I've never quite managed to get my head around this one. At the moment I have a 1800rpm stall in my modded 700r4. I am finding that I am producing too much torque at take off to really handle so surely the last thing I need to be doing is increasing the stall speed with a new ctorque convertor?? The car will then be uncontrollable.

The ZZ4 peaks at 3000 rpm to 3500 (peak torque) so a 2800 stall would probably not be a good idea??

How would it feel different on the street with the higher stall? Would I notice a change in characteristics?

Cheers:lala:

 

A 2800 would be about right for your application.

The higher stall converter allows the engine to reach higher rpms quicker. In your case your engine starts to build power at 3000 rpm. With a 1800 rpm stall, the engine is lugging down below where it starts to build power. A higher stall converter just slips more at the lower rpms and allows the engine to climb to the rpms where the engine can use it's power better.

Driving on the street won't be that noticable. The rpms will be a bit higher and gas mileage will decrease. A converter with any stall higher than stock needs an external cooler since when it is slipping at the lower rpms it generates a lot of heat.

Even my race car's converter that I can stall with the transbrake to 5000 rpm can still be driven around the pits with no problems. I put it in first gear and have to hit the gas a bit before it will move.

A higher stall converter can help ET because the engine doesn't have to work so much in the low rpms getting to the higher rpms where it's more efficient.

You can think of ot as a standard transmission's clutch. With the same engine you wouldn't want to launch at 1800 rpm when launching at 2800 rpm will give you getter 60' times and ET. The torque converter works roughly the same way.

Once the engine reaches the converters stall speed the converter is transmitting power in close to 1:1. There is still usually some slippage of around 8%. That's why lockup converters are more efficient. Once out of first gear and the engine is near or over the converter's stall point the converter can be locked and doesn't slip.

 

Usually a higher stall always helps et until you get to about the 5000 mark. The to worry about on street car is what is it going to do to fuel economy and drivability. Just remember a 2800 stall converter is usually going to be running about that RPM down the road.

 

converters work by tq input,just because its a 2800 stall speed doesnt mean it will take2800 get it moving or will start to slip at cruise speed.At low input a 2800 will be noticeable but not unlivable, just a little mushy.

 

Thanks a million guys. I will put that on my wish list then and save for a Vigilante..

Man the modding bug never ends does it!