Advice on torque converter and stall

[CZ-75]

OK, so I am ready to replace my FMX tranny with a wide ratio AOD. My intentions are a really nice drivable car that is a sleeper. What stall would you all recommend? The tranny guy is suggesting a 10 inch converter with a 2,800 stall. I am worried that may be a little too high.

What do you experts think?

 

[jbojo]

OK, so I am ready to replace my FMX tranny with a wide ratio AOD. My intentions are a really nice drivable car that is a sleeper. What stall would you all recommend? The tranny guy is suggesting a 10 inch converter with a 2,800 stall. I am worried that may be a little too high.

What do you experts think?

That is the same dilema I had. I went to various sources and the consensus came down to rear end ratio and cam used. My setup is a C6, 290 duration cam and 3.89 rear end and they all reccomended 2800 - 3000 stall. If I am not mistaken the Q coded cars had a converter with 2800 stall and it ran quite nicely. Unfortunately I haven't dropped this combo into the car yet so not sure how it will work.

-jbojo

 

[hyena429]

OK, so I am ready to replace my FMX tranny with a wide ratio AOD. My intentions are a really nice drivable car that is a sleeper. What stall would you all recommend? The tranny guy is suggesting a 10 inch converter with a 2,800 stall. I am worried that may be a little too high.

What do you experts think?

That is the same dilema I had. I went to various sources and the consensus came down to rear end ratio and cam used. My setup is a C6, 290 duration cam and 3.89 rear end and they all reccomended 2800 - 3000 stall. If I am not mistaken the Q coded cars had a converter with 2800 stall and it ran quite nicely. Unfortunately I haven't dropped this combo into the car yet so not sure how it will work.

-jbojo

Been alot of argument over the true stall speed of the little 10inch ford vert...I got my original stall in mine..And i have to admitt it turns into a diffrent car around 2800ish."but heads have a lot to do with that too".I heard anywere from 2200 too 3000...Ebay motor guide says 3,000...4v motors do love the high stall converter due to them large heads

 

[CZ-75]

I'm concerned about freeway speed RPMs. Here are RPMs at 70MPH (based on my 25" tall wheels) for my current setup (FMX with 2.75 rear end) and the wide ratio AOD with various rear ends:

FMX as is - 2,600

AOD wide ratio w/ 3.5 - 2,306

AOD wide ratio w/ 3.7 - 2,438

AOD wide ratio w/ 3.89 - 2,563

So, the 3.5 rear end will be the easiest on the motor, but with a 2,800 stall, the transmission is still slipping at cruising speed... or am I missing something? Seems like I would want a 2,000 - 2,400 stall, wouldn't I?

 

[Totalled]

2V or 4V? Lockup?

I put a 2,000 stall in mine, and I think it's a good compromise. It would have better off the line performance with the higher stall, but sucked to drive around with one.

A 2,000 stall would be plenty sporty for a 2V and make sure it has lockup for highway cruising.

Add an external cooler to the system too.

 

[Widowmaker00]

My car is a 4v and a 3000 rpm stall converter. It also has 4.11 gears though so it spends it's time highway driving well above that. I do have an external cooler also.

I don't notice any difference driving around town with a higher stall.

It seems by what you have said that a 2000-2200 rpm is what you are looking for, but there are people here that can steer you in a better direction than I can.

 

[CZ-75]

I have a 2V, and will be putting on a Performer Intake and 650CFM 4bbl carb.

I think I want a non-locking, which based on my research, it still "locks up" at stall setting.

 

[Widowmaker00]

http://www.dragzine.com/tech-stories/drivetrain/torque-converter-sizing-whats-right-for-me/

Just saw this article posted on my facebook. May be of some help.

 

[Mister 4x4]

I wish I knew more about what all the things like 'stall speed' specs actually mean. A torque converter is a torque converter, based on my limited knowledge. Having said that, I'll be using the one that came with my AOD, which is stock for an AOD-equipped '89 Mustang GT 5.0.

