LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Injectors

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Old Oct 25, 2008 | 11:34 PM
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From: Bolton Masshole
Default Injectors

Right now i have 30# SVO's (red tops) in my 383 in sig. I also have a 255lph pump, and a Holley adjustable FPR (still needs to be installed). The question is, for my current setup, are these injectors large enough? Over the winter i am considering doing a larger cam (575/575 somewhere around there). I would probably need to upgrade to atleast 36lb injectors then right? Opinions? Thanks guys
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Old Oct 26, 2008 | 12:28 PM
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it all depends on the hp numbers ur trying to reach. 30# injectors support somewhere around 385 hp then the 255lph pump should add a little more

Last edited by riceburnerZ28; Oct 26, 2008 at 01:25 PM.
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Old Oct 26, 2008 | 12:48 PM
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I would say your about on the verge of needing 36's now and if it were me I would sell your 30's and pick up some 36's especially since your going with a larger cam in the near future.
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Old Oct 26, 2008 | 12:50 PM
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From a calculator (Flywheel HP I presume):

Power: 400 horespower
Number of injectors: 8
BSFC: 0.40
Duty cycle: 0.80

This combination will require 262 cc/min injector (25.0 lbs/hour)

and your 30# (31.5# @ 43psi):

Injector size: 330 cc/min injectors(31.4 lbs/hour)
Number of injectors: 8
BSFC: 0.40
Duty cycle: 0.80

This combination will supply fuel for 502 horsepower


Now, take into account you have a AFPR, you'll be able to push the injectors higher. Don't know what your pump is capable of for pressure, and not sure if this is too high and not recommended BUT:

Old fuel pressure: 43
New fuel pressure: 60

At your new pressure, your 30 injectors will flow 35
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Old Oct 26, 2008 | 11:00 PM
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From: Bolton Masshole
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so your saying my red tops should support 500+hp? never heard anything like that before. I was thinking i should atleast upgrade to maybe some 36#ers
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Old Oct 27, 2008 | 12:31 AM
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yeah....... 30's support up to 400 tops every body tell u that safer is better if your running that setup step up to 36 or even 42 depending on your funds and say you add
n20 later safer is better......
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Old Oct 27, 2008 | 01:29 AM
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Originally Posted by MTBSully
so your saying my red tops should support 500+hp? never heard anything like that before. I was thinking i should atleast upgrade to maybe some 36#ers
You're right, I used an incorrect BSFC .40 was used where .50 is more accurate for our cars.

24# = 317hp (Which I was thinking 325 should be about what it shows up as)
31.5# (30# SVO) = 402hp
37.5# (36# SVO) = 481hp
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