Converter Stall Calculations and or Calculator

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340inabbody

340inabbody

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Looking for a definitive way to determine the correct stall for a given application.

If (and I don’t) had every piece of information about the application of my car how exactly does one calculate the correct converter stall RPM?

I have searched the web only to find lots of companies making broad suggestions based on differing variables some being quite sympathetic. Others just being vague as to how they come to a particular stall speed. Seems like it's more experience and tribal knowledge than a mathematical approach as I cannot find any equations or calculators to play with.

Since I don’t have some of the information I need like cam specs I want to do some what if’s but ca not get any solid methodical way to run the what if scenarios.

Thanks for reading.....
 
Is it a small block? Get a 3500 tight. That will work with any street performance motor pretty well. Unless you put the car or Engine on a Dyno there is no math to get there. Only Guesses. Usually a 3500 behind a big block will stall at 3400 -3500. I had one go to 3800. Put that same converter behind a small block and you'll get 3000 -3100. That is what I found when playing with a big block to small block truck same converter 3500. they both had 471 lift cam's in stock hp engines, Now those were the numbers on my engines . don't hold me to that . Get a cheap 3500 tight and throw it in. if you don't like it they are easier to sell than the lower stalls. Once you drive it you will like it unless you are towing a trailer with weight or if you don't like tire spin.
 
I make 525 hp and 552 tq at the flexplate. Big block car, Car is 3100 lbs 3300 with me in it. I have a 10" TCI 3500 stall, it flashes to 4000 with all that torque, yet drive like a regular torque converter on the street, doesnt make a lot of heat. For a small block i would go with a 9" unit, call a Converter company and have them pick something for you? Do you know your aprox HP and TQ. weight of car .
 
Give Lenny at Ultimate Converters a call he'll tell ya' and build ya' exactly what you need..
 
Fisher said:
I make 525 hp and 552 tq at the flexplate. Big block car, Car is 3100 lbs 3300 with me in it. I have a 10" TCI 3500 stall, it flashes to 4000 with all that torque, yet drive like a regular torque converter on the street, doesnt make a lot of heat. For a small block i would go with a 9" unit, call a Converter company and have them pick something for you? Do you know your aprox HP and TQ. weight of car .
Click to expand...


That 4000 flash out of a big block with torque is about right The brake stall should be around 3700. . I use a ATI 8" 5500 tight behind a small block. Foot braking above idle it leaves at 5400 It is a 416. shift light is set at 8000 the recall is 8300. car weighed 3650 with him in it. 10.688 @ 128. high elevation track. The car was good for a cruise. I had it on a 4 laner once . that was pushing it with 456's at. at 55mph the tach was at 35-37 the tires were 29's.



You can here the motor had a lot more to go in drive. I love listening to that video so I loaded it again. Its all I have until I get it back together. Video's! That was with mufflers and tail pipes with the spare and jack in the trunk. He said he was listening to the stereo on the return lane.
 
Oldmanmopar said:
That 4000 flash out of a big block with torque is about right The brake stall should be around 3700. . I use a ATI 8" 5500 tight behind a small block. Foot braking above idle it leaves at 5400 It is a 416. shift light is set at 8000 the recall is 8300. car weighed 3650 with him in it. 10.688 @ 128. high elevation track. The car was good for a cruise. I had it on a 4 laner once . that was pushing it with 456's at. at 55mph the tach was at 35-37 the tires were 29's.



You can here the motor had a lot more to go in drive. I love listening to that video so I loaded it again. Its all I have until I get it back together. Video's! That was with mufflers and tail pipes with the spare and jack in the trunk. He said he was listening to the stereo on the return lane.
Click to expand...


It will live again!
 
Guys I am asking about how I can run numbers (of variables everyone asks me abut that I don’t have like cam profile and exact compression ratio) and look at what if scenarios to see what stall numbers come out. Just so I can learn how those variables are used. There has to be a reason I am asked about CR, Cam Profile car wt diff ratio tire size etc. How are these numbers used? I get the feeling it’s mostly opinion based on experience and not a calculated estimation ....too much or too little stall leads to power loss efficiency and heat. Just wondering if there is a calculator to plug these variables into.......

That being said I probably will go with your recommendations that is a 9” or 10” 3500. After I get my 3:55’s in.

I see 3500 stall converters like $500 to $800 which is not what I call cheap.

@Oldmanmopar what is cheap and what is the source?

Car is my 1970 Plymouth Sport a Satellite has a big cam 340 high rise M1 manifold Holley 3150 650 DP and A904 trans. Long tune headers with glass packs. Estimated weight is 3200lbs. Unknown cam and CR. Tires are 15” an are total 25” diameter. HP/TQ estimated? You tell me.....
See it run here
 
HAHAHA. $500-$800 is cheap, a good race converter will run you at least $1500.00 but i have seen them knock 3-4 tenths off a guys time slip. I am glad i am done with the car hobby and have moved on.

