GT1-20b

Announcement:

Getrag W-160 6 speed ...OEM for Supra TT 2Jz adapted to Mazda 20b/ 13b

" TOTALY BOLT ON KIT "

No fab work, no welding, completly BOLT ON. and w/ off the shelf related components.
All CAD, CNC'd & Water Jet.

Adaptor plate, Dedicated Starter, Hardware, Trans Mount, Anular Release TO bearing,
Shifter Tripod, Instructions, Everything !

You supply gearbox

- Pictures and website coming soon !!


GT1-20b

FDNewbie

iTrader: (10)

GT1-20b, that sounds badass. I know those boxes have been run on 1,000 hp Supras, correct? My biggest immediate concern is, the Getrag tranny is *considerably* longer than the stock FD tranny. Wouldn't that mean everyone will have to modify the PPF and possibly the driveshaft? And if you're moving the 20B back at all, I'd think the tranny would interfere w/ - if not completely block - the exhaust path, would it not? At least those were my impressions/concerns, which is why I looked elsewhere. Other than that, the tranny is a MONSTER...

One last thing: I'm not too familiar w/ the Getrag; are there upgraded internals and different gear ratios available on that tranny? W/ the huge Supra market, I'd think there would be...

Thanks!
~Ramy

GT1-20b

a) On the contrary, the W-160 is substantially shorter than the FD's
b) It will require a custome made drive shaft.
c) Every custom part required for convertion, I have made up except drive shaft.
d) There is only one set of ratios available for this box, as it was Type Specific
for the TT Supra, but the grear drops are closer that the FD's and very
favoravble for rotaries specially w/ an Auto's 3.90
e) You will have to buy some components, ie: clutch, Flywheel, but all
" off the shelf "

GT1-20b

crispeed

I see you've been doing your homework.
The first thing I always ask all these tranny companies as to what they do about case flex and they always come up with the same answer which is notting. If you're seriously making power and you're putting that power to the ground then I don't care what gear set you have in that box it's going to send the cluster gears/counter shaft south right out the bottom.
Ever wonder why all the tranny companies here stress the fact about upgrading the case and strapping the two shafts together. Gear separation is the major killer. I have so many cracked factory cases that were about to send the counter shaft out the bottom. I remember back in the early 90's I saw a pic from one of the Aussie racers showing a counter shaft that came out the bottom of the tranny. The guy went to great lengths even making a girdle to fit around the main case to help with the problem.

crispeed

You're 100% sure of that Ernie?
Why don't you lend me your tranny for a weekend of racing.
Hope the tranny works out for you and it should. The second major draw back also with the stock tranny was the output shaft size. PPG has addrees that problem. Only time will tell if it can handle the abuse.
I really hope it works out for you Ernie.

FDNewbie

iTrader: (10)

Hmmm Dunno where I got from then lol.

Easily done.

Nice!

It's a 6 gear tranny rite? You know what the theoretical top speed is in 6th?

Sounds very nice The two questions I have are:

1) What bellhousing are you using? And how deep is it?
2) Can the shifter location be modified? Specifically, can it be moved forward some? I don't recall whether or not the Getrag has a forward mounted access plate or not...

FINALLY! lol. Thanks for your $0.02

You don't have a copy of that pic by any chance, do you? Because there have been quite a few unbelievers of what is essentially "common knowledge" in other rotary circles...

~Ramy

calculon

iTrader: (29)

The 6th gear in the getrag is actually shorter than the 5th in the FD. I don't remember exactly, it's not much. THe source is a thread where Jimlab posted up a few different tanny specs and pointed this out. . . if i remember right, this tranny makes 1st gear basically useless unless you get a much taller diff gear.

sorry for the lack of specificity, just too lazy to dig it up.

ryan

RX-Heven

iTrader: (1)

Are there dog-ring conversions available for this tranny?
I found one for the Gertrag V-160 6-speed offered by PPG. What is the differecne in case/internals design betweent the V and W versions?
http://www.powerhouseracing.com/file...ine%20Upgrades

FDNewbie

iTrader: (10)

That PPG gearset sounds sweet, esp w/ custom gear ratios With this new news, I really think we need a side-by-side comparison of the T56 vs. Getrag trannies. The obvious one here is that GT1-20b's kit is bolt-on, but I'm still waiting to hear back re: shifter (re)location info.

