4+3 Question.....
Thread Starter
Race Director
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4+3 Question.....
I am in the works of building a motor, It should have 400RWTQ at the low end. Question is, If and when the 4+3 goes, Can it be rebuilt alot stronger then the stock unit?
I think eventually the tranny will spit out, I think this might be the weak link. BTW, No major problems yet, I usually depress the clutch when I engage the OD.
Thanks.
Are there any guys with some good power behind there 4+3? and if so how are they holding?
I think eventually the tranny will spit out, I think this might be the weak link. BTW, No major problems yet, I usually depress the clutch when I engage the OD.
Thanks.
Are there any guys with some good power behind there 4+3? and if so how are they holding?
Instructor
Joined: Aug 2003
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From: Macon GA
The four speed portion of the transmission is apparently very stout. I have an 88 Callaway pushing 420rwhp and 586rwtq through it. Unfortunately, the overdrive unit has not fared so well though and ceases to function any more. Good luck with your buildup. Keep us posted with your numbers when you complete.
Justin
Justin
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Originally Posted by easycreeper
The four speed portion of the transmission is apparently very stout. I have an 88 Callaway pushing 420rwhp and 586rwtq through it. Unfortunately, the overdrive unit has not fared so well though and ceases to function any more. Good luck with your buildup. Keep us posted with your numbers when you complete.
Justin
Justin
That is good to hear Justin that the 4 speed is handling that stout motor you have........586rwtq, geez.
So what happened to your OD unit? You driving the car with just the 4 speed?
Instructor
Joined: Aug 2003
Posts: 105
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From: Macon GA
Yup, just the four speed. I think the OD unit might have seen one too many top speed runs... Still getting 20+MPG at a 65MPH cruising speed.
There's quite a bit more power to be had from the engine with an advance in timing and a little more octane and boost, but race fuel is hard to come by and is ridiculously expensive, so...
What kind of internals are you using? Displacement?
Justin
There's quite a bit more power to be had from the engine with an advance in timing and a little more octane and boost, but race fuel is hard to come by and is ridiculously expensive, so...
What kind of internals are you using? Displacement?
Justin
Le Mans Master
Joined: Sep 2000
Posts: 6,303
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From: Bartlett IL
Originally Posted by 88BlackZ-51
That is good to hear Justin that the 4 speed is handling that stout motor you have........586rwtq, geez.
So what happened to your OD unit? You driving the car with just the 4 speed?
So what happened to your OD unit? You driving the car with just the 4 speed?
Thread Starter
Race Director
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Originally Posted by Dominic Sorresso
GM is offering some good deals on ZF-6s. I did that on my Xfire. Best mod I ever did along with upgrading to C5 brakes.
the 4+3 keeps my car unique man, its a conversation piece.
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
The 4 speed ST10 unit is strong.
When you're not in od, the entire assembly rotates as one piece.
So... basically, don't dump 400 ft lbs when in overdrive and you'll be fine.
When you're not in od, the entire assembly rotates as one piece.
So... basically, don't dump 400 ft lbs when in overdrive and you'll be fine.
CF "Young" Senior Member
Joined: Feb 2005
Posts: 4,034
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From: Cupertino CA
St. Jude Donor '12
Originally Posted by 88BlackZ-51
the 4+3 keeps my car unique man, its a conversation piece.
my buddy wants me to do an upgrade to a 6 speed, but i keep tellin him "hey, my OD unit works, more than most can say"
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Thread Starter
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Originally Posted by flaagan
exactly.
my buddy wants me to do an upgrade to a 6 speed, but i keep tellin him "hey, my OD unit works, more than most can say"
my buddy wants me to do an upgrade to a 6 speed, but i keep tellin him "hey, my OD unit works, more than most can say"
if your buddy is going to give you $2000-$3000 to do it, then maybe do it.
Le Mans Master
Joined: Sep 2000
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From: Bartlett IL
Originally Posted by 88BlackZ-51
the 4+3 keeps my car unique man, its a conversation piece.
Thread Starter
Race Director
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Originally Posted by Dominic Sorresso
I don't mind talking about the 4+3. But I much enjoy driving the ZF. That and the C5 brakes make my Xfire very unique.
i get your point, but my car is very clean, and i want to keep the tranny stock.
Le Mans Master
Joined: Sep 2000
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From: Bartlett IL
Originally Posted by 88BlackZ-51
i get your point, but my car is very clean, and i want to keep the tranny stock.
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
fwiw, I broke the 4speed part of mine. The 85 overdrive works like a charm, and I use it too. I'd use it to force downshifts coming out of tight turns.
CF "Young" Senior Member
Joined: Feb 2005
Posts: 4,034
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From: Cupertino CA
St. Jude Donor '12
Originally Posted by 88BlackZ-51
if your buddy is going to give you $2000-$3000 to do it, then maybe do it.
