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Thread: Upgrade SD-33T

  1. #1
    Join Date
    Jan 2011
    Location
    Denver, CO
    Posts
    5

    Default Upgrade SD-33T

    I've got a stock '80 Scout II with the Nissan turbo diesel. I live in Denver and its got enough power for flat roads. When I take it up mountain passes it really loses a lot of power and I have to pull over on the shoulder and take it down to first gear. The altitude and steeper climbs really weaken it.

    My goals are to get more power and better fuel economy without damaging the engine. Can anyone recommend some safe, conservative upgrades with regard to the fuel pump, turbo, wastegate, intercooler, exhaust manifold? Again, not looking to turn it into a hot rod, but just want a little extra power out of the 6 cylinder SD-33T. Thanks

  2. #2
    Join Date
    Aug 2010
    Posts
    20

    Default

    Before you start changing things you need find out what the baseline numbers are for EGT and manifold pressure.
    Add a manifold pressure 0-10 psi and a Exhaust Temp with a max temp of 1500 F.
    First item I tackle is a larger air filter and/or cold air intake at the base of the windshield. The stock snorkel on the air filter is too restrictive, double the size or look at replacing it with a better unit.
    Second is exhaust. There is a restriction after the exhaust leaves the turbo, a sharp 90 degree bend. Google "scout elbow eliminator". From there increase the size of the exhaust piping, Up to 3" is good. Eliminate the muffler.
    I never got around to the cold air intake but did the muffler delete, no increase in noise in the cab.
    Then go after the fuel screw if desired.
    There is a replacement for the exhaust scroll with one off of a Mercedes Benz I5 Diesel, not sure which one, google is your friend.
    Good luck.
    1980 Scout, Cummins 4BTA, 92 Dodge CAC, NV4500, 3.73 gears, Atlas 4.33, rolling on 33/10.50 BFG muds, modified H1C.

  3. #3
    Join Date
    Aug 2010
    Posts
    20

    Default

    Did this help?
    1980 Scout, Cummins 4BTA, 92 Dodge CAC, NV4500, 3.73 gears, Atlas 4.33, rolling on 33/10.50 BFG muds, modified H1C.

  4. #4
    Join Date
    Oct 2009
    Posts
    7

    Default

    I have got a pretty heavily built SD33T. It has gobs of torque and is very "peppy". So far no problems but I have not really had the chance to run it much. The truck it is going in is still being built. A lot of research was done prior to building the engine. Wanted to make damn sure we wouldn't be building a time bomb. We addressed the issues with the SD33T and it's downfalls. In particular in the cooling department. It is running a Garret T3 turbo that is oil & water cooled. Dual intercoolers, large custom made aluminum radiator, top mount oil cooler. Large air intake, manifolds and head were ported and polished, 3.5" dump and lot's of ceramic coatings. So far I have not cracked 190 on the water temp. Have not had a chance to check EGTs yet as I need to fit gauges. Have not ran it but around the property but it runs extremely cool and is super smooth, throttle response is nice and it has zero lag. I can put my hand on the turbo after a good run around the property and everything else on the motor is even cooler. I am very keen to see what it is all at once I get some gauges fitted.

    you can read more about it here....

    http://www.binderbulletin.org/showth...ialup-warning*

    most of the pictures I have taken down but a few can be seen here...

    http://www.rmp-o.com/phpBB3/gallery2...5209&g2_page=2

    I have spent a lot of time learning about this engine and a lot of that info comes from the Aussies who have lot's of these in Nissan Patrols. The main issues are defiantly heat related and can be improved upon vastly. Being an indirect injection there is no way around the heat it can generate. But you can keep these temps under control IMHO and as such the motor will last a long long time even it built up like mine. Also over boosting will kill the engine. My rule of thumb is 15psi is ok, 20psi is ok too if you take percations and don't drive it like a teenager, anything over 20psi and you are going to risk killing it, it is a 4-bearing crank after all. I believe over boosting plays a roll in breaking cranks on these engines. Who knows maybe you can crack 20psi if you lower compression but I wouldn't want to and I really don't think much over 15psi is needed.

    Over on Patrol4x4 guys have done many things with this engine. Mine is probably the wildest but a few have built custom intake manifolds and reported great results. Other turbos too besides stock or the T3, intercoolers, water injection and so forth. Since they got these engines since 1980 and many are still on the road it is a good source for info in regards to reliability, mods and all that. A number of Aussies have reported 500,000+ks out of SD33Ts with no major repairs.

    Cheers

  5. #5
    Join Date
    Aug 2010
    Posts
    20

    Default

    RMP&O,
    Would love to see what it does on a dyno.
    1980 Scout, Cummins 4BTA, 92 Dodge CAC, NV4500, 3.73 gears, Atlas 4.33, rolling on 33/10.50 BFG muds, modified H1C.

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