Snufelupogus

iTrader: (2)

Hey, Im just wondering if anyone knows if its possible to change the 5-speed tranny into a 6-speed one. Its it just a case of changing the gear box or something? I dunno, I just think it would be cool to have a 6-speed instead of a 5, I like to be different.

0piston

iTrader: (9)

you can for a $7000US price tag either for a HKS or Greddy

Evil Aviator

... or a Lenco drag tranny. There is always the Hewland IGT-C for $20,000 USD. You could go cheap with a T-56 for $2,000 USD, but I have yet to find anybody who makes an adapter plate for rotaries.

Snufelupogus

iTrader: (2)

Yeah, I was just at the Quaife American website and they got a complete 6 speed dog engagement gearkit for like $6500US. But I hear with the dog engagement system you can shift gears like stink!!
Lil too pricey for me at the moment, maybe after I win the lottery Ill get it. But for those crazy ***** that gots lots o moneys, then check 'er out.
http://www.quaifeamerica.com/gears/rx7.htm I think its for second gen.
I'll see what I can come up with on that T-56 tranny though and get back to yah if I find sumfin.

tweaked

iTrader: (4)

I have heard a rumor that you can take the six speed from the aniversary Miata. It is supposed to be farly easy to do. just change afew things. I have been unable to verify this however, I have not looke very hard. I thought it would be easier to just put in a taller 5th gear

silvr94r2

iTrader: (3)

I have had lot's of people tell me that there is a 6spd for the Cosmo......is this true? If so, then why doesn't anyone try and make that work?

NevadaLoneWolf

But weren't ALL Cosmos automatics?

silvr94r2

iTrader: (3)

that's what I've always thought as well, but these people swear that there are 6spd cosmo's. I've got a friend who works for a engine importer and he says that they get 6spd trannies in with the 20b's. I don't know though......he could be mistaken. I've heard it elsewhere too......oh well.

13BAce

Yes. I've never heard otherwise.

13BAce

It may work, but I doubt that it would hold up to alot of power.

Snufelupogus

iTrader: (2)

I checked up on the miata 6-speed tranny, and it wont work unless someone fabricates an adaptor plate for it. Another thing, the Anniversay miata only has 140bhp, so I doubt it would be capable of withstanding a lot of more power.

I found an adaptor plate for a T-5, unforunently thats only a 5-speed, and the both pattern for the T-56 is different from the T-5 so that adaptor plate cannot be used.

I have been told from a camaro guy that building an adaptor plate is not very hard, just need access to a machine shop.

As for the 6-speed that comes with the 20B, anyone know what tranny that is or how much it goes for?

HWO

you can put a 6th foward cog into a FD box, a guy is aussie has done a few

13BAce

Having closer ratios would be nicer than just a tall 6th, unless you want to go 200 mph.

Snufelupogus

iTrader: (2)

Yeah, Id rather have the close ratio of a 6-speed than just a tall 6th gear.
You said that a guy in aussie has put a 6th speed into his FD gear box? If this is possible, could I just replace all the gears in the FD box and add that sixth gear while Im at it so that it becomes more like a real six speed with the close ratios?
Id rather do that than they and get fancy with adaptor plates and all that...

Evil Aviator

13BAce

Can't you do it with the T-56? I'm sure there are alot of gears available.

Snufelupogus

iTrader: (2)

i found the gear ratios for the 2nd gen tranny and the T-56, lemme know what you think, I dont know from gear ratios

2nd Gen 3.475:1
2.002:1
1.366:1
1:1
.711:1
Dunno Final Drive

Ford T-56 2.97
2.07
1.43
1.1
.80
.62
Dunno Final Drive

Viper T-56 2.66
1.78
1.30
1.1
.74
.50
Dunno Final Drive

Now that I think aboot it, it wouldnt really be much better for acceration situations, infact it would probably be worse huh?

Anyways, the car its going in only weighs like 1500lbs
For a car wieghing that much and being powered by the TII engine, which tanny would you suggest?
Im kinda hopin to go with the T-56, that way I can use a transfer case from a chevy or ford to complete my AWD system instead of staying with the TII tranny and trying to rig up the MPV transfer case (goo! MPV)
Any thoughts?

13BAce

If you want AWD then I guess you have no choice. The 2.97 is the only downside. That should be able to be changed if it becomes aproblem. All of the other gear ratios look good. Good detective work.

spyfish007

Gee I had started thinking of the Miata transmission not too long ago and I mentioned it to only a few people ..... I wonder if that rumor came from me? If so then people talk too much! I will say one thing .... I think that 6-speed is one of Mazda's little pet projects ... and Cosmo's are automatics.

HWO

Ever heard of changing the diff ratio?

change ya diff ratio so flat out in 6th is just slower than what you can achieve in 5th at the moment, that way 3/4/5/6 will be nice close ratio's

there is two ways to skin a cat

B430

you'd have to change the rear end since T-56s are built for cars with 5500 rpm redlines (i assume a LT1/LS1 redlines around there).

13BAce

All of the gear ratios are very similar to the TII 5 speed, except for 1st gear.

13BAce

Good point.

Snufelupogus

iTrader: (2)

Like 13BAce said, "All of the gear ratios are very similar to the TII 5 speed, except for 1st gear.", so why would you have to change the rear end? And what would changing the rear end do anyways?
Accelerating up to your top speed faster would be good. But with acceleration you lose a bit of top end speed. What Im looking for is something that will allow me to run through the first 4 gears fast so that I get up to speed fast but then have 5th and 6th a wider so that you can stretch out your RPM's and hit a higher top speed.
I had a look at a pic of a T-56 and it is a very large contraption. I doubt it would even fit into an RX-7 at all without having to make a new floor to compensate. Which is all fine and dandy for me 'cause I have to cut up the floor in the car that this tranny is going into anyways.
But, yeah changing the differential ratios would work too.
I dunno, keep thinkin of stuffs.
Anyone figured out what that 6-speed tranny for the 20B is yet?

Im out for a couple of days, so my R&D will continue upon my return. Friends 19th B-day taday!
Peace out!

kevinmfaust

Changing just the diff ratio would be a half assed fix. The 1st gear ratio is good where it is. The best thing to do would be to come up with new ratios that realy take advantage of the additional cog.
Kevin