no you have to lock it with HP Tuners

 

No, as has been mentioned in this thread the stock converter is not designed to lock up under WOT and the PCM programming does not allow it to do so. The PCM may be reprogramed or a switch installed to allow WOT lockup, but as I said, the converter lockup mechanism will not last long under these conditions.

Rich

 

I still dont think you guys fully understand t/c's. The thing that causes tourqe multiplication in a t/c is the stator. and the touqe mulitiplicaton of a auto tranny is around 2.5. A high stall converter allows you to bring the rpms up to max touqe before you launch. and when you let go of the trans brake or let go of the brakes the converter will multiply the touqe of ur engine 2.5 times. this is what causes to drag cars to run wheels up through the 60 feet or even pull wheelies. a lockup converter is for fuel economy at cruising speeds which means if you punch the gas it will unlock. also you shouldn't use a lock up when dragracing in case it would lock up going down the track you would lose your tourqe multiplication. hope this helps a little.

 

So on my 94 ta with the performance shift button I should program the computer to disable the tc lock up when I use it in performance mode at the track or while messing around on the street? Just keep the lock up functions enabled in the normal mode right?

 

GN guys use a 5 disk lock up TC down the track to help from having to use HUGE tires, how ever the TC must be made for it

 

With stock programming it will not lock up under WOT anyway.

Rich

 

Ok, so i've read the thread about "what broke your 4L60E" and it was mentioned in there that some TC companies have the habit of removing or not building their TCs with lock-up dampers which eventually leads to stuff breaking. So, I guess my question is, is this something we should concern ourselves with when shopping for a TC? If so, how do we be sure that the TC we buy has a damper since most websites i've seen don't make any mention of this?

 

I agree about the converter not lasting when locked @ WOT, but I've seen several programs, supposedly stock that lock the converter in 3rd and 4th gear @ 93% and 100% TPS at 95 MPH in performance mode. I re-flashed those values in my program so they are now 83 MPH and also entered the same values in the normal mode section of that same table. There is also another table 'TCC Apply MPH / Release MPH' that is accessible with LT1_Edit that evidentally overides the 'TCC apply in MPH vs TPS%' table values in WOT conditions, which I also have set to 83 MPH 3rd and 4th gear, but I have never actually felt the stock converter lock at that speed.
I read this thread about a week ago and again last night and posted this thread in the computer / programming section to be sure.
I wasn't dead sure about the stock program locking the TCC at WOT, thinking maybe all 4 of my 'supposedly stock' programs had been re-flashed, but sure enough, GM evidentally programs the TCC to lock @ WOT under the conditions I mentioned.
Does anyone have any further info about this?

 

Well, it doesn't appear to me that the TCC locks up under WOT based on what I have seen on the dyno. After all, isn't why A4's consistently dyno 15-20hp less than an M6? IF the TCC locked up, I think they should dyno ~ the same. But I sure could be worng on this one.

Rich

 

Ive had my 700r4 rebuilt the guy said he made it hydrolic lockup rather than electronic ..all i know is when it shifts into overdrive now its fully locked up the rpms drop way low. I cant tell so much in the 1st 2nd and 3rd gears .i did feel a power loss and now at 126 mph the car just wont go past that almost feels like a rev limited kickin in but i think it has something to do with it being locked up at that speed. thats my 86 im soon to part with after 10 yrs after you drive an ls1 the Tpi aint no fun..

 

Rich, some info from the turbo buick side of things....

The 200-4R tranny has an inability to lock the TCC in 1st gear, meaning the valvebody simply will not allow it. But with little more than a paperclip inserted into the right ports on the ALDL connector, the TCC will be locked up immediately after second gear is engaged, WOT or not. This trick has been known to knock off 2-3 tenths in the 1/4 on a 11-12sec heavy-weight GN, so there is definitely a benefit of locking the TCC after the torque multiplication has been utilized after the launch. The launch is when the TC's torque mulitplying ability takes place while it's in "overrun" state... meaning the shearing of the fluid acts like a large rubber band and thrusts the car forward while the two sides of the TC try to catch up to each other in regards to rpm. But after it does catch up, torque multiplication ceases and then the slippage eats up your power the rest of the way down the track... locking the TC after the overrun state is done combats this, but is pure hell on the TC clutch pack. And that's why most of the GN guys getting close to the 10s stop using this paperclip trick, it tears things up too bad.

Now if we could get a 4000+ stall converter with a REALLY beefy clutch, launch hard as crap with it unlocked to get the torque multiplication, then lock up the TCC once in second gear and holding it the rest of the way, this is as good as it gets. Autos and manuals seem to exhibit about the same amount of drivetrain loss when the auto has its TCC locked. But the manual does not have a torque multiplying ability like the auto does.

Only if...

 

Interesting, thanks. I wonder if the broad torque curve the Turbo GN has allows it to pull even with the converter locked up?

Rich

 

Super charged or turbo charged units "sometimes" do better when locking the TC in 3rd gear, but if a well designed TC is "matched" to the vehicle, motor, rear end gears, etc., then in most cases the locking up of the TC will do "little" if any in improvement over not locking the TC. There are "always" exceptions to the rule, but when building a vehicle, work with what "is proven".

 

Do you ever see any failure of stock TCC clutch frictions, apply piston or apply solenoid or seals due to a result of stock WOT 3rd gear TCC apply values via flash programming in factory LT1 F-body PCM entries in those tables?

 

I have a 1996 Z28 with a comp cam 224-236 @114, .555-.565 lift. I have SLP 3.42 gears. Stock were 2.73's. My car is for show and cruise only. When I ingage the car into drive (from park) it wants to jump forward, (RPMS are @ 1000). Will a stall help this? If so, what size do you recommend. I do more city than highway. The car rarely sees the highway. Also, my car is programmed with LT-1 Edit software. Thanks,For the help and suggestions.