Is it the right way to go? Should I get something different? Beats me... I just know that the car it came out of drove in under its own power using the equipment I now have in my car. Makes sense to me that it should work just fine.

My point would be that a stock AOD torque converter should work just fine (again, based on my limited knowledge of torque converters).

 

[hyena429]

I wish I knew more about what all the things like 'stall speed' specs actually mean. A torque converter is a torque converter, based on my limited knowledge. Having said that, I'll be using the one that came with my AOD, which is stock for an AOD-equipped '89 Mustang GT 5.0.

Is it the right way to go? Should I get something different? Beats me... I just know that the car it came out of drove in under its own power using the equipment I now have in my car. Makes sense to me that it should work just fine.

My point would be that a stock AOD torque converter should work just fine (again, based on my limited knowledge of torque converters).

If you have big heads like a 4v cleveland or some raced out motor...You need a semi high stall or the car will fall on it's arse if you decided to punch the gas...Below from a stall site.

you need a converter with a higher stall speed so that you can launch the car in the “fat” or proper part of the engine’s powerband. If the stall isn’t enough, the car won’t be making optimum power when you launch and you’ll bog the car off the line. If your car’s set up is really mismatched, the motor may even want to stall whenever you shift into gear at idle. A higher stall speed converter will improve acceleration without having an accurate and precise engine peak torque rating, it is better to conservatively estimate the engine torque rather than overestimate it. Generally speaking, the desired stall speed of a converter should be around 500 RPM-700 RPM below the engine RPM at peak torque.

So if a cleveland hits around 3,000 Your stall should be 2300-2500 if she is stock...If your built more than stock..You need a bit more stall.

So, the 3.5 rear end will be the easiest on the motor, but with a 2,800 stall, the transmission is still slipping at cruising speed... or am I missing something? Seems like I would want a 2,000 - 2,400 stall, wouldn't I?

Normal driving is not affected by stall speed up to approximately 3000 RPM, particularly with a well built converter. A car will begin to roll normally when a higher stall speed converter used. Quick acceleration will be favorably influenced by stall speed. A very high stall speed (above 3000 RPM) would not be satisfactory for every day street use....A higher stall speed converter is simply less efficient at RPM’s below its intended stall speed. It will act quite normally for every day street use...According to the experts...But you do have to worry about heat in higher stalls...Oil cooler not a bad idea if you go this route.

 

[PAPPY HAROLD]

definitley not a pro but I think some things might be being missed. First I would check the cam specs, if you have changed it. Find out where the power band of the cam kicks in. and see what the mfg. suggests for stall speed. On mine comp said no less than 2800 stall. Next thing I'm curious about is the AOD, nothing wrong but in OD are you going to be slipping constantly, thats where the heat comes in that the guys are mentioning. Long trips would be hard on it.

As an example: mine is a big block and was set to be a low rpm mid range torque. Meaning Cam power band starts at 2500 rpm, torque right there too. 2800 rpm stall, everything hitting together and even thou I just recently got it running a few tests in front of the house says when it hits it hits and I should be towards the top of the converter at about 60 mph. But I don't plan on long trips.

 

[Mister 4x4]

And that's exactly why I'm sticking with the stock torque converter that came with my AOD - I plan on mostly cruising and daily driving. Having a high stall converter is better for "racing" type performance (launching, etc.), but I'd really hate for all that slippage and 'burning up' the torque converter to be happening while just driving to work and back.

Or maybe I'm missing it altogether.

 

[Bill73Ragtop]

When I built my 69 vert with AOD I went with an 1800 - 1900 stall converter with 3:55 rear end. It's just about perfect for takeoff and drive-ability. Engine is EFI 302 at 290 hp / 300 ft lbs. Nothing crazy, but very smooth with plenty of cruising performance.

