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GM 383 TBI crate?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by fortcollinsram, Jan 17, 2002.

  1. fortcollinsram

    fortcollinsram 1/2 ton status

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    I was at the Chevy dealer in Littleton and I got to talking about engines (specifically the 383) and he was telling that GM is planning to introduce a FI version (probably TBI) of the current 383 HT crate motor! Just curious if anybody else had heard this...If this is truth and not just a wives tale, I am VERY interested... Later

    Chris

    Was that a speed bump? No, just a Rice Rocket </font color=red> <a target="_blank" href=http://coloradok5.com/gallery/fortcollinsram>My 87 Blazer</a>
     
  2. Boss

    Boss 1/2 ton status Author

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    That would be very good news if they did!!! If you find out anymore info on this, let us know...I'm veryyyyy interested.
    Boss

    Pic of my truck Before N' After
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  3. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Same here!!

    I would bet it is not smog-legal tho :( If you remember, can you ask?

    Dave

    Rehab is for quitters.
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  4. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Called Billings Chevy - good source for legal mods - they confirm the 383 in 3 versions: 325, 350+, and 400 HP!
    But alas, not smog legal.

    He went on to say some more about the TBI 350s - 383s under the TBI have a very short life span. Seems that the O2 sensor and TB confuse (?) each other and can never come to a steady state.
    Also asked about the Whipple SC (what I have been planning).
    He said they are good for about 35k miles if you plan on making it Ca smog legal. GRRRRR.

    Dave

    Rehab is for quitters.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  5. Boss

    Boss 1/2 ton status Author

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    Definately don't like the sound of that! 35K life span, need to make the $$ go a little further than that.
    Boss

    Pic of my truck Before N' After
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  6. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Just ragged on my engine builder about that also..... We will see.

    There is a B&amp;M smog legal unit that is in production now - supposed to be half the cost of the Whipple $3000.00. I'll keep everyone posted.

    Like a dumb fug I didn't ask if they had pricing on the 383 crates..... Damn.

    I am getting pissed about the entire engine thing. I want to keep it smog legal (just for compliance with the regs but I don't believe a well tuned engine of my choice is a gross-polluter - GGGRRRRR). I have family owned property in a smog exempt county in Ca - WHY SHOULD I NOT REGISTER IT THERE???????

    Dave

    Rehab is for quitters.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  7. Boss

    Boss 1/2 ton status Author

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    Yeah, I'm not "too" concerned with Smog legality or not. We just have the sniffer test here. They don't look at the motor or anything, just check if you have a Cat or not. Basically, I just want a motor where I can still use most of my TBI stuff, with basically just upgrading the injectors and chip. Defiantely keep us posted :)
    Boss

    Pic of my truck Before N' After
    <a target="_blank" href=http://coloradok5.com/gallery/BeforeNAfter>http://coloradok5.com/gallery/BeforeNAfter</a>
     
  8. There is a smog exempt county in califorina?? I thought the whole state was under the thumb
    Where?

    '84 K5

    Chevy in my blood.
     
  9. CaptCrunch

    CaptCrunch 1/2 ton status

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    Boss and i were just discussing some related topics.

    SDPC have a few motors that are 350's that are suppost to make 300 and 330 hp with no chip or TBI mods... I emailed the tech guy about them and he basically replied back with a link to this other motor. Needless to say I say screw them. Talked to a guy who plays the performance game and is head of the parts division up in Little Falls GM and he said basically the TBI's will work, but they won't make that kinda HP. Now with a Holley aftermarket TBI and the 80 lb injectors it has this could be a reality as I believe it is rated at about 670 cfm or so. When I called Holley to talk with them they said that TBI unit will handle just about an SBC and mild smaller BBC's. Most likely you will need to play around with fuel pressure and in worst case scenario get a chip done but they will work.

    From what I keep hearing, the TBI efi system is pretty leanant on stuff except for the cam selection, but if you were to tweak for top power, performance, and economy a few local guys highly recomended a port type injection. Much easier to play with I have heard if you decide to go to a DIY or aftermarket custom ECM. Also the lack of cams available to work the strick speed density parameters really limit your hp, so a 383 looks more like the way to go IMO. I also have heard of some guys burning chips to compromise for the cam selection's vacuum, but have yet to fiond a place that has said this.

