HD727 Stock Torque Converter RPM?

[bigmanjbmopar]

Anyone know what the stock converter was rated at? Mine seems like 600 rpm

 

[Cranky]

Do you have a tach? Idle speed is generally higher than that....what does it come up to when you hold the brake and give it the gas? That's not the correct way to check the stall but it will give you an idea...

 

[70redbee]

As I have never had a stall converter, what is the way to check the stall speed. I would also like to know what flash is and how to shift with a stall. I am planning a 3500 stall and manuel reverse valve body in my build with a 727. Maybe Cranky could tell us exactly how a stall converter works. Thanks from someone who always had 4 speed trans. in the old days.

 

[70rr-brian]

Stall speed is nothing more than when the converter is fully engaged allowing all engine power to the wheels.

 

[bigmanjbmopar]

Give it the gas? lmao beans give me the gas lol It idles in drive around 400-550 roughly If I give it gas it will just smoke the tires and go to 5k well at least with my lead foot.

A trans shop seemed to think the stock stall was 1400 It feels like 600 cuz it surges like let me outta here now kinda thing, I am hoping to help my idle by installing a 1800 stall.

 

[70rr-brian]

Give it the gas? lmao beans give me the gas lol It idles in drive around 400-550 roughly If I give it gas it will just smoke the tires and go to 5k well at least with my lead foot.

A trans shop seemed to think the stock stall was 1400 It feels like 600 cuz it surges like let me outta here now kinda thing, I am hoping to help my idle by installing a 1800 stall.

You have a stroker do you not? Most converter manufacturers recommend converters based on cam lift specs. If you are laying down 500+ horse you need something more to hold it back. Like 3k as a starting point. Again, call any converter manufacturer with your cam specs and see what they say.

 

[bigmanjbmopar]

interesting...the cam did mention a 2000 stall. but I am trying to get just under that for a good idle. Still want to know what the stock stall is.

 

[Cranky]

It's been a lot of years but the way I was told was to run about 20 mph with the car in high gear, floor it while using the brake to keep the speed of the car constant and read the tach. That procedure was for a race car and manual shift VB. A street car will down shift so just holding your brake sitting static is probably the best way to check yours. Btw, even a stock converter will have a higher stall with an engine with higher HP than an engine with less HP....but if your cam card says it works best with a 2000, it's not a bad idea to use one with that much....and a converter shouldn't have much effect if any on your idle speed. Yeah, the idle will come down some with a tight converter but don't pick a converter based on how you want the car to idle....

 

[kllrbee]

If I had to guess, Id say stock was around 1600.
Of course, it depends on your motor.
Just curious, and maybe I missed it, but what cam did you go with for that big *** stroker? And what gears you running in that 8 3/4?
Finally, what are you looking to do with the car? Street? Strip? All out race?

 

[Budnicks]

Put you foot on the brake, watch the tach. hold the car hit the throttle see what RPM it flashes to, before moving the car or spinning the tires, that is your effective stall speed, more torque you have & more gear (lower) the less effect of the flash, you need a looser converter (smaller diameter higher RPM) with the steeper (lower) the gears to an extent, what is you freeway cruising speed, RPM wise, get a converter in that RPM range if your going to drive it on the street a lot... like someone else said earlier, call an expert in the field, Happy hunting...

 

[bigmanjbmopar]

See image, gears are 3:55 car is set up for street not strip not going to put a roll cage in her to run the 1/4 out here(infineon raceway) the rule is under 14 seconds you have to load up with safety etc. I'm not a racer but thinking about it is there a way to sand bag it? I guess the first time you go under 14 they give the boot! lol

If I had to guess, Id say stock was around 1600.
Of course, it depends on your motor.
Just curious, and maybe I missed it, but what cam did you go with for that big *** stroker? And what gears you running in that 8 3/4?
Finally, what are you looking to do with the car? Street? Strip? All out race?

 

[bigmanjbmopar]

Put you foot on the brake, watch the tach. hold the car hit the throttle see what RPM it flashes to, before moving the car or spinning the tires, that is your effective stall speed, more torque you have & more gear (lower) the less effect of the flash, you need a looser converter (smaller diameter higher RPM) with the steeper (lower) the gears to an extent, what is you freeway cruising speed, RPM wise, get a converter in that RPM range if your going to drive it on the street a lot... like someone else said earlier, call an expert in the field, Happy hunting...

