Got a build working and trying to understand the fine points of a torque converter and its relationship to a set up.
-My car came stock with a 2,400 stall speed torque converter. As I understand it the fluid impeller is lined in a 1:1 relationship with the motor in terms of RPMS. As the rpms increase the impeller spins and creates spinning force transferred to adjacent fins of a turbine (turbine is spun by the force of fluid transfer only and this generates the rotational force needed to spin the input shaft from the transmission?) a stator replenishes spent fluid back to the impeller in order to generate the torque as quickly as possible, close?

It has been suggested that I replace my converter with something of a higher stall (9.5CR 224/230 cam'd 350 w/3:73/2004r).

My understanding is that the stall rpm is the point at which the engine has generated enough force to create enough force in the TC to apply power to the transmission and accelerate aka "flash stall"

An upgrade in TC with a higher flash stall rating will result in the transmission receiving a more powerful initial load of force from the engine as the engine will be closer to it's optimal power band based (or so you hope).

Questions:
- Without running a built engine on a dyno how can one determine where the power band arcs?
- What are some negatives of moving to a TC that is rated 2,800-3k (on the low end of a rating)?
-If I'm running the aforementioned rear+27.5in tire+.67 final drive trans I should be about 2k @ 65 (internet calculators). 400 rpm less than my advertised stall, isn't that where you want to be?

Thanks
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You've got a pretty good understanding of how the torque converter works. Check out Wikipedia and do some Google searched to learn more.

One of the biggest misunderstandings of high-stall torque converters is that they slip completely below stall speed then grab hard above stall speed. It's a much more gradual progression. Also, the slippage is proportional to the resistance the converter sees. In other words, at cruise or even slow acceleration under light throttle, a high-stall converter really doesn't slip much more than a lower-stall one. It's only when you get on it that you see a noticeable rise in engine RPM before the rest of the drivetrain catches up.

Having said that, if you have your original stock Hurst/Olds converter, I'd stick with it. It should already stall a little higher behind your slightly built 350 than it did with the 307. Plus it has the lock-up feature, which is available but not as common on higher-stall converters. Give it a try. If your engine idles rough enough or feels lifeless off the line, you can always move to an aftermarket higher-stall.

My only concern is whether that stock converter will handle the additional torque of your 350. You'll have to get advice from someone else regarding that.

 

My only concern is whether that stock converter will handle the additional torque of your 350. You'll have to get advice from someone else regarding that.

I used a 4 cyl VEGA behind a 455 for many years, never had a problem raced 2 nights a week (test and tune on Tuesday and Friday night comp) plus was my daily driver..

Give it a shot, they do make a HOLE SHOT conv but not good for street use.

 

1BOSS83, I thought I had posted this chart previously but a quick search didn't turn anything up. Chart is very basic & generic but it might give you some additional insight. TCI and others offer toll free info & help, internet access to FAQ's, etc. and even a form to email in for recommendations. Good luck with your project!

 

Thank you sir, 2400 on the nose in my application.