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torque converter for a rock crawler?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by laketex, Apr 1, 2002.

  1. laketex

    laketex 3/4 ton status

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    Which one should I get? I went stock this last time and that I hate that thing... I guess I kind of need a basic TorqueConv 101 here. What does what?
     
  2. ChadH82

    ChadH82 1/2 ton status

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  3. BorregoK5

    BorregoK5 1/2 ton status

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    I went with the low stall RV converter from TCI to keep the heat down and keep my revs down for crawling.... BUT, I have a hard time moving slow with my 415 and 3.07 gearing in 4 low. The first half inch of my pedal is my range of coast to jump forward which means my crawling is made of small burst of gas an brake. I imagine a good gearing drop would dramaticly improve my crawling.
     
  4. laketex

    laketex 3/4 ton status

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    hmmm...low stall RV...My gearing probably sucks as bad as yours right now. Got 4.10, but also have 38s. Saving pennies for that doubler!!!

    I'm reading torque converter 101 right now Chad, thanks.
     
  5. laketex

    laketex 3/4 ton status

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    Ok, so I'm seeing that overall gearing plays somewhat of a hand in selecting a torque converter. Here's what I'm running and probably will be for a couple years. Stock 350 engine, soon to be a 383. 4.10 gears, 38's, TH350, NP203. So with this combo, what would you run torque converter wise and why? Btw, I'm not impressed at all with the stock unit. I'd like to be able to sit still or slowly creep forward with my foot off the brake.
     
  6. BorregoK5

    BorregoK5 1/2 ton status

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    If your unhappy with your stock converter(1200-1500 stall) because it grabs at idle with a 350/350 combo you could move to a 2000 stall to help but... keep in mind that a torque increase in your engine (383 swap) can cause an increase in your converters stall speed so plan accordingly. My Low stall barely creeps without the brake. A full throttle snap from a stop will shoot me to 2000 rpms immediately on a 1200-1500 stall converter with the 415. I never ran the stock one on the 415 but I did on my 350, it felt like a lower stall than the low stall on the 415... hope that helps you decide what fits for you.
     
  7. laketex

    laketex 3/4 ton status

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    Thanks for all your help. I know what you're saying I guess. Mine tends to want to roll forward hard in drive. Maybe my stall is a little lower than yours. It sure would be cheaper to keep this same converter. It only has about 30 miles on it, but the tranny blew (again) and I figured if I was going to pull the tranny, I'd change the converter while i was at it. Maybe I should leave it in there and put the cash I saved toward a new engine!
     
  8. BorregoK5

    BorregoK5 1/2 ton status

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    Just make sure you drain the converter and flush it to get any contaminants out so you dont inadvertently send metal particles through your new tranny. I had the same scenario with mine which is how I ended up with the TCI converter. A stock stall is just about right for a rock crawler! I'm building a 383 as well right now, looking for an extremely small, scary light, pre 73 car to transplant it in... like an Opel Manta, 240z,VW Manx or ??? Good luck!
     
  9. laketex

    laketex 3/4 ton status

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    That'll be fun. I've got a buddy in lubbock that has a very hot 454 stuffed in his pro mod opal. It runs high 9's and he just had to get nhra certifications to be able to run it on the strip after he broke the 10 sec barrier.

    I've got a brother in law out in san diego at mirimar. Next time I'm out that way, i might look you up. Btw, I like the shackle hangars!
     
  10. Sandman

    Sandman 3/4 ton status Author

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    I run a B&M 2400 Stall with a 205 and 4.10's with 39.5 Swampers. It works great for mud and driving around town but rock crawling is not as good. The trouble I had was when trying to hop up a ledge, It would tend to break the tires loose real easy. I ended up riding the brake and the gas at the same time which worked but then the tranny started heating up. A doubler is on the wish list.
     
  11. BorregoK5

    BorregoK5 1/2 ton status

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    Definately let me know when your coming out this way, mirimar is rather close! I'm moving here at the end of the month but only about 5 miles from where I am now. (nicer garage.. but still doesn't fit the truck!)

    I'm going to run 4.11's with my 33's for a short time on my 14b after I swap it in, then move to 38's and be back to the same ratio of my 3.07's and 33's again. I'll regear once I find a good front end!
     
