Kurgan

If you read my other posts, you know that my goal is to have around 700 rwhp and make my street trimmed cars capable of dipping into the 9s.

Transmission requirements in order of importance:
1. Hold my torque
2. Be able to turn 8000 rpms
3. Have a clutch (as in a clutch on the floor)
4. Have a relatively stock located shifter

I have a couple of options for a transmission:

1. Some form of a T-56
2. Go with the all might Geforce tranny

T-56
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The highest torque rating I have been able to find on a T-56 is 450 ft/lbs. I'm pretty sure that I'll be over that with 700 rwhp (I should hope so). I have not been able to find out where the shifter will come out in my S5, but I assume it would be somewhere near the stock shifter... slightly off is ok, but I don't want to cut anything. Having a 6-speed would be NICE for highway crusing too.... Costs less than $3000 (maybe a lot less depending on where you get it from). Still would require a good clutch for the amount of power I'll be making.

Geforce:
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The king **** tranny. They have a rotary bellhousing adapter available. I've been told that the shifter comes out in relatively the same place as the stock shifter. Would have NO problem holding the power I'm going to put down. Completely sequential shifting, very BADASS. tranny starts at over $5000, then you get to add options and the bell housing adapter... so this is a big decision.

Clutch:
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Obviously, I'll need a multi disc clutch. I don't know anything about them... i've never seen one, installed one, talked to anyone that had one, or ridden in a car with one. I know OS Giken makes a dual and triple disc clutch. In looking at the torque specs, the dual disc may have a hard time (or be right on the brink) with the amount of power my motor will be making... so, I'm leaning towards the tripple disc (information obtained from Hyperex cuz I can't find CRAP on these clutches )

Who else makes a dual or tripple disc clutch? Are they harder to drive (not a deciding factor, i'm just curious). Will whatever clutch I get work with whatever tranny I get, or will I have to make up my mind before I buy either of them?

Thanks for any input!

Red-Rx7

Kurgan-

I am in the same boat you are.. except I don't plan on making that much power too often.

I have been looking at the OS double plated clutches, and trying to get some more specs on the Guru Racing dog box they make in Aussy land.

When I get the results there, I will post and let you know the torque specs.

Thanks,

Mike

mmaragos

I think jimlab is looking to use one from these guys:

http://www.mcleodind.com/

He is looking to push major HP and torque, plus he seems to do pretty comprehensive research.

Don't know if there will be any fitment issues.

mmaragos

http://www.jericoperformance.com/products/index.html

How about one of these?

jimlab

That rating is for 24 hours. Continuous. The T56 will hold a lot more than 450 lb.-ft. of torque, and the McLeod Street Twin twin disc clutch that I'm using will hold upwards of 850 horsepower reliably. There are Camaros in the 9s using this setup. D&D Performance is who you want to talk to for a beefed-up T56.

The T56 is shorter than the stock RX-7 5-speed, roughly 26" from the front of the bellhousing to the shifter, if I remember correctly.



Very badass in one direction... it's not a street transmission and upshifts well, but downshifting is another matter entirely. They make a "road race" version which supposedly downshifts, but I haven't heard of anyone using one, and they use straight cut dog gears = rev matching required and a lot of noise.

Multi-disc clutches are designed give the clutch far more gripping area to increase power handling without signficiantly increasing pedal effort with a much stiffer pressure plate.





