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Stroked 6.9

Discussion in '6.9L IH & 7.3L IDI Diesels' started by carsonlhammond, Oct 7, 2019.

  1. carsonlhammond

    carsonlhammond Full Access Member

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    Hey guys I know this has been ran through a lot but I haven’t seen anything recently about people stroking these things. All the threads are from like 08-13’ and people in those threads don’t seem to have any personal experience with them.
    http://www.barnetthighperformance.com/engines_diesel.htm

    This link was in one thread but it won’t open for me. Just wondering if in recent years anyone has done this or has experience with one. I’d imagine the low end torque gains of the stroker crank coupled with a my WW2 OBS turbo setup with hypermax style up-pipes and my current typ4 cam would do amazing for the hilly terrain and heavy towing I do with it. I know it’s a lot of money from what people have said before on previous threads but I’m willing to spend an extra 2-2500 when I rebuild the 6.9 in my highboy if it’s still doable for that price. It has 400 psi in every cylinder but it has SO much blow by now it’s time to rebuild soon. I’m actually questioning how many psi it has now, since I tested 8-9 months ago, it’s that bad.
     
  2. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Best thing you can do to these engines is just add fuel and air, mechanically these things are designed very well, and just giving them some more fuel and turbo really wakes them up. We just made over 400hp with a bone stock engine and pump with an ats 088 and some spray... F7DC17E2-90D2-48C6-BD48-EFD2AA4F31D2.jpeg
     
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  3. carsonlhammond

    carsonlhammond Full Access Member

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    Thing is Wes, how would that engine do for extended periods of time really being worked hard. How much boost was that? How much boost can I safely run on a studded 6.9? The engine still runs strong but the blow by scares me. How long will my current engine last if it has say 18 intercooled psi up long winding hills? I just figured with more crank throw I would be making WAY more torque than I currently do without changing anything else. I know you have tried and trued methods of making big power with these things, but with all respect to your knowledge I think this is something worth looking into. It’s proven on gas engines, lots of people build super torquey stroked big blocks specially for towing/woods driving.
     
  4. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    That engine will work hard reliably and still has, hes not using the nitrous hauling trailers but its a fun daily toy for him, dont know what kind of boost since the truck doesnt have any gauges, but you wouldnt want to run that much in a stock engine if you dont want to blow a head gasket. A studded 6.9 can handle 18 psi all day long but any more than 22 psi youre going to want to build a 7.3 instead.

    Yes a stroked big block is a proven method in the gas world, but our diesel V8s are basically already just that, a big stroke, big bore V8 with high compression. Sure you could increase the stroke, but even in the gas world that often opens a world of problems. A lot of the time we end up running smaller oil pumps, grinding into the block and main webbing for clearance, and limiting rpms which can hurt potential power, since with any stroker motor your piston speed is increased by a factor of how much the stroke is increased, and with our diesels the piston speed is already very limited because of the weight of our rotating assembly.

    If you have a cam, a stock tp38 with a billet wheel, and studs all you need is more fuel. You wont have second thoughts about stroker cranks or any other pita ways to make power, my 7200 daily driven IDI you can hardly keep straight on the entrance ramps if you get into it too hard, so a big db2 completely transforms these trucks. You can mod and tweak the stock pumps to put out some decent fuel, but nothing drives like an IDI with a properly built DB2 that has a lot of fuel to offer, most your driving and towing is done between 1/4 and half throttle with always power to spare passing semis on a good incline, if you want to take one of my rigs around the block youre welcome to come out to the texas idi roundup Im putting on Nov 12. We'll be at the shop in the morning and cruising to the dyno the rest of the day.
     
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  5. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    I think that the only way that you could build an IDI with a stroker crank is to have custom, shorter rods made. If you increase the stroke with stock rods, then the valve and pistons would hit. There's already just a few thousandths of clearance as it is. Where could you have the rods made? I have no idea. How much would it cost? I'd bet that the rods and crank would cost quite a bit more than $2500. I didn't get your link to work, but I'd bet that I've listed the reasons why nobody seemed to have any actual experience with a stroker crank in an IDI. Wes does know what he's talking about. He's got WAY more power out of an IDI than I expect that I ever will.
     
  6. carsonlhammond

    carsonlhammond Full Access Member

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    Alright, I’m picking up what you’re putting down. I like what you say about the being able to pass semis on hills, something I CAN NOT do right now haha. How size pump would you recommend in that case? Thank you for your input btw.
     
  7. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    It depends on how much turbo you plan on running. With an s300 frame the performer series (150cc) db2 will make 35+ psi, which wouldn’t be reliable on a 6.9. If ran that same pump on a smaller turbo like an s257 you would be fine and have great response. The 110 or the 130 would be my choice for a studded and intercooled 6.9.
     
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  8. carsonlhammond

    carsonlhammond Full Access Member

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    Last edited: Oct 9, 2019
  9. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Thats it, I put one on a customers truck with a stock pump an intercooler on the hypermax up pipes. I put some mojo into the stock pump and actually had to turn it down because it was making more than I felt comfortable on a stock engine. Settled with 17 psi, its scheduled to go on the dyno in about a month.
     
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  10. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    B3878323-9038-4160-B870-214E9CB48FFB.jpeg
     
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  11. carsonlhammond

    carsonlhammond Full Access Member

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    I’d love to hear how it does on the dyno. I’m not looking for crazy power but I want at least 280-300. Is that in the area you expect to see from his truck?
     
  12. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    we’re shooting for mid 300s once the better heads, studs and big db2 go on. It’s probably around 250-280 with a stock engine and fuel system, that’s close or a bit more than what Macrobb is making with his 110 pump.
     
  13. carsonlhammond

    carsonlhammond Full Access Member

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    Ok that’s what I like to hear haha. I’d like to have that amount of power as I feel it’s more than enough for my use and it would still be fairly reliable at that point I think.
     
  14. Fordman1920032003

    Fordman1920032003 Registered User

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    Better heads? I just got my 7.3 heads out of the machine shop. Valve job, surfaced, new valves, and 910 valve springs.
     
  15. 03wr250f

    03wr250f Full Access Member

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    are you talking about wheel horsepower or crank horsepower? makes a huge difference.
    I also would not push a 6.9 past 15 psi of boost studded. i wouldn't push one past 10 on bolts. I have heard of them lifting heads between 17-22 psi of boost.
    a healthy stock fuel system (new ip and injectors) a ats or banks kit and a intercooler will do all of that extremely reliably making roughly 220/475 at the wheels which is more than enough to get out of its own way and with a empty truck be able to set the cruise at 80 going up a 6% grade

    the hypermax piping is great the turbo is lacking and would make for quite as good of power.

    a 110 will lift heads on a studded 6.9
     

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