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Is the "dual thermostat" setup worth upgrading to?

Discussion in '1982-Present GM Diesel' started by Pookster, Aug 19, 2004.

  1. Pookster

    Pookster 1/2 ton status

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    Is the \"dual thermostat\" setup worth upgrading to?

    I keep seeing these on ebay- a dual 190 thermostat setup for 6.5 TD's. They say that the cooling was weak in the pre 97 6.5's.

    Since I plan on adding a turbo system to my truck, would this be a necessary upgrade? I've towed 8000 lbs at 65mph up some hills, and my truck has never climbed over 200, except when the radiator sprung a leak.

    Thoughts? comments?
     
  2. AgDieseler

    AgDieseler Certified Scrap Producer Premium Member GMOTM Winner

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    As always, it depends.

    If you're not going to run the high flow pump, then they're not necessary. That said, the 130 gpm pump is a ccw rotation pump and only works on serpentine setups.

    Peninsular diesel sells a cw rotation 110 gpm pump, but there is a good possibility that the longer veins in the pump will cavitate at higher rpms.

    If you're really looking to tow some loads, high flow cooling is the only way to go - dual t-stats and 130 gpm pump. A turbo will increase the intake temp up to about 300*F, and that will make EGTs much higher, and that will lead to higher water temps.

    Without knowing more about your truck, it's tough to give a well rounded answer.
     
  3. Pookster

    Pookster 1/2 ton status

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    I should update my profile!
     
  4. Pookster

    Pookster 1/2 ton status

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    I have a 92 k2500 6.2 diesel mated to a NV4500. It is a serpentine setup (single belt), so I think I am all set. I couldnt really tell the honest difference between my 6.2 and a 6.5, other than well, the lack of a turbo. /forums/images/graemlins/rotfl.gif My truck is the newer CK body style.

    (and the round air cleaner of course).

    The reason Im asking, is because Im starting to get most of my parts off EBAY slowly but surely. I just got a set of exhaust manifolds for a 6.5 TD, I've got a lead on a stock 6.5 turbo with 30k on it.

    I did want to know what vehicle the turbo you put on your truck came from: also what other stock turbos from other vehicles will fit. The one I have a lead on (6.5 turbo 30k on it) will run me about 120. I had heard some of the dodge turbo's fit as well.
     
  5. AgDieseler

    AgDieseler Certified Scrap Producer Premium Member GMOTM Winner

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    Man, you are ahead of the game. A high flow cooling upgrade (130 gpm pump, dual t-stat housing, 9 blade fan) would do you well as you tow larger loads with a turbo. Look at getting your radiator cleaned - it's cheap!

    Which turbo are you looking at? The better turbos were the GM5 through GM8. They will give good response, and should flow plenty of air for a fuel rate no more than 79 cu mm. Check that the turbo you're looking at doesn't have any end play, and no excessive side to side play. Oil pressure will center the bearing, but any contact with the compressor or impeller housing should be a no-go.

    My particular turbo is a Mitsubishi Heavy Industries TE06H. It was intended for use on a Ford 6.9/7.3 IDI diesel, and came in Banks turbo kits. It's wastegated, and provides excellent response without choking at the high end. They're tough to find, especially online.

    Cummins turbos are not a good match for our engines. You have to spin the crap out of them to get any air flow, and the Cummins has such a high pressure ratio that it can do that. Our engines do not.

    Banks standard issue T04B turbo has such a huge a/r ratio of 1.00 that it is almost non-responsive at the low end, yet very efficient on the highway.

    Personally, I advise you to start with a low mileage GM turbo. $120 is a very fair deal, and if it's in good condition - jump on it!
     
  6. Diesel Dan

    Diesel Dan 1/2 ton status

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    [ QUOTE ]
    Im starting to get most of my parts off EBAY slowly but surely. I just got a set of exhaust manifolds for a 6.5 TD,

    [/ QUOTE ]

    The LH manifold is the same, be it turbo or N/A. For the cross over and down pipe just get them from flowmaster. Around $80 for the pair new and they are mandrel bent. Get the aircleaner housing from the '96/'97 or newer. The round air filters work much better than the flat panel ones.
     
  7. Pookster

    Pookster 1/2 ton status

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    Doh. I just paid 65+ shipping for a pair.

    Thinking the same for the crossover and downpipe. I already have a 3" exhuast system in, so all I have to do is chop and weld that part.

    I am seriously considering an intercooler just to keep EGT's lower. Any thoughts?

    [ QUOTE ]
    [ QUOTE ]
    Im starting to get most of my parts off EBAY slowly but surely. I just got a set of exhaust manifolds for a 6.5 TD,

    [/ QUOTE ]

    The LH manifold is the same, be it turbo or N/A. For the cross over and down pipe just get them from flowmaster. Around $80 for the pair new and they are mandrel bent. Get the aircleaner housing from the '96/'97 or newer. The round air filters work much better than the flat panel ones.