Nice car by the way, motor sounds very healthy. The 3.55 gear will be ok with a 26-27 inch tire.
 
340inabbody said:
Guys I am asking about how I can run numbers (of variables everyone asks me abut that I don’t have like cam profile and exact compression ratio) and look at what if scenarios to see what stall numbers come out. Just so I can learn how those variables are used. There has to be a reason I am asked about CR, Cam Profile car wt diff ratio tire size etc. How are these numbers used? I get the feeling it’s mostly opinion based on experience and not a calculated estimation ....too much or too little stall leads to power loss efficiency and heat. Just wondering if there is a calculator to plug these variables into.......

That being said I probably will go with your recommendations that is a 9” or 10” 3500. After I get my 3:55’s in.

I see 3500 stall converters like $500 to $800 which is not what I call cheap.

@Oldmanmopar what is cheap and what is the source?

Car is my 1970 Plymouth Sport a Satellite has a big cam 340 high rise M1 manifold Holley 3150 650 DP and A904 trans. Long tune headers with glass packs. Estimated weight is 3200lbs. Unknown cam and CR. Tires are 15” an are total 25” diameter. HP/TQ estimated? You tell me.....
See it run here
Click to expand...


And your question has been answered. "That's not how it works" Read post #2 again. That's the correct answer.
 
RustyRatRod said:
And your question has been answered. "That's not how it works" Read post #2 again. That's the correct answer.
Click to expand...
Yup I just did. Ok so no calculations or direct use of any specific numbers. All your experience here and that from guys at the converter shop Lenny is where I will get my direction since I can not analyze myself.
@Oldmanmopar has some very good advice from his swapping the same TQ in several applications.
 
340inabbody said:
Yup I just did. Ok so no calculations or direct use of any specific numbers. All your experience here and that from guys at the converter shop Lenny is where I will get my direction since I can not analyze myself.
@Oldmanmopar has some very good advice from his swapping the same TQ in several applications.
Click to expand...

Well......Lenny or "whoever" that's an expert in the business. I would certainly pick Lenny out as "one of the best". If and when you call him, don't leave anything out. From everything in the engine from carburetor to oil pan, to car weight, gear ratio......you name it. The more info you give him, the better answer you'll get.

Lastly, don't be afraid of a high flash converter. You can have a converter made nowadays that is tight enough to have good cruise lockup but have the ability to flash to 5500 if that's what you need. The days of the "slipping converter" are over.
 
RustyRatRod said:
It will live again!
Click to expand...

340inabbody said:
Guys I am asking about how I can run numbers (of variables everyone asks me abut that I don’t have like cam profile and exact compression ratio) and look at what if scenarios to see what stall numbers come out. Just so I can learn how those variables are used. There has to be a reason I am asked about CR, Cam Profile car wt diff ratio tire size etc. How are these numbers used? I get the feeling it’s mostly opinion based on experience and not a calculated estimation ....too much or too little stall leads to power loss efficiency and heat. Just wondering if there is a calculator to plug these variables into.......

That being said I probably will go with your recommendations that is a 9” or 10” 3500. After I get my 3:55’s in.

I see 3500 stall converters like $500 to $800 which is not what I call cheap.

@Oldmanmopar what is cheap and what is the source?

Car is my 1970 Plymouth Sport a Satellite has a big cam 340 high rise M1 manifold Holley 3150 650 DP and A904 trans. Long tune headers with glass packs. Estimated weight is 3200lbs. Unknown cam and CR. Tires are 15” an are total 25” diameter. HP/TQ estimated? You tell me.....
See it run here
Click to expand...


340inabbody said:
Guys I am asking about how I can run numbers (of variables everyone asks me abut that I don’t have like cam profile and exact compression ratio) and look at what if scenarios to see what stall numbers come out. Just so I can learn how those variables are used. There has to be a reason I am asked about CR, Cam Profile car wt diff ratio tire size etc. How are these numbers used? I get the feeling it’s mostly opinion based on experience and not a calculated estimation ....too much or too little stall leads to power loss efficiency and heat. Just wondering if there is a calculator to plug these variables into.......

That being said I probably will go with your recommendations that is a 9” or 10” 3500. After I get my 3:55’s in.

I see 3500 stall converters like $500 to $800 which is not what I call cheap.

@Oldmanmopar what is cheap and what is the source?

