When to lock-up the TC on a MVB 4r70w

miscreant

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I have recently installed a Broader Performance Forward Manual Valvebody on my 4r70w while retaining the stock torque converter. The transmission sits behind a mild 351w and will be used for Street and some trips down the track. I was wondering if anybody here had knowledge of when I should lock the converter up going down the track. My previous knowledge states you should shift - lock converter - unlock converter - shift - repeat but my fellow enthusiast pointed out that trying to lock up the converter under high acceleration and high speed could cause the damage to the torque converter or worse which is why his tune does not lock up the converter under that kind of load. However his is 3600 stall in a c5 corvette. Would any one care to shed more light on this theory? I just don't want any part of the transmission joining me in the car. Thanks.

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lwarrior1016

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Ok, now this depends on the converter you have. If it is built to take a WOT shift while locked up, then you can try it in every gear until you get best result. Launch, roll into first, lock up-then shift second, and keep it locked through the shifts. Don’t try to lock and unlock. Once you lock it, keep it locked.

If your converter isn’t a triple disk billet converter that’s built to hold the lock up on a shift, then you need to just keep it unlocked the whole time. From what I understand though, the difference between locked and unlocked is negligible. However, I don’t know because I’ve left mine unlocked at WOT.
 

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If anyone will know, it be this guy ^

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miscreant

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Ok, now this depends on the converter you have. If it is built to take a WOT shift while locked up, then you can try it in every gear until you get best result. Launch, roll into first, lock up-then shift second, and keep it locked through the shifts. Don’t try to lock and unlock. Once you lock it, keep it locked.

If your converter isn’t a triple disk billet converter that’s built to hold the lock up on a shift, then you need to just keep it unlocked the whole time. From what I understand though, the difference between locked and unlocked is negligible. However, I don’t know because I’ve left mine unlocked at WOT.
Thank you so much. Seeing how I have a stock converter for now. I'll just leave it unlocked. For Street driving I assume I would just lock in 4th then?

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lwarrior1016

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You can wait until 4th to lock it. I have mine tuned to lock after third and stay locked on the 3-4 shift when driving normal. Anything over about 60% throttle and it unlocks. This is with a 4K stall too.
 
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miscreant

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You can wait until 4th to lock it. I have mine tuned to lock after third and stay locked on the 3-4 shift when driving normal. Anything over about 60% throttle and it unlocks. This is with a 4K stall too.
Thank for your help. I really appreciate it. Saved me from hurting my transmission.

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beyondEOD

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You can wait until 4th to lock it. I have mine tuned to lock after third and stay locked on the 3-4 shift when driving normal. Anything over about 60% throttle and it unlocks. This is with a 4K stall too.
How is the street driving with the 4k converter and tune? I'm looking to get a good amount of stall out of my setup but still have good street manners. I'll be tuning with a QH.

What converter are you running?

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lwarrior1016

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How is the street driving with the 4k converter and tune? I'm looking to get a good amount of stall out of my setup but still have good street manners. I'll be tuning with a QH.

What converter are you running?

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I will have to look back and make sure which converter I have but I think it’s a patc converter. It’s not bad at all on the street. The lockup is a little more drastic than stock but It’s not bad. I don’t mind it a bit.
 

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