    [/ QUOTE ]
     
  8. AgDieseler

    AgDieseler Certified Scrap Producer Premium Member GMOTM Winner

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    [ QUOTE ]
    I am seriously considering an intercooler just to keep EGT's lower. Any thoughts?

    [/ QUOTE ]
    Once again, it depends. How much will you pull? What kind of boost pressures are you going to run? How much fuel?

    Intake air can be heated to 300* F with only 7 psi of boost - if you're going for plain-jane performance like this, then you probably don't need an intercooler. If you want to see the full potential of your 6.5, then boost pressures ranging from 12-15 psi will be the norm, and you'll really want that intercooler to keep IATs down.

    Turbo Technology makes a kit as does Kennedy Diesel. Both intercoolers take the place of the front plastic skid plate, so don't run over anything and poke a hole in it. We're working on a design for an intercooler that will fit in the grill, but we're a ways away from getting in perfect.

    Go without an intercooler for a while; it can always be added down the line. That lets you spread your total project cost over a longer timeline, plus, getting a turbo to work perfectly on an NA engine is a big enough project on its own.

    Don't get it all done so quickly that you can't enjoy it! I made that mistake when building my engine, but I won't on this new project. /forums/images/graemlins/thumb.gif
     
  9. Pookster

    Pookster 1/2 ton status

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    Ahh, very true! I think I will keep stock boost pressures for now, since it is a stock 6.2. I know they replaced the engine about 50-60k ago, and everything is running great with it.

    I would rather err on the "safe" side rather than on the crazy side. My max towing load would probably be my k5 and trailer. I have thought about a slide in camper though.

    What do you mean by "getting it working"? Am I missing something here in the equation? I had figured that this would be a two day event at most- Take off old headers, bolt on new ones and cross over pipe, bolt on turbo, run an oil line.

    BTW, where does the oil line get pressure from?
     
  10. Pookster

    Pookster 1/2 ton status

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    Forgot to ask something else-
    Im looking for the stock 6.5 Air intake system- kinda hard to find in my neck of the woods. I have a stock system off a 96 vortec suburban, but dont think its the right size. I saw on yours that you built your own- Are you making them for production?
     
  11. AgDieseler

    AgDieseler Certified Scrap Producer Premium Member GMOTM Winner

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    Getting it working = getting to know your truck all over again. With a turbo, it will be as if you have doubled your power. The honeymoon with the skinny pedal took me a while to get over, plus there is a new baseline for performance to become accustomed. This is why I suggest spacing out the intercooler project. Definitely get one, just don't be in a hurry - continue looking for good deals online, etc.

    You're right, it takes about a weekend to build it, but it has taken me over a year to get used to the new power.

    Before your intercooler, keep boost below 12 psi or so, and afterward stick to 15-17 psi peaks.

    Oil pressure came come from one of two places depending on your engine's model year. Late 6.2s and all 6.5s have a boss in the valley, and if you have that I recommend sourcing your oil from there. You'll know it when you see it as it's the only thing in the valley. Earlier 6.2s draw turbo oil from a 1/4" NPT plug that is directly about the oil cooler lines which are above the oil filter boss. That's where I tapped.

    We haven't built the intake for either of the project engines, though the parts gathering is well underway. It will basically be a mandrel elbow with a big cone filter and heat barrier. I will share the design of the intake for free, but we have no plans for production.

    It sounds like you have a great project going. /forums/images/graemlins/thumb.gif
     
  12. Pookster

    Pookster 1/2 ton status

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    Hey, thanks for all your help! Its good to know someone else has already started this project, I dont have to start from scratch!
     
  13. Pookster

    Pookster 1/2 ton status

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    Hey, how are you controlling the turbo boost levels? I thought these turbo's were electronically controlled- is there a manual bleed screw?
     
  14. jac6695

    jac6695 1/2 ton status

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    If you use a 6.5 turbo, Heath Diesel has a Turbo-Master that is basically a manually adjustible wastegate controller that maintains a preset amount of boost. I think the first year or two of 6.5 TD engines had something like that from the factory.
     
  15. AgDieseler

    AgDieseler Certified Scrap Producer Premium Member GMOTM Winner

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    Re: Is the \"dual thermostat\" setup worth upgrading to?

    For our non-electronic engines, we can use a mechanical wastegate. The rod is usually threaded, and that allows for some range of adjustment. All the GM turbos are mechanically wastegated, but depending on the year their method of actuation may vary.

    92-93 had a fully mechanical spring loaded pot while 94+ used a vacuum system. Both have aftermarket alternatives through Heath Diesel.
     

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