That

Car is my 1970 Plymouth Sport a Satellite has a big cam 340 high rise M1 manifold Holley 3150 650 DP and A904 trans. Long tune headers with glass packs. Estimated weight is 3200lbs. Unknown cam and CR. Tires are 15” an are total 25” diameter. HP/TQ estimated? You tell me.....
See it run here
Click to expand...


That Satellite sounds real good. Like horses in gallop. What is the idle and how much does it drop in gear.

As far as Tight and loose. A tight converter will lock up a little sooner for a street-able Flare A loose converter you will have to use higher RPM's to move the car around and better for use of a trans brake. My cam operating torque range is 4900-7900 The car leaves at 5000 foot braking it @ 2000 The lower your initial RPM the higher it flashes. The cam I have is not that large for a naturally aspirated car It idles at 1500 drops to 1400 in gear. Timing is all in at idle. Here is what it idles like.



And in gear it is about the same .

The guys on the video were doing underground cable. They all had super fast hondas by mouth. I left them talk . I couldn't take it any more, So I sneaked next door and brought it over. I never told them I had it when they were bragging about the White Honda. I surprised them. They sent me the Video

 
Oldmanmopar said:
That Satellite sounds real good. Like horses in gallop. What is the idle and how much does it drop in gear.

As far as Tight and loose. A tight converter will lock up a little sooner for a street-able Flare A loose converter you will have to use higher RPM's to move the car around and better for use of a trans brake. My cam operating torque range is 4900-7900 The car leaves at 5000 foot braking it @ 2000 The lower your initial RPM the higher it flashes. The cam I have is not that large for a naturally aspirated car It idles at 1500 drops to 1400 in gear. Timing is all in at idle. Here is what it idles like.



And in gear it is about the same .

The guys on the video were doing underground cable. They all had super fast hondas by mouth. I left them talk . I couldn't take it any more, So I sneaked next door and brought it over. I never told them I had it when they were bragging about the White Honda. I surprised them. They sent me the Video

Click to expand...


I remember when you did that. LOL
 
Oldmanmopar said:
That Satellite sounds real good. Like horses in gallop. What is the idle and how much does it drop in gear.

As far as Tight and loose. A tight converter will lock up a little sooner for a street-able Flare A loose converter you will have to use higher RPM's to move the car around and better for use of a trans brake. My cam operating torque range is 4900-7900 The car leaves at 5000 foot braking it @ 2000 The lower your initial RPM the higher it flashes. The cam I have is not that large for a naturally aspirated car It idles at 1500 drops to 1400 in gear. Timing is all in at idle. Here is what it idles like.



And in gear it is about the same .

The guys on the video were doing underground cable. They all had super fast hondas by mouth. I left them talk . I couldn't take it any more, So I sneaked next door and brought it over. I never told them I had it when they were bragging about the White Honda. I surprised them. They sent me the Video

Click to expand...

Love that video! Its priceless!! My idle darn near drops off about half from 1100 rpm in park and 550 rpm in gear and needs just a bit more rpm to idle better. I think more timing will help but that’s really the main gripe I have. Will a stall converter affect this park to in gear transition at all? Automatics is a new world to me as I have only had 4 speed cars.
 
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340inabbody said:
Love that video! Its priceless!! My idle darn near drops off about half from 1100 rpm in park and 550 rpm in gear and needs just a bit more rpm to idle better. I think more timing will help but that’s really the main gripe I have. Will a stall converter affect this park to in gear transition at all? Automatics is a new world to me as I have only had 4 speed cars.
Click to expand...


Yes it will . If I were to put this in gear with a low stall it would kill the motor. You put a 3500 in it or if you can get a hold of a factory 10'" from a 340 or even an old 68-71 Hemi . It will wake your car up. I have a factory 340 I use to show guys what a 3000 works like in their cars . I put it in two cars already for friends to try. They both bought converters very quickly . They could not believe the difference. Timing drop off is should be 20 degrees @ idle its 35 total @2500 RPMs with no vacuum advance . If your cam is bigger than 470 lift .

Did you ever hear a motor go up and down in gear that is because the advance springs are to weak and the timing is going in and out. take out the heavy spring and add one light spring and it will hold the timing until around 2500 on a factory distributor. You will have to weld the slots up to shorten the with of the curve. Weld the inside will tighten the springs, Weld the outsides will loosen them. For a street car the looser the springs the quicker it will go to its total. The slots are 1/2 " make them 3/8's this will give you 20 degrees of travel. If you want it to come in after starting use two light springs. This will allow the motor to start and go to total at idle. A medium and a light it will go to total @ 2500.

