quad4 3.63fdr trans or 3.94fdr trans???

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speedy
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quad4 3.63fdr trans or 3.94fdr trans???

Post by speedy »

well, i baught a 91 gtz as many of you know, recently i sold the 394 trans from the quad z26 i had, the 91 uses the 3.63 trans and im building a quad motor for the car with some mods. i found a 394 trans in the yard in a 92 grand am with 180k on it but my question is, stick with the 363 trans or 394trans??? the 3.94 has a better final drive ratio for better gas milage and supposedly shaves a second of the 1/4 mile but i dont know that this has been proven.


1991 beretta GTZ- 2.3l w41 cams, ported 086 head with a 3 angle valve job, fidanza flywheel with exedy racing clutch, 3.94fdr from and scx, so much more..
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3400beretta
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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by 3400beretta »

Yeah its proven. Plus the 91 is the worst year of them all, they put the 3.77 first gear in it, so theres a big gap between first and second. Do it.

And its 3.61, fyi.


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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by Asylum »

Rodney is right. I have a '91 and the trans ratios are a little silly to be honest.

But a SECOND off the 1/4 mile time? I doubt it!!


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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by woody90gtz »

I was thinking 3.94 would be too much gear, but if your 3.61 trans is a 3.77 1st (13.60 total ratio), the 3.50 1st in the 3.94 isn't much different (13.79). Either way you're well above the 3.61/3.50 first like my v6 trans is at 12.63


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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by GTZfan »

My 3.94 quad uses half a liter less fuel per 100km compared to my 3.61 quad.
I dont drag race them, but the 3.94 feels more sophisticated to drive.


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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by twistedretta »

GTZfan wrote:My 3.94 quad uses half a liter less fuel per 100km compared to my 3.61 quad.
I dont drag race them, but the 3.94 feels more sophisticated to drive.
Is your 92 3.94 trans internal or external slave


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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by speedy »

i ended up picking up a 3.94fdr from an olds achieva scx, it was suppose to be a 92, but im guessing its an early 93, it has the internal slave rather then external slave, so my question is, if i can use the bell housing from the 91 on the 93???


1991 beretta GTZ- 2.3l w41 cams, ported 086 head with a 3 angle valve job, fidanza flywheel with exedy racing clutch, 3.94fdr from and scx, so much more..
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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by MY91GT(Z) »

if your goin to swap bellhousings might as well send the diff to jeff at ep and slip lsd in there also if this car is getting the best of the best.

If your 3.61 tranny wasnt a quad tranny i would trade you my 3.94 for your 3.61+cash


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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by speedy »

i have no idea what it costs to have that installed, but i dont imagine its cheap at all. if you want to trade, bring it down, then all you'd need to do is find a bell housing.


1991 beretta GTZ- 2.3l w41 cams, ported 086 head with a 3 angle valve job, fidanza flywheel with exedy racing clutch, 3.94fdr from and scx, so much more..
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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by 3X00-Modified »

$499 or possibly $599... depends on if he still has his winter sales.


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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by speedy »

yeah, thats what i was just told by rob. im kinda interested in rebuilding the trans with and putting the lsd in, but id hate to rebuild it, put it together, and find a problem shifting at 6,000 rpms a couple hundred miles later...


1991 beretta GTZ- 2.3l w41 cams, ported 086 head with a 3 angle valve job, fidanza flywheel with exedy racing clutch, 3.94fdr from and scx, so much more..
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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by MY91GT(Z) »

I shift my car at 6k no problem with mine (done bout 10k this yr alone)and im not to easy on my car nor was previous owner n i lay some nice marks in 2nd gear dumps, my lsd is doin good


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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by speedy »

i meant rebuilding the trans, not the lsd, i know the lsd should hold up.


1991 beretta GTZ- 2.3l w41 cams, ported 086 head with a 3 angle valve job, fidanza flywheel with exedy racing clutch, 3.94fdr from and scx, so much more..
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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by 3400beretta »

If I were you, I'd convert the car to internal slave (not too difficult) and use the new 3.94 trans as is untouched. Don't mess around with the bellhousings. Yeah you can swap them, but if the shims aren't right you can grenade that diff pretty quick.

If you are bent on rebuilding it (I don't know why you would with only 66k on it), it can be done if you take your time and follow the service manual. I did it, having never opened a transmission in my life. I only needed help pressing the gears on and off the shafts. And it is still alive (and shifting PERFECTLY) in the 3500 turbo car today. I would not put faith in your local tranny shop to do the job for you. Unless they have a proven track record with manual transmissions AND setting up rear ends. Even then I would be leary, but thats just me. I am a firm believer that if you want it done correctly, you do it yourself. OR send it down to Jeff at EP for the rebuild. I'm sure it won't be cheap though.


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Re: quad4 3.63fdr trans or 3.94fdr trans???

Post by 3X00-Modified »

Yeah not sure what Jeff would charge extra for doing a rebuild or simply a run through. I'm sure he will only replace parts that are needed unless you specify otherwise.


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