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Option 2 vs T5 interchange


RoadRace

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While I've never done it, I can pretty much guarantee that other than the bellhousing pattern they are entirely different. Different INPUT spline, the T-5 is much longer, heavier, wider, different rear mount, different output spline.

 

However, the only L-series "option 2" gearbox I saw was basically the same externally as a FS5W71A Nissan gearbox. Since "Option 2" only referrs to the gear set, it kind of matters what series transmission the base is. I've seen "Option 2" 56-series gearboxes for B210s. Not the same thing at all.

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There is almost nothing to like about the FS5R90A. It can handle an L28ET and barely a 300zx. It's reported that when they blow, owners have swapped in the non turbo FS5W71C with no further problems. The T-5 is often mistaken for the bulett proof "World Famous" Borg Warner transmissions used in the 5.0 and Canaros but it's not. The previous 5 speed, the FS5W71B, was pretty much at it's limit with the L28E and the next gen FS5W71C wasn't available untill '84 so Nissan cobbled this thing together to quickly get a 5 speed in their 280ZX turbo cars. In fact the first year or so the turbo option only came with an automatic. If this is for a 4 cyl stay away from the FS5R90A it's a monster and a monster waste of time. Get an FS5W71C and swap an L bell onto it. If you have an L28E or L28ET do the same. Only reason to have one is to keep a 280zx turbo original. Oh, the only good thing about the T-5? they are cheap to rebuild.

 

As for the option 2 it has much much closer ratio gears than the T-5 so, if that's what you're looking for there's another reason not to consider it.

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anybody put a nismo option gearbox in place of a T5? did the mounts line up, length different? output yoke different?

 

thanks

 

The option 2 gearbox was a nissan comp box with a 1 to 1 5th gear and they are not as tough as a T5 while it is nice to have the close ratio box that the option 2 offers the parts to rebuild one are hard to come by and to find one used could cost as much as $2500 or more if you have a T5 there are options for those also you can send it to G-Force (www.gforcetransmissions.com) and they will install whatever gear set you want that they offer and make it a straight cut gear box so it will be like a Jerico and you wouldnt have to use a clutch on upshifts or downshifts but this would be in a race application only

 

 

Clayton

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In Nissan parlance the Borg Warner T-5 was designated a FS5R90A. It was replaced in '87 by the Nissan made FS5R30A to handle the ever increasing power levels.

 

 

280zx

 

T-5 ratios:

 

1st.....3.500

2nd... 2.144

3rd.... 1.357

4th.... 1.000

5th.... 0.780

 

Non turbo 5spd ratios:

 

1st.... 3.062

2nd... 1.858

3rd.... 1.308

4th.... 1.000

5th.... 0.745

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On my slower than molasses next racecar build I will be using a 280ZX turbo bellhousing with a Ford Mustang World Class T5 transmission.

 

The Ford bolt pattern on the T5 bolts directly to the Datsun bellhousing. The T5's front bearing retainer will need to be machined down in OD to fit the ID bore on the Turbo bellhousing. The sleeve on the bearing retainer where the throw out bearing slides also needs to be reduced in diameter if you plan to use the original Datsun throw-out/clutch linkage. I am using a Quartermaster Clutch so it is just a matter of matching the Ford input spline on the disc to the clutch diameter and getting the correct spacer for the T/O Bearing to sleeve to get proper T/O distance on the pressure plate. You will also need to bore out the pilot bushing to fit the Ford input shaft diameter. A good stock World Class T5 is rated for 300 ft-lbs of torque. Aftermarket gear sets can get you to a 500 ft-lbs rating.

 

As mentioned by Clayton, G-Force makes gear kits for these transmissions. They no longer make the straight cut, dog ring ratios best suited for road racing. They had too much breakage from installs with solid center clutch discs. They recommend a sprung disc to take up some of the shock from clutch-less shifts, which the buyers were not using. They still offer those ratios in a helical gear with synchros.

