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tpi question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by skyrocco16v, Mar 7, 2005.

  1. skyrocco16v

    skyrocco16v Registered Member

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    i just recently bought a complete tpi setup off of a 91 IROC camero... i had to buy a fuel pump and speedo conversion sensor.... this is a speed density setup... what kind of a cam should i use? i work at a chevy dealer... and one of the guys is going to help me with the swap from my carburator to the tuned port. but i have heard of some issues with cams. i'm running a freshly rebuilt 355, with 9.5:1 pistons and an RV cam. i'm not sure what the profile of the cam is, but would it be better to get a custom PROM to match my current steup, or get a cam that is closer to the IROC engine? also, this setup is off of a 305 camero... should i get the 350 injectors or what? thanks guys!!
    corey.

    BTW, this is for my 86 k5 with 3.08 gears.
     
  2. Hossbaby50

    Hossbaby50 3/4 ton status

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    Yes, you need 350 injectors. You also will probably need a new prom burned anyway to bypass the VATS program in the computer. Otherwise the truck won't start when you do the swap.

    As for the cam a custom prom may work with it as long as it isn't to wild. If it is pretty wild then you will probably need to get a different cam that is closer to the TPI 350's cam specs. There is some leadway but I do not know how much.

    www.thirdgen.org is a great place to look around and find out info on GM fuel injection.

    Harley
     
  3. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    I swapped to speed density tpi about a year ago.
    My engine is around 9.5 : 1 compression, 64cc 041 casting heads. I put in the GM 300hp 350 cam that would be in a '69 corvette specs are
    212/222 duration @ .050 112LSA .435/.460 lift This cam is also now in the 350HP 350 crate motor.
    I ran this setup with a carb for 4 years.
    I ordered my wiring harness and custom eprom from Street and Performance.
    The chip seems good, but having someone burn you a chip based on your specs is only gonna get you in the ballpark.. not perfect.

    I think K5monsterchev also got a street and performance chip, he didn't know the specs on his cam so he took a vacuum reading at idle and gave them that info.

    If you read over on thridgen.org you'll learn about burning your own prom.. loging data with a laptop or scanner, then adjusting your BLM's so your VE tables are all reading perfect A/F ratio, not too rich or lean.. one of the guru's over there says it took him 700 chips to get his to what he would call "perfect".. and knowing what he knows now, he could get it perfect in more like 70 or 80 chips.
    For our purposes, i guess a chip from a reputable placle will get it running good enough, but the key is you want to keep a computer friendly or 'tpi friendly' cam in the engine with a wide 112 or 114 LSA.

    I've got a lot to learn about burning your own eproms, and want to start doing it in the near future... An aftermarket chip will offer a starting point to tune from, or if you have a chip burner you can download a 'safe base' chip from thirdgen.org.
     
  4. Thunder

    Thunder 3/4 ton status

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    Anyone used one of these ? Prominator

    Sure would save a bunch of chip burning
    Susposed to work with Win ALDL too.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    I'll verify that! You WILL need a chip burned, as with VATS enabled, (as it is now) your vehicle will just crank and crank and never start. It's an absolute MUST DO to start.

    I have no personal experience with MAP (yet) but even with MAF I can tell you that chip burning is on my list of things to do...it needs some tweaking to take full advantage of the larger engine, different heads, intake, injectors, and exhaust.
     
  6. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    No kidding, I got mine all finished, but the chip was still in the mail, so I though id try and start it. It cranked and cranked, I double checked dist, wires, everyhitng, then all of a sudden I realized, IT HJAS VATS, its not gonna start, DUH! After I got the new PROM, it fired right up, lol.

    When I got mine burned, I didnt have specs on the cam so he just had me take a vaccuum reading, which was 15". He said thats the lowest you want to go otherwise its not gonna run right.
     

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