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Gearbox choice dilemma...


Guest macks

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The T5 is not a close ratio trans in the ratios I've seen it listed. I thought about one at first, because I can get a nice Pro 5.0 shifter for it, and in a lightweight car if it will handle 300# torque or so I know I shouldn't have problems with it.

 

A T56 is another story altogether, you have a 6th gear and I know 5th and 6th are strong enough in a Z car to handle some power.

 

Then there is the boost thing too, as mentioned. I know there are folks running 3.70-3.90s with turbo cars but I haven't had the pleasure to experience that first hand.

 

Planning on 205/50 15" since I can't 215s for my 15x7" wheel, that puts me in 5th gear 122 MPH @ 6,000 RPM, that wont cut it. I already dont like the idea of 5th gear since its supposedly weak in this early 5 speed. With a 3.54 I can do 134 top in 5th. This is more acceptable but still a bit short, probably great at Thunderhill but if I get the chance to hit Buttonwillow, it wont cut it I'll be redlined everywhere. Until I can drop a meelion dollars on big butt wheels/tires, I need to have something that isn't going to redline me at such a low MPH.

 

So, with a later trans this will definately help, and I wont feel so guilty about putting it in 5th.

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hey zline,

 

give a bit more info with your posts please......i.e. which tranny for which rear??? and there are HUGE #s of Z guys in So Call, show up to a group z meeting some time......

 

A good rule of thumb for a N/A Z IMO is to find out what tranny you have and what rear ratio it was originally mated too and bump up to the next available ratio, in other words

 

72 thru 75 4 speed had a 3.36 so use a 3.54 (not recomended for street but the best option for autoXing in BSP class Solo 2 so they say....)

 

76-78 5 speed had a 3.54 so use a 3.7 (I had this setup using a Subi R160 LSD and liked it a lot on the street, but the 2nd to 3rd drop SUCKED for the trck)

 

79-83 5speed had a 3.9 and the 81-83 version tranny has a .74 5th gear, so I may try using a 4.38 rear over the 4.11....haven't decided but this tranny is said to be the most robust and has nice even gear spacing......

 

As far as the T5 goes, from what I understand, it came with a 3.54 rear and needs to be kept that way, especially for a turbo

 

Cheers,

 

Ian

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Guest empracing

funny how some ppl want /need low ratios and others like me want high ones i shudder when i hear of ppl taking a 3.45 out ill take it!!!

ps i have the 3.86 or what ever it is with a zx 5 speed and the bloody thing did 200kph in 4th ide hate to see it with a 45 wait no i wouldent

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Well I have run the 3.54 and now the 3.71 and I like the 3.71 the best. The car pulls hard, a 3.90 in my car would be stupid as I have a hard time with the car hitting 7K in first just about the time I need to shift, and second is not all that much better, more manageable tho.

I can run through 1 gear before I am all the way out of the drive way if I really get on it and then it hits the rev limiter.

Go with the 3.54 gear if you want to drive it on the freeway allot and if you want to race the car go with the 3.71 gear because it still is not that bad on the freeway.

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5th gear for me 2000 RPM is 35 MPH, 3400 RPM is 70 MPH. Unless my tach or something is way innacurate, which I doubt (I can check with a spare tach I guess), then I have some serious gear. From the way the engine sounds it sounds about right to me RPM wise.

 

Again with my tiny tires, I need a 3.54 I feel, I may keep the 3.90 since nobody wants it though :)

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5th gear for me 2000 RPM is 35 MPH' date=' 3400 RPM is 70 MPH. Unless my tach or something is way innacurate, which I doubt (I can check with a spare tach I guess), then I have some serious gear. From the way the engine sounds it sounds about right to me RPM wise.

 

Again with my tiny tires, I need a 3.54 I feel, I may keep the 3.90 since nobody wants it though :)[/quote']

 

hell ill take it =)

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Its $125 for anyone that wants it, it would be a bear to ship though. I'm in 94080, you are in SoCal? If so, thats a bit of a drive, for either one of us. If you live nearby Ian, he I'm betting can find one or something at some point. I know there is a guy near LA that knows of an import yard, and he seems to be able to find Z stuff down there. If nothing pans out and you seriously want it, lemme know via email or PM.

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More feedback on the NA trans being whup azz

 

The transmission is a '82 non-turbo unit, which I chose because of the better ratios (after much researching I found it had the same 1st - 4th gear ratio's as the Nissan Comp 'Close Ratio Overdrive' transmission), a better 0.754 overdrive and a 'reverse lockout' to keep you from grinding gears when shifting from 5th to 4th in a hurry. I talked to Ron Johnson from Nissan Motorsports regarding the strength of this unit, and he stated that the tranny could take up to 500 hp, but it was shock that would kill it. He said it was basically the same tranny they used in the 600 hp IMSA Z-cars in the early '80's. I have always hated the feel and the cantankerous shifting of the Borg-Warner unit used in the '83 ZX turbo (plus it has sh*tty ratio's), so I'm going to avoid resorting to it if at all possible.

 

http://zhome.com/rnt/StealthZ/swebbB1B.htm

 

I dont understand really why road racers would be looking at a T5 at all, unless they were getting a different gearset. The Nissan T5 setup is not a close ratio trans, I prefer to have an even RPM drop in every gear, it makes for a much more predictable drive, and it is just comforting, call me a pansy :)

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