Stall specs

[D-MAX Mafia]

Finally going to upgrade my Alli to a stage 5. I'm having the converter built by a local company but I'm not sure what stall speed I should go with. I have a 4094AVNT turbo and from what I've heard it requires a looser converter than stock. What stall should I go with?

 

[Chevy1925]

Whos doin your trans here?

 

[D-MAX Mafia]

Building the trans myself. Rev Max Converters is building the converter. I know some guys over at w w williams, they are helping me with the build.

 

[TrentNell]

Building the trans myself. Rev Max Converters is building the converter. I know some guys over at w w williams, they are helping me with the build.

You dont really need a higher stall for the 4094 AVNT , but if it was my truck I would go with a 2200 stall , I like looser converters though especially because i am at higher elevation, and that is close to were the ML precision is at ( 2100-2200 ) , the safest bet would a 2000 stall , that would put it the same as a Suncoast 1056 and also consider with your bigger tires that will make a converter act looser than with smaller tires.

 

[D-MAX Mafia]

Thanks Trent!

 

[SgtKilroy]

Please forgive the ignorance, but could you guys pretty please explain to me what stall is and what it does for the truck? Sorry for the derail, just trying to learn. Thanks.

 

[hondarider552]

Good luck with WW williams Ben. I have not had good luck with them at my work.

Why are you having a converter custom built when there are plenty of them out there that have been proven?

 

[durallymax]

Please forgive the ignorance, but could you guys pretty please explain to me what stall is and what it does for the truck? Sorry for the derail, just trying to learn. Thanks.

Stall speed is the RPM for when the converter wants to "go", simple laymens explanation

or heres a detailed one from TCI

Stall speed --- the rpm that a given torque converter (impeller) has to spin in order for it to overcome a given amount of load and begin moving the turbine. When referring to "how much stall will I get from this torque converter", it means how fast (rpm) must the torque converter spin to generate enough fluid force on the turbine to overcome the resting inertia of the vehicle at wide open throttle. Load originates from two places (1) From the torque imparted on the torque converter by the engine via the crankshaft. (This load varies over rpm, i.e. torque curve, and is directly affected by atmosphere, fuel and engine conditions.) (2) From inertia, the resistance of the vehicle to acceleration, which places a load on the torque converter through the drive train. This can be thought of as how difficult the drive train is to rotate with the vehicle at rest, and is affected by car weight, amount of gear reduction and tire size, ability of tire to stay adhered to ground and stiffness of chassis. (Does the car move as one entity or does it flex so much that not all the weight is transferred during initial motion?)

Note: While referring to the resistance of the vehicle to move while at rest, the torque converter's stall speed and much of its characteristics for a given application are also affected by the vehicle's resistance to accelerate relative to its rate of acceleration. This resistance has much to do with the rpm observed immediately after the vehicle starts moving, the amount of rpm drop observed during a gear change and the amount of slippage in the torque converter (turbine rpm relative to impeller pump rpm.) A discussion involving how resistance to acceleration affects a torque converter involves more theory than fact and must involve all the dozens of other variables that affect rpm and slippage. The primary thing we want to remember about torque converter stall speed is that a particular torque converter does not have a "preset from the factory" stall speed but rather its unique design will produce a certain range of stall speeds depending on the amount of load the torque converter is exposed to. This load comes from both the torque produced by the engine and the resistance of the vehicle to move from rest. The higher this combined load the higher stall we will observe from a particular torque converter, and conversely, the lower the load, the lower the stall speed. Naturally, if the engine is not at wide open throttle we will not expect to observe as high a stall speed as we would under a wide open throttle.

Another point concerning engine torque is that we are only concerned with what we'll call the "relevant range" of the engine torque curve when discussing initial stall speed. This means if our particular torque converter chosen has a design that should produce a stall speed in a range of say 2000 to 2600 rpm given the application then we would refer to this as the relevant range of our interest in the engine's torque curve for this particular torque converter. In other words, only the torque characteristics of the engine torque in this rpm range will affect the amount of stall speed we actually observe. If we are using a high horsepower/high rpm engine that does not make much torque before 3000 rpm, it does not matter that the engine makes excellent torque over 3000 rpm if we are trying to use the torque converter in this example because its relevant range is 2000-2600 rpm and we would expect to see poor stall (2000 rpm or less) due to the poor torque produced by the engine in this range.

 

[SgtKilroy]

Wow, that's awesome info. Thank you!

 

[McRat]

I've run a lot of converters over the years. Many for testing-only, all of them raced.

Converters don't work the same way on diesels as they do on gassers.

If you disable the converter lockup on a Dmax converter, the stall is higher than 3000rpm, often higher than 4000rpm. But it "feels" like 2000-2500.

Why is this? Converters work off torque.

With a gas engine, the torque curve is almost flat. With a diesel, the HP curve is almost flat. In fact, the torque curve on a diesel falls at 2500, where the car engine climbs usually. This is generalization, but when you look at a bunch of car dynos and truck dynos, you see a trend.

In general, you want the tightest converter that will permit you to spool to your launch RPM under your weather conditions. If you race at 100 deg and 5000ft, you will need something different than at sea level and 70.

It's pretty expensive to test a lot of converters, but to get the best performance, you really need to get the converter right.

I don't remember which model is in Wendy, but that model is VERY good for 540rwhp and higher DA's.

Guys who have been around awhile might remember the "McRat" converter. This was good for a couple of tenths in the quarter over what was available at the time. They have improved since then.

 

[Mike L.]

