454 vortech power and torque numbers and AFR

Discussion in 'Engine Performance + Maintenance' started by John Cunningham, Feb 13, 2019.

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  1. John Cunningham

    John Cunningham I'm Awesome

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    For those of you who might be interested I had my stock 454 on a chassis dyno today

    1997 7.4 Vortech

    The tuner said that it would be lean........and he was correct....so lean it was scary and you can easily pick up 60 hp with putting some fuel in the engine.

    15.1 AFR

    290 Ft pounds of torque at 3000 rpm

    200 HP at 4200 rpm

    so flywheel numbers would be:

    340 Ft pounds of Torque

    240 Horsepower

    So it feels real bad when towing and now I know why

    The problem is you cannot do much about it except send your box to blackbear and then put it back on the dyno to see what they did if anything.........start with wide open on a load throttle of 12.5 to 1
    not 15.1

    You could do a 0411 swap but it seems like "Lextech" is unreachable and even offering money does not work. I would love to purchase the printout but no response along with many other guys.
     
  2. Supercharged111

    Supercharged111 I'm Awesome

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    Wow, weird. I never would have guessed. FWIW though the tailpipe wideband tends to read lean, dynoing through an unlocked converter artificially imcreases torque. Did the dyno operator use bidirectional controls to hold the truck in gear with comverter locked? What gear did you dyno in? Got a graph?
     
  3. L31MaxExpress

    L31MaxExpress I'm Awesome

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    Probably has the same delayed PE that the later LQ4 6.0s and 8.1s do.

    Explains why the 454 I towed with years ago felt gutless compared to the way my L31 ran when it had the milled 906s with 2.02/1.60 valves, 395 cam, marine intake and thorley tri-ys. I did 303 tq @ 3,400 ([email protected] 2,900 where the pull started) and 230 hp @ 4,400 with bad valve springs. Swapped the springs and retainers to LS6/Comp787 and put down 310 tq @ 3,200 and 257 hp @ 4,800. Those were locked converter 2nd gear pulls through a 4L85E and GM 9.5" 14-bolt.

    On a different note you have atleast 25% drivetrain loss. That puts the HP at 266 and TQ at 386. Far closer to the 290/410 rating than 240/340.

    The fuel pump wiring being undersized and creating high resistance is a known issue and often the pumps have seen better days because of this (low fuel pressure is the result). The MAFs get dirty and under report airflow. Also the factory injectors tend to give issues. Factor in a distributor drive gear that likes to wear and possible tired ignition parts and that only means you can make drastic improvements without diving too deep into the engine.

    Hypertech's dyno testing of a stock 2000 C3500 454 gave 215 hp @ 4,250 and 320 tq @ 2,000.
     
    Last edited: Feb 13, 2019
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  4. Supercharged111

    Supercharged111 I'm Awesome

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    My 454 just doesn't punch as hard as the small block, but it's in a heavier truck. The 1500 just pulls my trailer harder, but when I put the camper on the back of the dually (5,000#) not much changes and I suspect the result would not be the same with the 1500 if it were able to deal with that much weight.
     
  5. L31MaxExpress

    L31MaxExpress I'm Awesome

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    I am sure the 454 has more torque lower in the RPM range but I also have a converter that was stalling 2,500 rpm behind the 350 so torque on the very bottem was not a huge factor.

    Speaking of which I am sure you probably used the B82 converter behind your 350. The 454 trucks use the B81 diesel converter. A B82 converter behind a stock 454 stalls about 2,500. I have one behind my cammed 8.1 and it stalls about 2,700. A stock small block converter would help the off the line punch of the 454 tremendously.
     
  6. Supercharged111

    Supercharged111 I'm Awesome

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    Gonna keep the B81 in the dually and add a blower, it's all rebuilt now and I just need enough time to reinstall and tune it between races which are just a few weeks out. When I pulled it the truck still had a black box and Whippletronics. My only concern from there is fuel range/$$$.
     
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  7. John Cunningham

    John Cunningham I'm Awesome

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    I think we got it to lock.......he tried a couple of times........I do have a graph from my cell phone.......not sure how to post it
     
  8. John Cunningham

    John Cunningham I'm Awesome

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    he claimed a 20% loss.......I am an engine dyno guy so I have no clue
     
  9. Supercharged111

    Supercharged111 I'm Awesome

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    Click upload a file down by the post reply button, let it upload, click full image and it should show up.
     
  10. Supercharged111

    Supercharged111 I'm Awesome

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    I think it's higher on the trucks.
     

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