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Looking for advice...

Discussion in '1982-Present GM Diesel' started by chevy4x4, Apr 16, 2001.

  1. chevy4x4

    chevy4x4 1/2 ton status

    Apr 27, 2000
    Likes Received:
    I'd want to get around 200 hp out of a 6.2 without getting a turbo or spending a lot of money. Getting better mileage and more torque would also be great. Anyway, here is what I had in mind:
    J code intake mainfold
    Building a snorkle (not for power)
    Building dual 3 inch exhaust pipes with a balance pipe
    K&N filter
    Advancing (?) the injectors

    Anyother suggestion? How many HP would I gain? MPG? Torque?



    P.S. Could someone (BlueBlazer maybe) explain the J code intake manifolds a bit more.

  2. k20diesel

    k20diesel Registered Member

    Apr 18, 2001
    Likes Received:
    Won't happen. Maximum HP for an N/A was 165hp. You can modifiy it to get about 175hp, possibly 185hp with a set of headers but those are pricey. 190hp or higher requires a turbo, no way around it. Staying N/A you will need to run at least a 4" diameter air intake line in place of the puny 2" factory one. A 2-1/2" dual exhaust with balance pipe and free flowing mufflers is all you need. That will get you about 170hp and 1-2mpg. To get more power you have to increase the fuel delivery rate of the injection pump. But you best have an EGT gauge and pyrometer first - otherwise there is no way to know how much is too much and you could melt pistons, crack the heads or blow head gaskets. EGT gauges generally run about $150 for a good one. ISSPRO, Autometer or VDO are good ones.

    Keep in mind that HP is relatively meaningless - diesels operate at such a low rpm that torque is what will make the difference. HP = torque x rpm / 5252.
  3. childs

    childs Registered Member

    Mar 15, 2001
    Likes Received:
    delaware usa
    K20diesel just about said it all. If you are looking for HP you have the wrong engine. 3" exhaust is overkill and the headers are only 2 1/4" anyway. The K&N will help some. The diesel wants as mush cold fresh air as you can give it. I noticed the biggest when I moved to the coast. I am now 4500' lower. You can advance the timing pump by turning the line on the pump to the drivers side. Only turn it two or three line widths. An advanced pump will blow blacker fuel as a retarted pump will blow a whiter or blueish smoke. It is my understanding that you would definetly need to measure the exhaust temp. when adjusting a turbo but you won't need one without a turbo. Be careful when turning up the fuel. You can take the injector pump off or you can go thruogh the governor. I won't tell you how to go through the governor because if you put it back together wrong your engine will run away until it blows. You can get someone to show you. When you get there, you will turn a hex head screw. For every flat side of the screw you turn will add 20% black smoke. Turning the "in" will add fuel so turning it "out" will subtract fuel. A new injection pump can add more power. A diesel show around you probably make improved rebuilt pumps. Lastly, the 6.2 will never be a Cummins or Powerstroke but it will run for a long long time.

    DE k5
  4. NewK5Guy

    NewK5Guy 1/2 ton status

    Mar 2, 2001
    Likes Received:
    Alexandria, VA
    An expensive option is to have your stock injection pump rebuilt. There are a few companies(including one not far from me here in Richmond, VA) that will rebuild and basically blueprint the injection pump. My former surpervisor had his done and was amazed at the difference.
    The pumps are manufactured to output within a tolerance(let's say 10-20). As long as it tests on the bench somewhere in that range, it will leave the bench as "passed". My supervisor took his pump to a diesel service and they rebuilt it from the ground up(he had some bad internal seals) and they built it to output at the top end of the factory tolerance(in the case of the 6.2, he told me that the magic number was 26. It's at it's most efficient and most powerful without the need for advancing the injection pump timing and adding smoke to your exhaust. His cost was near $700. I plan on having mine done as well someday and expect the same. I'll ask him again about the details and get his best guesstimate as to what sort of power he gained.

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