Help: How do I choose my torque convertor?

[kenny]

I think I titled it wrong the first time so I'm trying this again.
I'm hoping to get a response from the man himself on this one. I have been researching your topic board on the tranny 's all morning trying to figure out how to choose the right torque convertor for my application. A little more insight would be greatly appreciated on the manner in how they operate. I have somewhat of an understanding, but the tech from someone who really knows these units throughout would greatly clarify this for me. I'm planning on having the tranny done to a stage 4, but don't know how to choose a TC. I am currently running a hot tune, and I am in the process of procuring a TT kit in the future after the tranny gets done. Thanks again.

 

[Mike L.]

I think I titled it wrong the first time so I'm trying this again.
I'm hoping to get a response from the man himself on this one. I have been researching your topic board on the tranny 's all morning trying to figure out how to choose the right torque convertor for my application. A little more insight would be greatly appreciated on the manner in how they operate. I have somewhat of an understanding, but the tech from someone who really knows these units throughout would greatly clarify this for me. I'm planning on having the tranny done to a stage 4, but don't know how to choose a TC. I am currently running a hot tune, and I am in the process of procuring a TT kit in the future after the tranny gets done. Thanks again.

You're going to want a tight converter. Suncoast 1054 is one option and there will be a new one coming out from Precision in about a couple of weeks. it's being tested right now. Anything else will be too loose for what you have planned.

 

[kenny]

So now I'm curious to know what those numbers really mean Mike? Is it the stall speed that is being referred to? Just curious to know what you mean by tight? Is that when it shifts, and when you step into the throttle, the truck remains very responsive? Thanks again Mike.

 

[WolfLMM]

Tight= Good fluid coupling. The tires will feel more "connected" to the engine, when unlocked. A tight converter makes the truck feel more responsive.

 

[kenny]

Sweet! That is exactly how I want the truck to be. Thanks man.

 

[kenny]

I didn't know we had

So, I'm still curious to know how the sizes of the TC's compare to each other by what people have described of them. I'm under the impression that the 1054 is very tight and direct with the transfer of engine power to the ground, correct? How will this TC affect towing? So the higher TC's are mainly used for spooling on the line for take off? How do they operate under load once vehicle is underway? Do they also have a engaged feeling like as if you were in T/H mode? That is the way I would like the truck to respond and feel when engine power is applied. Again, thank you Mike for the technical insight. Thanks bro. On a side note, what kind of deals are you willing to work with me on to do my tranny to a level four?

 

[BIG DIPPER]

1054 is an awesome converter and would be great in an LBZ/LMM truck.

I have been testing/using a Precision converter and to the best of my knowledge is the one Mike will be trying here real soon.......it hasn't/won't be available to everyone as far as I know, but Mike could verify this.

 

[TrentNell]

a tight converter is a great thing if you have a turbo system that responds well to it . if it doesnt looser will feel more responsive . but standard twins/vvt truck will really like a tighter converter like the 1054 .

 

[dmaxvaz]

a tight converter is a great thing if you have a turbo system that responds well to it . if it doesnt looser will feel more responsive . but standard twins/vvt truck will really like a tighter converter like the 1054 .

SO, I'M screwed with the 1057 huh?

 

[TrentNell]

SO, I'M screwed with the 1057 huh?

no because the 1057 is a good match for your little turbo . as i stated just depends on the turbo system . elevation plays a role as well .

 

[dmaxvaz]

yeah, but the ihi doesnt spool quick. ihmo think its too tight

 

[TrentNell]

yeah, but the ihi doesnt spool quick. ihmo think its too tight

i cant say , spooling/converter feel seems to be very much a preference thing . pat ran a 1057 with his gt 42 and liked it . i ran a 1054 with my s300 , i thought it was way too tight the 1055 is way loose for my s300 and i love it... but others seem to really like the 1054 with there vvt trucks . the 1056 is the safest bet imop... felt very much like stock to me but held the power. worked well on my brothers truck with the IHI .

 

[malibu795]

i cant say , spooling/converter feel seems to be very much a preference thing . pat ran a 1057 with his gt 42 and liked it . i ran a 1054 with my s300 , i thought it was way too tight the 1055 is way loose for my s300 and i love it... but others seem to really like the 1054 with there vvt trucks . the 1056 is the safest bet imop... felt very much like stock to me but held the power. worked well on my brothers truck with the IHI .

and driving/tuning styles

1056 + IHI + 35"= really loose... on a launch on 1-2 and 2-3 my rpm drop less then 300rpm this also includ a TC lock shortly after 1-2 shift... this is form a stop to 68mph when i shift to 4th.

with out locking the rpms barely move between shifts ie less then 200rpm drops if at all.... and barely loads the trubo ~25psi of boost. to the full 32 the w/g is set at with the TC engaged

when towing~10k. it was easy to get up to 2000-2500rpm of the line when starting... i could easily stall it @ 2800-3000. IMO works very well in a T/H setup towing

persoanlly would like a tighter conveter...

i am far from knocking it... it is a very good all around convertor.

 

[BIG DIPPER]

Of course it will feel looser when you have 10k extra behind it as you will be creating more HP loading the motor.....all converters will react the same.