I have noticed 2500 at around 55-60 not sure I just this 42 year old speedo but but close.

 

[70rr-brian]

My cam is a tad more radical than yours but it too is an extreme energy although solid.

.582 intake lift .588 exhaust and I run a 4k stall. I still have trouble with the 727 breaking 3.55's loose on take offs even before coming close to reaching stall speed.

I am guessing what about 490hpish? I would guess a good 2.8-3k stall for you. Anything less and you will be frying tires all the time and it will be a handful in turns etc when it breaks loose. If you go with something in the 1xxx range if I am guessing right on the HP then you better be good at muzzle control and making sure you have that thing pointed in the right direction when you accelerate.

 

[splicer]

Just a few thoughts....I have a little bit milder hydraulic(Extreme Energy), 505 stroker, 3:55 gears, and went with a 2400 stall converter.

Your motor makes bags of torque and the converter will probably actually stall a couple of hundred rpm higher than it's rating.Mine probably stalls at 2600 under full throttle...

I'm running M/T ET street radials and the car hooks up HARD, but has very nice street manners...

The higher you go with stall speed, the more violent the shock to the drivetrain under full throttle launch and the more tire you need to stay stuck......also more tranny heat...

Splicer

 

[bigmanjbmopar]

Well I going to see what the trans shop guys say about it, there may be more to the trans than meets the eye already. I'll let them take it out see what's happening and give me a recommendation, its probably going to be around 2l stall I'm sure. Got to wait till the money tree blooms again...

 

[lewtot184]

a stock 11 3/4" conveter (440 or 383 2bbl) will flash about 1600-1800rpm. a stock 10 3/4" converter (340, 383 4bbl, street hemi) will flash about 1800-2000rpm. there are variables to this. more low end torque will give a higher number, weight of car, gear, all that stuff. but, these numbers are fairly realistic. on my street cars i usually drive along about 25-30mph in high gear and mat it to check the flash. not real scientific but gets me close.

 

[splicer]

Not sure anyone has addressed this..but you seem to be expecting a better idle by increasing converter stall speed to 2100....Not going to happen...When you put it into drive from park, you're gunna see the same 100 to 150 rpm drop in engine speed with corresponding load on the engine.
That's the way my 2400 stall converter works...can't tell any difference in idle load from stock...

Splicer

 

[bigmanjbmopar]

Not sure anyone has addressed this..but you seem to be expecting a better idle by increasing converter stall speed to 2100....Not going to happen...When you put it into drive from park, you're gunna see the same 100 to 150 rpm drop in engine speed with corresponding load on the engine.
That's the way my 2400 stall converter works...can't tell any difference in idle load from stock...

Splicer

Then what could be causing the idle crash in drive? Especially when warmed up, bad timing?

 

[splicer]

I'm not sure what's happening...if I plug your cam into the Camquest program for my engine, I see the same idle characteristics and stall recommendations as the cam I'm running(21-224-4 Hydraulic).

What is your initial timing ? Are you running vacuum advance ? Timed port or full time vacuum ?

Our engines are similiar(505 Stroker) so let's see where setup differs...

Splicer

 

[bigmanjbmopar]

I'm not sure what's happening...if I plug your cam into the Camquest program for my engine, I see the same idle characteristics and stall recommendations as the cam I'm running(21-224-4 Hydraulic).

What is your initial timing ? Are you running vacuum advance ? Timed port or full time vacuum ?

Our engines are similiar(505 Stroker) so let's see where setup differs...

Splicer

Initial timing right now is 12 total is 34, mech advance no vacuum at all anywhere. Something is just not right some were, my crank gear for the chain and cam was set on at 4A mark in the gear. see if I can find a pic. I did not use any special guide or do any fancy settings when I installed the cam just put #1 at top and lined up the dots on the cam gear and crank gear put chain on and went with it. Now you got me wondering if getting a new stall is not going to work now??? dam...

Here is a thread on my distrib
http://www.forbbodiesonly.com/moparforum/showthread.php?t=22251


Here is the thread on my carb lol trying to put it all together
http://www.forbbodiesonly.com/moparforum/showthread.php?t=22529