Overriding governor/restrictor
#52
TGO Supporter
Joined: Jul 1999
Posts: 10,907
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From: The Bone Yard
Car: Death Mobile
Engine: 666 c.i.
The other possibility, I note you have an auto. It may be that you are hitting "up-shift into 4th in WOT" issue that plague most of the 700R4/4L60 auto trannies used in F-bodies. There's a fix for that involving changing to a valve that came in the Corvette & the B4C/Police F-bodies (and some 1991 & 1992 L98 cars). Check out the Tranny Board for the proper fix.
#53
Senior Member
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Joined: Apr 2006
Posts: 882
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From: Wisconsin
Car: 1989 Trans Am t-top WS6
Engine: 305 tpi
Transmission: 700R4
Axle/Gears: 3.23
Re: Overriding governor/restrictor
I dont know about speed limiters and governors but I have had my 89t/a with the 305 over 100 or should I say just over... fast enough for me
#54
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Joined: Jul 1999
Posts: 12,212
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From: Bertram (outside Austin), TX
Car: 87 GTA
Engine: L98
Transmission: 700R4
Axle/Gears: Dana M78 3.27 posi
Re: Overriding governor/restrictor
If you hit 100mph, you were only 14mph away from hitting the limiter. If you go for it, be ready for the sudden shut off of power When your speed drops low enough (like 110, you'll get power again...and lose it again if you stay on the gas, and hit 114mph. It's a real roller coaster ride, if you stay on the gas.
#56
Re: Overriding governor/restrictor
My GTA didn't have a limiter, but it had the factory 16" wheels, thus 245/50/16Z tires.
As for the trans, switching to WOT 4th gear upshift ability in a stock internal 700r4 is not a wise idea unless you are wanting to rebuild. The stock clutch pack and 4th gear servo aren't up to the task of a WOT assualt.
- Also, fluid ALWAYS flows through the cooler, TC locked or unlocked, any gear. The issue is that in 4th gear, it bypasses the cooler flow approx 80%, diverting it directly into the TC, to help lessen slippage and aid in clutch apply. OD creates excessive TC slippage in the first place, thus generating more heat and with less of the fluid going through the cooler, it will cook itself in short time. - This is why the aftermarket add-on OD units(gear vendors type) for T350's, T400's,etc don't use more than a .72 OD ratio. Any steeper will create too much converter slippage and lead to the death of the trans.
As for the trans, switching to WOT 4th gear upshift ability in a stock internal 700r4 is not a wise idea unless you are wanting to rebuild. The stock clutch pack and 4th gear servo aren't up to the task of a WOT assualt.
- Also, fluid ALWAYS flows through the cooler, TC locked or unlocked, any gear. The issue is that in 4th gear, it bypasses the cooler flow approx 80%, diverting it directly into the TC, to help lessen slippage and aid in clutch apply. OD creates excessive TC slippage in the first place, thus generating more heat and with less of the fluid going through the cooler, it will cook itself in short time. - This is why the aftermarket add-on OD units(gear vendors type) for T350's, T400's,etc don't use more than a .72 OD ratio. Any steeper will create too much converter slippage and lead to the death of the trans.
#57
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Joined: Jul 1999
Posts: 12,212
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From: Bertram (outside Austin), TX
Car: 87 GTA
Engine: L98
Transmission: 700R4
Axle/Gears: Dana M78 3.27 posi
Re: Overriding governor/restrictor
If that is the case, then why did the GM warranty apply, to Corvettes? Their 700R4 could shift into 4th at WOT, thereby ataining, a "true" top speed, unlike a "tranny governed" top speed..
#58
Re: Overriding governor/restrictor
Top speed is usually rated with a 1:1 trans ratio, which would be 3rd in a 700r. OD gears are not meant for performance, just fuel economy. Same goes for a 5 speed car, there's a reason 5th has basically no syncro.
The vette servos have more holding power than other stock 700r units, and that was a rating from a brand new, zero mile car. Take an 16+ year old car and ask it to do something it wasn't meant to...see what happens. It may hold a while but it's borrowed time.
Everything I'm saying can be confirmed by any decent transmission rebuilder. Not trying to rain on anyone's parade, just noting there's a reason race set-ups are designed around a 1:1 trans ratio. - The only time this differs is in salt flats type applications where you have miles of wind up in light weight low aero drag vehicles.
The vette servos have more holding power than other stock 700r units, and that was a rating from a brand new, zero mile car. Take an 16+ year old car and ask it to do something it wasn't meant to...see what happens. It may hold a while but it's borrowed time.
Everything I'm saying can be confirmed by any decent transmission rebuilder. Not trying to rain on anyone's parade, just noting there's a reason race set-ups are designed around a 1:1 trans ratio. - The only time this differs is in salt flats type applications where you have miles of wind up in light weight low aero drag vehicles.
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