Hope that helps.

j9fd3s

iTrader: (3)

hey jim is that your clutch? i have an act copper one and i hate it, that organic twin plate looks perfect though.

mike

jimlab

Yep, that's my Street Twin. The clutch plates are organic on one side, and Kevlar on the other... dual disc, dual friction, if you will.

j9fd3s

iTrader: (3)

thats a sexy clutch, jim.

mike

DELTA_Rotary

Jim I thought the H-Pattern version of the G-force was pretty streetable? Also anyone thought about a Tilton? Lots of the High HP street-class supras are running them.

twint78

ive talked with gforce about this.jim is right the sequential shifter is six speeds up.it is totally for the strip.it does not downshift.they have a street version but not really strong.a t56 would be better.

matter of fact quaifeamerica has a street seq. shifter that is able to hold this amt of power..and make it to fit ur bellhousing also.

jimlab

John Moss (the guy who builds all the cool concept cars for Chevrolet) put a Lenco "road race" 5-speed transmission in the 572 CID Camaro ZL1 he built. He said that it was such a pain in the *** that they decided to pull it and slap a Tremec TKO 5-speed in its place instead.

jimlab

Quaife makes a 6-speed sequential transmission for the Viper, but it is not rated for the power levels you're talking about, and it's about $10,000-11,000, depending on the conversion rate. ~$400 for the dash-mount LCD gear indicator, and custom bellhousings are available at extra cost.

sbertolone

how often do you think your 600ftlbs+ of torque will hook up . tranny normally take a **** in either 1st or 2nd when theres traction because one synchro is signigantly smaller than the other. i doubt you'll be wide open in 6th very often which would have about the same size synchros as 2nd with a t56. clutch wise mcleod probably makes a slipper clutch with a metallic disc which would help 60' times. I have seen 4000 lbs roadrunner with 6.5inch oe redline tires on it cut a 1.79 with that clutch

Evil Aviator

Lenco makes a streetable transmission, but like the G-force, it can't downshift. It's not a big deal if you just drag race, and don't mind blowing through brake pads and rotors while street driving. The air-shift option is especially cool IMO.
http://www.lencoracing.com/

Any idea of where to get a T56 adapter plate for a rotary? (Preferably one which works with the Quarter Master 5" 2-disk clutch pack).

mmaragos

Potential here for a T56 adapter:

http://www.kennedyeng.com/other.htm

DELTA_Rotary

Jim what the stories I've heard of the T-56 not being able to handle the high rpms of the rotary?

jimlab

Would I be using one if they had a problem with high rpm?

There are many people taking them to 6,800-7,000 rpm regularly in their Camaros and Firebirds without issue, and those who have solid roller cams and aftermarket engine management are taking them above that limit. There are F-body cars in the 9s with T56s. If there's a limitation other than nearly 1,000 horsepower to using the T56, I'm not aware of it, and neither are the folks at CamaroZ28.com (www.camaross.com/forums/) as far as I can tell.

Dyre

For some reason i remeber crispeed mentioning he tried the T-56 and it was worse for his use than the TII tranny he was using. I thought he said the probably was the rotary makes peak torque much higher in the RPM band than the typical piston engine, and we all knoe torque is what kills trannies, not hp...

Of course, cris also shifts at something like 9k rpms...

I would search and find the thread, but im sure it has been lost in one of the hacks, or in the pruning of old posts. It was some time ago.

Kurgan

Here is Crispeed's post that I found in this thread :

twint78

it doesnt matter where u make torque at with a tranny to kill it,as long as it in its range of capability.
ur thinking that a t56 can handle 550 ft lbs of torque at 5k rpms but cant handle 385 ft lbs at 7500rpms?

t-von

iTrader: (8)

Had to bring this one back from the dead. Sorry Anyways, has anyone ever tried the Spec stage 3 clutch from Rx7 store? It's rated at 550 lbs torque and is suppose to be very streetable. Thats the one I would like to purchase for my 20b. Just need some input.

94RHDFD

iTrader: (3)

That's the clutch I have it's a sprung 6 puck, although I have not try'd mine out yet, Bryan (BNR) has one in his car and it feels very streetable

sbertolone

hey i found out this month that gforce is making a t5 trans with dog ring gears for 2200.

t-von

iTrader: (8)

What flywheel are you using? Did you have to do any balancing?

Kurgan

a gforce tranny for $2200? what are the torque specs on it? Any more information?