87zjeff

iTrader: (4)

i really hate to sound ignorant,but what the heck is this?
does it mean that below the specified speed the tcc will not unlock?
does it mean that above the specified speed the tcc will not unlock?

longhorn450

iTrader: (1)

I think it means that above that vehicle speed the TCC will NOT unlock under any circumstances. Even at WOT it will still be locked and can be rough on the converter.

Fast355

iTrader: (2)

Means that above that speed the TCC will be locked, regardless of throttle postion. Stock ranges from 85-100 mph depending on the vehicle and calibration.

You can watch this TBI truck fall on its face when it locks at 75 mph.
http://media.putfile.com/MOV00002-17

longhorn450

iTrader: (1)

Why does a mandatory lock like that have such a negative effect on performance?

Fast355

iTrader: (2)

Because it eliminates torque multiplication through the converter. You typically see more effect on this, the heavier the vehicle, the taller the gear ratio, and the less HP the vehicle makes.

Being a 210 HP L05 350 in a 5,500 lbs Extended Cab 2wd truck, with 3.08 gears and 32" tall tires, you see it exagerated. The truck has long tube headers and 2 1/2" duals or quite honestly, it would have been even worse.

On Kurt's 95, we disabled the WOT TCC lockup, changed the air/fuel mixture in PE mode, changed the timing table to a large extent, and fine tweaked the shift points. His truck now has the power it was missing from the beginning. I wish I had a new video from him.

longhorn450

iTrader: (1)

O ok. Yeah that was definetely exagerated.

87zjeff

iTrader: (4)

thanks. i was wondering. mine is set to 75 mph but i have no power loss at that speed from it. mt tc is already locked at that point.

Fast355

iTrader: (2)

Try bumping the setting up to about 115 and see what happens, I bet you can feel the difference.

87zjeff

iTrader: (4)

would this affect normal tc lock-up functions?

Fast355

iTrader: (2)

Not at all, just at WOT above 75 mph it will stay un-locked.

Z69

Only WOT???
Table or constant?

I hate my truck with 3.42 and 30" tires in a 4wd.....can't imagine a 3.08.
I'll get time to tune it eventually. After I do the exh though. I get a nice hiss above 2500 or so currently.

RBob

iTrader: (1)

All of the time, whenever over the unlock prevent speed the TCC stays locked. This is coasting, steady state, accelerating. . .

It is a single constant.

RBob.

Fast355

iTrader: (2)

That it does, but the reason I say WOT only, is because most of the TCC settings in stock calibrations hold the torque converter locked until 99.61% TPS at 60 mph and above.

RBob

iTrader: (1)

So true, at higher MPH levels some cals can take a lot of TPS to unlock the TCC.

I was just thinking, a light touch of the brake pedal will unlock the TCC no matter the MPH and ECM control. There is always a way to bypass something.

RBob.

Fast355

iTrader: (2)

LOL, so true. I never thought about it that way. A manual switch will do the same thing.

anesthes

iTrader: (12)

How do you have your TCC set?

I'm on the fence about it. I have a $580 9" raptor 5x lockup converter. I dont know what to do with the lockup. I've read a few opinions.. what would you do with my combination and 285/40/17" tires ?

-- Joe

RBob

iTrader: (1)

Part of the issue with TCC lockup has to do with the tranny cooler.

The early 700R4 ('82-'84) transmissions stop the flow of ATF to the cooler whenever the TCC is unlocked. This will cause heat to build up in the transmission.

The later units ('85-93) the flow of ATF to the cooler is cut nearly in half whenever the TCC is unlocked.

By locking up the TCC the cooling of the transmission is increased.

RBob.

anesthes

iTrader: (12)

Thats retarded. Any way to bypass this and run cooling all the time? I have an '87 unit.

For a street strip car, (mine for example) what would you do? Lock always in 4th above 45mph only? A lot of folks recommend not locking in 1-2-3 for racing/street applications, but having a 4th gear lock programmed for cruising.

