Hello guy's this is what i wanna know what's involved in hooking up a supra gear box to the 20b also which supra box is the best to be used and just how much power can the box handle thanxx guys....

 

i would go with the mkiv getrag 6-speed. couldn't give you an exact torque/power rating on those, but suffice to say. . . they are bulletproof.

kiwi-re sells adapters for any toyota tranny, but i have no personal experience with them. kiwi-re is highly reputable in the community though, so i'm sure it's a quality product.

you can find those trannies used from around 3K if you look constantly on ebay and you can get them new for 4500ish all over the place.

 

what kinda hp do you want. They are guys in Austrialia, that runs 9's with fd box. Unless your going faster. But then again, thats the jspec box unlike what the guys use in the us. But if you wanna spend, GReddy and HKS and Guru motorsports have stuff for that box.

 

Because obviously Jspec boxes are stronger than ours maybe they're filled with magical JDM gummy bears. The FD box pretty much has the same guts as a TII tranny. Runing 9's on a stock tranny? Dont think i've heard of this one before. Correct me if i'm wrong but the biggest weak link in the TII and FD trannys is 3rd gear at around the 500 hp mark correct?

 

MMM your wrong there buddie, thats why the JDM gearbox was never plaqued with the stupid 5th gear syncro issue the american model have. Trust me, when I tell you that I feel the same way about the whole jdm better than american parts but , I have enough rx7 piece that tells me what I know. I'll try and find the link for the ausie car, it was even being discuss in one of the hreads the other day. I'm gonna look ....
And if memory serves me right, both ari yallon and cameron worth both have 9 sec fd's with the 5 speed gear box.

Actually I'm sure Cameron has one cause I've seen the car. Only saw Ari's car run in video. But Steve kan should be able to clear that up easily.

 

Here is your ausey video of a 9 sec with gear box https://www.rx7club.com/showthread.p...5&highlight=FD
...more than likey is a FD Box.

And here are other cars in the US that are running 9's with the stock box:
http://www.jigsawrx7.com/main.html
http://www.rx7.com/racing.html

Now I know they are a few more else where, but with proper driving and a good drivetrain setup, the FD box will last.

 

Well it's easily possible. If I wanted to, I could put a NA tranny in a car that weighed 1000lbs & with enough power run 9's and "NOT" break that weaker tranny. In the end, torque and abuse is what will kill the stock tranny.

Example...2 Rx7's running 9's. One with a 13b and the other with a 20b. I guarantee you the tranny on the 20b will break more often than the one on the 13b because of the torque difference. With a full drag set-up, your not abusing the tranny as much. The large drag tires take much of the stress away because of all the give and wrinkling of the tire at launch however, drag tires will allow you to put more power down to the ground therefore adding additional stress to the tranny since there is no longer any wheel spin. In this situation, the stronger engine will break the tranny faster in those middle gears because now the engine is in it's peak power range.

 

^ Actually, the one on the 13b would break more because of the big turbo and associated torque spike vs. the 20b with a much smoother torque increase in comparison. everything else is right, though.

 

for 3000-4500 You could buy a full race HK$ or Greedy dogmission!!!

 

theres a kit available for the older toyota boxes and its around $200-300AUD but the few cars that i've seen with the 6spd box built there own custom adapter plate to mate the bellhousing to the motor....i think that CLR in Florida used a getrag box on a 20b, u should contact Carlos to verify if this..
click this link to see the adapter plates available in oz
http://www.japperformance.com/

 

I see your point about the gradual increases but remember, both example engines are making the same amounts of power to run 9's, the 20b will still make more torque than the 13b regardless of turbo size. Remember when your shifting, your shifting at your peak power range for best acceleration (usually keeping the rpm's above 4.5k the whole time). On a 13b with a large single, this is usually your peak torque range. At peak rpm range, torque spikes are irrelevant because the torque is already maxed out and leveling out. So when the power is being put down to the ground, the engine making more torque will break the stock tranny more often. In this situation, that would still be the tranny bolted to the 20b.

 

https://www.rx7club.com/se-rx-7-forum-35/9-second-run-timemachines-553051/

 

Isnt the tranny gonna fail from flex in the case, the gears pushing away from eachother? Im lookin at using the straght cut gears to try and save the stock tranny. After reading about the russian FD breakin his pilot shaft at 700 it may not be a real solution. That was on a dyno right. BTW launching isnt gonna kill the tranny is it? When you start loading it up hard in the higher gears, where the load comes from trying to accelerate the car past 100mph is the real killer, right? Id expect the most stress in 3rd and up. Tires arent gonna break loose or absorb the torque,
Seems like at some point youve just gotta get rid of the stock box. in favor of something stronger. Id concider a viper or supra tranny. They seem alot stronger. finding and shipping tii trannys donst sound like a viable option.

 

well, fd and 89 t2 trannies are basically the same. tires will break lose in 3rd...ask me how i know. launching is the single hardest thing you can do to your driveline in terms of stress.

 

what about in foruth. I wondering why the russian FD broke his pilot shaft on the dyno. Thats a smooth load. Its just too much for the tranny. As you begin to gain traction in 4th and 5th gear the load across the tranny becomes greater. The car is no longer accelerating as quickly, so all the power your motor is making must be held along the driveline to fight the wind resistance and try to accelerate it that few MPH quicker persecond. Does that make sense? Maybe Im wrong. Im kinda thinking the faster you go the more power you need, exponentially, right. So the 4th gear and 5th gear runs where you cant break the tires loose and the car is barely accelerating is harder on the case.
I guess im thinking it just a matter of time when the car makes that much power before the tranny lets go. Im assuming most 20b owners are looking at putting down 600 or more, at least one day. For me its going to be in stages. Im getting the turbos fit up now. I eventually want to make somewhere around 700-800. I guess Im thinking for all the work Ive done and will have to do to get the car reliable im going to have to get a beefier tranny. I hope the rearend will handle the power if I keep to street tires.
I just worry after hearing about that russian car. Theres nothing you can really do the keep the pilot shaft from shearing.