LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

24lb injector vs. 30lb injector

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Old 12-29-2003, 01:41 AM
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24lb injector vs. 30lb injector

i have a question:
what would be better?
1. stock 24lb injector at 58psi and injector constant programmed at 30lb.
2. SVO 30lb injector at 43.5psi and injector constant programmed at 30lb.

i dont believe i need to upgrade to 30lb svo. what do you all think?

also what is the rwhp limit of a 30lb injector?

BTW my stock fuel pump could not keep up at 58psi, now i have a WALBRO 255lph.

jesse
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Old 12-29-2003, 01:53 AM
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30lbs injectors hold about a 100 more hp then stock maybe 75.
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Old 12-29-2003, 01:54 AM
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so technically i can make my stockers "act" like #30 injectors?

jesse
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Old 12-29-2003, 02:03 AM
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Turning up the pressure on a stock injector isn't going to work. The computer will over-ride the extra fuel by trimming down the spray time...

What are you trying to accomplish? Just put your car on the datamaster and see where the duty cycle is.. With your mods in the sig I would imagine that 30's would be a good choice for you...
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Old 12-29-2003, 02:06 AM
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Originally posted by InjectedSS
Turning up the pressure on a stock injector isn't going to work. The computer will over-ride the extra fuel by trimming down the spray time...
the computer will not over-ride the extra fuel, because it is programmed for 30lb injectors......

jesse
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Old 12-29-2003, 02:13 AM
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Originally posted by QCKZ28
the computer will not over-ride the extra fuel, because it is programmed for 30lb injectors......

jesse
So basically now your LYING to the computer.. Your going to OVER WORK your injectors... They can only spray so much.. There is a REASON that they sell bigger injectors
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Old 12-29-2003, 02:29 AM
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Originally posted by InjectedSS
So basically now your LYING to the computer.. Your going to OVER WORK your injectors... They can only spray so much.. There is a REASON that they sell bigger injectors

yeah the are being pushed a bit i dont think too much....
if i were to increase the pressure to 70psi they would definately lock up, but right they work fine at 58psi....

stock LS1 have 26-28lb injectors but at 58psi
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Old 12-29-2003, 07:47 AM
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You are (almost) always better off usng a bigger injector to a smaller percentage of it's duty cycle.

Plus, the SVO injectors fail in the "on" position, which is very important if you ever decide to spray your motor, because it'll keep your motor from spraying all over the track.

The only time that you would want to be careful is when you get near the 50# mark on our motors. At that point you want to do the conversion to low impedence injectors that go past the 50# "barrier"
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Old 12-29-2003, 03:49 PM
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so would i benefit from #30 injectors with 43.5psi?
or is that the same as #24 injectors with 58psi?

jesse
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Old 12-29-2003, 09:06 PM
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Correct me if I'm wrong (happens WAY too often!), but I believe programming your computer for 30# injectors would shorten the "open time" of the injector (bigger injector will flow more in an equal amount of time). You would be turning up the pressure to get more flow then commanding the injectors not stay open as long and have less flow. Not to mention the effects at idle and part throttle of really cutting back fuel.

If your car is running good at 58 psi and 24#, I'd leave it (my old GN ran great at 62 psi). If you think it is running out of fuel, I'd get the computer reprogrammed and get the 30#. Think of the flow potential if you wanted to start turning up the pressure then!
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Old 12-29-2003, 10:34 PM
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Originally posted by QCKZ28
so would i benefit from #30 injectors with 43.5psi?
or is that the same as #24 injectors with 58psi?

jesse
It's really 6 one way or half dozen the other.

Some may argue that 58 psi / 24 lb/hr will get you better fuel atomization.

Some others may argue that you are overworking your fuel pump.

Some will argue that your fuel pump capacity will be less at 58 than at 43.5.

Others might warn of the possibility of the stock injectors locking closed at the higher pressure.

All are true and valid concerns. You just have to decide what risks you're willing to live with.

Mike
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Old 12-30-2003, 06:28 PM
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Originally posted by engineermike
It's really 6 one way or half dozen the other.

Some may argue that 58 psi / 24 lb/hr will get you better fuel atomization.

Some others may argue that you are overworking your fuel pump.

Some will argue that your fuel pump capacity will be less at 58 than at 43.5.

Others might warn of the possibility of the stock injectors locking closed at the higher pressure.

All are true and valid concerns. You just have to decide what risks you're willing to live with.

Mike

thank you mike.

jesse
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