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Thread: 1997 Express LT4 Cammed L31...0411 Swapped, Tuned, Dyno'd....Ran out of engine!!!

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  1. #1
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    1997 Express LT4 Cammed L31...0411 Swapped, Tuned, Dyno'd....Ran out of engine!!!

    Felt like sharing this about the 0411 swap. Dialing it in is super easy. I never even had a wideband on it, until the dyno this afternoon and my target/commanded air/fuel ratios were practically identical to the wideband on the Dyno. This Mustang Dyno has been verified to be 10% lower than a Dynojet. This is 3rd gear with the torque converter locked, commanded 3rd/Lockup at 30 MPH and 1,500 rpm. Engine is the stock long block save for the LT4 cam, 1.6:1 roller rockers, and LT4 valve springs, retainers, etc. Has stock manifolds (tired of cheap, leaking shorty headers) on it again, stock HD truck sized exhaust, highflow cats and magnaflow muffler. The intake manifold is stock, has the GM MFI injector upgrade, a reworked stock throttle body and an 0411 PCM swap with HP Tuners. Also ditched the mechanical fan, added a pair of E-fans and an underdrive pulley I found on Ebay. I think its making decent power for just a little L31 350. 281 RWHP @ 5,540 and 295 RWTQ @ 4,440 with 240 RWTQ from 1,500 rpm the LT4 cam advanced 4* is anything but gutless on the bottem. On the street with the L35 S10 Converter it flashes to 2,700ish and puts me in an area the engine is making over 270 RWTQ. Run #2 was made heat soaked, immediately after Run#1, E-fans roaring on high fan speed trying to keep the engine from going above 180*F. The IATs were very elevated on run #2 and it was causing the ECM to retard the timing about 4-5*. On a Dynojet it would read around 310 RWHP/330 RWTQ.

    Last edited by Fast355; 02-17-2013 at 07:24 AM.

  2. #2
    Super Moderator dave w's Avatar
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    Thanks for sharing.

    dave w

  3. #3
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    Those are excellent numbers, especially through stock exhaust manifolds and cats.

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    Fuel Injected! one92rs's Avatar
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    damn fast still pushing it with that ol express. great work man. good to see names i know from thirdgen. im still a little lost on here with the tuning. but people and eaglemark are trying like hell to teach me.

  5. #5
    RIP EagleMark's Avatar
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    With that torque curve and converter it should be real crisp drive!

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

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    Thanks for sharing Fast. Those headpipes and cam must really wake the L31 up.
    The difference is huge.
    HD truck pipes on left, stock 1/2 ton truck pipes on right. Look at the tiny 1 7/8" pipe that gets crimped WAY down in those bends.bends


    This pic shows the bad crimp bend in the bank 1 pipe



    Do your headpipes curve over to the passenger side like the pic? I have seen some van pipes that look like they head straight back from the exhaust manifold.

    I'm happy to finally see an L31 grunted down to such a low rpm. I'd like to see a 5.3 during the same testing procedure.

    How do you like the LT4 production cam compared to the L30/31 cam? Looks like it would work great for me.

    I know of a guy running a Vortec 350 2462 1hkr LT Hooker headers, ZZ4 cam, PCMforLess dyno PCM tune and is only nabbing 255rwhp in an ecab 2wd over on FSC. He runs a Yank 3600 stall and tickles the 13's NA and mid 13's with a 50hp dry shot. He would be very jealous of your results.

    Youve got a very nice setup there Fast, using all GM parts. That setup should be very durable.

    peace
    Hog
    Last edited by Hog; 02-20-2013 at 02:07 AM.

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    Quote Originally Posted by EagleMark View Post
    With that torque curve and converter it should be real crisp drive!
    Its very fun to drive, suprises a few people and have a few tricks left up my sleeve for it. I really want a 4.10 posi for it.

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