Just curious if changing from a stock converter to a 'towing' type, does that add more torque to the wheels, or does it just help keep trans fluid temps down?

 

A high stall TC of any type allows the engine to spin more rpms for a given load or road speed and that will put more torque to the ground but it also increases fuel consumption and heat generation.

 

But the towing converters are usually lower stall. That will lower the RPM at a given load or road speed, reduce heat, and lower fuel consumption.

 

Lower than stock? There really isn't any room to go lower is there? My old F150 would run away if I set the idle speed too high which to me suggests the stock converter "stalled" at 800-1000rpm. And of course that is ignoring the lockup function which occurs in the higher gears, that bypasses the TC action altogether and an aftermarket converter won't change that unless you make the mistake of buying a converter that doesn't include a lockup. I guess stall speed could be different for the different transmissions.. I have never owned an E4OD truck.

 

Stock stall speed is around 2000 RPM. I've never seen a converter with a stall speed as low as 1100 RPM. Your higher idle doesn't mean that's the stall speed.

 

2000rpm seems a bit high to me, I'm sure if I stood on the brake with the motor in gear I couldn't make it turn 2000rpm. But who knows.. I'll have to try it out and see for myself. If it really does stall at that speed then yeah lower stall speed could help some or hurt.. depends upon the motor in question. For example there's no point to try and make a 4.6 or 5.0 pull at anything below 2000rpm.. there just isn't any output down there worth talking about, but if you got a big block or diesel motor then sure.

 

I don't care if it seems high to you. And maybe your's can't get there, your engine could be weak.

I know what the factory spec was, I was there. And I tested many of them when I worked there. Ford always seems to want the stall speed at 2000-2200, except for diesels, which were also too high at 1900-2100.

 

Hey Mark.. I'm not calling your experience into question I consider you an expert on this topic, just trying to understand if there were differences and if I am totally wrong on the main question here then that's fine. So are you saying TC stall speed was the same for all transmissions? I have owned AODs, C6s and now a 4R70w and have driven some E4OD trucks, of all those the C6 and E4OD did seem to have a looser TC than the AOD trucks. Although thinking about it if one were driving around in stop and go traffic using the bottom ratios only the engine typically turns about 2000rpm give or take unless you get going fast enough for the lockup to engage. And yeah I'm aware the AOD functions totally different than the electronic transmissions but "lockup" doesn't happen in 1st or 2nd with any of them IIRC.

 

OK.. so looks like the TC in my van will flash to to somewhere around 2000rpm if I hold the brake and goose the throttle, so call that settled and lets go back to the OPs question.
Would a towing torque converter with a lower stall speed be of any benefit? Like anything I guess it depends, it depends upon the motor in the truck and the trans too of course and how the truck is used. With a big block or diesel it would be beneficial overall but there is no point trying to make the 5.0 operate below 2000rpm.. it doesn't make any usable power down there. And the trans will have some effect too, the C6 doesn't have a lockup so the lower stall will be effective at reducing rpms in all gears which can help fuel milage. With the AOD it will only be a benefit in the first 2 gears, once it hits 3rd the torque converter is bypassed so it won't matter. With the other 2 electronic 4speeds it will primarily benefit the lower two gears but the computer does unlock the TC in some situations in the top gears too.