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What size injector?

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Old Jan 31, 2011 | 07:05 PM
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Default What size injector?

I have a 408 with 12.5:1 compression. The motor with 13.2:1 made 52x hp.

I would like to use my stock injectors if possible("01 6.0 truck). If these won't flow enough then obviously my question is how many lb injectors do I need. I am using a TBSS intake and the stock TB with adapter for now, unless I find a larger TB that i can afford before installing the motor. I will upgrade at some point so I might as well plan for it with the injectors.

Little bit more info, I won't drive this truck much and 99% of the time it will be driven at the track on a wet nitrous kit. I am planning on spinning this motor to 7000 to start with if that matters.

Thanks trying to get everything to drop it in.
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Old Jan 31, 2011 | 07:36 PM
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The builder said 43-46 lbs injectors. Does this seem correct.
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Old Jan 31, 2011 | 07:43 PM
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Originally Posted by custm2500
I have a 408 with 12.5:1 compression. The motor with 13.2:1 made 52x hp.

I would like to use my stock injectors if possible("01 6.0 truck). If these won't flow enough then obviously my question is how many lb injectors do I need. I am using a TBSS intake and the stock TB with adapter for now, unless I find a larger TB that i can afford before installing the motor. I will upgrade at some point so I might as well plan for it with the injectors.

Little bit more info, I won't drive this truck much and 99% of the time it will be driven at the track on a wet nitrous kit. I am planning on spinning this motor to 7000 to start with if that matters.

Thanks trying to get everything to drop it in.
with those numbers you need a 50lb @58psi. we like to use the bosch ev14 they will be a direct bolt in no mods.we also sell a plug and play wire adapter or pigtails.we sell the complete kit for $399.00.
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Old Jan 31, 2011 | 07:47 PM
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Hi,
should have you in the ball park......what size fuel pump??????????
Check wallace racing for info that may help you decide..have a blessed day...........jim
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Old Jan 31, 2011 | 08:09 PM
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I have a walbro 255. I am planning on that being enough pump for the motor and a 100-150 shot.
When I plan to go above 150 of nitrous I will get a stand alone.

What duty cycle will the 50s probably run at?

You bring up pig tails does that mean the stock wiring won't work with the bigger injectors.
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Old Jan 31, 2011 | 09:35 PM
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Originally Posted by custm2500
I have a walbro 255. I am planning on that being enough pump for the motor and a 100-150 shot.
When I plan to go above 150 of nitrous I will get a stand alone.

What duty cycle will the 50s probably run at?

You bring up pig tails does that mean the stock wiring won't work with the bigger injectors.
you should be around 80%.all injectors in the pounds you need will have a different plug.its no big deal we have wire adapters that will plug from injector into stock harness.they are included in the kit.
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Old Jan 31, 2011 | 11:04 PM
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I have a 408 LS2 running the 33lb@58 injectors with the adapters that FICInjectors mentioned and a walboro 255 pump. I agree with him on a 50lb injector. Running the 1/4 you will probably see close to a 90% inj duty cycle, spaying on top of that would make them almost statically open. I sprayed 100 a few weeks back and hit 95% inj duty cycle, anything above 80% and I would look at upgrading.
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Old Feb 1, 2011 | 04:25 AM
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For referance, how many lb are my stock 01 6.0 injectors.

Also does everyone agree the 255 will easily support motor and atleast a 150 shot. I think it might support a little more but I am figuring on going to a higher fuel for the nitrous over 150 due to such high compression. Let me know how much nitrous the 255 should support on the motor making 475-500 N/A. Thanks.

Last edited by custm2500; Feb 1, 2011 at 05:03 AM.
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Old Feb 1, 2011 | 12:21 PM
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https://ls1tech.com/forums/fueling-i...ump-chart.html

Also, www.rceng.com and go to TECHNICAL / Sizing. Please understand the fuel system items.

fuel injectors are usually rated at 3 Bar or 43.5psi, there are a few (possibly increasing) manufacturers that are using 4 Bar or 58psi

If you have a fuel system at 58psi, and you use an injector that is rated at 43.5psi, you will actually have a larger fuel injector in your application.


*Lets say your ACTUAL FUEL PRESSURE is 58psi, period.
For instance, this 50 LB/Hr injector @ 58psi is just that, a 50LB/hr injector

HOWEVER
if you have a 50LB/Hr injector @ 43.5psi and you are running it at 58psi, you actually have a 57# injector; therefore giving you more breathing room.

I would recommend a 47# or slightly higher injector at 43.5psi RATING. Is this vehicles ACTUAL fuel pressure 58psi?
If avoidable, I would not run injectors above 80% Duty Cycle
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Old Feb 1, 2011 | 02:08 PM
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Yes my pressure was 58.

I fully understand that injectors are rated at a certain psi.
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