~Ramy

mirabile

and price of the GT1-20B set up?

FDNewbie

iTrader: (10)

Oh yea...and that too

patman

iTrader: (3)

i was under the impression that the supra getrag trannies were pretty rare and hard to find? Gt1-20B do you have a source for them that they would come with the kit, or would the buyer have to find one?

FDNewbie

iTrader: (10)

Last I checked, they're still available new. And for those who would be getting the PPG gearset, there's no prob in buying a used blown one off of Supraforums

Howard Coleman

iTrader: (6)

93 supra TT ratios

1st---3.83--- really low unusable... supra had a 3.4 rear end
2nd---2.36--38% drop. from 7000 to 4319 rpm too much spacing
3rd--1.69---28% drop from 7000 to 5012. o k
4th--1.3----22% drop from 7000 to 5426 nice
5th--1----24% drop from 7000 to 5343 nice
6th--.79---21% drop from 7000 to 5530 nice but limits top speed to around 150 w 4.1 rear and there is no real low cruising mileage 6th.

how does the box shift at 7500+ rpm?

what is the weight of the box?

hc

RX-Heven

iTrader: (1)

For an easy comparison....

Standard TII ratios:
3.483 / 2.015 / 1.391 / 1.1 / 0.719

PPG offerings for the Supra 6-speed gearbox:
3.20 / 2.19 / 1.56 / 1.20 / 1.00 / 0.83

Borg Warner 6sp T-56 Gear Ratios:
2.66 / 1.78 / 1.30 / 1.00 / 0.74 / 0.50

PPG ratios for the dog box conversion in a stock RX7 case:
2.527 / 1.805 / 1.381 / 1.155 / 1.000

And Gurus offerings for a dog box conversion in a stock RX-7 case...
Guru Circuit gear ratios:
2.387 / 1.705 / 1.339 / 1.444 / 1.0

Guru Targa gear ratios:
2.648 / 1.804 / 1.406 / 1.162 / 1.0

RX-Heven

iTrader: (1)

If GT1-20b could answer this:

Are there dog-ring conversions available for this tranny?
I found one for the Gertrag V-160 6-speed offered by PPG. What is the differecne in case/internals design betweent the V-160 and W-160 versions or are there any?

I will be all over this if I can fit the PPG dog gears in the tranny he is doing the conversion for. Hell, I'll be first in line for that matter by placing a pre-order as this is EXACTLY what I have wanted and been hoping for all along.

GT1-20b

Stand corrected.

The correct Getrag designation IS V-160
Apologies for the Typo error.
Thank You.

Now, I'll try to answer some questions ...

This gearbox is Type Specific to the Toyota Supra TT. meaning it was specifically designed for that car, that engine.
The 2Jz. Therefore the bellhousing is NOT detachable or removable.
The bellhousing is part of the main case. So you must convert the engine to gearbox bolt patern to that which the boxe's bellhousing will accept.
The "Kit's" adaptor plate, adopts and places the bolt pattern of the 2Jz onto the Mazda, so the Supra's TT gearbox just " SLIPS ON ".
A dedicated Tilton style Reverse Rotation Super Starter is then installed in the hole were originaly the Supra's clutch release slave cylinder would normally go.

The box is crossectionally bulkier, but substantially shorter than the FD's.
This will be illustraded in a side-by-side comparison when the pics. are uploaded.

Stock, this gearbox is capable of handling well over 1000 HP, corresponding monster torque, with sure & lightning fast shifts.

The shifter sits in a tripod base separate from the main case.
Theoretically, one could place the shifter as close or as far away as nesesarry.
No forward access cover provided or nesesarry.

The box is stronger, lighter, and physicaly smaller (more compact) than a T-56.