As far as the drop between shifts unlocked, remember you are dealing with a trans that has a minimum of 5 gears and a tight ratio....this isn't a 2 or 3 speed trans with the drop in RPMs of the days of old. The whole idea was to add gears and keep the truck in the power range more and this will make it tough to "fit" a converter, especially with the amount of torque these trucks make.

 

[TrentNell]

and driving/tuning styles

1056 + IHI + 35"= really loose... on a launch on 1-2 and 2-3 my rpm drop less then 300rpm this also includ a TC lock shortly after 1-2 shift... this is form a stop to 68mph when i shift to 4th.

with out locking the rpms barely move between shifts ie less then 200rpm drops if at all.... and barely loads the trubo ~25psi of boost. to the full 32 the w/g is set at with the TC engaged

when towing~10k. it was easy to get up to 2000-2500rpm of the line when starting... i could easily stall it @ 2800-3000. IMO works very well in a T/H setup towing

persoanlly would like a tighter conveter...

i am far from knocking it... it is a very good all around convertor.

good point about the tire size adam about changing stall speed . on the rpm drop ....with my 1055 i see a 450 rpm drop from gear to gear 1,2,3 & a 1000 rpm drop 4,5 , its not easy chosing a converter and to be honest i dont know much about it... just the ones i have used and driven on other trucks and how they felt .

 

[TrentNell]

Of course it will feel looser when you have 10k extra behind it as you will be creating more HP loading the motor.....all converters will react the same.

As far as the drop between shifts unlocked, remember you are dealing with a trans that has a minimum of 5 gears and a tight ratio....this isn't a 2 or 3 speed trans with the drop in RPMs of the days of old. The whole idea was to add gears and keep the truck in the power range more and this will make it tough to "fit" a converter, especially with the amount of torque these trucks make.

thats why you and mike are they experts . it is tuff finding the right converter , i think mostly getting a good answer of how the truck will be used and what the future mods will be . ask mike about how i have thrown him for a loop on the same subject :rofl: do you think he would have ever sold me a stage 3 if either one of us would have known what my plans were going to be

 

[Mike L.]

SO, I'M screwed with the 1057 huh?

See guys. This idiot cannot post tech.

 

[Mike L.]

Tight= Good fluid coupling. The tires will feel more "connected" to the engine, when unlocked. A tight converter makes the truck feel more responsive.

No.
Tight does not neccessarily mean good coupling. It depends on who builds it. Tight can mean low stall which is a machined down stator.

Tight means a lower stall plus quicker coupling and less tq mutiplication. Loose converter means a lot of slip and high stall and the turbine wheel sits still ( stalled ) and this allows the engine to create a lot of rpm without moving the truck. ( slip ) Torque multiplication is a controlled stall ( stator design ) designed to get a load moving and graudally start coupling ( less slip and more efficient ).

 

[malibu795]

Of course it will feel looser when you have 10k extra behind it as you will be creating more HP loading the motor.....all converters will react the same.wasnt saying that there was anything worng with that... just point it out

As far as the drop between shifts unlocked, remember you are dealing with a trans that has a minimum of 5 gears and a tight ratio....this isn't a 2 or 3 speed trans with the drop in RPMs of the days of old. The whole idea was to add gears and keep the truck in the power range more and this will make it tough to "fit" a converter, especially with the amount of torque these trucks make.

1-2 is a 42% drop
2-3 is a 23% drop
3-4 is a 29% drop
4-5 is a 29% drop

42% of 3500 is 1470 rpm drop.. 3500 to 2000 that is NOT a tight drop sir.
23% of 3500 is 750 rpm drop. 3500 to 2750 on a shift...

something here is not adding up for me... to me i shouldnt be seeing a stall rpm chang of some 700rpm..(.ie form 2200/2300 to 3000rpm) 2200rpm is about all i can get before the rear tires spin... yet cordign to the logs its it closer to 3,200rpm.. my thinking is stall is say 2500rpm.. my 1-2 shift @3500 1500rpm shift drop.. would pull the motor down to stall speed due to the mech gearing of a ~1500rpm drop.... but alas it doesnt it... dropped from 3500 to 3100rpm

i can tell you right now TC principle are the same.. be it any motor they are behind... example.. i have a B&M 2400 hole shot.. i have had 2 differnet motors in front of it... a 275hp 305(2300 stall) and a 450hp 383(~2500) stall on both these engine as with in 10% of each other.. once above stall speed you get in or out of the engine rpm change ~100-200rpms untill you feel back below stall speed. this includes shifting... if mech gearing goes below the stall engine drops to stall speed... or mech gearing IF rpm is above stall speed.
IE 2500stall 2000rpm drop shift at 4000rpm engine drops to 2500rpm being that stall is 2500rpm and fluid coupling cant not pull it down farther.
same 2000rpm drop shift at 5000rpm engine drops to 3000rpm

stall is dependent on tq of motor motor and were is falls in the rpm


not saying makeing a TC is easy at all... at more load to a turbo diesel get more boost make more power... all that the same X rpm... can be a PITA

IMO i agree twin turbo in future stay away from the 1056

need soemthing ALOT tighter then that to make use of it...the TT