looking at a stall for a 6.0 and 4l80e set up, i plan on spraying right out of the hole, maybe a big shot even. below is the only converter yank lists for a 4l80e. i have a 4wd and will have an extremely strong driveline. would a higher STR help? that 2.10str seems kind of low. can they make it higher if i want and what would be the drawbacks?

YANK TRUCK THRUSTER 3200HD (6.0 and 8.1L with 4L80E trans) (258mm, 3200 stall, 2.10 STR) $950 This converter is for the Heavy Duty truck and SUV "hot rodder". It will allow over 3,200 rpm stall, with only a 1,700 rpm drop between shifts. This converter has a maximum recommended towing capacity of 4,000 lbs. Should you need to tow more, please consider the Truck Thruster 2600HD.

 

called yank, they said they can make any converter i want for the 4l80e, after asking a bunch of questions he sugested the pro yank 3400e, lots of starting line torque, easy daily driver, great nitrous converter.

i dont know crap about converters, anyone want to chime in here and help me be more sure about this decision?

 

Mike won't steer you in the wrong direction, he's the best.

For the nitrous you'll want a high STR, wich is probably one of the reasons he sent you in the PY3400E direction.

One question. In your post, you say you are building a 6.0/4L80E combo. But your sig says you have a 4.8. Am I missing something here?

 

i have a 6.0 and a 4l80e on the way right now, going to put in the the 03 RCSB, figured i should do a converter while i am at it.

 

parish 8,the PY3400E sounds like a great setup because the 4L80E has a taller 1st gear,you'll need a higher stall to launch the truck and the higher STR ratio will make the converter hit harder.I would definately consider going with at least a 4.10 rear end to wake up 3rd gear accellaration.

 

Mike gave you solid advise. I was at his place yesterday installing a new converter when you called. He can custom-build you a converter that will rock! The Pro Yank 3400 would be killer in your truck.

 

thanks for the help, proyank3400e it is then.

 

I thought that this might be of some interest to you guys...

From www.converter.com

STR has been talked and argued about for many years. The following information is what we at Precision Industries have found by doing our own testing to be helpful for you to try to understand this subject. Our competitors must have a crystal ball to figure the STR of their torque converters. There are a couple of companies in the performance torque converter business that do have the capability to test STR, MOST DO NOT! Precision Industries happens to be one that does have. Our test dyno has the capability to test from 200 ft. lbs. of torque up to 900 ft. lbs. of torque. The other companies use dynamometers that vary from 100 ft. lb. of torque to approximately 300 ft. lb. of torque. There is an old GM printed sheet that has floated around our industry for about 10 years showing the STR of stock GM torque converters that were built back then. Our competitors either use this sheet or are guessing because they have no way of knowing what the STR really is. They also advertise STR’s of 2.7, 2.9, 3.0, 3.2, etc. this is pure BS. All torque converter companies use the impellers, turbines and stators that come in the factory torque converters. In our tests we have never seen an STR over 2.55. Precision Industries do have torque converters with STR over 2.55 but these units have specially machined stators in them and are not worth the high cost for a street/strip application. If our competitors try to tell you differently just ask them to show you a picture of their test machine, not just a printout. The formula for STR is EXACT OUTPUT TORQUE ÷ EXACT INPUT TORQUE = STR. This requires a known power source and a data recovery system. STR is just what the name implies. The ratio of torque multiplication at stall. As soon as the turbine rotates (car moves) the ratio starts dropping rapidly until enough RPM has been reached for the ratio to drop to 1:1. The RPM that the ratio reaches 1:1 varies depending on other factors in and out of the torque converter such as impeller exit angle, stator design, impeller to turbine clearance, input torque (engine), etc. A fact that most everyone overlooks is that a torque converter does not make torque! It takes the torque the engine produces and multiplies it for a very short period of time. This is why some cars perform better than others with the same torque converter.

Some car enthusiasts put all kinds of money in the engine, transmission, torque converter, NOS, rear end gears, etc. then want to cripple the torque converter by lowering the STR to try and prevent wheel spin on take off. This is as foolish as pulling off one of the plug wires. Why don’t they finish the project and work on the rear suspension? Trying to tune your car by using STR is probably not very smart seeing how our competitors don’t have a clue about what STR their converters have, after all the stock torque converter you took out of your car has a STR of 1.9-1.94. The best way to get the right torque converter for your car is to buy it from a company that has a large database of previous sales for your kind of car. Then tell the sales person what mods you have made and what mods you intend to make and let that people help with the decision. The key words here are large database. The “Johnny come lately companies” have no large database or experience with what works with these late vehicles. Why try to reinvent the wheel with your hard earned money when there is bound to be someone in our database that has the same mods as you do and their torque converter/engine combination ROCKS! At Precision Industries we found out 10 years ago that STR is not the most important consideration when deciding on a torque converter it is the whole COMBINATION!

Thanks,
Mitch
FLP
630-820-9294 ext. 222

 

Nice one Mitch. My hat's off to you. Well said.

 

MITCH........
OK, what is the deal with Yank claiming to use a Multi-Million dollar GM Dyno to develope their converters?

 

highgear, he said, "There are a couple of companies in the performance torque converter business that do have the capability to test STR, MOST DO NOT!"

Yank is one of the few that does have the capability.

I would disagree with one statement above concerning using lower STRs for traction purposes being like pulling a plug wire. Adding slicks and drag race specific suspension parts are not something that everyone wants to do to their car nor is running less power (like pulling a plug wire) a suitable option. So, they are left with the choice of a car that is difficult to launch efficiently or they can use a softer hitting converter. A perfectly fine solution for some people, IMO. Pulling a plug wire will slow your trap speed. Using a softer hitting converter will not.

 

Mitch, i am a big fan of chucks transmisions and hope he will build a 4l80e for me prety soon here. seems like i have heard you and chuck dont care for yank converters.

since that brand i am looking at is there anything i should know that would make a diferent brand better?

 

TT on the question for mitch.