driving with different stall speeds?

[Glenwood]

Maybe a dumb question, but I've never had a decent performance muscle car, just old junkers I pieced together when I was young and poor. Now that I'm old and poor, I'm slowly working towards building my car to perform as an old muscle should, at least in my mind. I know there are nearly endless combinations, so what I really want to know is what do your cars drive like at different stall speeds? Where is the line between good off the line torque and comfort?
My 64 Polara being a convertible will never see a race track, so street use is all I'm after, but I want it to feel like it will pull hard when I step on it.

Soon, I will need to select a cam for the 426 (413 bored) and possibly a new 19 spline TC, but I have no idea what driving a car with say 2000 stall vs say 3000 stall feels like on the street.
I sort of jumped the gun and decided on 3.55 rear gears which I am having installed at present, but I think it is still a reasonable ratio for street and occasional highway use.

 

[Darter6]

Good call on the gears.Truth be told you will never see much difference between a 2K to 3K converter on the street under normal driving.My 65 Belvedere has a 28-3K converter in it and is very streetable ride.

 

[dan juhasz]

Stick with realistic cam profile with a heavy car and you really won't need a high stall converter.

 

[Johnny Mac]

And when you're ready for a converter, you call a reputable converter MFG, like Hughes, or ATI, etc...and give them your complete vehicle specs. everything from cam profile, to tire size, and weight.

This way its matched to YOUR car, and it's not just "close enough"

An unnecessarily high stall will just build excessive heat on the street, as the converter is slipping until the stall speed is reached.

Its a 2 way street.
The higher the stall speed, the more the engine winds up before attempting to move the car, thus putting more power to the ground for launches
But..that also means cruising at 2500 RPM, with a 3000 stall conveter...that you're "slipping" to a degree and building unnecessary heat.

Getting a matched converter helps find the "sweet spot" so you get a snappy launch, and good cruise characteristics

 

[mmissile]

PTC convertor. Mr. Ford is the man to talk with.

 

[super-bee_ski]

Stick with realistic cam profile with a heavy car and you really won't need a high stall converter.

Go for Torque.....
Keep the power between 1,600 RPM and 4,000 RPM

As far a Torque convertors go:
Simple explanation is If you put your foot on the brake and rev the engine, a 2,000 Stall will allow the wheels to "break free" and spin at 2,000 RPM.
(You can sit there and "light up the tires without rolling the car forward)
A 3,000 RPM stall or Torque convertor holds the "spinning of the tires back until the RPMs are at 3,000 RPM.

 

[Glenwood]

At represent, my pb 727 is being rebuilt and the stock tc is being tweaked but they say the most they can get out of it is around 2200 to maybe 2400. I hadn't thought about wheel size and heat. Great points!
Although there aren't many 19 spline to select from, i may still buy new instead of the old one. Is it too backwards to select a cam based on already having this tc and gearing?
I guess it depends on what I'm trying to achieve with the engine build.
Sorry for my noobness, trying to sponge all of this stuff up into my grey matter as i move from metal fab to mechanical fun.

 

[Johnny Mac]

Go for Torque.....
Keep the power between 1,600 RPM and 4,000 RPM

As far a Torque convertors go:
Simple explanation is If you put your foot on the brake and rev the engine, a 2,000 Stall will allow the wheels to "break free" and spin at 2,000 RPM.
(You can sit there and "light up the tires without rolling the car forward)
A 3,000 RPM stall or Torque convertor holds the "spinning of the tires back until the RPMs are at 3,000 RPM.

Foot-brake stall, and advertised flash/stall rating are not the same thing. The example you're giving would be how to determine stall, only if locked in "3rd" when the transmission is in a 1:1 ratio.
If you're sitting at a red light and mash the throttle, the RPM will flash to actual stall speed, then boom, off we go.
If you're sitting at a redlight in 1st, trying to do a burnout, a 3000 flash converter will NOT footbrake to 3000. If it does..you're 3 quarts low on trans fluid.

 

[Sweet5ltr]

Maybe a dumb question, but I've never had a decent performance muscle car, just old junkers I pieced together when I was young and poor. Now that I'm old and poor, I'm slowly working towards building my car to perform as an old muscle should, at least in my mind. I know there are nearly endless combinations, so what I really want to know is what do your cars drive like at different stall speeds? Where is the line between good off the line torque and comfort?
My 64 Polara being a convertible will never see a race track, so street use is all I'm after, but I want it to feel like it will pull hard when I step on it.

Soon, I will need to select a cam for the 426 (413 bored) and possibly a new 19 spline TC, but I have no idea what driving a car with say 2000 stall vs say 3000 stall feels like on the street.
I sort of jumped the gun and decided on 3.55 rear gears which I am having installed at present, but I think it is still a reasonable ratio for street and occasional highway use.

