shift points

[Bobs rare 6]

What is the best way to modify the governor to up the wot shift points? I have a brf trans and would like a 5600-5800 shift with a ptc conv. Im getting from Dusty. I can manually shift the 2-3, but not the 1-2. Its a column shift car and is a pain to man. shift! Is there a certain amount to take off of gov. to ballpark that rpm range? Thanks, Bob.

 

[SSedan64]

Governor Weights

I read on this site, 1gram = 120-200rpm. Hope this helps you out.
http://www.turbobuick.com/forums/tr...ng-non-gn-governor-increase-shift-points.html

http://www.turbobuick.com/forums/tr...fied-200-4r-governor-higher-shift-points.html

 

[BEATAV8]

What is the best way to modify the governor to up the wot shift points? I have a brf trans and would like a 5600-5800 shift with a ptc conv. Im getting from Dusty. I can manually shift the 2-3, but not the 1-2. Its a column shift car and is a pain to man. shift! Is there a certain amount to take off of gov. to ballpark that rpm range? Thanks, Bob.

CKperf has a new modified valve body (code KC) that's supposed to do the job without modifying the governor. I ordered one up and expect to receive it late this week. It may be a bit too high for your shift goal, but you could always use it with a slightly heavier governor instead of a lighter one like the BR from a GN.

Check with Bison. The man is "in the know" on these things. He recommends not to substantially lighten the already light-weight BR governor, as it could become erratic with inconsistent shift points.

 

[TKGN1]

Just did the mod this past weekend. Same issue as you Bob.
Here is what I found:
I drilled 16, 1/8" holes which removed approximately 3 grams of wieght. I'm hoping to see a change of atleast 600 rpm +/-100 to get a baseline as to where I'm at now. I drilled holes as a better "base" to start with, ex: one 1/8" hole = X rpm. As soon as I take the car through some wide open passes to check shift points I will post back conclusions.
HTH
Here is a pic of the modified part:

 

[bison]

Lightening the governor works but it can become slightly erratic when removing more than a gram. The easiest way to get to 5600 would be to use a CZ vb and governor from a MCSS or use a KC (olds 307) and use a GN governor but replace the light governor weight with a medium one. If you run the light weight it will be around 5800-5900. Or higher if you have a converter that doesnt couple. Mine shifts at about 5900 at 3% slip with a KC and a PTC 9.5".

 

[TKGN1]

Thanks Bison, if the mod I did does not work I might go the route you are talking about. I'm running the PTC 9.5 nl also, thus the reason behind the rpm drop I believe.

 

[bison]

Thanks Bison, if the mod I did does not work I might go the route you are talking about. I'm running the PTC 9.5 nl also, thus the reason behind the rpm drop I believe.

The rpm drop wont have an effect on the shift point. Its the driveshaft speed and the vb and gov calibration that will determine the WOT upshift rpm.

 

[JDSfastGN]

The rpm drop wont have an effect on the shift point. Its the driveshaft speed and the vb and gov calibration that will determine the WOT upshift rpm.

no but efficiency would correct? If you go from a very inefficient converter that has you doing higher rpms at a given speed than a tighter converter does, would the shifts not come earlier since it shifts mostly off of driveshaft rpm or speed? This is my understanding and have had a couple customers that changed to a tighter stall and thus the transmission started to shift earlier at WOT.

 

[bison]

no but efficiency would correct? If you go from a very inefficient converter that has you doing higher rpms at a given speed than a tighter converter does, would the shifts not come earlier since it shifts mostly off of driveshaft rpm or speed? This is my understanding and have had a couple customers that changed to a tighter stall and thus the transmission started to shift earlier at WOT.

Efficiency when the shift occurs certainly will. This could also be a problem if the converter is not run as it was spec'd. It could actually pull the engine down too much and out of the powerband hurting e.t. even though it looks good up top. Usually the 60' and 330' will suck if the converter is too tight also. If you order a 9.5" PTC the boost that will be run is A very important consideration. If i ran 20 psi on the combo i have below the converter would need to be loosened quite a bit or it would lose a lot of e.t. from the resulting lower flash stall of the converter (which would be about 4500 at that boost). It flashes to about 5000 at 28psi. The same rpm it falls to on a ratio change at that boost level. It wants to be over 4800 at all times in my combo for the best e.t.'s. Its like a missile when the engine is kept between 5000 and 5700. Which is where it spends 97% of its time when i run it hard. The pump/stator combo has a lot more to do with it than simply the stall speed.

 

[TKGN1]

Thought I would post an update on lightning the gov.
After multiple WOT pulls and logging with FAST, RPM at 1-2 and 2-3 shifts went from 5050 rpm with the unmodified gov. to 5600 rpm after modification.
550 rpm gain
conclusion:
1/8" hole = 34.3 rpm

I'm sure there is a considerable +/- range, but at least this will give some a good starting point.
HTH
Todd

 

[Bobs rare 6]

Thanks for the update Todd! I ended up putting two 1/16 holes in small weight on gov. Will see how this works at the track in a week or two. Also got new ptc 9.5 conv. installed. Wow! This conv . is awesome! Later, Bob.