Stock Injector Size
I think your 94' is 22# stock. I know 28# is fine with a baby cam but wouldn't push it past that. 26# might be better but best to have a fuel gauge installed first.
Checked FAQ: 94's had stock 24#
https://ls1tech.com/forums/showthrea...52#post2682252
Checked FAQ: 94's had stock 24#
https://ls1tech.com/forums/showthrea...52#post2682252
I second what Vendetta said..... 
24# Injectors are usually good up until the 340rwhp to 360rwhp range, after that consider a upgrade to 30# injectors. I would not use the 28# LS1 injectors, the LS1 fuel system operates at a different pressure than the LT1 fuel system, the LS1 injectors end up flowing just a hair over 24 pounds when hooked up to the LT1 fuel system... big waste of money imo.
Most people upgrade to 30# SVO injectors with no problems, you could also use 32# injectors from Racetronix.com just keep in mind when you upgrade your injectors you also need to tune your car on a dyno for the larger injectors, or at least get a PCM tune from one of the many online tuners. Good luck!
Shea
24# Injectors are usually good up until the 340rwhp to 360rwhp range, after that consider a upgrade to 30# injectors. I would not use the 28# LS1 injectors, the LS1 fuel system operates at a different pressure than the LT1 fuel system, the LS1 injectors end up flowing just a hair over 24 pounds when hooked up to the LT1 fuel system... big waste of money imo.
Most people upgrade to 30# SVO injectors with no problems, you could also use 32# injectors from Racetronix.com just keep in mind when you upgrade your injectors you also need to tune your car on a dyno for the larger injectors, or at least get a PCM tune from one of the many online tuners. Good luck!
Shea
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I trapped 118 (3,250lbs with me) with my bigger cam before tuning, all I did was got an adjustable fuel pressure regulator which I dont even think I need. I dont know how much hp that is but prolly better than 360rwhp
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From: That Southern Fried Space City
Originally Posted by Houdini
I second what Vendetta said.....
24# Injectors are usually good up until the 340rwhp to 360rwhp range, after that consider a upgrade to 30# injectors. I would not use the 28# LS1 injectors, the LS1 fuel system operates at a different pressure than the LT1 fuel system, the LS1 injectors end up flowing just a hair over 24 pounds when hooked up to the LT1 fuel system... big waste of money imo.
Most people upgrade to 30# SVO injectors with no problems, you could also use 32# injectors from Racetronix.com just keep in mind when you upgrade your injectors you also need to tune your car on a dyno for the larger injectors, or at least get a PCM tune from one of the many online tuners. Good luck!
Shea
24# Injectors are usually good up until the 340rwhp to 360rwhp range, after that consider a upgrade to 30# injectors. I would not use the 28# LS1 injectors, the LS1 fuel system operates at a different pressure than the LT1 fuel system, the LS1 injectors end up flowing just a hair over 24 pounds when hooked up to the LT1 fuel system... big waste of money imo.
Most people upgrade to 30# SVO injectors with no problems, you could also use 32# injectors from Racetronix.com just keep in mind when you upgrade your injectors you also need to tune your car on a dyno for the larger injectors, or at least get a PCM tune from one of the many online tuners. Good luck!
Shea
You can run 30#'ers without a tune but nothing beats a good dyno tune to see how the car is acting and what it likes and doesn't like...
An adjustable regulator can make injectors act bigger just the same way the LS1 injectors act 24# in the LT1 system instead of their rated 28#, it is however the wrong way to do things as it makes tuning harder and if overpressured the stockers lock closed can you say BANG.
What power they are good to depends a lot on how far you want to push them once over 80% duty cycle it is about time to begin thinking of an upgrade as this is hard on them, start getting over 90% and they become less accurate because they are not fully closing before they open again this could lead to cylinder balance issues and just plain less performance than there is potential for. One of the FAST Impalas was running stock injectors beyond 400crank hp and the DC was 100% or close to it most of the time depending on conditions he swore that was fine till he was talked into swapping in some 28# at LT1 pressure injectors think they were from a GN and low and behold they did work better because the duty cycle was lower and they could more precisely control the fuel. This depends on the tune too a rich tune may max them out at 400flywheel where a leaner one might stretch them to 450hp.