-- Joe

8UpAFord

I leave mine unlocked until 255MPH. I've never had a problem, remember this is at WOT you all are talking about. so it will lock up(if programmed in other areas) it's just when u give it WOT it will stay unlocked until your reached the limit or stay under the TPS limit. so over heating can happen but it's not likley you will drive around all day at WOT. Reason i leave it the way it is is so it moves out of the hole at crusiing speeds quicker with my gearing 3:55s.

For racing i'd leave it at 255mph, unless you have 4:11s or some really low end gears then it might benift you to lock up sooner, since the TPI is a Tq monster and don't rev to high

V8Astro Captain

iTrader: (1)

Interesting. I always thought it was the other way around...

Fast355

iTrader: (2)

Some of the older 700r4s NEVER reduced the cooler flow. Lockup or No Lockup

anesthes

iTrader: (12)

So why the change, do you think?

-- Joe

8UpAFord

V8Astro Captain, well at least thats the results i get with my E6 bin. can someone else back that please

anesthes

iTrader: (12)

What he said..?

91chevz71

IF the converter locks at say 1600 rpm naturally, does it even matter if you're turning 2200 rpm at 70 mph? The conv is locked already, so why would changing the unlock TPS% (EBL) value matter if you're already above stall rpm?

I guess I don't get it...you're cruising at 70 mph, locked in 4th. You go WOT, downshift to 3, rpm climbs to 3500 or so. Conv is locked regardless of TCC engagement, correct?

anesthes

iTrader: (12)

Wouldn't you want the converter to unlock when you nailed it, to build up torque?

From everything I read, the converter lock is for economy part throttle cruise.
It seems part of the benefit of using an automatic is the ability of the converter to slip.

After reviewing a lot, I think i'm going to change my tcc settings dramaticly. I don't think the converter should ever lock in 1st or 2nd. I think if I recall, the tdf/xdf allows for setting mph lock/unlock thresholds. I think locking in 3rd is ok if not in PE, and it should probably always be locked in 4th above 45mph.

-- Joe

91chevz71

I totally agree with ya-
I definitely WOULD want the converter to unlock when I nailed it, but I'm asking if it is going to spin any faster when the engine is already above the converter's lockup rpm? Maybe my understanding of torque converters is off (probably is).
pardon the lack of knowledge...

RBob

iTrader: (1)

There is always going to be some slip in the convertor unless locked. One of the reasons for TCC lockup is that with overdrive auto's the cruising RPM is low. It can get close to the stall speed of the convertor. This causes a lot of slip and attendant heat build up.

OTOH, by having a TCC the convertor stall speed can be increased for better off the line performance. And no loss of fuel economy during cruise.

RBob.

87_TA

Whats funny, I actually had a TCI tech argue with me there is always TC slip - even when locked, at that time mine was slipping under any load.. I demended another tech, and he agreed the other guy is stupid..lol

The tcc can be a great track tool, and even though losing TQ multiplication
a can will generally put more power to the ground when locked due to better effeciency.. It generally kills performance because when it locks it drops out of your power range - however if you have the gearing for, and use it to
drop to your peak TQ range, you will see good results and generally better trap speeds. Just as a standard car usually traps better than an Auto with same power/weight due to no tc loss.

anesthes

iTrader: (12)

I'm not sure that $8d has the logic you suggest though... It sounds like you would want to lock it right around peak torque, but also in 4th gear for economy. Not sure the code allows for both operation.

-- Joe

87_TA

You took that wrong,
The 8D has all the logic needed - I was stating for performance use at wot, when it locks you want it to drop rpm no lower than peak tq.. Thats why alot of cars fall off being they drop out of power range when locked..
As was the case with my car after modded, I was un aware of this table at that time, it would lock at 75 mph and drop rpm down to about 3600.. well my peak tq is at about 4400.. so I changed lock speed to enable force lock at 96 mph or about 5000 rpm, so when it locked it placed me right above peak tq and just below peak hp..