Re: 1997 Chevy Express Cobra Conversion | Joined: Apr 2007 Posts: 273 Likes: 66 G Van Man | OP G Van Man Joined: Apr 2007 Posts: 273 Likes: 66 | Startup of the 383 in the Express with the factory L31 based manifold and ignition, running on a Green/Blue P59 out of a 2004 DBC 6.0L van. So far I have segment swapped the 4L85E, turned the VATS off, set the injector flow rate to match the AUS Injection 48 lb/hr spider and copied the MAF table from a 2002 L31 van into the 2005 Mexican tune. Had to populate the idle tables that were not used with the manual trans. Other than that the mexican cal is relatively stock GM issue. Ran it on the old 0411 the other day. https://youtu.be/FzEDpuSIwJc
1983 G20 Conversion Van, 350 TPI, Reed Hydraulic Roller cam, Ported 906 Vortec, Edelbrock 3817 TPI-Vortec Base, Doug Thorley Tri-Ys, Dual 2 1/2" exhaust, Speed Density 7730 ECM tuned by ME, 700r4 by ME, Stock 1,600 rpm converter, Rebuilt Stock 10 bolt with posi by ME, 3.08 gears, 358 RWHP @ 5,200, 384 RWTQ @ 3,400, 14.66 @ 95.43 w 2.28s 60'
| | | Re: 1997 Chevy Express Cobra Conversion | Joined: Jul 2019 Posts: 11,383 Likes: 430 Post Junkie | Post Junkie Joined: Jul 2019 Posts: 11,383 Likes: 430 | Brother that sounds and looks clean. Thanks for the video. | | | Re: 1997 Chevy Express Cobra Conversion | Joined: Nov 2013 Posts: 3,692 Likes: 32 pooh-bah | pooh-bah Joined: Nov 2013 Posts: 3,692 Likes: 32 | Nice work!
I've often though that a GM 383 replacement for my L31 would be nice. But the old L31 just keeps running so nice, I don't see it happening until it dies. | | | Re: 1997 Chevy Express Cobra Conversion | Joined: Apr 2007 Posts: 273 Likes: 66 G Van Man | OP G Van Man Joined: Apr 2007 Posts: 273 Likes: 66 | Hooked up the exhaust, topped off the cooling system and let it run long enough to get up to full temp with the closed loop enabled. Pulling about 10-15% on the long terms. Still have the cutouts open and need to hook them up again. Tamed down alot in closed loop. Also disabled the catalyst warmup spark retard. https://youtu.be/FPEuk8hibPg
1983 G20 Conversion Van, 350 TPI, Reed Hydraulic Roller cam, Ported 906 Vortec, Edelbrock 3817 TPI-Vortec Base, Doug Thorley Tri-Ys, Dual 2 1/2" exhaust, Speed Density 7730 ECM tuned by ME, 700r4 by ME, Stock 1,600 rpm converter, Rebuilt Stock 10 bolt with posi by ME, 3.08 gears, 358 RWHP @ 5,200, 384 RWTQ @ 3,400, 14.66 @ 95.43 w 2.28s 60'
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frscke1 | | | Re: 1997 Chevy Express Cobra Conversion | Joined: Feb 2002 Posts: 32,763 Likes: 175 Old Timer | Old Timer Joined: Feb 2002 Posts: 32,763 Likes: 175 |
Jim & Lucy Newkirk 1965 Chevy Bad Influence 1981 Chevy-the Love Shack 2012 Chevy Van , 2020 chevy van 2020 Chevy van Sapphire Sweet. Club Vannerz. vanninvanner@comcast.net | | | Re: 1997 Chevy Express Cobra Conversion | Joined: Apr 2007 Posts: 273 Likes: 66 G Van Man | OP G Van Man Joined: Apr 2007 Posts: 273 Likes: 66 | Hooked up a water hose to the heater return on the water pump and dumped the waste water out of the shop to really get all the heater core, and lines really flushed out today. Got it dialed in pretty good after adding a 4" MAF into the mixture. Also figured out the bog off-idle when first starting to open the throttle. Transmission abuse mode was kicking in even in Park and cutting the ignition timing to negative 15 or 15 after top dead center. Disabled abuse mode and it rips now. Its taken on some nice exhaust crackle and popping going into decel fuel cut as well. On throttle snap up to fuel kill at 5,200 it leaps up the RPM band. To hit the air/fuel ratio target the MAF is reading 410 gms/sec at 5,200 rpm. Given the formula of 1 gm/sec is 1.2 hp, that means I am feeding it 492 hp worth of fuel. Predicted torque on the torque model is reaching 512 ft/lbs at about 3,700 rpm. The cyl/air reading holds pretty flat at 1.03-1.09 gms/cyl from about 3,000-5,200. It is moving a ton of air through the engine and the exhaust just booms because of it. https://youtu.be/iEn1Ht6Ta-shttps://youtu.be/1xXFPoS3Y2Y
Last edited by 1983G20Van; October 24th 2021 9:52 pm.
1983 G20 Conversion Van, 350 TPI, Reed Hydraulic Roller cam, Ported 906 Vortec, Edelbrock 3817 TPI-Vortec Base, Doug Thorley Tri-Ys, Dual 2 1/2" exhaust, Speed Density 7730 ECM tuned by ME, 700r4 by ME, Stock 1,600 rpm converter, Rebuilt Stock 10 bolt with posi by ME, 3.08 gears, 358 RWHP @ 5,200, 384 RWTQ @ 3,400, 14.66 @ 95.43 w 2.28s 60'
| | | Re: 1997 Chevy Express Cobra Conversion | Joined: Jul 2019 Posts: 11,383 Likes: 430 Post Junkie | Post Junkie Joined: Jul 2019 Posts: 11,383 Likes: 430 | | | | Re: 1997 Chevy Express Cobra Conversion | Joined: Apr 2007 Posts: 273 Likes: 66 G Van Man | OP G Van Man Joined: Apr 2007 Posts: 273 Likes: 66 |
1983 G20 Conversion Van, 350 TPI, Reed Hydraulic Roller cam, Ported 906 Vortec, Edelbrock 3817 TPI-Vortec Base, Doug Thorley Tri-Ys, Dual 2 1/2" exhaust, Speed Density 7730 ECM tuned by ME, 700r4 by ME, Stock 1,600 rpm converter, Rebuilt Stock 10 bolt with posi by ME, 3.08 gears, 358 RWHP @ 5,200, 384 RWTQ @ 3,400, 14.66 @ 95.43 w 2.28s 60'
| | | Re: 1997 Chevy Express Cobra Conversion | Joined: Apr 2007 Posts: 273 Likes: 66 G Van Man | OP G Van Man Joined: Apr 2007 Posts: 273 Likes: 66 | Been playing around with the tuning and finally decided it was safe to crank up the RPM. Engine has seen 6,500 rpm with the carb. Have the fuel kill set at 6,200 now in the tune. Absolutely rips up the rpm range. https://youtu.be/J4v4Z9rAKio
1983 G20 Conversion Van, 350 TPI, Reed Hydraulic Roller cam, Ported 906 Vortec, Edelbrock 3817 TPI-Vortec Base, Doug Thorley Tri-Ys, Dual 2 1/2" exhaust, Speed Density 7730 ECM tuned by ME, 700r4 by ME, Stock 1,600 rpm converter, Rebuilt Stock 10 bolt with posi by ME, 3.08 gears, 358 RWHP @ 5,200, 384 RWTQ @ 3,400, 14.66 @ 95.43 w 2.28s 60'
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