When to lock converter?

[GTEATER]

With a 500rwhp full weight car, what is the ideal time to lock converter to minimize the chace of breaking the tranny?

Tranny is PMAC with all hardened parts.

Thanks

 

[Lee Thompson]

?

Top of 3rd gear. If doing with chip 84 MPH is a good starting point, assuming speedo is correct

 

[NCTTA]

It's actually a FAST system on the car not a chip, but I'm sure the prinicipal is the same.

This the 3rd to OD any less harsh than the 2nd to 3rd?

 

[REDS HOT AIR]

it is not fully locked on shifts no matter what you do since it works off pressure switches for each gear so when 3rd releases it unlocks it and when pressure hits 4th the 4th gear switch locks it...all happens so quick you dont even know it.

you should be talking in the range my car was before and i locked it in 2nd and carried it on thru.. with the torque they're making at that level i try to lock it soon as possible...the slower cars need to hold off longer.

in Lees case he's not i/c so im betting locking the converter early brings knock into the picture.

am i right there Lee ?

 

[NC87GN]

One thing I wanted to pass on is lock the tranny after 3rd gear. Rodney mentioned its TORTURE on your forward drum from 2nd to 3rd when the convertor is locked. HTH

Mike Banas
87GN

 

[Lee Thompson]

locking convertor

This has been my experience---I used to lock with a manual switch before leaving the line. So it would lock once shifted to second, and that worked fine with my old convertor as my car was a mid 12 second at that time. After finnaly using up that con. I bought a Precision Industries multi dics. Their suggestion is to lock at the top of a gear, just before it shifts as all the parts are rotating at close to the same speed. Red Armstrong has been very helpful in tailoring my chip. He uses the torque convertor lock signal to lock the con. and at the same time pull out some timing. My original chip was locking at 84 MPH, this was too soon. My RPMs would drop too far and the eng. was sluggish for a while until it climbed out of it. I have always thought my car would run quicker locking as soon as it goes into second, but afraid to try it now. My car shifts 1-2 at 5700-5800, 2-3 5700 5800, when it reaches 5400 in 3rd the con. locks (90 MPH) RPMs drop to 4800-4900 and then climbs back to 5700-5800 through the traps as I hold it in manual 3rd. Hope this is the info you are looking for. This is my 3rd season on this con. with no trouble YET.
This is what works for. Maybe a better way, if so I/m open to suggestions.

 

[REDS HOT AIR]

i got Bruces 9-11 he says give it heii so i have locked it right after second shift at 26# and it locked without a glitch..pulled like ********* when it locked.

every car will act differently so play with it till you find what works best.

Lee if they told me only to lock it when it was slipping the least i would question why they dont have faith in it to handle a full torque lockup..

 

[Lee Thompson]

/

Remember, when a convertor is locked it can/t multiply torque. Then again, when it is locked it is not slipping. I guess what ever works best for each case.

 

[turbov6joe]

In most cases with a "hard parts" tranny, locking it at the line should be fine. I just sold a car that made 523 rwhp and locked my 9/11 at the line every time with 0 problems. I also had all hard parts, so that helps. I previously had a PMAC tranny that lasted for over 6 years (seasons) and literly hundreds of 1/4 mile passes before a blown front pump seal sent it to its grave
BTW, I also used a T brake. Again, in most cases, your MPH will be higher when locking it at the line, versus in 3rd. If you car is running "fat" locking it will slow you down considerbly, and thus lower ET/MPH. In my former car's case, it would slow by .4 and at least 3 mph. When I finally got the fuel curve set correctly, locking it was the diff between running 119 mph and 123 mph out the back door. Good luck!