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Tpi power limits

Discussion in 'The Garage' started by beastofablaze, Apr 11, 2006.

  1. beastofablaze

    beastofablaze 1/2 ton status

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    What kind of hp and tq can a tpi system support... I am thinking about putting some dart iron eagle on my rig or maybe even some afr's if the wallet allows and want to know if tpi is a better solution than my 670 cfm tbi and prominator setup which will handle somewhere from 375 to 400 hp.

    I am looking for somewhere around 450 hp and 475 ft lbs of torque out of the head swap and want to know if I can do it with tpi.
     
  2. 79k20350

    79k20350 3/4 ton status

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    if ya got a stock motor its tbi, not tpi and is not incredibly upgrade frinedly

    never mind, i only read half the post :doh:
     
    Last edited: Apr 11, 2006
  3. 1979jimmy350

    1979jimmy350 1/2 ton status

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    unless your motor is already really modifyed i don't think you are going to be getting thoes numbers from a head swap, TPI would be way better on the higher horsepower numbers though becasue it has a injector for each cylinder, but the stock TPI is going to have trouble supporting that much power stock you might want to look in to TPI upgrades. But if your running a pretty much stock engine with new heads the TPI sould be fine for you
     
  4. Blue85

    Blue85 Troll Premium Member

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    the guys at thirdgen.org can tell you. The TPI doesn't support huge flow. The plenum can be reworked with some grinding to open it up a lot. You will still need a larger throttle body (52-54mm I suppose) and larger runners, possibly the siamesed kind. You can also get shorter runners that move the torque peak to a higher rpm. After a point, though, you end up switching to a whole aftermarket intake system, so whether or not that's still TPI is a matter of your definition. I'm not sure what the rpm/power limit is, though.
     
  5. beastofablaze

    beastofablaze 1/2 ton status

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    The motor has a cam, 10:1, intake, older corvette heads, headers, 3 inch single, k and n, bigger fuel pump and tbi, etc.

    Should be around 330 hp now... with darts I figure I'm looking at 400 plus, with afr's maybe more around 450.

    How much would a tpi (used) system run me? How much to get it to 450 hp with starving the motor?

    thanks in advance.
     
  6. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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  7. Blue85

    Blue85 Troll Premium Member

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  8. beater_k20

    beater_k20 Banned

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    dirtwarrior? is that you? :haha:

    i would just look into modifying your existing TBI setup. the gains for swapping to TPI arent really all that great IMO. that's why i'm stuffing an LT1 under the hood of my C1500 next winter.

    for TBI mods, check out:

    www.turbocity.com
    www.cfm-tech.com
     
  9. mo

    mo 1/2 ton status

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    depends too what rpm range you're running, stock TPI components don't flow enough much past 5500 rpm on a stock L98 (350 that came in the camaros) and even that number maybe a little high, pry realisticly around 5200. with a larger TB, ported plenum, aftermarket intake (ported if you want) and siamesed runners, you will definitely increase the flow potential of the TPI system. this might help to feed a hungry engine, whether it will be enough for you, not sure, but I've read about a lot of folks running TPI on their 383's some are happy with that and some seem to skip the upgrading the tpi steps and go straight to mini ram or LT1 intakes

    with the mods on my 91 I can pull to about 6300, but there's no internal mods to that engine...
     
  10. beastofablaze

    beastofablaze 1/2 ton status

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    huh?:confused:


    2bbl tbi will definetly be restricting my limits tho. I'm looking for more than your regular old mild sb.

    I dunno tho... I may just go with darts and I'll probably be plenty happy with my 375 hp (if I get darts) but if I have the cash and the resources to pull it off Afr's will get bolted to her for sure.
     
  11. sled_dog

    sled_dog 1 ton status

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    so I'm not hte only one who thought the exact samething... :haha:
     
  12. sled_dog

    sled_dog 1 ton status

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    I don't ever recommend expecting huge gains from any one thing.

    what intake manifold are you using? I wouldn't predict a 45 horsepower gain with Iron Eagle heads. Close maybe.
     
  13. beastofablaze

    beastofablaze 1/2 ton status

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    I forgot to say the cam will get swapped out for one of the 4x4 crane cams (most likely the 1000-5200) and the Darts I'm thinking about are Platinum iron eagles. Not the original iron eagles.


    The intake manifold is the 2" 2bbl one from holley.
     
  14. beater_k20

    beater_k20 Banned

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    the TPI setup has a small 2bbl throttle body as well. with the mods shown on the 2 sites i linked to, and some good ECM tuning, you shouldnt have a problem achieving your goal.

    another thing you definitely need to take into consideration...

    you're working with a heavy truck, not a Vega. horsepower doesnt mean squat without torque. build for torque, rather than HP, you'll be much happier with the results.
     
  15. beastofablaze

    beastofablaze 1/2 ton status

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    Yeah... I agree with that... which is why I'm going with a 4x4 cam. I have a higher stall converter so the thing should have plenty of grunt when launching or towing... just need to get a tranny cooler to make up for the higher stall.

    Honestly though I'm gonna go with the darts... 450 hp is WAY too much power for my drivetrain. Not to mention the fact that I don't have the money to do all this... I just dumped it all into getting a place and getting this thing running. I can swing the darts and cam tho. 375 hp and Im gonna guess around 440 ft lbs of tq give or take will be more than plenty to romp with. It's gonna be nice to smoke 35's... most power I've ever had a chance to drive is my work truck( vortec 350 3500 silverado ) and beleive me I do understand that tq is a huge part of how a truck moves. Our work truck is around 8g's by itself with the bottles, stick welder and tons of tools... put a trailer on it and it doesn't want to move without hitting 5 grand. Still does pretty damn good... good tq.
     

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