BRUNO Shaft upgrade

Discussion in 'PSI Superchargers Tech Questions' started by lucky devil, Oct 29, 2018.

  1. lucky devil

    lucky devil Member

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    I love this Website/ Forum. Its very helpful with lots of experience and opinions.
    I only asked about changing the shaft on my BRUNO :)
     
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  2. jay70cuda

    jay70cuda Well-Known Member

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    Back to changing the shaft and fluid restrictions it seems as no one wants to give a straight answer. Is seems as most converter places wanna sell you generic converters for your setup. But then when you start expirementing yourself there isn’t a clear path or answer. Like pump size. Does the same pump work in 1/8 to 1/4 mile? From roots to screw. Let’s face it some of these high powered legal cars make almost same power as a tafc. Isn’t the whole point to try and jam the fluid into the converter to try and make it act as a lock up ? And yes we’re talking non lock up converters here.
     
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  3. rb0804

    rb0804 Active Member

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    Just a few thoughts, would pulling some timing when you depress the transbrake button help get it get it in and out of gear a little easier? I can see having a bypass button on a bracket car with a delay box, but don’t see it necessary on a heads up car.

    If the timer start is triggered off the TB button it runs the fuel/timing program no matter what happens during the run. It would be the same as starting your timers off of the WOT switch on a latching relay.

    As far as converter tailoring goes more pressure will tighten the converter per se. You do have to worry about pushing the crank forward if you get crazy with it. Mostly an issue with the turbo cars that are on the two step for a long time. A torrington bearing setup off the front of the crank helps this issue. The move was to guys running a tighter overall converter but using a converter dump to still get the rpm up in low gear. I think most of that was due to adding more pressure up top not really doing much because if you look at the converter pressure on the data log it steady declines as the converter approaches “coupling”. The above relates to a blown application. In my experience it’s been the pump and turbine sides of the converter are going to be similar to the next guys for your HP range and the stators are used for the fine tuning. They do make atleast 3 versions of each side for your turbine and pump; One that has straight blades, one with the blades cocked counter clockwise and one with the blades cocked clockwise. You also have a little adjustment with each stator as shimming it one way or the other will tighten or loosen your converter slightly. If your brave enough you can do some machining on the stator itself to change its characteristics. If you need more than a couple hundred rpm either way it’s time for a stator change. Some of those NHRA guys will have the converter out 3-4 times a weekend. The important thing to remember is you want to bring the input shaft up to the engine rpm, not the engine down to the input shaft.

    A little off on a tangent but still somewhat applicable here, Gale Banks has been doing a series on YouTube about rear end covers and their effect on bearing lube, which got me thinking about the work we put on the fluid and what we get back out of it. At the end of the day in a converter we are using the fluid to drive the car, there is no mechanical couple between the input shaft and the crankshaft like on a clutch. We have to use the fluid as efficiently as possible. If we don’t we are still doing “work” but we are not gaining anything and just generating heat, which was an issue in the article I linked below. I think the biggest misconception in torque converters is that converter slip is wasted energy and this is true in certain circumstances. So if your converter has more than 20% slip it is in torque multiplication mode, any less than that and it’s just slipping. So if your slipping 21-25% range out the back the converter could be considered more efficient because you are getting more out of it than you are putting into it due to the torque multiplication. If you are 18-19% your “wasting” power. That’s 18-19% that could be used to drive the car, so if we are down in the 2-5% range that could also be considered efficient.


    I linked an article about stator modification by a guy who is local to me and holds a couple automatic trans patents. The modification to the stator doesn’t really do what you might think it does. He’s a pretty sharp guy and thankfully I get to bend his ear from time to time:



    https://www.sonnax.com/tech_resources/64-myth-busters-i-performance-converter-modification
     
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