Stall is tq multiplication. Our truck need it for the initial launch to spool the turbo. Fifty feet out of the hole the converter should start coupling hard. The converter should start trying to get to a 1.1 ratio ( which it cannot till TC lock ) asap as the turbo is now doing the work. Any tq multiplication after launch is useless in our trucks and the power goes out the tail pipe.
I like a slightly loose converter as it gives you more control during launch. It will allow you to launch easy at a lower rpm or hard.
Casper is a perfect example if you've ever watched Kat and Pat launch. They run identical times but Pat launches smoother and Kat blows off the line hard.
A tighter converter does not like coming out of the hole easy, and a little tricky but will blow the tires off when launched at the proper rpm and do well. Depends on the driver.
I allways had trouble launching a tight converter as I am too impatient at trying to achieve the optimum launching rpm.

 

[Mike L.]

Wendy is running the McRat converter which is a Suncoast 1057. Myself and Joe Webb and Ron at Suncoast with Pat came up with the 1057 in '05. It still is one of the best out there but pricey.
The Precision In. ML was built as a one off converter for Casper to replace the 1057 after some lazy launches at Las Vegas. I never knew it would be as good as it is.

 

[D-MAX Mafia]

Good luck with WW williams Ben. I have not had good luck with them at my work.

Why are you having a converter custom built when there are plenty of them out there that have been proven?

WW Williams isn't building my trans. They are restricted to Allison only parts and as far as I know have only built one after market trans before Allison shut them down. So if your having problems at your "work" its with stock trans. Also, I didnt know Discount Tire worked on transmissions? Lol!

The reason I'm going with a local company is because the price is good and they are proud to say their tc is 100% Made in the USA! If it doesnt hold up I will go another route. Plus if I do have problems they are only 20 minutes from the house. I'm gonna give them a chance to prove themselves. I have done some research and could not find one person that did not like their converter.

 

[hondarider552]

WW Williams isn't building my trans. They are restricted to Allison only parts and as far as I know have only built one after market trans before Allison shut them down. So if your having problems at your "work" its with stock trans. Also, I didnt know Discount Tire worked on transmissions? Lol!

The reason I'm going with a local company is because the price is good and they are proud to say their tc is 100% Made in the USA! If it doesnt hold up I will go another route. Plus if I do have problems they are only 20 minutes from the house. I'm gonna give them a chance to prove themselves. I have done some research and could not find one person that did not like their converter.

I quit discount because they wouldnt let me go full time, and treat their employees like shit. :thumb:

I work at Bartling enterprise in QC since last November. and that allions I had to pull was probably the one WW williams built, because thats where he told me where it was built.

 

[McRat]

Wendy is running the McRat converter which is a Suncoast 1057. Myself and Joe Webb and Ron at Suncoast with Pat came up with the 1057 in '05. It still is one of the best out there but pricey.
The Precision In. ML was built as a one off converter for Casper to replace the 1057 after some lazy launches at Las Vegas. I never knew it would be as good as it is.

The ML converter is very sweet with a big charger, and even spooled a GT45 single without issues to 1.5x sixty-foot times. Without nitrous assist. At the time, folk thought I was BS'g or running a bottle.

Converter choice is pretty critical with big chargers or high altitude. Too tight, and you're going home with 2.0 sixties.

1057 is a "stock charger" max effort converter. For bigun's, you need to loosen up.

 

[SgtKilroy]

This is why I love this forum. So much good info! Thank you Mike and McRat!
So basically, you get a target RPM you want to launch at based on your power output and traction that you want to hit for your stall speed when the converter locks? My understanding of converter lock is when the transmission is getting the power from the motor at that 1:1 ratio, and both halves of the converter spin at the same speed. "Tight" converters would lock up at a lower RPM, and loose, the opposite. Correct?
(This is why I'm getting my transmission from you, Mike! This stuff confuses the hell out of me.:hug

 

[Mike L.]

Converter lock is when the converter clutch applys. At that point the converter is nothing but a shaft and it doesn't matter who's converter you have. What matters it what happens before the converter locks.
A few years ago I was running a tight converter that came out of Guys truck. He hated it I installed a looser converter in his truck that couples fast and he loved it. I installed that converter in my '04 LB7 running a TTS extreme program. Every time I tried to launch it below 2200 rpm it would bog off the line. I finaly brought it to 2300 and it blew the tires off and jumped sideways, but it launched. I went back to a looser converter and was able to control my launches better. I am not saying you will be quicker with a looser converter; but I was and I have seen other that were also.
The key is to dial the converter to your setup like Pat said.

 

[SgtKilroy]

Gotcha. Thank you.

 

[duramaximizer]

That is my problem with the stock converter....or maybe not now. I had 3 wheel peel (I have 4 wheel now). Anything below 2300 on the stock converter, it would just bog out out of the whole and it made for poor 60' times. At 2300 or above I would blaze the tires away, so I went down in tire pressure. Down to 25 psi. That only created a limp on the big end.

At last, I am stuck with a junk trans and for now have given up on drag racing with my transgo.

I MAY try it one more time with a lighter smaller tire/wheel setup, and with my locker in the front now, I may be able to get off of the line at a more reasonable 35-40psi tire pressure and up the shift points. I maybe able to stop the limp.

For now my best is a 13.17 at 103mph. It was killing me I wanted a low 12, but the track was rotten and I couldn't get off the line at all. Any advise for this year, I'd appreciate it.

 

[Kat]

Casper is a perfect example if you've ever watched Kat and Pat launch. They run identical times but Pat launches smoother and Kat blows off the line hard.

That's because I don't have to fix stuff if it breaks :woott::hug::happy2:

Besides I have to keep of my reputation WWW :witch:

Pat and Robert still have replace the hitch I bent on Wendy from the last sled pull :baby: