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Turbo Performance Update!!

Discussion in '1982-Present GM Diesel' started by arveetek, Aug 27, 2004.

  1. arveetek

    arveetek 1/2 ton status

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    I've logged around 4000 miles since my turbo installation, including my RV trip to Colorado. I haven't had a single problem, other than a few minor bugs that I got worked out at the beginning. No blown head gaskets, no blown rear main seal, nothing of that sort.

    Today I turned the injection pump up another 1/4 turn. I didn't turn up the pump when I first installed the turbo, because I had previously turned it up a 1/4 turn when running N/A. So I now have turned up the stock 4126 pump a whole 1/2 turn. Let me tell you, what a difference that makes! I was smoking like a freight train before the turbo, showing that I didn't have enough air. But after the turbo, no visible smoke at all showing not enough fuel. Now I can smoke some on take-off, and now I can burn some rubber! With the new 31" tires, I just couldn't get them to break loose on dry pavement before. But now, if I powerbrake, I can get the tires smoking! Yee-ha!

    Before the pump adjustment, I could only build about 2 lbs of boost while powerbraking. Now I can build about 5 psi. That makes a lot of difference. I've also hit near 15 psi at full throttle. My EGT's rose some, of course. I could only hit 1100 degrees while pulling hard all day long with the trailer. Without the trailer, I could never get above 975. Now I can hit about 1000 degrees without too much trouble. That's just about where I want it.

    Man, if installed a 4911 pump, some high-performance injectors, and an intercooler, there's no telling how much fun I could have! And this is all with a stock '82 motor!

    My next project, actually, is to start on an intercooler. I think I've got enough boost to warrant it and have it be useful. After that, perhaps some fuel injection upgrades. And then after that, perhaps a better, waste-gated turbo.

    Casey

    Proud owner of a hot-roddin' 6.2L Turbo Diesel! /forums/images/graemlins/woot.gif
     
  2. AgDieseler

    AgDieseler Certified Scrap Producer Premium Member GMOTM Winner

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    That's awesome Casey. The 4126 is a good pump, and should provide you all the fuel you want. Think about some 6.5TD injectors as an upgrade. The higher pop pressure should help you get a better burn, lowering EGTs, smoke, and increasing power and boost.

    You've done a great job of building turbo power on a budget. /forums/images/graemlins/peace.gif
     
  3. arveetek

    arveetek 1/2 ton status

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    [ QUOTE ]
    That's awesome Casey. The 4126 is a good pump, and should provide you all the fuel you want. Think about some 6.5TD injectors as an upgrade. The higher pop pressure should help you get a better burn, lowering EGTs, smoke, and increasing power and boost.

    You've done a great job of building turbo power on a budget. /forums/images/graemlins/peace.gif

    [/ QUOTE ]

    Thanks for the kind words, David!

    As for injectors, I have an '82 motor with what I assume are the coarse-thread injectors. I've never pulled one out to compare to the later injectors, so I'm just assuming that they are. So, if that's the case, I wouldn't be able to install standard 6.5L injectors in my current heads. However, shouldn't a fuel injection shop be able to build me a custom set of injectors using my current injector bodies? I've often wondered about that.

    Casey
     
  4. AgDieseler

    AgDieseler Certified Scrap Producer Premium Member GMOTM Winner

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    You're right. I didn't even think about the threads. As for shimming long style injectors for a higher pressure - it can be done, sort of.

    The long style injector doesn't have the same internal structure as the short style 6.5 injector, and it isn't designed to hold the number of shims necessary to achieve anything past about 2000 psi. Machining is almost certainly needed for pop pressures above that, and the cost/benefit ratio is just too high since stock 6.5 injectors would then be cheaper than a custom 6.2 set and provide better atomization.

    If you engine is/was red, then it's safe to say you have coarse thread injectors, but if not, give it a look-see. You may be pleasantly surprised.
     
  5. arveetek

    arveetek 1/2 ton status

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    The engine was originally red, and I replaced all the injectors when I initially rebuilt the engine, and I've replaced one or two since then because they started leaking, but I never bothered to look at the threads to compare them with later injectors. I may not have much choice as far as injectors go. I don't want to replace my heads if I don't need to. I'm not taking them off unless something breaks!

    Casey
     
  6. BlueBlazer

    BlueBlazer 1/2 ton status

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    Hey Casey, since you seem to like experimenting with homebrew modifications, maybe you can try to make some sort of water injection setup for your engine and let us know how it works. If built right it should work just as good as an intercooler, only drawback is you would of course need a water source for it and find a way to control it without dumping too much water into the engine. I plan on using water injection someday either with the 6.2 or whatever engine I swap in there someday, so I wanted to see if it works OK.
     
  7. arveetek

    arveetek 1/2 ton status

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    Well, honestly, I'm not interested in water injection. I never did like the thought of injecting corrosive water into my running engine, even though it's been done and proven reliable. Plus, I don't want to have to mess with a water tank and have to fill it up all the time.

    An intercooler shouldn't be too hard to fab up, and once it's installed, it's virtually maintenance free! No water tanks, no pumps, no injector nozzles, no switches...just a simple air to air cooler.

    A home-brew intercooler is next on my list! /forums/images/graemlins/whistling.gif

    Casey
     
  8. Pookster

    Pookster 1/2 ton status

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    You could still use water injection with an intercooler , but just as an intercooler sprayer. Nothing added to the engine! /forums/images/graemlins/smile.gif
     
  9. Steve_87K5

    Steve_87K5 1/2 ton status

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    Casey, I've looked around for the materials I'd need to homebrew an IC and haven't come up with much. It's the core material that I am on the hunt for.
     
  10. Sandman

    Sandman 3/4 ton status Author

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    I think that Volvo's (cars) had a pretty good IC setup. Very Large one IIRC.
     

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