Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

quad-to-tbi conversion?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by jsrail, Jun 1, 2004.

  1. jsrail

    jsrail Registered Member

    Joined:
    May 28, 2004
    Posts:
    23
    Likes Received:
    0
    Location:
    UT
    Hate to sound like an idiot but does anyone know if you can upgrade a carbed 350 crate motor to a tbi set-up without using an after market efi system? Are the heads different between the two?

    Jay
    85 Jimmy
     
  2. juanblzer

    juanblzer 1/2 ton status

    Joined:
    Sep 12, 2001
    Posts:
    1,614
    Likes Received:
    9
    Location:
    Chandler, Arizona
    It's not that hard to do... if you have the right help (thanks forever Mark).
    The Tbi intake needs to be altered a bit to fit the older angle on the heads. That is a major PITA even with a dremel (I actually bought one for this purpose, after I killed Marks). Make sure you get all wiring available from the donor to make your life easier. You might have a little trouble dialing it in but then angles here you come. /forums/images/graemlins/grin.gif
     
  3. jsrail

    jsrail Registered Member

    Joined:
    May 28, 2004
    Posts:
    23
    Likes Received:
    0
    Location:
    UT
    Thanks for the tip. Do you think its worth the hassle? I just hear many horror stories about the aftermarket set-ups. I only have about 30K on the crate and hate to waste it by buying another used motor, etc. Could a machine shop grind the intake? How much grinding is involved?

    Jay
    85 Jimmy
     
  4. azblazor

    azblazor 1/2 ton status Premium Member

    Joined:
    May 5, 2001
    Posts:
    1,953
    Likes Received:
    0
    Location:
    Arizona, Phoenix area
    Juan is right. Pretty easy especially if you have a donor vehicle. The manifold drilling is not that big of a deal. We have done a couple that way with good results. As long as your crate motor has a fairly stock cam , you will be pleased with the TBI.
     
  5. azblazor

    azblazor 1/2 ton status Premium Member

    Joined:
    May 5, 2001
    Posts:
    1,953
    Likes Received:
    0
    Location:
    Arizona, Phoenix area
    Juan,
    So how is it running now. Any smoking guns?
     
  6. jsrail

    jsrail Registered Member

    Joined:
    May 28, 2004
    Posts:
    23
    Likes Received:
    0
    Location:
    UT
    juan and azblazor:

    Thanks to both you guys for the info. I think I'll start looking for the parts soon (need some tires and wheels first). Would you guys care if I emailed you after I've collected these parts....I'm sure I could use the help.

    Jay
     
  7. Hossbaby50

    Hossbaby50 3/4 ton status

    Joined:
    Sep 1, 2001
    Posts:
    8,972
    Likes Received:
    0
    Location:
    Peoria, AZ
    I converted my truck to TPI awhile back. As said above the 4 holes at the center of the manifold need to be opened up. I used an air grinder with a drill bit in it to open my holes in the manifold. It was a bi*ch for sure. It took alot of time and alot of compressed air. I personally would look into having a machine shop open the holes to save the hassle.

    FI is DEFINITLY worth the time. You get more MPG, more torque, more HP's, more throttle response, and the ability to run at any angle. FI is a huge advantage in the rocks. You don't have to worry about the carb loading up or stalling at high angle which is a definite plus.

    Harley
     
  8. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    If you guys saw the video of me from the most recent badlands run you'd really appreciate your EFI. I was doing awesome all day long, but when I was fighting the carb to run I was having a really rough time.
     
  9. Hossbaby50

    Hossbaby50 3/4 ton status

    Joined:
    Sep 1, 2001
    Posts:
    8,972
    Likes Received:
    0
    Location:
    Peoria, AZ
    Yep, I have seen carbs in action on the trail. They do ok to a point. Alot of problems with carbs is the tuning but they are still only good to a certain point. A poorly tuned carb is a nightmare on the trail, and depending on what you wheel a properly tuned carb can still be a nightmare. That is why EFI is so worth it.

    I ran my Qjet for many years but in nothing to extreme. It did pretty well for most things but I did get it to start cutting out on a steep loose hill climb which was kind of unnerving since very bad things could have happened if it stalled. It made it up the hill by feathering the pedal so the accelerator pumps kept it running but it was not fun.

    Harley
     
  10. Mastiff

    Mastiff 1/2 ton status Premium Member

    Joined:
    Jul 21, 2002
    Posts:
    2,755
    Likes Received:
    48
    Location:
    Tucson, AZ
    Sorry to be stupid, but what drilling are you guys talking about? I'm about ready to start the install of a TBI on my Q-jet K5 and am unaware of any grinding/drilling, etc.
     
  11. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    If you want to install the factory TBI intake you're going to have to make it fit. I'm just going to use an adapter instead.
     