Right now with ZZ3 cam 1.5 rockers good intake stock exhaust manifolds and cats(a few more weeks only till longtubes) to a good 2.5" x-pipe exhaust system. I have not asked Bryan for an update for my most recent mods(waiting on headers to bother him once) so the tune is a tad rich like 930mv and I am hitting 84-85%DC, again she is a bit rich though. This is a MILD cam at the shift she just taps 6000rpms, I dynoed it a year ago with slightly lesser intake and exhaust mods and heavier drivetrain parts and it put 263hp to the rollers at about 5400rpms on 87 octane. I figured about 320 or so at the crank considering the heavy parts, and at that time the AFR was better and DC a little lower just occasionally touching 80%. I know guys who found a little more power swapping to 30#s with the HOT cam on otherwise stock motors too again it was a DC thing and the other thing to consider is that rpm comes into play because the faster the engine spins the less time the injector has to spray the fuel. This is probably part of the reason Bobby was able to keep the stocker with that much power, the blower didn't need rpms to make the power so the injectors had more time to stay open and deliver it.
What power they are good to depends a lot on how far you want to push them once over 80% duty cycle it is about time to begin thinking of an upgrade as this is hard on them, start getting over 90% and they become less accurate because they are not fully closing before they open again this could lead to cylinder balance issues and just plain less performance than there is potential for. One of the FAST Impalas was running stock injectors beyond 400crank hp and the DC was 100% or close to it most of the time depending on conditions he swore that was fine till he was talked into swapping in some 28# at LT1 pressure injectors think they were from a GN and low and behold they did work better because the duty cycle was lower and they could more precisely control the fuel. This depends on the tune too a rich tune may max them out at 400flywheel where a leaner one might stretch them to 450hp.
Right now with ZZ3 cam 1.5 rockers good intake stock exhaust manifolds and cats(a few more weeks only till longtubes) to a good 2.5" x-pipe exhaust system. I have not asked Bryan for an update for my most recent mods(waiting on headers to bother him once) so the tune is a tad rich like 930mv and I am hitting 84-85%DC, again she is a bit rich though. This is a MILD cam at the shift she just taps 6000rpms, I dynoed it a year ago with slightly lesser intake and exhaust mods and heavier drivetrain parts and it put 263hp to the rollers at about 5400rpms on 87 octane. I figured about 320 or so at the crank considering the heavy parts, and at that time the AFR was better and DC a little lower just occasionally touching 80%. I know guys who found a little more power swapping to 30#s with the HOT cam on otherwise stock motors too again it was a DC thing and the other thing to consider is that rpm comes into play because the faster the engine spins the less time the injector has to spray the fuel. This is probably part of the reason Bobby was able to keep the stocker with that much power, the blower didn't need rpms to make the power so the injectors had more time to stay open and deliver it.
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From: That Southern Fried Space City
Originally Posted by 96capricemgr
An adjustable regulator can make injectors act bigger just the same way the LS1 injectors act 24# in the LT1 system instead of their rated 28#, it is however the wrong way to do things as it makes tuning harder and if overpressured the stockers lock closed can you say BANG.
What power they are good to depends a lot on how far you want to push them once over 80% duty cycle it is about time to begin thinking of an upgrade as this is hard on them, start getting over 90% and they become less accurate because they are not fully closing before they open again this could lead to cylinder balance issues and just plain less performance than there is potential for. One of the FAST Impalas was running stock injectors beyond 400crank hp and the DC was 100% or close to it most of the time depending on conditions he swore that was fine till he was talked into swapping in some 28# at LT1 pressure injectors think they were from a GN and low and behold they did work better because the duty cycle was lower and they could more precisely control the fuel. This depends on the tune too a rich tune may max them out at 400flywheel where a leaner one might stretch them to 450hp.
Right now with ZZ3 cam 1.5 rockers good intake stock exhaust manifolds and cats(a few more weeks only till longtubes) to a good 2.5" x-pipe exhaust system. I have not asked Bryan for an update for my most recent mods(waiting on headers to bother him once) so the tune is a tad rich like 930mv and I am hitting 84-85%DC, again she is a bit rich though. This is a MILD cam at the shift she just taps 6000rpms, I dynoed it a year ago with slightly lesser intake and exhaust mods and heavier drivetrain parts and it put 263hp to the rollers at about 5400rpms on 87 octane. I figured about 320 or so at the crank considering the heavy parts, and at that time the AFR was better and DC a little lower just occasionally touching 80%. I know guys who found a little more power swapping to 30#s with the HOT cam on otherwise stock motors too again it was a DC thing and the other thing to consider is that rpm comes into play because the faster the engine spins the less time the injector has to spray the fuel. This is probably part of the reason Bobby was able to keep the stocker with that much power, the blower didn't need rpms to make the power so the injectors had more time to stay open and deliver it.
