At what point would you switch to a non-lockup converter?

[V6UnderPressure]

I've been reading alot that many have converted to non-lockup converters due to the converters not locking up while racing etc. This could be for 10 second guys, 9 second guys, I don't know. My main question is at what point is a non-locking converter useless? Let's assume an 11.5 second car. Would you still go with a lockup? The car would be mostly street driven with maybe 1 autocross a year, and maybe one drag strip a year. Would love to hear what all the gurus have to say. I remember the days when people were locking their converters early with a paper clip, and now it seems like those who race prefer the non lockups. I think I missed alot during all this downtime.

 

[StageII86]

For me - it would be on any car that I wanted max coupling (efficiency) in a platform that could be easily tailored to my specific goals/combo that IS NOT my daily transportation. In a 12.0-13.0 TA49 stockish combo I'm happy with the D5.

I've been down the performance lock up road in both the Buick (9x11's, vig) and LS platform (vig, yank, TCI). At the end of the day, locking up the converter while racing tears stuff up. No way around it. I will say some of the LS vendors have brought the lockups pretty far in terms of launching hard and coupling well up top while unlocked. Yank and Circle-D have good converters for those cars, but they are much easier to make work on a NA V8 where you have more RPM range to move fluid.

I'm looking forward to trying one of the PTC 9.5" NL's

 

[Dusty Bradford]

For me - it would be on any car that I wanted max coupling (efficiency) in a platform that could be easily tailored to my specific goals/combo that IS NOT my daily transportation. In a 12.0-13.0 TA49 stockish combo I'm happy with the D5.

I've been down the performance lock up road in both the Buick (9x11's, vig) and LS platform (vig, yank, TCI). At the end of the day, locking up the converter while racing tears stuff up. No way around it. I will say some of the LS vendors have brought the lockups pretty far in terms of launching hard and coupling well up top while unlocked. Yank and Circle-D have good converters for those cars, but they are much easier to make work on a NA V8 where you have more RPM range to move fluid.

I'm looking forward to trying one of the PTC 9.5" NL's

This summed it up well.

For your question about an 11.50 car. A lock-up converter is capable of working well in this application. This much power can effectively be coupled in the rpm range a Buick operates in. Once into the 10's it's not easy to couple that much power under 6000 rpm with the cores used to build a lock-up without having slow spool up. An LS car that's capable of another 500-1000 rpm can run into the 9's efficiently with the same converter. It's all about the power put to the converter and what rpm range it runs in.

To put it plainly using identical converters.

Higher rpm means more efficiency at a given power level. A 10.50 car shifting at 5700 rpm may have 16% slip while an LS engine shifting at 6700 can run 10.50 with only 5% slip.

 

[V6UnderPressure]

I've read about tearing stuff up, if it weren't for the heat, I'd easily change to a non-locking. My biggest worry is the extra heat generated...

 

[Dusty Bradford]

For an 11 second car the lock-up works well unlocked at the track and drives like a stock converter on the interstate. Only once you get into the 10's does the non lock-up begin to really shine over the lock up on the track. Street driving with a non lock isn't an issue for 99% of the guys out there. Guys in the mountains usually prefer a lock-up for interstate driving.

A lot of heavy driving with a stall requires a good cooling system regardless. When driving with a heavy throttle up hill even a lock up often runs unlocked and builds heat. A good external helps but when combined with a factory style liquid cooler heating isn't an issue for any converter.

 

[Pronto]

What temps would be considered as a "safe" range? Can that range be had with a large external cooler only?

 

[StageII86]

Running through the stock submerged cooler and then using the biggest B&M cooler (the real large thick one w/ the big screw-in fittings, cant recall part number) always worked for me. I like to keep the trans under 180* and there needs to be some viscosity to make sure everything works so, warm is good at least 120* - others should probably chime in for a minimum temp. I think there are articles out there that say something like the protection begins to be compromised starting at 190* or something...