    But all in all I look at the current 383 HT that is now availble and I love the sounds of it. One thing to watch is compression ratios on the GM crates... many will be stricly 92 octane so if you wanted 87 you would be in for a shock. You guys might want to look at Chevy High Performance back issues or research them on their website. With'n the past 6 months or so I know they built a 400 with vortec heads that ran all day on 87 and made like 350-400 hp. I don't remeber the issue though. Can't remeber the carb they used but this kinda shows you what the vortecs can do so it might be worth buying a set and getting a short block done locally for cheaper. If I stay TBI I'm going to try and just use the Holley TBI unit and probably trust the guys at Crower to nail me the best cam I can get. If money was no option a custom FI setup like F.A.S.T., Cal-map, Haltech, Kahlmar(sp?), or a one of the Holley systems would be the way to go.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
     
  10. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Thanks Capt.

    The entire issue of efficiency vs. emissions pisses me off.

    The vette gets great power AND great mileage from using better technology but we are prevented from using any of that cuz of the bureaucratic BS.... I will keep you posted and will bounce ideas off you guys as I get closer to a decision.

    I should just put the 502 crate in :)

    On a side note I told my buddy to look for an aluminum BB. Now that would be a sweet buildup!

    Dave

    Rehab is for quitters.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  11. HarryH3

    HarryH3 1 ton status Author

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    Speed density systems are pretty "ignorant" in the fact that they have zero information available to the ECM about how much air is flowing into the engine. Their 3 main inputs, that control the majority of the fuel curve, are throttle position, manifold pressure and engine RPM.

    The system is NOT able to determine that your former 200 HP engine has just been replaced with an engine that can put out 300 HP, if properly fed. Since the ECM is ignorant of the change, it will continue to supply fuel just as if the old 200 HP engine were still installed. The fuel injector timing is controlled by looking up information in 3-dimensional tables of parameters stored in the computers memory chip. So for say, 37% throttle, at 7 inches of mercury, at 1,500 RPM, the computer will look in the table and see that it is supposed to enable the injectors for a pulse width of X amount of time. X doesn't change just because the new engine has been installed. [​IMG] So now you're running your new engine WAY too lean.

    After the engine warms up, the oxygen sensor will see that the engine is running lean, and tell the ECM to richen up the fuel mixture. But there are hard coded limits within the computer chip as to just how much of an "adjustment" to the fuel flow that it can make. Once you've reached that limit, the ECM can't inject any more fuel. That limit is reached long before the ECM has supplied enough extra fuel to create 50% more horespower than it's stock parameters.

    Also, since manifold pressure is one of the 3 main inputs, it's easy to see why the cam plays such a big part in the equation. Hotter cams affect the manifold vacuum, especially at low speeds. This affects the manifold pressure readings being reported to the ECM by the manifold pressure sensor, causing driveability problems.

    You can get the new engine to run, but it won't run at anywhere near its full potential until you reprogram the computer so that the value of "X" for the injector timing has been changed throughout all the tables, to account for the actual fuel demands of the new engine, at each point in the fuel and timing curves. Bumping the fuel pressure and/or installing new injectors will help to mask the root cause, but until the computer has a much better understanding of how it should react for a given input, the engine won't perform at its peak. [​IMG]


    <font color=black>HarryH3 - '75 K5</font color=black>
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  12. HarryH3

    HarryH3 1 ton status Author

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    In most states you can install all of the technology of the 'vette into your K5. It just has to pass a special inspection in some of them, to prove that all of the emission controls of the later engine are in place and working properly. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
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  13. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Yeah, I have thought of re-certifying. But I was told to prepare for 6 months to a year of down time (no driving while in review or some blather) for the process.

    Anyone have friends in CARB that can tell me if Siskiyou County is exempt? And I wonder what happens if I register up there - no more requests for smog certificates with my registration......?


    Dave

    Rehab is for quitters.
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  14. ChevyCaGal

    ChevyCaGal 3/4 ton status

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    There's lot of non smogging counties.... just need to look them up with the DMV. Once you find one see if you can register your truck there and no smog to deal with...

    <a target="_blank" href=http://www.chevycagal.homestead.com/steph.html>Steph's Webpage</a>
    Suck Fumes Ford Boy
    Stop Global Whining
    I'm in shape.... round is a shape......
     
  15. Dznutz70

    Dznutz70 Registered Member

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    I didnt see the county you specified on the list but here is the DMV smog webpage!

    <a target="_blank" href=http://www.dmv.ca.gov/vr/smogfaq.htm>here</a>
     

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