Servus

hey i just wanted to know, which upgrades can be done to make the S5 TII tranny wider in 5th gear. aiming for 165mph

would apreciate any answer

 

I'm not the one to ask... but here's "any answer". You can change the final drive ratio. Rotary Performance (www.rx7.com) has the parts. I bet other places do too.

Wow... you're in Germany already. Lucky bastard.

 

because i live here lol, u thought i want to move over from usa? haha

@rx7.com

they offer 160mph at 7500rpm.. its the same i have 4.10.

the NON-Turbo ones go up to 190mph at 7500

i am cunfused

 

Top speed is power limited. If you could manage to get to 7500 rpm in 5th gear with 3.9 rear end, you would be doing about 190 MPH. The problem is, you don't have the power to get to that speed. You will have your foot in it and engine will hit a point where it will not go any faster.

For comparison, the FD with 255bhp had a top speed of around 166 mph.

The 4.3 rear end will make the car accelerate faster, because it puts more torque to the wheels for a given engine RPM. The cost is that you go through the gears quicker (the speed at which you have to shift is lower for each gear).

Most FC racers (real club racing on road course tracks) here in the states try to get their hands on a 4.9 or 5.1 rear end.

-b

 

4.8? 5.1? out of what? or who makes them readily? just wonderin thanks!

 

Uhh, the 4.9 and 5.1 are ratios of the ring and pinion gears in the differential. So 4.875:1 or 5.125:1 would be more accurate. It represents the number of turns of the input driveshaft makes compared to the output axle shafts.

Mazda Motorsports has them available in their competition catalog for around $350 and $600 for the 4.9 and 5.1 gearsets, but IIRC these sets need some machining to fit. I believe ISC racing used to sell complete torsen differentials with the 5.1 gears for around $1500.

 

4.8 is nothing for me now.. 4.3 is nice for accelerating, but it kills my top speed.

i dont want to reach the 165mph on a stock 7, aiming for 270bhp, so i think its possible to reach nearby 160mph. i have a 4.10 now

 

you could always step down to a n/a rear end for the speed but it will not handle low speed high torque abuse but it should hold up to straight line top end speed if that is all you are after.

 

thats the problem, i thought a NA rear end could be ok, but wasnt sure whether it could handle the torque or not.. i accelerate a LOT, so the NA tranny should not least long time.. crap

i could punch my car up to 7500 with some power, but those are 500rpm, im afraid of that, dont want to kill my engine just to reach some 160mph

ot: does someone play GranTurismo 4? why the hell do the infini and GT-X have the redline starting at 7500rpm? all cars i have seen (EDM/USDM/JDM) have it at 7000rpm.

 

well the n/a diff should handle the power you said so long as it is not abrupt force, like sidestepping the clutch to second gear or clutch/engine braking from high RPMs suddenly with oversized tires. your only alternative i suppose would be see if a ring and pinion facility has moulds for a TII ring and pinion or can make one for a reasonable price. i never had much luck finding different ring and pinions for TIIs so i figured it was a lost cause, 165MPH is good enough for me.

only alternate suggestion i can think of is contacting racing beat and find out what they used in their land speed record FD for gears.

 

hey thx very much for all your help

so you say i could get a NA rear end, but shouldnt drive roughly huh? well.. lets see, if i can get a rear end very cheap, im going to do that.

 

yep, sudden force is the hardest on drivetrain components so if that is your only alternative for speed then you will just have to live with either having the sturdier TII diff for more spirited driving or the n/a diff for overall speed. if you do switch to the n/a diff then you will need to use the n/a driveshaft and half shafts also.

 

guise louise, i stay with my nasty TII rear end lol

 

6 spd transmission would help but it cost ALOT of $$$ ive heard you can hit 180 easy with stock rear end with the 6 speed tranny

 

how much are ALOT $$$?

 

$6-8k?

 

Yeah cheapest i have seen was like 5.5k.... You can try looking for a used one but it is almost impossible to find. Those things are expensive but they r the real deal its a kick *** upgrade

 

you can find them used at the recyclers here in Sacramento but first we need to clear some things up.

1) a RX8 transmission is not a direct bolt in
2) the final drive on the 6 speed is .83 which is in fact slower than the final drive on the TII tranny which is .71
3) the transmission is weaker and is only really made to handle just over 200RWHP which is what the 8 came with stock
4) the extra gear will add time in shifting ultimately making straight line acceleration slower but it may come in handy on road courses just not overall acceleration

any other questions?

 

well, i suppose talk was more about HKS 6speed dogbox for FC

 

I know you guys wont like this answer and you prob already know this but if you got an ls1/t56 you'de have no problems cruising at 165mph. The top of 5th gear in the t56 would bring you to around 180mph so 6th gear would deff allow you to cruise quite comfortably at 165mph.

I know its not rotary but its just an idea.

 

I just have one question, even though there is more time spent shifting. Wouldent having an extra gear mean the gears are closer together which would be very good for an engine like the 13b which has such a narrow powerband

 

forgot HKS offered that still, i wonder if they even have any collecting dust still in their wherehouses.


i suppose it would in some situations, which is why i mentioned road racing courses where you would be shifting around 2-3 at times. autocrosses it would be useless since you never get out of second hardly. it would also be nice in some sprited mountain driving.

 

Just to throw this out, you can get a 3.9 ratio 3rd member out of any S4 Vert. Someone step in here and confirm, but I believe any S4 auto RX7 coup has 3.9 third member. Maybe S5's as well?

Mazdatrix has already solved the TII tranny to NA 3rd member drive shaft situation to marry it all up.