 

G Force T5 Gear Kit

(Helical Gears/Sychromesh)

 

1st – 2.42

2nd – 1.53

3rd – 1.23

4th – 1.00

5th - .90

 

There is an option that can be performed to most any transmission by Liberty’s Gears www.libertysgears.com called “Face Plating” where they take the gear, remove the synchronizer ring and replace it with a “face plate” basically creating a type of dog engagement transmission. These are not designed to be clutchless shifting but will reduce "gear grinding" at high RPM shifts typical on sychromesh transmissions. The cost is $80/gear. I assume the coupling ring modification/replacement is additional.

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On my slower than molasses next racecar build I will be using a 280ZX turbo bellhousing with a Ford Mustang World Class T5 transmission.

 

The Ford bolt pattern on the T5 bolts directly to the Datsun bellhousing. The T5's front bearing retainer will need to be machined down in OD to fit the ID bore on the Turbo bellhousing. The sleeve on the bearing retainer where the throw out bearing slides also needs to be reduced in diameter if you plan to use the original Datsun throw-out/clutch linkage. I am using a Quartermaster Clutch so it is just a matter of matching the Ford input spline on the disc to the clutch diameter and getting the correct spacer for the T/O Bearing to sleeve to get proper T/O distance on the pressure plate. You will also need to bore out the pilot bushing to fit the Ford input shaft diameter. A good stock World Class T5 is rated for 300 ft-lbs of torque. Aftermarket gear sets can get you to a 500 ft-lbs rating.

 

As mentioned by Clayton, G-Force makes gear kits for these transmissions. They no longer make the straight cut, dog ring ratios best suited for road racing. They had too much breakage from installs with solid center clutch discs. They recommend a sprung disc to take up some of the shock from clutch-less shifts, which the buyers were not using. They still offer those ratios in a helical gear with synchros.

 

G Force T5 Gear Kit

(Helical Gears/Sychromesh)

 

1st – 2.42

2nd – 1.53

3rd – 1.23

4th – 1.00

5th - .90

 

There is an option that can be performed to most any transmission by Liberty’s Gears www.libertysgears.com called “Face Plating” where they take the gear, remove the synchronizer ring and replace it with a “face plate” basically creating a type of dog engagement transmission. These are not designed to be clutchless shifting but will reduce "gear grinding" at high RPM shifts typical on sychromesh transmissions. The cost is $80/gear. I assume the coupling ring modification/replacement is additional.

 

first off - thanks for the info from Liberty - good stuff, i talked to Gforce and they really weren't interested in doing any work to the T5 - and as its an early, NWC trans, it has brass syncros, not the fibre blocking rings in the later models that they are catering to. good info on the fitment issues - i'm putting that in my "handy info" folder, but why did you specify "slower than molasses next racecar " when you stated that the T5 you're using has a capacity of 300lbft? or am i reading that wrong? that much torque in a datsun might be pretty quick...

 

the T5 input spline is the same as a normal datsun trans, but i haven't taken the D/Shaft off the race car to verify the output on the T5 and i've got the option box apart for inspection right now.

 

I thought the Option 3 was the DD 5th? in anycase, the trans i have is the 'Ultra Close Ratio" box.

1.858

1.388

1.217

1.000

0.852

it was raced for years without incident behind an L18 like mine, i'm not keen on the T5's gear splits and despite the fact that the syncros are in good shape, and i've tried a couple different lubricants, it still manages to grind - as mentioned above.

 

I dunno dave - can i ask what you would do if you had an ultra close gearbox and a stock T5 both in great shape ready to go into the car?

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The T-5 is often mistaken for the bulett proof "World Famous" Borg Warner transmissions used in the 5.0 and Camaros but it's not.

 

The T-5 behind the 5.0 Mustang were MUCH stronger than the ones that wen't behind the Chevy Camaro's ,,, it is common practice to swap Mustang 5.0 T-5 guts into Camaro T-5 chevy trans for an "Un-Disputed Upgrade" ...

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RoadRace,

It appears I mispoke on Liberty's Gears doing face plating on T5 transmissions, they do not. They do T56 and the later TKO transmissions but the T5 has been passed by because of its lower torque capacity in comparison to newer transmissions.

 

My slower that molasses racecar was refering to the build rate, hopefully the car goes much faster once complete. It will be for SCCA - GTL or GT3 when I am done. The power will be either an SR16VE or SR20VE depending on class, so the 300 ftlbs is a safety margin for my use.

