tbi performance

Discussion in 'Performance & Fuel' started by brianj, Jun 6, 2010.

  1. brianj

    brianj Rockstar

    Hi all! I have a 95 2500 two wheel drive w/3.73 posi and the 4l80e trans. The problem I am having is that the truck is basicaly a slug. I have heard many people advise putting on long tube headers, cold air intake, and duals as a quick upgrade, but I wanted to hear from anyone who actualy has a similar truck, and what helped the most. I am particularly interested in anyone who has done a cam swap with the stock tbi, and how they made out. Any advice appreciated. thanks.
     
  2. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    How do you mean a slug??? I have a 1988 2500 with 3.73s and a 5spd man. with the same motor and it goes well for the TBI... I am just asking because these motors provided good power for what they were and I am wondering if there might be something wrong with yours???
     
  3. brianj

    brianj Rockstar

    That is kind of the question I have. I know about the truck since new. It has 50000 miles on it, and it has always not had a lot of power. I had a 92 ford f150 4x4 with a 302 and 33" that would chew this truck up and spit it out, and I never modified the stock motor or changed the gears to compensate for the taller tires. I have always thought it swhould have more power, but i have no clue why it does not.
     
  4. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Is it a 305 or a 350???
     
  5. brianj

    brianj Rockstar

    350. would understand if it was a 305
     
  6. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Hmm yeah I think you need to do something. Have you done anything tune up wise etc? Fuel Filter etc... Seeing as i know my 4X4 (well you see the pick of my truck) has enough. It wont win any races.. But i know an RV towing cam will do a lot with a good set of headers. You might also want to look into a bit better throttle body if you are goig to spend the money.
     
  7. brianj

    brianj Rockstar

    I may go with a r.v cam, and I was hoping I could get some recommendations from people who had done a cam swap. I think these cams from the factory are set up 4 degrees retarded, and I was going to look into a decent cam set straight up. The throttle body I may look at doing some porting type work on, as I have done many sets of heads, and I can see some major improvements to be had with flow on it. I do not know, however, at what point I may need a new program for the computer, larger injectors, etct. etct. All of the tune up type parts are new, the timing is set about 2 to 4 degrees advanced instead of at 0, (and yes, I know to unplug the timing connector first) and everything is mechanicaly good. I did have to replace the head gaskets, and I need to check the cat to make sure it is not restricted, but I doubt it is- it is not acting like a blocked cat.
     
    Last edited: Jun 6, 2010
  8. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    Part of your problem is that you are comparing it to your 96 Tahoe. There are two major differences.
    First, your Hoe is Vortec, the truck is TBI. The Vortecs are night and day better.
    Second, your drivetrain is heavier. The 4L80 is less efficient than a 4L60, and the 14 bolt is heavier than the 10 bolt. So both of these rob power.

    I bought a 97 K2500 w/350Vortec/4L80/4.10. Truck drove fine, but never a speedster. Plenty of towing power. Then I bought a 95 Tahoe w/350TBI/4L60/3.42. Tahoe was slightly snappier around town, but any added load you really felt it.

    Then I bought a 96 Tahoe. 350Vortec/4L60/3.73. This thing is a rocket compared to the other two.

    First thing I would do is put some Vortec heads on, with a TBI to Vortec intake manifold from GMPP. Of course, this would be a great time to replace the cam, and maybe some headers. I wouldn't bother with a CAI. Put one on a 89 305. Just made the cabin louder, I hated it. Never felt any power improvement.
     
  9. brianj

    brianj Rockstar

    Well aware of the difference. However, this thing is a flat out turd compared to other comparable trucks I have driven. I have not been able to get it on a chassis dyno to see what it is actualy making for power, but that may be my first step. I have put vortec heads on other motors- I got 382 hp. out of a 305 (flywheel, not r.w.h.p.) ,and while they are a nice piece, aftermarket aluminums will do better,for not much more money. I am tempted to rip off the tbi and go cave man style with a carb- I can get 300hp out of this motor in my sleep.

    (as an afterthought- we had three 95 pickups at my work -- same 2500, 350 and tbi- but also dragging along 4x4 components. still quicker than mine)
     
    Last edited: Jun 7, 2010
  10. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    Sounds like you don't need us......
     

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