  12. laketex

    laketex 3/4 ton status

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    looks like you're right in the middle of things. I think my regear mod will be a doubler. I think you gain a lot more with this route and when it's all said and done, it's just a tad bit more expensive than swapping in 5.29s front and rear. Plus more options.
     
  13. RaisedK5

    RaisedK5 1/2 ton status

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    Or you could see how that 383 performs in a 75 Blazer/forums/images/icons/smile.gif/forums/images/icons/smile.gif.
     
  14. 84_Chevy_K10

    84_Chevy_K10 Banned

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    4.10 or 4.09 fronts are easy to come by, just find a 3/4 ton front, almost all have them.

    You gonna mail that chart tomorrow?
     
  15. BorregoK5

    BorregoK5 1/2 ton status

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    I've got a line on an 8 lug conversion for cheap, since I've already got the later production Dana 44. Gears are relatively cheap and somewhat easy to install ( just time consuming). I looked everywhere for an 8 lug Dana in the yards here but nothing, and the people selling them usually want more than I'm willing to pay unless I start heading into a Dana 60. Lifts, tires and axle swaps take so dang long on a daily driver!!!

    Oh yeah, the charts... hmm , ok, I'll go to work tomorrow so I can send them (been playing hookey!)
     
  16. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Just get a 10 bolt front. Everyone thinks they're garbage so you can always get them for $100 or less. I paid nothing for the axles under my truck right now, but I've bought 10 bolt fronts from the junkyard for $50 before.

    On the charts, thanks a lot. I'm really anxious to see them as the last guy that did a dyno for me screwed the specs all up. It still made 253 HP @ 8.5:1 CR!
     
  17. BorregoK5

    BorregoK5 1/2 ton status

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    $50 for a 10 bolt... even the pick it yourself yards around here charge $150 for one! And with 38's, I'll eat a 10 bolt up with the things I do with my truck/forums/images/icons/smile.gif. If I was to stay 33's I might keep my current dana44 and be done with it. Its been a good axle so far and never any troubles! My goal is to have enough axle to play extremely hard and drive it there and back with minimum breakage (cause we all know its when and not if)!
     
  18. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    The old 10 bolt - D44 thing pops up again! Do some research, there's not a lot of difference in them, I'd take whichever had the right gears.

    On the torque converter, without deeper gears, don't plan on crawling without using your brake. The basic technique is to give it gas till it starts to push then control the speed with the brake pedal. It is a heat builder in the trans but gives you decent control.

    Stall speed can be highly engine dependent, at TTC (near sea level) I stalled around 2400, ouch! Up here it's a much more civilized 2000 or so.

    I know Greg Schneggie went from a stock converter to one that stalled around 1700 (?) or so and really liked the way it performed. This was pre-Doubler for him with just the 2:1 low gear. I think it just got the motor to a point that it ran smoother than being at 1200 or so.
     
  19. BorregoK5

    BorregoK5 1/2 ton status

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    I agree on the Dana44/10 bolt strength comparison. My comment in keeping the Dana44 was simply because I already have it. You'd be suprised how few 8-lug fronts there are available in southern cal but they seem to be plentiful everywhere else... if shipping wasn't so much I'd jump on one with the typical 4.10's as Tim was saying. Might be time for a Colorado road trip!!!

    Your completely right on the low stall / tall gear issue... the videos I posted previously show that real well /forums/images/icons/smile.gif

    Other than engine torque being effected at altitude, which directly effects your stall speed, are there other things you've noticed that seem to effect stall like cold weather? I'm a desert low lander and don't get up above 3000 ft very often.

    My high stall (2200) had a tendency to dig in more than my low stall but I can appreciate matching a stall to an engines power band. Consequently, I ended up smoking my tranny with the higher stall... much cooler now.

    And speeking of TTC, do you have pics from the last one... I missed out last time they went around!
     
  20. laketex

    laketex 3/4 ton status

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    Where are these videos you speak of?

    Thanks guys, now I'm beginning to understand better the mystery of torque converters. I think I'll stick with my stock stall and later when I pull the engine, swap to a higher unit if i need to. Just more pressing issues right now.

    Bryan
     

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