Only problem with the above mentioned cooler setup is that on the rare occasion in TX when I'd drive the cars in 30-40deg weather, the trans took dang near all day to warm up!

Regarding those who live in the mountains...I'd hate to drive any stalled TR up a steep grade for a long time! Especially stop and go... That would suck regardless of having a LU or NLU.

 

[bison]

What I've found is that the cars will run quicker with a properly specified NL in almost any instance. Especially when they have larger than stock turbos. Even when very close to stock. Some can't deal with the less than 5% slip a NL may add cruising but I roll my eyes at that. The NL conversions allow for full cooling circuit flow when installed. So in reality cruising around town will net lower trans temps than an unlocked lockup since the cooling circuit flow isn't fully directed through the cooler unlocked.


Posted from the TurboBuick.Com mobile app

 

[Dusty Bradford]

What temps would be considered as a "safe" range? Can that range be had with a large external cooler only?

Ideally under 200 degrees is good. The heat doesn't kill the trans, it kills normal trans fluid. The trans pieces begin to have issues when sustained over 250 degrees. The synthetic fluid can withstand a higher temp without breaking down.

I change the fluid in my duramax every 25,000 miles because I pull a 48' enclosed and have seen temps over 220 for periods of time.

When using a trans brake fluid temps exiting the converter increase 75-100 degrees every second the car sits on the brake. Imagine how high the temp gets when someone sits on the trans brake and 2 step for 3 seconds.

Whether someone can use an external cooler only depends on the environment it's driven in and how its driven. I used only an external cooler with a converter less efficient than the 9.5 and never had issues. Cruising on the interstate at 70 up small hills weren't a problem. I wasn't racing the car up hill or anything. The harder a car is pushed whether on level ground or an incline, the more cooling capacity is needed and this goes for lock up or non lock.


Posted from the TurboBuick.Com mobile app

 

[StageII86]

When using a trans brake fluid temps exiting the converter increase 75-100 degrees every second the car sits on the brake. Imagine how high the temp gets when someone sits on the trans brake and 2 step for 3 seconds.


Posted from the TurboBuick.Com mobile app

I totally cooked at very nice Neil Chance one time waiting for some genius to trip the 2nd bulb...

I never staged first again after that.

 

[2QUICK2B6]

when u reach low under mid 11's ... I blew through a top guys converter ... told him every spec of the motor ...im not calling any names but it wasn't a PTC! so im out near 1k converter an a blown hg

 

[V6UnderPressure]

What I've found is that the cars will run quicker with a properly specified NL in almost any instance. Especially when they have larger than stock turbos. Even when very close to stock. Some can't deal with the less than 5% slip a NL may add cruising but I roll my eyes at that. The NL conversions allow for full cooling circuit flow when installed. So in reality cruising around town will net lower trans temps than an unlocked lockup since the cooling circuit flow isn't fully directed through the cooler unlocked.


Posted from the TurboBuick.Com mobile app

This is a very good point and kinda what I wanted to hear. I'm not worried about the 5% slip, but I never thought about the full cooling flow for the NL's.

 

[turbojoe1]

Sounds like a win win to me.....

 

[Dusty Bradford]

I totally cooked at very nice Neil Chance one time waiting for some genius to trip the 2nd bulb...

I never staged first again after that.

For trans brake cars I always recommend using tractor fluid. Hy-hard, Hy trans ultra, etc......It won't foam like regular trans fluid and can't withstand alot more heat. I've been hung on the trans brake for a full 7 seconds at 4200rpm and it will still drop rpm where regular fluid may not drop any at all abd would be cooked. I also keep extra fluid in my ice chest. If I get into a situation like that I can drain the pan and refill with cold fluid.

 

[2QUICK2B6]

im talking foot brake ... told him specs....... 9x11 bruces here it is in black an white ... hate me like me ... posting facts

 

[2QUICK2B6]

yes tractor hydrolic fluid is better ... it has no detegents so it wont take the bite out of the plates...... but im a stupid young kid