Torque Converter Questionnaire/Laundry List

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340inabbody

340inabbody

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Just curious, if any of you guys know what specific questions (like a laundry list) the torque converter guys will ask me. I want to prepare before I talk to them having as much information as possible. I was wondering if anybody has gone through this process and has a list of all the specifics that are typically needed to spec out a converter for an application.
I’ve looked for this several places and couldn’t find anything exhaustive. If none really exist, maybe we can generate one here and compile it for future interest I understand that the more information we can provide the torque converter guys the better job they can do in developing one that will work optimally the first time.
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they'll ask the usual engine stuff: cam specs, compression, induction/exhaust
then they'll ask all the drivetrain stuff: trans (obviously), gear ratio, tire height, weight
if they don't ask you how you're going to use it, then i'd go with somebody else.

it's imperative that you're honest with them about the specs on the engine and the current drive train set up as well as how you are going to use the car. spec for a street/strip unit is very different for full race or something that you intend to put some mileage on.
 
Converter technology is light years ahead of what it once was. They can pretty much make the converter do what you want. Idle around town like stock, but flash to 5K on a hard launch if you want. Or anywhere in between.
 
Ok maybe we can break this down to 4 areas. Here is what I have off the top of my head. What else might they ask?

Engine:
1. Cam specifications
2. Torque/HP curve if available with AF
3. Vacuum at idle
4. Carburetor CFM
5. Fuel type
6. Lifter/Rocker type solid/roller flat tappet etc.


Car:
1. Weight
2. Tire height
3. Rear gear ratio
4. Suspension?

Transmission:
1. Automatic or Manual
2. Gear ratios
3. Shift kit


Usage:
1. Street/highway economy driving
2. Around town show off low end torque and burnouts show off
3. Performance street
4. Street 90% Strip 10%
5. Street 50% Strip 50%
6. Street 10% Strip 90% (don’t see why but…)
7. 100% Strip
 
I can't make it any plainer. Tell them what you WANT out of a converter and they'll do it. You gotta have some idea of how you want the thing to act, right? If you don't do that, you're gonna end up with someone else's interpretation of what's "right" for you. So think on it awhile.
 
they will want it know as much about your engine/trans, gear and tire size as you can give them.. and the biggest thing is intended use.. if not honest with it all there is a good chance that you may not be happy with the results.. call them and find out for sure what they wan tto know.. can always call back with correct information.
 
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340inabbody said:
Ok maybe we can break this down to 4 areas. Here is what I have off the top of my head. What else might they ask?

Engine:
1. Cam specifications
2. Torque/HP curve if available with AF
3. Vacuum at idle
4. Carburetor CFM
5. Fuel type
6. Lifter/Rocker type solid/roller flat tappet etc.


Car:
1. Weight
2. Tire height
3. Rear gear ratio
4. Suspension?

Transmission:
1. Automatic or Manual
2. Gear ratios
3. Shift kit


Usage:
1. Street/highway economy driving
2. Around town show off low end torque and burnouts show off
3. Performance street
4. Street 90% Strip 10%
5. Street 50% Strip 50%
6. Street 10% Strip 90% (don’t see why but…)
7. 100% Strip
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****, i didn't go into that much detail when ordering any of my converters over the years... with the one in the car now told them the basic combo, estimated weight of the car, gear ratio and that i wanted it on the tighter sider because its probably never gonna be raced but will be a cruiser.. stop over thinkng it and just call.. if they stump you on something hang up, find out and call back.. its really not that difficult.
 
I’m not trying to make this difficult. I’m trying to learn something and trying to gather my information before I contact them. I am at a slight disadvantage as I don’t know what cam is in there. That’s why I want to make sure I have everything else that I can possibly give them. I do know what I want. That’s not a question.

Not having the cam spec is an issue and it leads me to my second question. That is if I Dyno the set up and actually get a torque/HP curve is that actually better info than having the cam specs since it’s actual performance for setting the flash?

I will contact the converter manufacturer before I do anything that will cost money but wanted to learn from others here before I got on the phone with them.
 
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You must ask yourself the questions

How do you want the car to respond to the engine you built.

If you want the car to perform. The converter should brake stall at the operating RPM's of the cam you selected. I ran a 5500 tight with a 686 roller on the street. Worked great, I would never go anything lower then a 3500 for any performance application.

These cars stalled at around 3000 from the factory in 340 cars. All cars that come here for engines for the street get 3500's. Race motors 4500 -5500.

Ask anyone that owned a 4 speed car at what RPM did the launch their car from a dead stop for the best performance with a stock engine. Usually it was 3000.
 
I'm in a similar situation as the OP. I do not know what cam is installed in my 440 Duster only thing I know is it was built for the street not strip. Engine has not been run/broke in yet. It sounds like a 3000 stall would be about right for the estimated 425hp +- using a 727 trans, 3.55 rearend gear, and 28" tall tires.

One thing I'm confused about is using a non-lockup vs lockup converter. From, my research it seems like the lockup style will suit my use case, but unsure as both have plusses and minuses.

Sorry, did not mean to hijack the thread.
 

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Detail Specs​

Name
Email
Phone
Transmission Type Manual Automatic
Transmission Make
Low Gear
Input Shaft
Converter Bolt Pattern
Transmission Brake
Full or Pro Tree
Two Step RPM
RPM @ Shift Point
Expected Stall RPM
Ft Brake or Transmission
What Size and Stall?
Mid Plate Thickness
1/4 Mile or 1/8 Mile or Other
Altitude of Track
Make of Car
Weight of Car
Type of Rear Suspension
Engine Size
Bore
Stroke
Rod Length
Cylinder Heads
Compression
Intake Manifold
Carburetor CFM
Fuel
Nitrous
Supercharged/Turbocharged
Camshaft
Lift
Adv Duration
Duration @ .050
Rear End Ratio
Tire Height or Rollout
Tire Width
Average 60' Time
Avg 1/4 Mi ET & MPH
Other Instructions / Comments


These people make awesome converters, one of the best in the industry.
 
Mistabreeze said:
I'm in a similar situation as the OP. I do not know what cam is installed in my 440 Duster only thing I know is it was built for the street not strip. Engine has not been run/broke in yet. It sounds like a 3000 stall would be about right for the estimated 425hp +- using a 727 trans, 3.55 rearend gear, and 28" tall tires.

One thing I'm confused about is using a non-lockup vs lockup converter. From, my research it seems like the lockup style will suit my use case, but unsure as both have plusses and minuses.

Sorry, did not mean to hijack the thread.
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lock up and non-lock up transmissions are different, you can't make a non-lock up unit a lock up with a converter.
 
junkyardhero said:
lock up and non-lock up transmissions are different, you can't make a non-lock up unit a lock up with a converter.
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It's a standard rebuilt 727 with red clutch discs. It's still automatic, not mrvb. Not sure if it's a lockup or not? Is there anyway to tell?
 
Mistabreeze said:
It's a standard rebuilt 727 with red clutch discs. It's still automatic, not mrvb. Not sure if it's a lockup or not? Is there anyway to tell?
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run the #'s on the pan. lock up debuted in 1978

or, if you have the torque converter out: straight input, fully splined to the end is non-lock up. a stepped input with about 1/2" on the end machined and 23 splines is lock up.

hth
 
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