  12. Hossbaby50

    Hossbaby50 3/4 ton status

    Joined:
    Sep 1, 2001
    Posts:
    8,972
    Likes Received:
    0
    Location:
    Peoria, AZ
    The center 2 bolt holes on each side of the manifold don't line up between FI heads and Carb heads so you must open them up to get them to fit.
     
  13. jsrail

    jsrail Registered Member

    Joined:
    May 28, 2004
    Posts:
    23
    Likes Received:
    0
    Location:
    UT
    Now all I need is money and parts! I will keep my eyes open for a set-up. Does it matter what year TBI (whats difference to a TPI?) set-up I buy? I have an 85 and a crate motor?

    Jay
     
  14. Hossbaby50

    Hossbaby50 3/4 ton status

    Joined:
    Sep 1, 2001
    Posts:
    8,972
    Likes Received:
    0
    Location:
    Peoria, AZ
    TBI vs TPI

    TBI:

    cheaper install
    easier install
    originally on K5s
    not much room for more power over a stock/mild motor

    TPI:
    More power & mileage then TBI
    Little harder install
    More money for install
    Option to add more power to the system

    TBI & TPI are about the same to price purchase a system, but TPI will cost more in the end. You get more power though and a little better mileage with TPI. TPI looks cooler too /forums/images/graemlins/thumb.gif

    Both are good options but make an informed choice so you don't kick yourself in the end. I personally lean toward TPI because that is what I swapped to and I love it. Worth every penny. It was a night and day differnce from a carb.

    http://coloradok5.com/forums/showflat.php/Cat/0/Number/1092752/page/0/view/collapsed/sb/5/o/all/fpart/1

    Harley

    You can see a pic of my motor in my webshots below.
     
  15. Mastiff

    Mastiff 1/2 ton status Premium Member

    Joined:
    Jul 21, 2002
    Posts:
    2,755
    Likes Received:
    48
    Location:
    Tucson, AZ
    [ QUOTE ]
    The center 2 bolt holes on each side of the manifold don't line up between FI heads and Carb heads so you must open them up to get them to fit.

    [/ QUOTE ]

    Oh. /forums/images/graemlins/thinking.gif I'm keeping my intake and everything and using an adapter to get the TBI on. I didn't realize the adapter was doing much except making up for the spread-bore. I'll know more when the kit shows up in the mail, hopefully this week.
     
  16. jsrail

    jsrail Registered Member

    Joined:
    May 28, 2004
    Posts:
    23
    Likes Received:
    0
    Location:
    UT
    Very Cool Set-Up! Where did you find your system?

    Jay
     
  17. Hossbaby50

    Hossbaby50 3/4 ton status

    Joined:
    Sep 1, 2001
    Posts:
    8,972
    Likes Received:
    0
    Location:
    Peoria, AZ
    I bought my system off a local CK5'er. He ran it for awhile then decided that he wanted a new chanllenge an installed a Vortech motor and 4L60E tranny in his Jimmy. So he sold me his old TPI system.

    When you get a FI system make sure you get everything available from the donor vehicle if at all possible. Wiring, ECM, manifold, distributor, all sensors, all relays, throttle body, air intake setup, etc.

    Once you get closer to making up your mind on what you want and a purchase start searching for info. There is alot to learn about installing FI and you don't want to learn as you go. I tried, and it sucked. I can fill you in as much as possible to if you need me too.

    Harley
     
  18. jsrail

    jsrail Registered Member

    Joined:
    May 28, 2004
    Posts:
    23
    Likes Received:
    0
    Location:
    UT
    Thanks man......I will keep you posted.

    Jay
     
  19. jsrail

    jsrail Registered Member

    Joined:
    May 28, 2004
    Posts:
    23
    Likes Received:
    0
    Location:
    UT
    Okay....one last ?. Does it matter what year TPI or TBI I buy? Does it have to be the same year as my vehicle?

    Jay
     
  20. Hossbaby50

    Hossbaby50 3/4 ton status

    Joined:
    Sep 1, 2001
    Posts:
    8,972
    Likes Received:
    0
    Location:
    Peoria, AZ
    No

    TBI was the same (I think) from about 87-95
    TPI was 85-92. There are 2 forms of TPI though, and several variations in the early years. The ones you want are 87-89 TPI or 90-92.

    87-89 was MAF (uses mass airflow sensor)
    90-92 was MAP (uses manifold absolute pressure sensor)

    Both have there pro's and con's. I run MAF and I know people who run MAP. Both work well. The link above is a MAP setup. MAF is a little easier to swap since you don't have to have custom chips burned. If you do a search there is alot of info on TPI on this site and alot more on www.thirdgen.org

    Harley
     

Share This Page