 

[hyena429]

And that's exactly why I'm sticking with the stock torque converter that came with my AOD - I plan on mostly cruising and daily driving. Having a high stall converter is better for "racing" type performance (launching, etc.), but I'd really hate for all that slippage and 'burning up' the torque converter to be happening while just driving to work and back.

Or maybe I'm missing it altogether.

Thats fine if your runing a 2v motor with out alot of heavy mods.....1800 stall in AOD is not enough for most 4v motor's...the desired stall speed of a converter should be around 500 RPM-700 RPM below the engine RPM at peak torque..".Right stall for right build i guess" ... 4v cleveland don't get it on till around 2800-3000 for max TQ...Reason why all 4v auto cleveland come with such a small vert stock....Heck i drove mine for 18 years..Too school and too work all the time..Nothing but town driving all its life and never any type of real racing....Transmission still solid as the day i got her ...Original high stall vert still in it...outlasted the motor twice over....its around 2,200 or 2,300 im sure...If you don't have the right stall for your build...Your car will be hell at stop lights..Won't have a good launch...Will drop on its arse when you punch it at low rpm's...With right stall..You will not have that issue.

 

[droptop73]

Just another side to this discussion. "Loose" torque converters build heat in the transmission and heat can lead to transmission failure without a very good trans cooler.

 

[CZ-75]

Decided to go with a 12 inch inverter with a 2,200 to 2,400 stall, which should work better given my application.

 

[droptop73]

That is a good choice

 

[Mister 4x4]

And that's exactly why I'm sticking with the stock torque converter that came with my AOD - I plan on mostly cruising and daily driving. Having a high stall converter is better for "racing" type performance (launching, etc.), but I'd really hate for all that slippage and 'burning up' the torque converter to be happening while just driving to work and back.

Or maybe I'm missing it altogether.

Thats fine if your runing a 2v motor with out alot of heavy mods.....1800 stall in AOD is not enough for most 4v motor's...the desired stall speed of a converter should be around 500 RPM-700 RPM below the engine RPM at peak torque..".Right stall for right build i guess" ... 4v cleveland don't get it on till around 2800-3000 for max TQ...Reason why all 4v auto cleveland come with such a small vert stock....Heck i drove mine for 18 years..Too school and too work all the time..Nothing but town driving all its life and never any type of real racing....Transmission still solid as the day i got her ...Original high stall vert still in it...outlasted the motor twice over....its around 2,200 or 2,300 im sure...If you don't have the right stall for your build...Your car will be hell at stop lights..Won't have a good launch...Will drop on its arse when you punch it at low rpm's...With right stall..You will not have that issue.

Here's my dilemma: the stock AOD TC is 1800-ish (I believe). According to CompCams, I should expect around 400-ish from my 2V engine with the choices I've made (which I think is an over-generous estimate). My plans for the car are daily driver, with it seeing a good portion of the driving on a 'freeway' (65-70 mph). 65 mph in OD with 3.00:1 gears and 26"-27" wheels should roll about 1800-1900 rpm.

Do I care about launchability? Not really - I'm not planning on racing. So... why do I 'need' a higher stall-speed TC again, anyway? Seriously - I don't get it. You keep making arguments that support racing or launching (which is probably fine for CZ-75 - sorry to hijack the thread, Bro).

Here's my argument to sticking with the stock TC: Ford put this TC in an '89 5.0 Mustang GT - which was a pretty healthy machine, if I remember right. They never seemed to have issues 'launching,' , beating Camaros, doing burn-outs, or even just putt-putt-putting down the road as a daily driver. So tell me the benefits of a higher stall-speed TC "besides" standing on my brakes and running up the RPMs to 'launch' my car?

I'm not trying to be a douche, either. I just really am not getting it, I guess.

 

[Totalled]

Higher stall is fine, but you better get a lockup tc if you plan on freeway driving. Otherwise, the converter will be slipping to it's stall speed while in overdrive, and it will build heat and nuke the trans.