Convertor stall and you

[TylerZ281500]

whats stock stall on that truck? operating range is 2k+ ik go with something right around there but im also not a pulling truck guy so im of no help.

 

[brutpwr]

I'm not a truck puller either but I'd guess you need about 25% lower gear ratio.

 

[ROBERT McCORMICK]

stall is only one part, everything matters. tcs just built me a 2500 stall for my blown vortec, takes off pretty normal, little more rpm, smoother, lights tires easier, trans runs hotter around town and off road, add a cooler with fan on top of the two it may have, I run 3 and still get hot pulling sand hills wot lol. I'm running a bigger body billet single disk converter. I lock it up a little earlier in trans tune to keep mileage up hahaha, has plenty of torque, anyways talk to a couple guys a tcs in lake havasu they will steering you in the right direction, if you have the relevant information. Ill put it in for you and tune it. Torque converters are amazing tech choose wisely.

 

[GMTMark]

Brake stall only means some people own better brakes than others. True stall (bad description) only shows that if you lock the transbrake your motor has enough power to blow through the converter, false info. Shock stall is the only real test of stall. Also too many people over stall. Your shock stall should be about 1500 rpm under the shift point. If you can dyno your engine the shift point should be where the horsepower and torque lines intersect. If they intersect at 6500 rpm then your shock stall should be around 5,000. Most people can’t afford to do all the testing and changing involved to achieve this but the closer you get, the better performance you will have.

 

[Hipster]

Brake stall only means some people own better brakes than others. True stall (bad description) only shows that if you lock the transbrake your motor has enough power to blow through the converter, false info. Shock stall is the only real test of stall. Also too many people over stall. Your shock stall should be about 1500 rpm under the shift point. If you can dyno your engine the shift point should be where the horsepower and torque lines intersect. If they intersect at 6500 rpm then your shock stall should be around 5,000. Most people can’t afford to do all the testing and changing involved to achieve this but the closer you get, the better performance you will have.

Numbers on a dyno sheet always intersect at 5250 rpm. It's a division number used in the calculations. I could post 100 different dyno sheets from a 100 hp 4 banger to a 700 hp big block and the hp and tq curves will cross at 5250 on every one. Look at some actual dyno sheets. Dyno's measure tq then it calculated out to hp and the actual number used in the calculation is 5252.

Look at the 2 very different engines and where the hp and tq cross.

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[Erik the Awful]

Your shock stall should be about 1500 rpm under the shift point.

I don't think there's a good rule of thumb on this. It depends on the motor's torque curve. If your torque curve is broad, you'd be giving up performance. If you have a very peaky engine, this might work, but that's a very narrow rpm band.

 

[GMTMark]

It’s just rule of thumb. It’s hard to determine where to start for so many people.

 

[jgreen16]

Choosing the right stall converter for any particular combination has always been difficult for me to determine. Had many a built Pontiac 400 engines, and probably never had the right stall, LOL

 

[GMTMark]

It’s not easy at times. I bracket raced for almost 40 years and getting the stall speed to work right was sometimes a nightmare. BTE is local to me and so was TCI. I watched them build torque converters and only learned how much I don’t know .

 

[Supercharged111]

I don't think there's a good rule of thumb on this. It depends on the motor's torque curve. If your torque curve is broad, you'd be giving up performance. If you have a very peaky engine, this might work, but that's a very narrow rpm band.

There is and the answer is that it's vehicle dependent. First you need a Dyno that takes you a ways past peak hp. Next calculate your RPM drop for each shift. You're going to want to pick a shift point that keeps the area under the curve as high as possible so you produce the most power possible. This WILL take you past peak hp, shifting at peak hp is dumb and slow. Consider that, even though power is dropping after peak, you still have the mechanical advantage of being in a lower gear.