Many vendors I see advertise that they can build a converter to stall at a certain RPM in your specific engine based on the inputs you give them about your setup. But does anything happen to how that converter stalls if the power were to say increase from that given engine?

For example, I am currently running an FTI 3600 stall in a 370rwhp LS2. How would how the stall flashes change if I were to install a stroker motor with a bigger cam and better heads that is pushing high 400s rwhp and rwtq? Would there be any changes to what RPM it would flash to or how much throttle input it would take to get it moving?

 

370rwhp to 400rwhp isn't much of a change,but the torque convertor characteristics is more dependent on torque figures. If the mods shift/change the torque curve,that would influence 'flash'.
'how much throttle to get it moving' is more dependent on the resistance of the vehicle. If the mods change the torque curve upward at midrange and lessen the torque at low range,a little more throttle(theoretically) would be required,but that 'little more' you might not even be able to sense/feel.
If I was changing from 370 to 400,I wouldn't anticipate feeling any difference in acceleration until it was in the 5000-6000 range.

 

I meant high 400s, as in 480+ and similar torque. I assume that's a bit more of a difference right going from 370 to 480?

And going to a 402 would increase torque throughout the range, which is why I asked how the stall would behave under a completely different engine.

 

Given the weight of the vehicle, gearing, ect remained the same, more power would mean a higher stall speed. For your example, approximately 100 hp increase could raise the stall 3-500 rpm.

-Brian

 

So basically it would act like a ~4000 stall? And if I wanted to remain with a 3600 I would have to have it stalled down to take into effect the more powerful engine?

Thanks!

 

Something along those lines. It's hard to say because everybody's setup differs in one way or another. I would keep what you have and see how you like it. My guess it will stall 3,842 rpm. Haha. If it's too loose for your taste, send it back for a restall.

-Brian

 

This all will depend on how you make your power.
If you only add airflow improvement at the top end,
the converter isn't really being given anything different
in the region where it's slipping and multiplying. But if
you add midrange torque, the picture would change a
fair bit. That's why nitrous converters are a different
sort of beast; have to handle much more torque at
the same-ish RPM and not slip right on past the shiftpoint.

 

My stall already flashed to ~4200, and I'm going from a bone stock lid/cat back LS1 to a H/C 408, so it could be near a 5000 after its all said and done?