Converter Opinions

[coldLBZ]

I have a 2006 LBZ with a SCIV and a 1056. When cruising at part throttle with the converter unlocked it seems kinda loose to me. At 40 mph if I go WOT the RPM will climb to about 3000 and stay there until the converter locks at about 70 mph. I am running a stock turbo, and a PPE 160 tune currently. I want to try the ML converter because I read somewhere on here that it has a stronger fluid coupling. Would the stronger fluid coupling make the converter feel tighter before it locks, and maybe keep the RPM down and help the truck pull better? Take it easy on me as I don't know too much about this. Thanks.

 

[1chevy02]

I really like the fluid coupling of the ML Precision on my lb7. Friend of mine had one in a lbz and it was flawless as well.

 

[Mike L.]

You have other problems. lock up will not change with converters. Talk to your builder.

 

[THEFERMANATOR]

You have other problems. lock up will not change with converters. Talk to your builder.

I think he's trying to say it feels to loose when it is unlocked, but is fine once it locks up. If that is so, then I think you'll be happy with an ML. I know mine couples NICELY, and I don't normally get a big RPM drop when it locks up as it couples so efficiently even after almost 20K miles of useage.

 

[coldLBZ]

Thanks FERM, that's what I was getting at. I am wanting a tighter converter since I'm with a stock turbo. Sorry for the confusion. And my truck does the same thing as turbojamie's truck in this thread: http://www.duramaxdiesels.com/forum/showthread.php?t=27528&page=1
I figure I might as well change the converter since the trans may have to come out anyway, possible flexplate issue.

 

[[email protected]]

I have a 1056 too and I can't really remember how the stock converter is. I feel like mine is too lose and dosent have the coupling it should on my stock LLY with a 500hp tune.

It seems really bad when it is at cruse in 5th or 4th and you press on the gas to speed up and it will stall to over 2000rpms and seems like it dosent increase speed at all. If it dosent intially lock at wot it is just as bad too.

From a stop and 1st and 2nd gear it feels a lot better, but you would think it the looseness of it would help spool up from a dead stop but it still takes about 3.5 to 4 seconds with stock lly turbo.

 

[Mike L.]

Without driving your truck and seeing what it does or doesn't do, it is hard to diagnose. The SC 1056 is a good converter. Tuning can cause issues with the converter. If the converter is locked it is nothing more than a shaft and does not affaect trans.

 

[McRat]

Mike is right. No matter what convertor you run, you won't float at 3000 until 70mph unless something is wrong.

I've run "tight" convertors, "loose" convertors, stock to 900HP+, and that isn't normal.

The Holy Grail for a stock turbo truck is a convertor that allows you to powerbrake up to 2500, but then gets very aggressive before you hit 3000. It depends on turbo and altitude as to which convertor is optimum.

A very old experiment I did was running down the 1/4mi with the convertor unlocked using different convertors. Guess what? Regardless of how tight the convertor is, they have no "stall speed". They will go past peak HP rpm and stay there as it runs through the gears.

 

[xcablb7]

Mike is right. No matter what convertor you run, you won't float at 3000 until 70mph unless something is wrong.

I've run "tight" convertors, "loose" convertors, stock to 900HP+, and that isn't normal.

The Holy Grail for a stock turbo truck is a convertor that allows you to powerbrake up to 2500, but then gets very aggressive before you hit 3000. It depends on turbo and altitude as to which convertor is optimum.

A very old experiment I did was running down the 1/4mi with the convertor unlocked using different convertors. Guess what? Regardless of how tight the convertor is, they have no "stall speed". They will go past peak HP rpm and stay there as it runs through the gears.

i'm a little confused here ? if the converter was too loose and the motor was pushing through it wouldnt rpm flare way up and hang there as mph increased ? until it locked of course.
i tuned a mustang on a dyno and the converter was way off initialy you would go wot and it would flash to 5500 and mph would just keep climbing, then it would couple up around 6200 and mph and rpm would climb together to 7200.
I've noticed now my truck will flash to 4000 and hang there if i roll into it from about 40 but a log only shows converter slip no clutch slippage

 

[suark]

I have a 1054, it drives around like the stock converter did, just a hair tighter.

 

[Mike L.]

i'm a little confused here ? if the converter was too loose and the motor was pushing through it wouldnt rpm flare way up and hang there as mph increased ? until it locked of course.
i tuned a mustang on a dyno and the converter was way off initialy you would go wot and it would flash to 5500 and mph would just keep climbing, then it would couple up around 6200 and mph and rpm would climb together to 7200.
I've noticed now my truck will flash to 4000 and hang there if i roll into it from about 40 but a log only shows converter slip no clutch slippage

Your converter is not locking soon enough and you are hanging at the rev limiter. You need a locking device like Ben makes. You will go faster.