Torque Converter Talk

chappy · Jun 25, 2012

Man I'm glad i'm not the only one dissapointed in a suncoast convertor. My truck wouldn't spool with a pmax. It was absolutely horrible to drive so a stocker went back in. Its good to see rcd is still having some love for these trucks.

Pizza pig · Jun 25, 2012

Jared @ River City Diesel said:
Greg.

My personal non vgt truck had an RCD spec 2200 stall converter with the billet stator. 64/71 with 190s was the pair. The truck lit much more responsibly than my buddies truck with a suncoast, it was slightly looser than stock, and was a blast to street drive. I wouldn't do it any other way if I had to, it made the non vgt more of a blast on the street.

Jared

Sent from somewhere away from my desk using magic.

Thanks for the input Jared, looks like you may have a call coming from me shortly.

Breaking Habits · Jun 26, 2012

pizza pig said:
Thanks for the input Jared, looks like you may have a call coming from me shortly.

Sounds good buddy. I spoke with Sean about trying out a different spec one like I had in my old 6leaker, hopefully one of these days he will. I know he's running a customer 1800rpm 6.0 converter with a powermax, stock injector truck and said it light stupid fast.

I wanna see THAT truck in person.

Mdub707 · Jun 26, 2012

Where's that torqshift engineer that's been floating around the boards, he's always good for some trans insight.

The RPM at which the converter stalls changes depending on mods on the truck too, something I never knew. Although, auto transmissions are like black magic to me.

Pizza pig · Jun 26, 2012

Jared @ River City Diesel said:
Sounds good buddy. I spoke with Sean about trying out a different spec one like I had in my old 6leaker, hopefully one of these days he will. I know he's running a customer 1800rpm 6.0 converter with a powermax, stock injector truck and said it light stupid fast.

I wanna see THAT truck in person.

Ill have to head over to Seans one of these days, maybe even talk him into letting me test that bitch out, its not like he doesnt have another truck to drive :hammer:

Mdub707 said:
Where's that torqshift engineer that's been floating around the boards, he's always good for some trans insight.

The RPM at which the converter stalls changes depending on mods on the truck too, something I never knew. Although, auto transmissions are like black magic to me.

Mark Kovalsky or something like that?

FaSSt9602 · Jun 26, 2012

Mdub707 said:
The RPM at which the converter stalls changes depending on mods on the truck too, something I never knew. Although, auto transmissions are like black magic to me.

Exactly...

I had a built 4L60E with a 2600 rpm stall in my 96 Impala SS. With a mostly stock car, it stalled at, or maybe just below 2600rpm. Once I built my 396 stoker for it (much higher HP), that same converter flashed to almost 3000rpm, which was actually better with my setup.

Not sure how that compares to the 5R, but food for thought...

Pizza pig · Jun 26, 2012

yep but take into account that diesels have a much smaller rpm range than a gas engine, so effects such as that wont have as much effect.

Keep up the info guys :gun:

Mark Kovalsky · Jun 28, 2012

Torque converter stall speed is just the highest speed the engine can turn the torque converter when the truck is kept from moving. It makes sense that if the engine makes more torque with the same torque converter the stall speed will go up.

That's about all I have to add to this thread. I don't have any experience with aftermarket converters, so I have no recommendation.

Mdub707 · Jun 28, 2012

Mark Kovalsky said:
Torque converter stall speed is just the highest speed the engine can turn the torque converter when the truck is kept from moving. It makes sense that if the engine makes more torque with the same torque converter the stall speed will go up.

That's about all I have to add to this thread. I don't have any experience with aftermarket converters, so I have no recommendation.

Even just reading that though, it really makes you wonder how they're rated right? I mean one torque converter would have two different stall speeds in two different trucks. It would almost need to be built per truck. Which I'm sure some guys will do, but it's kind of funny seeing a torque converter advertised somewhere with a specific stall speed on it...

Pizza pig · Jun 28, 2012

usually most converters are built for stock trucks, but beefed for towing, thats the way i look at it at least. Question is, how does one determine their stall speed? And when that stall speed is determined when the converter is built and put in the truck, does it stay at say 2200 rpm stall in a truck that needs a 2200 stall converter.
:jawdrop:

Mdub707 · Jun 29, 2012

Mark explained how to find the stall speed in another thread actually, but of course it has to be IN the truck to figure it out.

Pizza pig · Jun 29, 2012

Mdub707 said:
Mark explained how to find the stall speed in another thread actually, but of course it has to be IN the truck to figure it out.

Nothing like twice the labor. Im definitely going to be looking into testing the current stall im at with the stock converter as I dont plan on changing my truck up much (right now). I could have a converter built exactly to my specs, which would be nice.

Mdub707 · Jun 29, 2012

That's exactly what I was thinking, you already want one basically like you have right, just "beefier?"

Test yours and see what you get first I guess.

SootPowered · Jun 29, 2012

Another thing that plays a role in stall is tire size. I would take that into consideration when making my choices as well.

Mark Kovalsky · Jun 30, 2012

How so? How can tire size affect stall speed?

Pizza pig · Jun 30, 2012

Larger tires creates more rolling resistance. Therefore youre going to need more rpm to spin the tire. It changes the overal gear ratio. Then again I dont have any first hand experience and not much knowledge in that department, im just spit balling. Ill leave that to someone else:blitzed:

Mark Kovalsky · Jul 1, 2012

Tires have NO role in stall speed. None. Zip.

Pizza pig · Jul 1, 2012

it may not effect the actual stall speed, but it will determine the drivability of whichever stall you so choose.

Mark Kovalsky · Jul 1, 2012

I don't agree.

Stall speed should be determined by the engine torque curve. If you are using stall speed to tune the truck to tire size, you're using the wrong tool. Gear ratio is the way to compensate for tire size. Doing it with stall speed only will make the engine operate at an RPM where it isn't making enough torque.