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What cylinders run leaner on an LS1?

This is a discussion on What cylinders run leaner on an LS1? within the Forced Induction forums, part of the LSx Technical Help Section category; I have a Vortec 6.0 that has been modified to a 408 Stroker with a ProComp Triple ball bearing turbo ...

  1. #1
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    What cylinders run leaner on an LS1?

    I have a Vortec 6.0 that has been modified to a 408 Stroker with a ProComp Triple ball bearing turbo pushing 14.5 lbs of boost. I have 72# injectors from "Deatsch Werks" that have been flow mapped. I need to know the cylinders that run leaner for the LS1 so I can install the higher flow injectors on those cylinders.

    I heard that 7 and 8 are usualy lean, 7 being the worst, is this true? And also what about the rest of the cylinders? I want to match up the injectors with the best cylinders for that injector.

    I just built and installed this engine I want to make sure that I do everything as correctly as possible. I built this engine Specificaly for this Turbo Setup.

    Meling high flow oil pump, high flow water pump, Walbro high flow fuel pump, Forged pistons, rods and crank. Ported heads with Jesel 2K rockers, custom cam for turbo's. And 2 Bar Speed Dencity tuning.. and a built 4L80E Trans that can handle up to 1000 hp. (I snapped the output shaft on the stock
    4L60E prety fast).
    Last edited by bly123; 04-17-2010 at 06:09 PM.

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    Anyone? Am I wrong about this?

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    Not sure of the answer, but wouldn't the issue be best resolved by reading the plugs and then making adjustments to your injector pulse width and such through tuning?

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    I guess the whole point of flow mapping new injectors is because not all injectors will flow exactly at the same rate no matter how hard they try.

    Since some will flow slightly more than others and some cylinders run slightly leaner than others, it's a common practice to put the higher flow injectors in the lean locations. Why not? You already know the injector flow. We are not taling a huge difference in flow. Like 72.7 as apossed to 72.1 difference in the injectors. Seems like a supper small thing but every little thing helps.

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    Ok -- that makes sense. From your original post I thought you were planning on installing something like 80 lb. injectors in the lean cylinders and 72 lb. in the rest (or something like that). I went back and re-read it and now I understand.

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    Junior Member Trevorws6's Avatar
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    you could also go with a edelbrock victor jr efi manifold and an intake elbow. that seems to solve peoples lean cynlinder problems.

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    Quote Originally Posted by Trevorws6 View Post
    you could also go with a edelbrock victor jr efi manifold and an intake elbow. that seems to solve peoples lean cynlinder problems.
    dont think those clear the stock size hoods

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    I thought port fuel injection basicly fixed the lean cylinder problems you usally have with a carb.

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    Quote Originally Posted by bly123 View Post
    I have a Vortec 6.0 that has been modified to a 408 Stroker with a ProComp Triple ball bearing turbo pushing 14.5 lbs of boost. I have 72# injectors from "Deatsch Werks" that have been flow mapped. I need to know the cylinders that run leaner for the LS1 so I can install the higher flow injectors on those cylinders.

    I heard that 7 and 8 are usualy lean, 7 being the worst, is this true? And also what about the rest of the cylinders? I want to match up the injectors with the best cylinders for that injector.
    I just built and installed this engine I want to make sure that I do everything as correctly as possible. I built this engine Specificaly for this Turbo Setup.

    Meling high flow oil pump, high flow water pump, Walbro high flow fuel pump, Forged pistons, rods and crank. Ported heads with Jesel 2K rockers, custom cam for turbo's. And 2 Bar Speed Dencity tuning.. and a built 4L80E Trans that can handle up to 1000 hp. (I snapped the output shaft on the stock
    4L60E prety fast).
    this is what I've heard but I have no data that backs that up. You could always get EGT readings from the cylinders and go by that as to which ones are leaner.

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    Theoretically no cylinders should run any leaner than any other cylinders. These engines are port injected, so given all injectors are functioning properly, each cylinder gets an identical fuel supply during the intake stroke.

    The only real way to check it would be to check EGT's or use a wideband in each primary, which isn't all that practical.

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    Quote Originally Posted by 67CamaroRSSS View Post
    I thought port fuel injection basicly fixed the lean cylinder problems you usally have with a carb.
    That was my thought. We used EGT probes in the dyno cell to tune with, and would stagger jet the carb to compensate for a lean cylinder, or change intake manifold for a better design. We never had many LS motors on the dyno.

    I would think that port fuel injection would cure that, or at the very least you could play with injector pulse width in the tune on the offending cylinders to compensate for it.

    As long as LS motors have been around now I would think there are tuners out there that have seen this issue,,,if there is one.

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    The back two cylinders (7,8) get a little more air in forced induction applications using the stock style intake (LS1, LS6, F.A.S.T.) which is why we offer Flow matched injectors so you can compensate by putting the higher flowing injectors in the back.


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