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TBI Vortec How-To With Pics

This is a discussion on TBI Vortec How-To With Pics within the TBI Tuning (87-95 / OBD I) ECM/PCM forums, part of the Performance category; Everybody loves pics so behold. Here is the GM Performance Parts TBI to Vortec intake manifold. Note there is no ...

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    TBI Vortec How-To With Pics


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    Everybody loves pics so behold.

    Here is the GM Performance Parts TBI to Vortec intake manifold. Note there is no vacuum port for power brakes. The arrow points to the place where the throttle cable bracket needs to be bent and re-drilled (behind) to work with the different intake manifold bolting of a Vortec (straight down rather than at an angle like the swirl port heads - green arrows). I ground it out bigger to match the "ported" throttle body. Other than that, everything pretty much fits and works and bolts right up.



    Here is a "ported" throttle body from CFM-Tech and my favorite tools for re-contouring the entrance. I like the long die grinders so I can 2-hand for better control and stability.


    The red arrows show where I re-contoured, the blue show where CFM Technologies cut off the tops of the passages to unshroud the injectors. I would like to see a little left around the outside to help locate the air cleaner.


    When you use an injector spacer and a thick gasket the fuel fittings won't screw in. This shot shows where I clearanced for the fuel fittings.


    Here you can see how I drilled/tapped a fuel line extension at an angle for the fuel pressure gage. If you do not, the gage will hit the throttle bodt and interfere with the fuel line and/or the o-ring sealing surface. It fits with the air cleaner with room to spare. I opted to go this rout rather than buy one pre-drilled is because a pre-drilled one might end up pointing the other direction - 5 in 6 chance of that happening. I used Prematex thread sealer and blue Locktite throughout. I'd hate to have a screw rattle out and drop down the intake.


    The next two shots show how the pacer is drilled/tapped for the power brake port. I also ground out the spacer to match the "ported" throttle body.


    Her you can see the angle I drilled at.


    I modified the air cleaner to get rid of the spacer on top of the throttle body and unshroud the injectors a bit. I had to re-index the locating tabs to fit it on properly without the spacer.



    GM, in their great wisdom, didn't simply line up the locators top to bottom. Why??? Because that would make too much sense. The only reason I can see for this piece to even exist is so you don't need to remove the crank case fresh air hose (or whatever it's called) to remove the air cleaner. Not a big concern in my application.


    Overall the power is much better than the 210 HP stocker and the truck is now fun to drive. The job was pretty straight forward and not too technical. The chip from Westers Garage in Canada worked pretty darn well the first time - just tell them what you have. I am going to need a better fuel pump though because the fuel pressure tops out at 12 PSI and drops to 8 PSI when manually gunning the throttle in park.

    Specs:
    89 Suburban, '96 5.7 Vortec, 1 1/2 headers w/ 3" pipe and hi flow cat, "ported" TBI, chip, T400, 4:11, 10 bolt front, 14 bolt 9 3/4 RG Gov Lock rear, 6" lift (all springs), 31575/R16.
    Last edited by Eric_S; 09-30-2008 at 11:24 PM.

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    Re: TBI Vortec How-To With Pics

    on the tbi spacer. hog out the center so that its just one big oval opening.

    i got the best gains with my tbi spacer hogged out like that.
    -mark
    89 blazer 2dr 2wd L31 vortec 355|T56|8.5
    0411 pcm powered

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    Re: TBI Vortec How-To With Pics

    Nice writeup.

    Quote Originally Posted by Big Angry
    Hey ****face, (yes I am violating the rules and flaming you, whaah)

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    Re: TBI Vortec How-To With Pics

    Quote Originally Posted by tippmann243
    on the tbi spacer. hog out the center so that its just one big oval opening.

    i got the best gains with my tbi spacer hogged out like that.
    Is that top HP (seems like it would be) or low end torque? I do lpts of towing and need grunt. The Vortec swap gave me the biggest gains. ;^)

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    Re: TBI Vortec How-To With Pics

    You must have a different set up than me. I ran the vacuum for my brakes to the manifold. I used the port that is in the middle of your two fuel lines in the first picture. What's that go to anyway?
    '91 C1500 with a 406 AFR Heads, Compcams 12-423-8 retro-roller camshaft, Thorley headers, Holley 770 carb, Edelbrock Air Gap manifold, K&N X-Stream, and quickly balding rear tires

    '08 K2500HD LTZ "Southern Comfort" crew cab, Duramax, 6" lift, 35" tires with Procomp wheels, EFILive

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    Re: TBI Vortec How-To With Pics

    Quote Originally Posted by Pre-StrokerC150
    You must have a different set up than me. I ran the vacuum for my brakes to the manifold. I used the port that is in the middle of your two fuel lines in the first picture. What's that go to anyway?
    Theres a hole on the side of the manifold where the stock tube threads into. I would re-use that hole.

    1995 350 "Tool Box Injection"
    Going 4/6 with 20" Billet Specialties

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    Re: TBI Vortec How-To With Pics

    Quote Originally Posted by Pre-StrokerC150
    You must have a different set up than me. I ran the vacuum for my brakes to the manifold. I used the port that is in the middle of your two fuel lines in the first picture. What's that go to anyway?
    That thing goes to the vacuum modulator (top) and cruise control (rear).


    Quote Originally Posted by SuperStepside
    Theres a hole on the side of the manifold where the stock tube threads into. I would re-use that hole.
    On a stocker, but not on the GM Performance Parts TBI Vortec manifold.
    Last edited by Eric_S; 09-30-2008 at 08:43 PM.

 

 

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