys! I’m putting a Lightning engine in a 94 Bronco for my sons first vehicle. I’m trying to keep it as simple as possible and resist the urge to modify everything about it. I’ve already gone overboard and bought some GT40X heads from another board member. He’s turning 15 in October so he will have a full year to decide if he wants to push it further or just drive it. He’s not a huge car fanatic but he does like Broncos. I figured what the heck, and I’ll add a few small touches.....Lightning intake, GT40X heads, headers, Bassani exhaust, e-fan....just slightly more modded than a stock Bronco! I’m really not wanting to add a wideband, custom tune it for 30# injectors, or swap over to MAF. Do you guys think the Lightning intake, GT40X heads, and exhaust will eclipse the 300hp threshold? It’s keeping the stock 94 Bronco roller cam. I had a similar setup but with AFR heads, mustang cam, 70MM Tb, and roller rockers.....it would hit 14.1-13.7 AFR at wot with stock 19’s. Too lean for my taste, but the Bronco cam and the X heads should make a little less hp than my old setup. What’s your thoughts? Think 19’s will cut it? Think 275-295 crank hp?
 
Diabolic said:
Hey guys! I’m putting a Lightning engine in a 94 Bronco for my sons first vehicle. I’m trying to keep it as simple as possible and resist the urge to modify everything about it. I’ve already gone overboard and bought some GT40X heads from another board member. He’s turning 15 in October so he will have a full year to decide if he wants to push it further or just drive it. He’s not a huge car fanatic but he does like Broncos. I figured what the heck, and I’ll add a few small touches.....Lightning intake, GT40X heads, headers, Bassani exhaust, e-fan....just slightly more modded than a stock Bronco! I’m really not wanting to add a wideband, custom tune it for 30# injectors, or swap over to MAF. Do you guys think the Lightning intake, GT40X heads, and exhaust will eclipse the 300hp threshold? It’s keeping the stock 94 Bronco roller cam. I had a similar setup but with AFR heads, mustang cam, 70MM Tb, and roller rockers.....it would hit 14.1-13.7 AFR at wot with stock 19’s. Too lean for my taste, but the Bronco cam and the X heads should make a little less hp than my old setup. What’s your thoughts? Think 19’s will cut it? Think 275-295 crank hp?
Click to expand...

It'll be fine with the 19's. If anything you could bump up the FP, but I doubt you'll need it in N/A form.
 
I'd keep the 19's and add an adjustable fuel pressure regulator for heavy throttle/WOT tuning. The MAF ecu is in open loop in these conditions so it doesn't look at the O2 sensor for fuel correction, just a calculated fuel table.
 
It’s speed density, not maf. If I up the base fuel pressure then the adaptive learning should dial it back in, but I believe it also applied these changes to wot.
 
A few lbs to help at WOT is easily doable. But I think you’re way overthinking this :)


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Well just in case he ever has an OJ moment, I don’t want it running lean if it’s at wot for 30-45mins straight.😁
 
So if I'm reading this right, it's essentially a stock Lightning engine but with the stock Bronco cam and some exhaust mods? A stock 351W made 210hp, and a stock Lightning engine made 240hp, so your build should be somewhere between those two numbers and I wouldn't think you'd have any fuel issues either.
 
Stock 1994 bronco 351w should be a roller motor and has a little more lift than the Lightnings. You could take the vacuum line off the fuel pressure regulator and jump it up to 39 pounds on the rail. Then also add a fmu for a little fuel reserve.


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How would an FMU work without boost?

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You almost read it correctly. I’m adding GT40X aluminum heads.

needmorepower said:
So if I'm reading this right, it's essentially a stock Lightning engine but with the stock Bronco cam and some exhaust mods? A stock 351W made 210hp, and a stock Lightning engine made 240hp, so your build should be somewhere between those two numbers and I wouldn't think you'd have any fuel issues either.
Click to expand...
 
Wouldnt worry about injectors unless you go up past the 40x heads and stock cam then 30s and a simple tweecer would make it a sweet combo.
My 02
Steve
 
Good to hear from you Steve. I probably have some old tunes, really old, that have 30# injectors in them. My tuning laptop was stolen years ago with all my stuff on it. Then I misplaced my replacement computer and dongle for about ehhhh......4 years! Answer a question for me please. Why don’t the Lightning calibrations have a high and low slope? All the other Fords do. This means breakpoint is useless? When entering slope for 30’s, do you use the published high or low slope value?
 
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