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

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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; 02-16-2013 at 09:24 PM.

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    Super Moderator dave w's Avatar
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    Thanks for sharing.

    dave w

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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.

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    EFI GearHead ! 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; 02-19-2013 at 04:07 PM.

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    in an express van?! 2% vanners! lets see some smokey burnout vids!
    '86 Grand National

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    Quote Originally Posted by Hog View Post
    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
    I know who you are talking about on the FSC board, the guy that has the quick LT1 SS Impala right??

    I am not sure why his truck runs as weakly as it does as far as HP/TQ is concerned. Don't get me wrong he has some decent track times, but his dyno's just seem low. 255 RWHP seems low for an engine that should be cranking out 350+ at the flywheel. The ZZ4 makes 355 HP and 405 TQ with aluminum heads that flow substantially less than the Vortecs out of the box. 255 RWHP is about 310 FWHP with a 18% loss. Just for the record, a few years ago I tuned a L30 with an 0411 swap in a C1500 with full bolt-ons that made 235 RWHP and 308 RWTQ on a Dynojet.

    I laughed the first time I saw those tiny head pipes on a truck. This G1500 never had that smaller size, although I have seen others that did. Also seen others with a single cat and Y-pipe setup.

    As for your exhaust question, I guess the way I stated it, it was a little missleading. You are correct on the van pipes, I have never seen any that curve to the passenger side like the ones you posted. The van pipes all tuck tighter to the transmission, probably because they do not have 4x4 to deal with unless they are a Quigley then that is a different story.

    My setup is a little different, I hate to give up all my secrets....It has stock manifolds on it, but they are B-car LT1 manifolds. Shorty headers truck style actually fit the Express chassis, but constant leaks, warping, and floorboard heat makes them not worth the effort. The stock truck manifolds are horrible in flow. My brother and I were going to do a V8 S10 swap, I did not read into it much, but saw the LT1 B-car manifolds on a car and thought they would fit the V8 S10. Well they didn't even come close to clearing the steering shaft. I had them hanging on my garage wall when the Summit brand aka Pacesetter shorties started leaking profusely. The stock RH manifold cracked years ago on the Express so they had been thrown out. I modified the LT1 manifold by drilling one new hole in each flange to accept the Vortec heads bolt pattern. The LT1 manifolds fit perfectly. I plugged one of the AIR ports, the EGR port on the passenger manifold and sourced my EGR from the driverside manifold air fitting by carefully shortening a stock L31 egr tube. I am running the stock 2.5" sized head pipes out of the LT1 manifolds into metal core highflow cats. Seems to flow well enough to make power. This setup seems to have woken it up better than the shorty headers and everything else stock.

    I love the LT4 cam, I have never found it lacking compared to the L31 cam. It definately wakes it up through the mid-upper RPM range.

    The cam and 1.6:1 rockers woke it up so much that after having spent a week on the Gulf fishing last summer I was trying to get out of the HOV lane in Houston while a retired P71 Crown Victoria was trying to block me. The guy was really acting like a prick, he did not want me to move over and kept changing speeds to match mine. Finally after dragging him down from 80 mph to 65 mph, someone who remains namless floored it, caught 2nd gear again at 65 mph, fully loaded with 5 people, our week worth of luggage, and fishing gear passed this weak P71 and got back onto the main road. Its got some passing power from 65-90+.

    This was with the 0411 swap, stock shift points. I need to get another video, its running much stronger now.
    http://www.youtube.com/watch?v=NPHR6mzCDoY

    http://www.youtube.com/watch?v=L5ndiqubbJo

    Apples to Oranges, but its still as quick if not quicker than comparable current GM offerings, like the 5.3/6spd in the 2013 Suburban.
    http://www.youtube.com/watch?v=r1iObp1m25g

    My old black box tune was pretty merciless on the 4L60E....It has a Transgo Kit setup on RV/Fleet/Taxi aka FIRM mode, but doesn't change the fact its a ticking time bomb. I left more torque management in the 0411 PCM, than simply eliminating it like before.

    http://www.youtube.com/watch?v=7SgptElOCpY
    Last edited by Fast355; 02-20-2013 at 11:01 PM.

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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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    EFI GearHead ! EagleMark's Avatar
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    Lower gears are always a pleasant suprise! Did the vans ever come with them?

    Really enjoying the actual Hot Rod talk here! I've seen the pictures Hog posted of the exhasut system before and it was a shock, but the LT-1 manifolds, now there's to tricks!

    What's with the "RV/Fleet/Taxi aka FIRM mode" ?

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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    Quote Originally Posted by EagleMark View Post
    Lower gears are always a pleasant suprise! Did the vans ever come with them?

    Really enjoying the actual Hot Rod talk here! I've seen the pictures Hog posted of the exhasut system before and it was a shock, but the LT-1 manifolds, now there's to tricks!

    What's with the "RV/Fleet/Taxi aka FIRM mode" ?
    When you setup a Transgo shift kit, the instructions guide you through drilling the seperator plate, shimming the accumulator sprongs and spring selection. They have 3 different levels of firmness. Mild, Firm, Race or something to that effect. I set mine up as firmly as recomeended on a stock torque converter. While it shifts firmly, the vans weight and high gear ratio helps smooth it out.

    I would not recomeend removing as much torque management from a stock transmission without the Transgo. My EPC is also cranked up about 30 psi. I am running the same maximum line pressure as the old performajce oriented 700r4s, 235 psi. You can test the pressure by unplugging the 13 pin case connector, hooking up a line pressure gauge, starting the truck and shifting into D, and raising the engine rpm to ~1,500 only long enough to stabilize the pressure and read the gauge, as you are quickly building heat in the converter. I Also played with the tables to increase the pressure at lower calculated torque values. Part throttle shifts really firm up around 1/2 throttle.
    Last edited by Fast355; 02-21-2013 at 06:56 AM.

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