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Stall Converter?

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by Ryan B., Oct 25, 2001.

  1. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    I was wondering if anyone has an oppinion on this...
    I went to a tranny shop and talked to the Tranny guru there, I told him i wanted to put a mild stall converter in my K/5's TH-350...
    He advised just to stick with the stock torque convertor since that is where a lot of the torque is made that I need for the street?
    I don't belive this to be 100% true.
    I told him I wanted to go with something like an 1800-2000 stall convertor, and he told me there isn't such a thing for a TH350 under a 2000 stall. THat is unless I wanted to put a 1800 Ford C4 stall converter in it which would just weaken it.
    I mainly use my blazer for street, and sand dragging, so keeping the RPM's above 2,000 when I'm moving shouldn't be a problem.
    My friend has a 3,000 stall in his '72 K/5 and it seems like too much even with his 460HP 388 stroker engine.

    Anyone got a stall converter they're happy with... or not happy with?
     
  2. LKJR

    LKJR 1/2 ton status

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    understanding I have is a 1500rpm and others are that much above your stock shift points. so if your shifts at 200 now it would shift at 3500.

    thats about all I know about em.

    LES

    Like em big and topless
    Excuse me...Would you mind removing your import from under my chevy?
     
  3. chevyracing

    chevyracing 1/2 ton status

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    A stall converter is good if you have a huge cam with a rough idle. The biggest problem with a stall converter is they run the tranny temp up much higher than a stock converter. Heat is an automatic transmissions worst enemy. If you put a stall converter in you should put in heavy duty clutches too.
    A trick a friend of mine told me about is running a Vega torque converter. You can get them all over the place and they raise your stall about 300 rpm.
    Just out of curiosity, why do you want to put a stall converter in? If you are having torque problems from a stop or low rpm's I would consider a cam change before putting in a stall converter.

    John

    Like to go sloppin' 'round in da mud in a rapid fashion....=) [​IMG]

    <a target="_blank" href=http://community.webshots.com/user/chevyracing>http://community.webshots.com/user/chevyracing</a>
     
  4. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    My understanding of a stall converter is not that it rasies your shift points by that many rpm's...
    But that it rasies the RPM of which it engages into gear.
    So if I put a 2000 stall converter in, the torque conveter would slip and "flash" below 2000 RPM's and once it hit 2K it would fully engage giving you better launches.?.
     
  5. HarryL

    HarryL 1/2 ton status

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    Ryan,

    almost 2 years ago I bought a 72 K5 without a motor. It came with everything else, including a 2800rpm stall converter. The previous owner used the blazer as a mud dragger, and used to have a way built 327 in it. I put a hot little 350 in the blazer, and kept the 2800 SC in it. Big mistake. Winter in Utah is bad enough, but with a detroit in the rear, a hot 350, 2800 SC and snow, I was doing lots and lots of donuts. I even went throught the neighbors fence one snowy, icy day.

    My truck would not go anywhere until the tach hit 25-2800 rpm, then it was off to the races. Wanna smoke the tires? I finally got tired of listening to my wife complain about the funny engine in the blazer. So I went back to the stock SC (I think it's 1500rpm or so). If you want to get the PRMs up before you launch, go with a higher rpm SC. Dr. Chin explained all this to me awhile back.

    I still have the 2800 SC for sale if anyone is interested.

    Best of luck,

    Harry
     
  6. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Re: Stall Converter? Dr Chin?

    That doesn't sound like what I'm after.
    Mine seems like the stall speed is 1100-1200 RPMS.
    I wouldn't mind 1500 or 1800 but even 2K seems a bit high.
    Dr. Chin a little advice to straighten this out here?

    In the last few months I've noticed a little chatter also right around the stall speed that I belive to be coming from the Torque converter. I've checked the converter to flexplate bolts and there nice and tight. My buddy said it could be the tranny oil pump in the front of the tranny making a little noise. Its a rebuilt TH-350 with about 3 years and 15,000 miles on it.
     
  7. ZZ4x4

    ZZ4x4 1/2 ton status

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    Re: Stall Converter? Dr Chin?

    Ryan,
    I have a B&amp;M Holeshot 2000 Stall converter in my 71. While I haven't finished tuning the motor for its max power, I am extremely happy with this choice. I've run around the block a few times and nailed the gas. The truck launches off the line like I can't beleive. It is only 400-500rpm higher stall than stock, but this makes a big difference in getting into the power band of the motor. The shift points are great and there is no problem moving at slow speeds. The idle still pulls the truck in stop and go conditions. I would do the same thing again. JT
     
  8. Steve_Chin

    Steve_Chin 1/2 ton status

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    A torque converter with a higher flash or stall speed won't change the shift points in your transmission, Ryan. Only a reprogramming of the valve body and/or shift governor will do that. Converter design in itself is kind of a black art. You can take two converters with identical stall speeds and have them perform differently at speeds below that RPM. Stall speed is also affected by vehicle weight, gearing, tire diameter, and engine torque output (which is why a Vega converter will stall pretty high in a passenger car with a V8 in it, but it will also blow up before a correctly-designed converter will).

    That said, I don't deal too much in torque converters since I use manual transmissions. I would estimate that in a 4x4 you would want a torque converter that has a 12" diameter and flashes to 1800-2000 RPM. I would suggest you talk to some real experts on the subject. I know that Coan and Continental will both build custom converters depending on your needs and specifications.
     
  9. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Thanks for the input from everyone.
    ZZ4X4- that holeshot 2000 stall converter sounds like what I just might be looking for.
    Maybe I'll just hold out with the torque converter I have right now, until I build up that killer 415cid smallblock engine I've been dreaming about.
    It would probally be much better suited with an engine like that.
     

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