 

I have been told that BG Sychro Shift II is the stuff to use in brass synchro transmissions (never used it). I have been using Redline MTL in my brass synchro transmission in my current racecar.

 

Is the ultra close a steel band sychro or brass? The DD box synchros are steel. Also if you are running a brass synchro trans you need to be using GL4 lube. Most of today's gear lube is GL5 and it is corrosive to brass as well as too slippery for the brass rings to work properly at high RPM.

 

I'd use the ultra close and make sure you have a good GL4 lube in it.

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thanks again Dave - i'm going to look into the BG Syncro Shift II. i tried 3 diferent weights of oil in the T5 (synth and normal), but i can't honestly remember if they were GL4 or 5, - but i also didn't know it had brass syncro's until i pulled it apart last year. i had the best luck with Dex 3 ATF - typically used in the fibre syncro T5's.

 

the UCR box is a Brass syncro unit. i never tried the Redline MTL - but i use RL in the engine and shockproof heavy in the diff - i'll try the MTL in the gearbox.

 

time to get it ready for next year.

 

UPDATE: Liberty has confirmed that they can 'Pro Shift' modify the early NWC T5, but warns that this mod will render the trans not streetable...not really an issue anyway.

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  • 4 years later...

There is almost nothing to like about the FS5R90A. It can handle an L28ET and barely a 300zx. It's reported that when they blow, owners have swapped in the non turbo FS5W71C with no further problems. The T-5 is often mistaken for the bulett proof "World Famous" Borg Warner transmissions used in the 5.0 and Canaros but it's not. The previous 5 speed, the FS5W71B, was pretty much at it's limit with the L28E and the next gen FS5W71C wasn't available untill '84 so Nissan cobbled this thing together to quickly get a 5 speed in their 280ZX turbo cars. In fact the first year or so the turbo option only came with an automatic. If this is for a 4 cyl stay away from the FS5R90A it's a monster and a monster waste of time. Get an FS5W71C and swap an L bell onto it. If you have an L28E or L28ET do the same. Only reason to have one is to keep a 280zx turbo original. Oh, the only good thing about the T-5? they are cheap to rebuild.

 

As for the option 2 it has much much closer ratio gears than the T-5 so, if that's what you're looking for there's another reason not to consider it.

There is almost nothing to like about the T5? Really? I would think YOU of all people Mike would find SOMETHING to like about it.

 

How about the fact that its endlessly modifiable beyond that of an FS5?

 

Or the fact that it has a 265 ft lb torque rating (thats normally for instantaneous loading)

 

Or the fact that theres a crap load of parts availability, a crap load of trannies that can be bought for scrap prices and a ton of parts interchange in between different models used by over 10 manufacturers?

 

Or the ease of rebuilding a T5

 

Or the fact that the torque rating of a NISMO prepped FS5W71C is about 289 FT-LB, compared to the stock out of the factory T5 at 265 FT LB Too close to honestly justify the cost of the Nismo. And for the record, a stock factory FS5W71C is rated at 215 FT LB or 30KGFM.

 

Or the valuable bell housing that can be used to even put a World Class T5 in which holds 300 FT lb from the factory.

 

The fact that TREMEC still makes the tranny and its the longest produced 5 speed transmission on the market.

 

Reason I add this here is that I took my T5 apart and took the cases in for hot tank to a professional race shop.  He plead with me to sell him the T5 and went over all the above info with me (most of which I knew but kept to myself because of the general tone of this thread). He went on and on about how much better the T5 is actually.

 

So not that the FS5 is a bad tranny, But according to a professional race shop, it isnt a Borg Warner T5.

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Nissan also did not "cobble this thing together" it was only available for 1 year prior to Nissan using it, The T5 came out in 1981 and was used by Nissan in 1982.

 

Yes, it is the "world famous" transmission used by Ford, it was the Camaro and Firebird trannies that were weak, the Nissan box is more similar to the Ford version than it is the Chevy version. All the parts are interchangeable between all these trannies. So how is it not the same tranny?

 

Also, theres more gear ratios available for the T5 than there are for almost any Nissan transmission.

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