Honestly, what you're asking is a very difficult question. I can tell you one thing however, you do get what you pay for. PTC, ATI, TSI, and FTI; all leaders in converter manufacturing. I had a 3.4k TSI 10" F/I converter, that allowed more slippage down low than my current 5k FTI 9" N/A converter. Both of these converters drove like stock, meaning they allow very little slippage down low and on the big end, but as soon as an ample torque load is applied (nailing the throttle) they flashed right to their respected stall speeds. You don't want an incredible amount of overlap, choose a camshaft with 110-112 LSA, find one that offers the most lift per given duration, meaning best power -under the curve- (Check Lunati Voodoo series, developed by UDHarold) and others. You will sacrifice very little actual HP and make buying the correct converter, that much easier. You will be happy with a 3,800-4,000 stall for your intended purpose, just install a large tranny cooler and fan setup. Take a look on Racing Junk or Moparts for a 9-10" converter as they are swapped often and sold for 1/2-1/3 of what they cost new, please just don't purchase one of those Saturday Night Special converters from the Summit catalog. The torque converter is literally one of the most important aspects of any performance build.

Another B-Body with FTI 9.5" 4k converter

 

[Glenwood]

Thanks for the replies. I realize my question is subjective to individual driving style which makes ot kind of tough to answer. Just trying to get a sense of how a car feels with different stall speeds and I guess different cam and gear/wheel combos. All of your replies are quite helpful!

 

[super-bee_ski]

QUOTE="super-bee_ski, post: 910610129, member: 5102"]Go for Torque.....
Keep the power between 1,600 RPM and 4,000 RPM[/QUOTE]

Foot-brake stall, and advertised flash/stall rating are not the same thing. The example you're giving would be how to determine stall, only if locked in "3rd" when the transmission is in a 1:1 ratio.
If you're sitting at a red light and mash the throttle, the RPM will flash to actual stall speed, then boom, off we go.
If you're sitting at a redlight in 1st, trying to do a burnout, a 3000 flash converter will NOT footbrake to 3000. If it does..you're 3 quarts low on trans fluid.

Thank you for the correction Johnny Pace
Yes: You are correct!
(I was trying to keep it very basic for "O.P.")

 

[Darter6]

Johnny Pace hit the nail on the head.So many variables, all has to be accounted for...And don't be cheap.It is worth it to have a converter built to your needs.

 

[68gtxman]

After rebuilding my 440 and using a Mopar Performance cam (484/484 280) that said to change to a 2,800 stall speed TC, I didn't. It drove fine on the street! Then I bought a MP high stall speed TC (2,800 rpm) and had it installed. It did do better under high acceleration take-offs (not often on the street), but now I can't drive it on the highway without it overheating due to the excessive heat from the slippage. Stick with the stock TC if you are driving on the street. I'll probably switch back to stock myself.

 

[Glenwood]

After rebuilding my 440 and using a Mopar Performance cam (484/484 280) that said to change to a 2,800 stall speed TC, I didn't. It drove fine on the street! Then I bought a MP high stall speed TC (2,800 rpm) and had it installed. It did do better under high acceleration take-offs (not often on the street), but now I can't drive it on the highway without it overheating due to the excessive heat from the slippage. Stick with the stock TC if you are driving on the street. I'll probably switch back to stock myself.

Do you have a trans cooler?

 

[68gtxman]

Do you have a trans cooler?

Yes, a nice double unit setup. I have it inline before the radiator. I added it before the TC change and it solved my overheating problem until I changed to the higher stall speed TC.

 

[Darter6]

How deep are your gears ?

 

[68gtxman]

How deep are your gears ?

He said 3.55.

 

[67Charger]

And when you're ready for a converter, you call a reputable converter MFG, like Hughes, or ATI, etc...and give them your complete vehicle specs. everything from cam profile, to tire size, and weight.

This way its matched to YOUR car, and it's not just "close enough"

An unnecessarily high stall will just build excessive heat on the street, as the converter is slipping until the stall speed is reached.

Its a 2 way street.
The higher the stall speed, the more the engine winds up before attempting to move the car, thus putting more power to the ground for launches
But..that also means cruising at 2500 RPM, with a 3000 stall conveter...that you're "slipping" to a degree and building unnecessary heat.

Getting a matched converter helps find the "sweet spot" so you get a snappy launch, and good cruise characteristics

Truth told right there. My '67 is a relatively high power (647HP/687lb.ft) 496 stroker that at one point had 4.10's and a 5k stall converter in it. Stupid fast off the line, but doing 65 at 3400 rpm or so, if I hit the gas moderately quick, the converter would still flash up to nearly 4000 as it accelerated. Fun, but lots of heat and very inefficient. When I went to open road racing, I changed to 2.76's and had COAN build me a converter with sustained high speed in mind. I can (and do) hold the car at 140mph at 4900 rpm for nearly 100 miles and be running under 200° trans temp, slipping under 2%. It will still flash to 3000 off the line, but the converter WORKS because I worked with them to get hte right one for the car.

 

[Darter6]

I'M sorry, My question was for you 68gtxman,What gears are in your car ?

 

[Photon440]

Although there aren't many 19 spline to select from, i may still buy new instead of the old one.

If the transmission is being rebuilt anyway, why not have a newer 24 spline input shaft installed and have the choice of more modern converter options?