[Mark 89 Mustang]

OK...so the stock AOD converter stall is about 1700...you drive down the road at 2,000 rpm and here that nice Flowmaster tone. What happens if you change to a 2600 stall converter? Can you still drive the car at 2000 rpm? What is going on when you are in OD at 70 mph and 2000 rpms? How do you drive a car at a RPM lower than the stall rpm? Does the lock up function have something to do with it?

Can you tell I am new to automatics?

 

[That_Is_My_El_Camino]

A 2600 RPM stall converter doesn't mean that it won't move until you hit 2,600 RPM. It means (and I'm not 110% certain but I am pretty confident) that the converter slips (doesn't transfer every revolution from the engine to the transmission) up to around 2,600 RPM. How much it really slips and where it stops slipping is really dependent on your setup. So yes, you can still drive the car at 2,000 RPM, it will just slip more than a stock converter.

And as far as I know, the AOD converter locks up (meaning no slippage) in overdrive.

 

[ceyko]

The overall explainations I received match El_Camino's as well. Very good questions too IMO.

 

[Mark 89 Mustang]

Any other explainations? Please.

 

[propellerhead]

I've been wanting to read up more on higher stall converters. All I know is you can hold your brake and bring the RPMs higher during a launch. I'm not sure how yet but I guess it allows more slipping.

I really want to know too how it behaves under normal street driving.

... subscribing.

 

[Jimbo]

Understand that just because you bought a "2500rpm" stall converter doesn't mean thats where it will brake stall or flash. Every car is different. More torque will stall higher, as will the same combo in a heavier car.

 

[SSMAN]

Understand that just because you bought a "2500rpm" stall converter doesn't mean thats where it will brake stall or flash. Every car is different. More torque will stall higher, as will the same combo in a heavier car.

Jimbo is correct. In the older days ( and still stands true in some instances), it was based on a chevy motor producing 230 ft/lbs of torque as to what stall speed you had. The more torque straight out of the hole.........the more stall. If you get a 2600 stall and you will be cruising at 70 mph at 2000 rpm............then you will only be approx 90 percent efficient on your torque convertor. ( this is just a swag ) There will be some small amount of slippage when under the stall speed. If you do a lot of highway driving then the stall is going to wear on your clutches in the tranny and cause excess heat. I have a 2700-3000 stall in my car. At 70 mph I am at 3300-3400 rpm. I was looking to go to the 3500 stall and was advised that it may or may not lock up and it would cause more wear. Its also good to run a trans cooler on top of your factory one. The cooler you keep your tranny..........the more life you will get out of it.

Best way around it...............get your 2600 stall, and put 4:10 gears in it. You will really like it then.

 

[ceyko]

SSMAN, great explaination and it really helped clear some confusion for me. Sounds like a stall might be better saved for a car that is always on track duty. 2600 max if a DD. My understanding is that tranny coolers are good no matter what.

Take care!

 

[SSMAN]

SSMAN, great explaination and it really helped clear some confusion for me. Sounds like a stall might be better saved for a car that is always on track duty. 2600 max if a DD. My understanding is that tranny coolers are good no matter what.

Take care!

Your right............tranny coolers are good for all tranny's. But.......4:10's and that stall would make all the difference in the world on that car. You would be happy. Find out from some on who has 4:10 gears with an AOD and what rpm they are at on the highway. It should be close. And your right..........DD........2600 would be about right. Good luck. Oh and just to clear up some confusion.............normal city driving...........you really can't tell you have a stall. You only know it when you nail the shit out of it.

 

[propellerhead]

I know the 4r70w in my 2004 GT locks in 3rd and 4th/OD under certain conditions, under the control of the computer. One test I read and tried was to cruise steadily around 50 MPH and tap the breaks lightly with your left foot without moving your right foot off the gas pedal. You should see and hear the RPMs go up a bit, which is an indication that the transmission was locked and now went back into slip mode. (I know I'm butchering the technical terms here.)

Would the computer not be able to lock the transmission with a higher stall converter? Would the computer need to be reprogrammed to take advantage of the higher stall?

 

[SSMAN]

I know the 4r70w in my 2004 GT locks in 3rd and 4th/OD under certain conditions, under the control of the computer. One test I read and tried was to cruise steadily around 50 MPH and tap the breaks lightly with your left foot without moving your right foot off the gas pedal. You should see and hear the RPMs go up a bit, which is an indication that the transmission was locked and now went back into slip mode. (I know I'm butchering the technical terms here.)

Would the computer not be able to lock the transmission with a higher stall converter? Would the computer need to be reprogrammed to take advantage of the higher stall?

Good question...................Now your into computers.............I am useless. The computer in my car is fairly simple

 

[Nate]

why do you see all those fast ls1's running 4400-4600 stalls then.

 

[SSMAN]

why do you see all those fast ls1's running 4400-4600 stalls then.

The CROW is running a 3800 and doing quite well

 

[propellerhead]

I've been reading a lot on torque converters. It seems most are intended for race applications and above 3000 seems to be the favored one. I haven't come across any that are built and meant for street use.

I'll keep reading but at this point it seems like I should just wait until my car's purpose shifts from daily driver to weekend track car, and get 4.10s along with a higher stall converter.

 

[ceyko]

pphead,
I think you have the right idea as far as I know. However, the bump up to 2600ish is intended as an upgrade for us AODE guys. Basically, 2600 if you need it for a DD, want to improve your times and mainly do red light to red light showing off. The higher stalls are not very DD friendly.

4.10s, with or without the stall man. However, since your car is white it is slower...you may wish to use 4.30s. haha jking.

Take care,

 

[mikeb]

In the older days ( and still stands true in some instances), it was based on a chevy motor producing 230 ft/lbs of torque as to what stall speed you had. The more torque straight out of the hole.........the more stall

Chevys

Actually, this is right - a lot of mainstream converters are rated with the SBC in mind. But, there are a lot of other factors to consider - engine torque and RPM range, car weight, converter diameter, and rear gearing come to mind.

I bought a TCI "super street fighter" 10 inch 4200 stall converter. My bird weighed 3600 with me in it, and I had 3.55 gears and > 500 ft/lbs torque. I "drove right through" that converter - i'd almost redline as soon as I stabbed the gas. The converter basically cried uncle since the load I was putting on it effectively made it stall far higher than 4200 rpm. I was getting > 20% slip at the end of the 1/4 mile. It was the wrong converter for my car, but would work nicely behind a high winding SBC in a lighter car (anyone need a slightly used TCI converter for a TH350-TH400? )

Now i'm running an 11 inch JW 3400 stall converter. It feels like it would be an excellent street converter (for my car) and I don't drive through it on the launch. It doesn't seem "loose" at all driving around in the pits.

My suggestion would be to talk to people running a similar combo as yours, and chat up the tech line at some converter companies.

Also, very important - you get what you pay for in the converter world. Cheaper is most definitely not better. Expect to spend a few hundred on a quality street/strip converter.

 

[propellerhead]

A Google search on "choosing high* (torque or stall) converter" returns many good links to read.

My car might be slower but I get to drive it everyday. Hahaha!

 

[ceyko]

My car might be slower but I get to drive it everyday. Hahaha!

-gives middle finger-
----------------------------------------

Speaking of cost...that is one thing you don't see much of. How much is something like this isntalled? I'd assume you would not throw it on a stock AODE, you'd need to make the tranny be able to handle more abuse. Anyway, this tranny work seems like an easy 2-3K investment. A good one, but a big one.

Take care,

 

[White90GT]

I've been through a few converters. Stock with the AOD, then when I built a motor for it, went with a Precision Industries (www.converter.com) Stallion 2800 rpm converter. It hit right close to 3000 rpm behind a 347 with heads/cam/intake, etc... and cut 1.61-1.63 sixty foots n/a on average. I then switched to a C4 transmission by Performance Automatic and a PA 3000-4000 rpm 10" converter. That converter hit about the same as the PI converter 3000 or so and the car sixty foot 1.60, but picked up some ET due to the lighter weight transmission and less rotational mass.
Recently with my current 347, I switched to an 8" Trans King converter. When I first got it I was told it hit at 5000 behind a 600+ horsepwer mod motor car on nitrous and that it should be something around 4200 behind my motor. Not the case, on the dyno I stabbed it to the tune of 5200 rpms before settling down and pulling to the 6250 rpm rev limiter. That converter was awesome for 60 ft, but it slipped a lot on the big end of the track getting me a 1.54 sixty foot and [email protected] I pulled it and had it tightened up and now I think its hitting around 3500 or so (will found out on the dyno tonight). The car has run 1.59 sixty foot and [email protected] mph with the re-stalled 8". Tonight I'm going to get a chip to bypass the factory rev limiter and then do some more track tuning to see what I can get out of it. If I can't get it down to 11.1x range then this converter may come out in favor of having my old 10" PA converter re-stalled and put back in. The 10" converter is way more efficient on the top end. With this 8" converter, on the nitrous I hit the rev limiter at the 1000 ft mark and only trapped 121mph off the gas, with the old one the car trapped 126mph under the factory rev limiter.

So that said, a 10" 3000 stall would actually be totally streetable. With the 10" in the AOD, it really felt like a stock converter when daily driving, but would annhilate the tires at WOT. With the 8" converter I have now, it feels pretty loose and revs on up over 2000-2200 or so to really get moving easy from a light.

 

[SSMAN]

If you want first hand answers..........Drive to Midlothian to Hobarts Performance. He makes convertors there. He will explain every step and show you by taking a convertor apart.

Even though he did not fix my rear end............I would still recommend him for convertors.