? on stall speed.

[JDSfastGN]

I have a 9/11 converter in my dads 86 GN. The converter was said to be a 3000 stall but after power braking and getting to about 3 lbs of boost it was at 3400 and the tire broke loose(peg leg lol). anyways my ? pertains to how engine output affects the stall speed. The car right now has heads/cam, 50# injectors ATR headers, full exhaust etc... but is still on the stock turbo/intercooler for a short while. Is the stock turbo being on there why the converter stalls at 3400 or would it still stall around 3400 if say i put a PT61 turbo on there? Im just trying to get an idea as i know every car and every setup is different but i don't want to go too big with the turbo and have a mismatched combo. Thanks for any help or ideas.
J.D.

 

[JDSfastGN]

anybody ?

 

[Zoliaster]

From my understanding, (keep in mind that it is very limited understanding!), stall speed is rated at a specific torque. So say for example your converter is rated 3000 rpm stall at 400ftlbs of torque if you put that converter on a car that makes 500ftlbs of torque the converter will stall a little higher. If the car makes too much torque for the converter it will run through it.

My guess is if you put that 61 one on it will still stall at 3400 or maybe even a little higher if you could keep the wheels from spinning.

HTH

 

[chris718]

jd that info is usually only true if the brakes can hold the engine torque which is never the case with these buicks under boost unless its got a brake.the engine power is not stifled by the load placed on the converter pump that turns with the engine verses the converter turbine which moves and loads the turbine shaft as a result of fluid leaving the converter pump that is sent to the turbine and after flow is interrupted by the stator as it is sent back to the pump when stationary will the stator multiplies engine torque by changing the direction of the oil flowing from the turbine back to the pump .this in turn increases the leverage sent to the turbine assisting it in rotating .if the brakes are not overpowered by additional output and the final drive additional power allows the engine to reach higher rpm under stall because of its ability to overpower hydraulic resistance and the stators assistance.