Bringing TBI and Multi Port Fuel Injection to a New Level.     EFI Conversions and Tuning! Seattle to Portland! E-mail Tuning Consultant!
Page 6 of 6 FirstFirst 123456
Results 76 to 81 of 81

Thread: The "Tan Brick" aka my 1997 Express Cobra conversion

  1. #76
    Fuel Injected!
    Join Date
    Feb 2013
    Location
    Euless, TX
    Posts
    1,600
    So I have a few snags to overcome such as rebuilding the dog house area, a new doghouse/engine access cover and finding a frame to motor mount bracket all of which have been discontinued.

    I am going to have to cut the firewall and floor to put in the floor section of a 6.5 or 8.1 van.






    I really don't understand why GM didn't just use the larger doghouse and opening for ALL vans. Would have made things like plug changes, exhaust manifold work and intake work MUCH easier. Especially with the big blocks 4" rearward mounting location.

  2. #77
    Fuel Injected!
    Join Date
    Feb 2013
    Location
    Euless, TX
    Posts
    1,600
    Finally have it dialed in pretty well. Its cool, dry and windy. Was running in my normal testing area but into a bit of a headwind (~15-20 mph out of the North). When I let off around 80-85 mph it had the 100+ mph wind tunnel sound too it. I need to get a video when the wind is calmer for comparison purposes.

    http://www.youtube.com/watch?v=7P8rDokWges

    http://www.youtube.com/watch?v=dtn58oN-snM

  3. #78
    Fuel Injected!
    Join Date
    Feb 2013
    Location
    Euless, TX
    Posts
    1,600
    Had a chance to mess with it a bit more today, then put some E85 in the tank. This was on 93 octane and it pulled nearly 5 of timing on this run!!! After adding 26 gallons of E85 and reflashing the PCM with the correct Stoich value I was still seeing tons of knock retard. Banging my head I took some SeaFoam with a HOT engine and ran it through the vacuum hose that ties into the PCV port. I use a vaccum "T" with one leg open as a vent and one in the SeaFoam. Near the end of the can I tried to stall it by putting my finger over the vent side to pull in more. At the same time I cut the key. The engine actually tried to diesel on the stuff. I let the engine sit for a good hour before trying to start it again. After a little cranking with my foot on the throttle it came to life and blew out a monster smoke cloud. I took it for a 10 minute drive and beat the ever living snot out of it. Finally went back to the shop with a hot engine again and did the same with a quart of distilled water. I took it out and drove it again. NO KNOCK RETARD on 31 of advance and a quick advance curve and it absolutely flies now.

    This was on 93 before I messed with it!
    http://www.youtube.com/watch?v=bpPSgILR6wc
    Last edited by Fast355; 11-22-2015 at 09:28 PM.

  4. #79
    Fuel Injected!
    Join Date
    Feb 2013
    Location
    Euless, TX
    Posts
    1,600
    Well it is time to pull this old pig apart yet again. I pulled the old L31 and opened it up to fix an oiling issue about 6 months ago. I put a Lunati Bare Bones 218/228 cam in it. I failed to notice the spring pressure Lunati recomended and ended up floating valves and scoring a couple of cam lobes and trashed some LS7 lifters. About to order another GM Performance parts cam. Going with the cam in the 357 HP 350 engine. Basically it is a Hotcam revised to work in a stock L31 long block. 215/223 @ .050 roller with .473/.473" lift. Running the GM 330HP HO intake and a set of headers it is rated at 357 Hp @ 5,500 and 407 TQ @ 4,000, looks to make about 400 TQ @ 3,000 according to the advertised GM dyno chart.

    The oiling issue was the use of a 5qt pan with a 4 qt pan windage tray. Ended up going to a 7qt Moroso pan and a big block oil pump with matching Moroso oil pickup. 40 psi idle, 70 psi hot at crusing speed. Yea its overkill but it seems to work well.

    It may end up with TPI on it this time around. I have an Edelbrock Vortec TPI base, fuel rail modified for rear feed and return, and siamesed SLP runners with a fully ported plenum and LT1 throttle body. I also have an accessory setup from a 1995 TBI G-van that looks like it will work in the Express van with an Astro van a/c hose setup if I go that route.

  5. #80
    Fuel Injected!
    Join Date
    Feb 2013
    Location
    Euless, TX
    Posts
    1,600
    Been at this old Express van again. Swapped a 4.56 re-geared 10.5" full floating 14-bolt under it. 1 ton springs. 1 ton front control arms and knuckles up front. All the 1-ton brake parts. Pulled the L31 out of it. Sitting on the stand now. Built a set of 205cc Assault Racing aluminum heads for the future 396 small block. Currently putting those heads on a stock bottem end 5.7. Adding 1.7 roller rockers on them. Should be in the 440 hp range when I am done. Need to get a picture of it now that the suspension is all 1-ton but I have one as a bit of a 1500/3500 hybrid, lol.

    I ended up with the 205cc heads because my 60cc milled Etec170s ended up on the 305 in the Tahoe after finding a crack in one of the heads on it. Got that engine running great again (around 330 hp/350tq) and smoked the 130k mile 4L60E within a few weeks. Work on modified stuff never seems to stop.
    Attached Images Attached Images
    Last edited by Fast355; 05-12-2018 at 09:13 PM.

  6. #81
    Fuel Injected!
    Join Date
    Feb 2013
    Location
    Euless, TX
    Posts
    1,600
    Been on vacation this week from work. I got the engine in last night and buttoned up today and fired up a few hours ago. I bumped the WOT shift speeds to 6,200 and left the old tune in place. Drove it around a bit. Its actually running a bit rich. At 11:1 afr and only 30 of timing, all I can say is HOLY SMOKES!!! 205cc intake ports on a 350 Vortec with a ported marine intake and a small cam runs like a bat out of hades! I wrapped the headers this time away and it made a tremendous differemce in engine compartmemt heat. I need to burn out the nearly year old gas in the tank and do some fine tuning but I am already grinning. Also reminded of how well the a/c in this beast works :) Gotta say at 6,200 it PEGS the 80 psi oil pressure gauge, lol!
    Last edited by Fast355; 05-15-2018 at 07:25 PM.

Similar Threads

  1. Replies: 55
    Last Post: 11-13-2013, 05:55 AM
  2. Replies: 16
    Last Post: 02-27-2013, 08:38 PM
  3. Replies: 10
    Last Post: 02-21-2013, 06:46 AM
  4. Replies: 4
    Last Post: 07-09-2012, 10:38 PM
  5. Knock Sensor Tech "Topic of Week! 2/12/2012"
    By EagleMark in forum GM EFI Systems
    Replies: 26
    Last Post: 02-15-2012, 05:25 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •