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Modifying Full Throttle Upshifts BW M12

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DAMX View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DAMX Quote  Post ReplyReply Direct Link To This Post Topic: Modifying Full Throttle Upshifts BW M12
    Posted: Nov/24/2021 at 10:24pm
How can the full throttle upshift point be moved up on a Borg Warner M12 when the transmission selection is Drive. Now the transmission is shifting at about 4000 rpm. I'd like 5000 to 5500 rpm if possible.

Regards

Dono
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Post Options Post Options   Thanks (0) Thanks(0)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Nov/25/2021 at 5:03am
Modulator may or may not be adjustable to a point. The governor will control the WOT upshift. 

Personally, Id leave it alone as parts can be difficult to find..

Just manually shift it..and its better if you do manually shift it
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mixed up Quote  Post ReplyReply Direct Link To This Post Posted: Nov/25/2021 at 6:10am
X2 on leave it alone those BW do not like to much abuse and yes parts are getting hard to find  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Nov/25/2021 at 6:54am
About them M11 and M12 trannys... I had a vintage HotRod Mag that had an artical on the 69 AMX. They went through various steps on doing a few strip runs. If anyone has the artical I am talking about, it mentions a spider leg in the carb throat. Ha! Anyway they mentioned the tranny quickly became an issue after a few runs. If you are wanting to keep your times close, pack a lot of ice with you and cool the tranny pan after every run. Heat is a problem with keeping good shifts. Never had one to experience for my self, just the artical has been a bit of knowlege, for my own curiosity.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sweatlock Quote  Post ReplyReply Direct Link To This Post Posted: Nov/25/2021 at 9:05am
X3 on leave it alone - if you’re wanting it to upshift automatically at redline you should start looking for another tranny. Not because the M11/11B/12 weren’t good transmissions, because for their day they were, but rebuild kits and hard parts are getting very scarce and hence expensive $$$. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DAMX Quote  Post ReplyReply Direct Link To This Post Posted: Nov/25/2021 at 11:04am
I was afraid thats what the answer would be. I guess manual shifting is the answer. 
Unfortunately a transmission swap is difficult because of the small pilot bushing crank in the 68 390. I wonder if a custom torque converter could be made so the crank would need to be modified? 

Regards

Dono
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Post Options Post Options   Thanks (0) Thanks(0)   Quote scott Quote  Post ReplyReply Direct Link To This Post Posted: Nov/25/2021 at 11:49am
There is some info about the vacuum modulator adjustment in this thread. Not sure what effect, if any, it would have on the full throttle shift point.

"Prolly" is not a word.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: Nov/25/2021 at 5:22pm
Modulator isn't going to override the governor setting.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Nov/25/2021 at 5:40pm
I have an article that states the stock M12 with shift lever if left in 2nd, will shift to 3rd at 5400 RPM regardless.
It also states going to a modern band material with more friction and oil distribution grooves will reduce heat generated substantially.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ramblinrev Quote  Post ReplyReply Direct Link To This Post Posted: Nov/25/2021 at 7:22pm
Isn't there a note in the Owner's Manual, that a BW, in the "2" position will automatically upshift to 3rd at 70-something MPH?

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