The Kit's ancillary components, ie: Clutch, Flywheel, Release bearing, ect. are all
"off the shelf " components.
The phylosophy of design was based around the use of readily available proven name brand pieces and components.

Street: Tilton 8.5 Dual Disc OT series on either Aluminum or Steel Flywheels, w/ 750 Lbs/Ft. torque holding capasity.

Race: compatible with any 7.25 or 5" inch 2, 3, 4, disc, or Carbon/Carbon clutch pacage.

Racing: several vendors offer Dog ring engagement close ratio gear sets for this box. ie: the PPG as previously mentioned.

Ryan mentiones: the " USELESS " 1st. gear, and shorter top gear than FD's
This is partly true but NOT correct. Depends on use and intended purpose
This box as used in the Supra, was combined w/ a 3.13 Ring & Pinion final drive.
As oposed to the FD's Standard 4.10 or 3.90 for the Auto's.
As a Street racer and weekend Drag warrior, the gears are perfect for hard launches, best acceleration, and great ET. 6th. gear, not 1st. then becones useless as it will never be used in that senario.
As a Track day car, again the very close grear drops combine w/ the FD's final drive provide for excelent ratios for ANY track.
In this senareo 1st gear would not be used except for pit row.

Even with this low 4.10 final drive, asuning a 26.5" diameter of an average 17" wheel & tire, at 8200 Rpm in top gear if ther is enough power to get to that RPM, it equates to 198.99 MPH.
With the Auto's 3.90 now we're talking 209.30 MPH.

I wonder how many of us have the COJONES to drive our "street cars" that fast ?
I know I don't !, ...and as most of you know, I drive and have driven some pretty fast racecars.

Now, If Non-Real world Hypothetical numbers game turns on your fancy, and Theoretical MPH #'s is what you'r after, do as the V-8 guys do, install a Cobra 8.8 IRS Diff, pick the terminal speed you want from a wish list, do the math and
install the gear that will get you there. ...v For example:
A common Ford final gear like a 3.08 X a top gear of .793 as in the Supra box's top 6th gear at say 8000 Rpm. with the same 26.5" rear tire diameter.
That will yield a top speed of 258.59 MPH. WOW,
This is absolutly unreal and imposible but in theoretical terms ?? what the heck !.

As for a price, I don't have one figured out as yet.
But I know it will be substantially cheaper that a complete T-56 convertion.
For now it will be on a per order basis.
I have built enough parts for 3 Kits besides my own.
Who knows, if enough interest is generetad, maybe a GP can be arranged.

If interested or have specific questions, PM me.

Thanks

GT1-20b

RX-Heven

iTrader: (1)

I got first dibs on one of them you have available.
pm me any deposit info

FDNewbie

iTrader: (10)

If everything works out as previously described, I'm 2nd in line.

Doc Holiday

iTrader: (2)

Why not just throw a Richmond box behind it? Seems like it would cost a lot less.

mirabile

Group Buy Group Buy Group Buy

GT1-20b

True, would cost less.
But not as elegant or presice

Plus the external shift rods to constantly deal with.

FDNewbie

iTrader: (10)

https://www.rx7club.com/showpost.php...5&postcount=12 They have a very low torque rating. Useless IMO.

IronMdnX

iTrader: (1)

Just saw this update.
Very interested, Looking forward for pictures and more info.

Howard Coleman

iTrader: (6)

re the supra trans.

since the bellhousing must be supra it will be important that it is not too bulky for some.

i run two 3 inch downpipes and the FD bellhousing works just right in relation to the tunnel. should the supra bellhousing be larger i would have a problem and would not hack up the tunnel to fix it.

i understand that others might not have the problem and of course you would have lots more latitude if you are running a dedicated racecar or if you run a 20b and have it moved back a bit.

i do agree w Carlos that if you ran the cobra rear and had a wide array of rear axle ratios that the overall gearing w regard to trans ratios could be worked out... and we each could pick what would work according to our needs.

i am planning on running the Silver State Classic so i need a bit of legs to my final drive ratio and it could be done w, say, a 3.12 and turn 4th into a 1 to 1.

howard coleman