fc8s
 

i was thinking of swaping in a rx-8 trans in my fc3s TII but it said in the faq that theres know real advantage to the rx8 trans over the fc trans but there is. the more gears means a closer ratio and that means less loss of power to the rear end when shifting and it said on the faqs that 6th gear was taller than 5th on the fc trans which would mean better fuel economy and higher top speed, the only problem would be that if the car didn't have any sound preformance up grades, then the engine might not have enough power to make it to the top speed of the rx-8 trans. any who i think 6 speeds are just cooler any way.

i think the rx8 tranny can only handle like 250-275 hp, also i think 6th in the rx8 tranny is either the same as 5th in the rx7 tranny, its kinda like adding an extra shift, but i like 6 speeds, dont know why. but i do.

I believe that it should say the rx-8 has a shorter top gear, since it definately states that it will result in lower highway gas milage. Also, the shorter gearing is designed for the rx-8 powerband, so it might not work well with our engines. If you want to drop the money on the rx-8 tranny and get it to fit, more power to you, but I personally think its a waste of time and money.
My ideal tranny would be about the same as the stock 5 speed, but with a shorter 5th, and a super tall 6th like in v-8 sports cars where its only like 1600 rpm on the higway.

IIRC the 8's trans is the same strength as an NA trans. I would stick with a T2 trans for reliability and also fewer shifts with a taller (more efficient last gear).

maybe you should reread that.
a little searching shows the fc has .711:1 and .697:1 5th gear ratios.
iirc .711 being turbo II.

that .83 will give pretty bad milage on the highway...
rx-8 is similar to miata tranny (.81 5th gear IIRC)

ratio's
http://www.mazdatrix.com/g1.htm

Cool link, not sure how I missed that all this time. So my trranny has the tallest 5th gear of any rx-7. Cool! No wonder I pulled off such good highway milage.

If you like shifting more often, then go for it...


-Ted

If you want a six speed, drop a shitload of money into figuring out how to get a T-56 in there.

Then tell me how to do it.

T-56 wouldnt be so much hard, as expensive. one off custom parts FTW!

fitting a t-56 in there is easy! it just has to be mated to an ls1....

^^ +1 grab the motor too, and watch your HP and gas mileage raise!!!

ive got a mechaic friend that works on transmissions alone and has a whole trans machining rig for fixing and changing (ratios) transmissions. he can also get custom gears made for cheap out of any kind of stock you want (titanium, kevlar, etc...) so if i could finde a rx8 trans out of a wrecked car i could have him gut it and change 1-5 like normal TII and then change 6th into a .5 gear (160+ WOOT WOOT)

Yeah, my old mustang GT ran at 1500 rpms at 60 mph. It still got similar gas milage to a modded turbo rx7 though :(

So by the reckoning in this thread, a 3 speed transmission would be an upgrade because you'd have to shift less?...........



And kevlar and titanium gears?,.......

its the more shifting for no real change that is the issue.

How exactly do you come up with no change? The shorter ratios that having 6 speeds covering the same range allows is going to directly translate to quicker acceleration.

i got JDM titanium gears YO!

Get a TII tranny and be done with it.

Don't know what is it with people and their six-speed fetishes. Maybe they admire the 18 wheelers and their 10+ speed transmissions.

your all screwed when i put a lexus 8 speed tranny in. I shift MaD qUiCk Yo!

it takes longer to shift. why do dragsters run 3 speed trannys and not 5 or 6 speeds.
not to mention as stated in the FAQ with the ratios it has its like adding an extra gear between 2nd and 3rd.

WTF?
Kevlar has very low compression strength, so why would you make gears out of it?


-Ted

well 5k hp and a 1/4mile commute also have something to do with that

and i dont see any epoxy or resin helping out...

well the kevlar would most likely be used for the bushings and other misc parts he didn't tell me what there used for he just said "yea, i can build up transmissins with all the best materials." then he listed a bunch of them kevlar an titanium is the only ones i remember

gear grinder
if he actually got a higher top speed I would be all over using the rx8 tranny that he modded.