What power they are good to depends a lot on how far you want to push them once over 80% duty cycle it is about time to begin thinking of an upgrade as this is hard on them, start getting over 90% and they become less accurate because they are not fully closing before they open again this could lead to cylinder balance issues and just plain less performance than there is potential for. One of the FAST Impalas was running stock injectors beyond 400crank hp and the DC was 100% or close to it most of the time depending on conditions he swore that was fine till he was talked into swapping in some 28# at LT1 pressure injectors think they were from a GN and low and behold they did work better because the duty cycle was lower and they could more precisely control the fuel. This depends on the tune too a rich tune may max them out at 400flywheel where a leaner one might stretch them to 450hp.
Right now with ZZ3 cam 1.5 rockers good intake stock exhaust manifolds and cats(a few more weeks only till longtubes) to a good 2.5" x-pipe exhaust system. I have not asked Bryan for an update for my most recent mods(waiting on headers to bother him once) so the tune is a tad rich like 930mv and I am hitting 84-85%DC, again she is a bit rich though. This is a MILD cam at the shift she just taps 6000rpms, I dynoed it a year ago with slightly lesser intake and exhaust mods and heavier drivetrain parts and it put 263hp to the rollers at about 5400rpms on 87 octane. I figured about 320 or so at the crank considering the heavy parts, and at that time the AFR was better and DC a little lower just occasionally touching 80%. I know guys who found a little more power swapping to 30#s with the HOT cam on otherwise stock motors too again it was a DC thing and the other thing to consider is that rpm comes into play because the faster the engine spins the less time the injector has to spray the fuel. This is probably part of the reason Bobby was able to keep the stocker with that much power, the blower didn't need rpms to make the power so the injectors had more time to stay open and deliver it.
I should have clarified a bit...I didn't use stock injectors but stock sized injectors (SVO 24's). However the blower was a Vortech and as you know it doesn't make boost until the rpms start to climb so your statement was a bit inaccurate.
There is another guy that post on here as InsuranceGuy or something like that and I watched his car (93 Z28) make over 600hp and some ungodly amount of torque (800+ if I remember correctly, he can chime in) using those same SVO injectors (24#'s).
Now I'm not telling everybody to go out and buy 24's for their appy, I'm just saying that some of what I have read isn't accurate and just backing it up with some real life examples and not "hearsay" or anything like that.
Yes adjustable regulators are a waste with a stock computer some guys do however use them to make injectors act larger in conjunction with tuning so as not to make part throttle rich and have the pcm pull fuel.
As far as your blower, how high did you rev it?
Guys I know who needed bigger injectors with just a cam swap were spinning 6500, even if your blower did like revs I would guess with a stock cam you still stayed well below that.
The clue to the injectors needing time to work is in their very rating of pounds per HOUR.
Also the Ford injectors are rated at a slightly lower pressure like 39psi instead of our 43.5psi so in an LT1 with stock fuel pressure they actually act larger than 24#.
The stock FPR works to keep a constant pressure difference at low throttle manifold pressure is low and fuel pressure is lowered to keep the differential constant. When we use a pressure gauge it reads as compared to atmospheric pressure not manifold pressure. If it didn't do this when you got into boost the pressure difference would be small say you had 10psi in the manifold and 43psi at the fuel rail then the injectors would only spray fuel like they were at 33psi this is why the vacuum line. I wonder if there is less pressure at the port than up in the manifold, well there is because otherwise there would be no flow but I wonder if it is enough to make the regulator see a little more pressure under boost than the injector tips actually encounter and if that plays into why some boosted motors are able to use such small injectors.
As far as your blower, how high did you rev it?
Guys I know who needed bigger injectors with just a cam swap were spinning 6500, even if your blower did like revs I would guess with a stock cam you still stayed well below that.
The clue to the injectors needing time to work is in their very rating of pounds per HOUR.
Also the Ford injectors are rated at a slightly lower pressure like 39psi instead of our 43.5psi so in an LT1 with stock fuel pressure they actually act larger than 24#.
The stock FPR works to keep a constant pressure difference at low throttle manifold pressure is low and fuel pressure is lowered to keep the differential constant. When we use a pressure gauge it reads as compared to atmospheric pressure not manifold pressure. If it didn't do this when you got into boost the pressure difference would be small say you had 10psi in the manifold and 43psi at the fuel rail then the injectors would only spray fuel like they were at 33psi this is why the vacuum line. I wonder if there is less pressure at the port than up in the manifold, well there is because otherwise there would be no flow but I wonder if it is enough to make the regulator see a little more pressure under boost than the injector tips actually encounter and if that plays into why some boosted motors are able to use such small injectors.
