BHR

back to your original post here before you started modifying the gov. by following others instructions to try to "mask" the issue by removing springs

if indeed both your 1-2 and 2-3 WOT shifts where both at 4500 and you where in 4th by 25 then this is normal b/c of your 3.73 rear gear i would then put both original springs back in and reduce both of your inner weights

this can be done with out removing the inner weights if you dont have a b&m kit, by grinding the original weights down with a small carbide grinder bit but be sure to clean the gov. good before you put it back in

stock C stamped double inner weight govs weight about 15 grams
stock V shaped single inner weight govs weight about 10 grams these are the weights of just each inner weights

the tpi C4 corvette had single rectangular shaped inner weights that weigh about 12 grams each this is around where you want to be to get a 52-5500 WOT shift

Pro Built Automatics

When I recommend to remove the lighter of the two springs in the governor, this is to fine tune it because of rear end gear ratio, torque converter stall change, camshaft change in duration, etc. This is to get slightly later part throttle 1-2 shifts. The other gain here might not necessarily be wanted, is slightly easier downshifts. I always recommend the valve body and governor matchup to get the WOT shifts pretty much the same rpm for the 1-2 & 2-3 WOT shifts. You made this change and for some reason it made a "drastic" change in your case. I have not seen this type of change that you experienced, as I have done this modification if called for, since 1996 on quite a few transmissions and have recommended this to others and have not seen or heard of this happening before. I cannot explain what happened in your case. As stated earlier "removal of the weaker spring resulted in acceptable part throttle shift points, but had little or no effect on WOT shift points."

86LG4Bird

iTrader: (1)

Dana, I don't think my results are necessarily anything different than you predicted. Removing the weaker spring did in fact raise the part throttle shifts slightly. You must have missed one of my posts where I said I experimented further by removing the second stronger spring in addition to the weaker one. That ended up giving great ET performance while sacrificing some driveability.
I'll experiment further by re-installing just the weaker spring and will report back.

86LG4Bird

iTrader: (1)

Reporting back.... Wow, I think I've been pretty lucky with just swapping the two stock springs around! some good results
Re-installed just the weaker spring, still stock weights.
1-2 WOT is 5800 rpm ....perfect! (was 6000 with no springs)
2-3 WOT is 4900 rpm .... a tad lower than I'd like (was 5000 with no springs)

Very light throttle, just off idle, shifts are great:
1-2: 12 mph
2-3: 22 mph
3-4: 33 mph
....perfect for the 3.73 gears.

So......how do I now get about a 5600 rpm 2-3 WOT shift without affecting anything else? shift valve in the valve body?

ProfessorStarks

It may not give you the drivability you want, but I used a governor straight out of an 89 700r4 V6 Camaro. It put my shifts at 5500-5600rpm WOT. At least you'll have peace-of-mind while racing.

86LG4Bird

iTrader: (1)

What rearend gearing were you running?

Tootie Pang

iTrader: (2)

So if I have a bone-stock 305 LB9 with a 3.42 rear and the corvette servo, would a good start still be to remove the lightest spring? Does the vette servo change any of that?

86LG4Bird

iTrader: (1)

If your part throttle shifts are too low, yes, removing the lightest spring will raise them a bit. It won't affect WOT shift points.
No, the 'vette servo has no effect on the shift points.

ProfessorStarks

28" tires with 4.11 gearing. I did an engine swap. This particular transmission was behind a 2.8L engine. I'm not sure what make and models came with this combo. Maybe Camaro's and S10's. I'm sure the guys on this thread could assist if necessary.

Tootie Pang

iTrader: (2)

Updated link:

https://www.dragracingonline.com/arc...vi_9-bm-1.html

Here's my rudimentary understanding of things (please correct me if I am wrong):

1. The governor controls part throttle and WOT shift points
2. The side with the lighter weight controls WOT and the heavier controls the part throttle
3. The governor is driven off the output shaft and is therefor linked to the driveshaft speed- and road speed via the rear end ratio.
4. Because of 3. above, changing the rear ratio changes the speeds at which the same governor actuates shifts, therefore it should be re calibrated for the new ratio, especially if it its a significant change.
5. The governor works by spinning. The faster it spins, the weights and springs lift away from the center shaft and plunge a pin down the center which moves the valve eventually effectuating a shift. The springs fine tune the weights. The counter force to the weights spinning and pressing the valve is the fluid pressure on the valve itself. The more fluid pressure, the faster the weights have to spin to create more counter pressure to eventually force the valve. That's it.
6. The governor works with the TV valve to determine real time shift points. The TV valve effects transmission control fluid pressure in conjunction with the governor. The TV valve simply detects the throttle position. If the pedal is mashed, the fluid pressure goes high and the lighter WOT governor weights are selected (by the valve body) control the shift points. If the throttle is part, the heavier weights control.

skinny z

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