My car starts at 14 degrees before TDC and the MSD digital 6 unit puts it @ 34 degrees when it reaches 800 rpm's. It idles @ 1500 in nuetral. My dist. is locked. the box does the advance for you.. 20 is the number for movement. That is why it is built into these new digital boxes they are all in a 800 rpm's. Idle @ 15 degrees and all in at 35 degrees. The magic number is 20 degrees. the rpm it comes in is @ 2500 for a street motor. A big cam motor all in @ idle right after it starts.
 
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340inabbody said:
Looking for a definitive way to determine the correct stall for a given application.

If (and I don’t) had every piece of information about the application of my car how exactly does one calculate the correct converter stall RPM?

I have searched the web only to find lots of companies making broad suggestions based on differing variables some being quite sympathetic. Others just being vague as to how they come to a particular stall speed. Seems like it's more experience and tribal knowledge than a mathematical approach as I cannot find any equations or calculators to play with.

Since I don’t have some of the information I need like cam specs I want to do some what if’s but ca not get any solid methodical way to run the what if scenarios.

Thanks for reading.....
Click to expand...
I don`t think it`s rocket science. Just match ur convertor stall speed and cam !
 
There is a rough guide based on camshaft duration.
i think one of the cam manufacturers had it on their website.
 
340inabbody said:
Guys I am asking about how I can run numbers (of variables everyone asks me abut that I don’t have like cam profile and exact compression ratio) and look at what if scenarios to see what stall numbers come out. Just so I can learn how those variables are used. There has to be a reason I am asked about CR, Cam Profile car wt diff ratio tire size etc. How are these numbers used? I get the feeling it’s mostly opinion based on experience and not a calculated estimation ....too much or too little stall leads to power loss efficiency and heat. Just wondering if there is a calculator to plug these variables into.......

That being said I probably will go with your recommendations that is a 9” or 10” 3500. After I get my 3:55’s in.

I see 3500 stall converters like $500 to $800 which is not what I call cheap.

@Oldmanmopar what is cheap and what is the source?

Car is my 1970 Plymouth Sport a Satellite has a big cam 340 high rise M1 manifold Holley 3150 650 DP and A904 trans. Long tune headers with glass packs. Estimated weight is 3200lbs. Unknown cam and CR. Tires are 15” an are total 25” diameter. HP/TQ estimated? You tell me.....
See it run here
Click to expand...

I really don't care who you purchase your converter from, so long as it's a reputable converter company. Buy direct from the builder of the converter rather than one of the many outlets you can get them from. I've said in other posts I've done, that while the person behind the counter or on the phone at these outlets can sell you many items the company stocks, he/she typically has limited knowledge on performance converters, while the converter builder has years of experience building converters.
If possible, get the car on a dyno and find out what your engine is actually putting out horsepower and torque wise. A lack of this type of information makes it very difficult for any converter builder to build you what your car needs stall-wise.
Don't let price be your guide line in making your purchase. I've seen enough in-expensive converters apart to tell you, "you only get what you pay for".
As for the 340 or hemi converters, that is might be a good starting point. There is an issue though in making that decision. The 340 Duster I bought brand new had an 11" converter in it(called a 10 3/4" by Chrysler), and I've never seen a true 10" diameter factory 340 converter. The stall speed on at 340 converter is factory rated at around 2300-2400 rpm, which as I recall was about what my Duster stalled at. It was a stock 340, with 3:55 rear axle ratio.
When I worked in the industry, any hemi converter was always a custom build(no core stock because of the rarity of the hemi), and usually while there might have been a 340 converter in stock, we wouldn't release them until we knew the customers core was a true 340 converter.
I don't envy your position. As mentioned by others: Not enough or too much stall will not give you what you're looking for.
JMHO
 
Call Lenny, one of the best calls ive ever made.

Great video oldman!

That was priceless!
 
I've tried searching for definitive answers as well without much luck. Unfortunately it's not similar to figuring out which head gasket to use to achieve a certain compression.(0.023" vs 0.038" vs 0.045"). Which is computable as long as you have the majority of the measured variables.
AND friggin torque converters have no markings/ratings that I have seen. So a lot of trial&error=experience and $$.
 
4spdragtop said:
I've tried searching for definitive answers as well without much luck. Unfortunately it's not similar to figuring out which head gasket to use to achieve a certain compression.(0.023" vs 0.038" vs 0.045"). Which is computable as long as you have the majority of the measured variables.
AND friggin torque converters have no markings/ratings that I have seen. So a lot of trial&error=experience and $$.
Click to expand...

Yeah.....I plan to work with Lenny directly and have one made if he feels the information I can provide is sufficient. I was just hoping to be able to gain some insight myself but it seems that there are too many variables and loosely correlated math where experience is what links everything together. Going with a reputable and knowledgeable manufacturer seems like the only way to go......
 
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