that depents on what you want , I have a 4.33 ( it comes with a 4.10) on my fd and from a roll the car is much faster but launching is more dificult to the point that firts gear is all tire spin no hook up, the revs climb too fast, I also have a mazdaspeed light flywheel.

if you are going turbo dont change the dif gears.

 

Unless you want to go up to a 4.1 and have the best of both worlds. You could theoretically get better mileage than the normally aspirated crew at cruising rpms.
I may even provide a 3.9.
Paul.

 

4.10 will give you better milage but I love the way the car feels with the 4.33 specially in the low rpm, so firts try the car with the 4.44 and then if you feel the need to upgrade go with the 4.10.

 

huh?

 

what I mean is, this is IMO this is a good solution to get better perfomance for the money. RB intake doesn't do **** and it affects gas milage.
better performance = worst gas milage. At least this one we can control it in a way.

 

ah ok got ya..was a lill lost at first...but it's hard comment on the preformance gains of changing to a 4.778 if no on has done it and posted up befor and after 0-60 of 1/4 mile......bu tit does seem liek it woudl be worth it i'd have to agree with you..seems liek this would be worth wild.

 

My uncle has swapped rear ends in his Cameros and most recently his 50th anniversary Vette Z06. He says it is a night and day difference and believes it would drop around .6 off of quarter mile times to go with 5.13 (5.125) on our cars. That is significant dropping .6 seconds off of quarter.

I had brought up the 4.78 ring and pinion and he was the one who brought up the 5.13 as being even better.

 

as my name suggest's I have some experience with diff gears/ratios. Like everything the ratio has to be balanced to what you want to do. A lower diff number--- yea the car will have more snap to it---BUT if it causes you to have to shift where as before you didnt---hmmm then it may not be of benefit--it may actually hurt. I wish we had a "quick change" rear diff (I can wish at Christmas --right?). So guys from experience --if you gear it down and then have to take a long trip after meeting that babe that lives 200 miles away you may find the benefit is not worth the price.I hate buzzy cars.
One word of caution-- take care of the wheel hop issue before you do this.
If you want accleration then lowering the ratio will help.
Settle on your gear ratio before you do any aftermarket tuning.
Suggest also before you do this just try smaller rims/tires and see how you like it.
olddragger

 

the rx8 is 4.444

 

^indeed it is

 

Going to the junkyard today to pull a kia sportage front pumpkin

 

^sweet keep us posted

also how much would a kia front diff cost to snag from your junk yard (hopefully mine isn't more money)

 

I would still send the recycled Kia gear to be Cryogenically treated.

 

^how much would that cost..i'm sure there can't be to many places you can have that done.

all i'm in agreement to make them stronger...but i wonder how much stronger the treatment will make the gears

 

^^ $100. These are also the people that are behind Frozen Rotors.

http://www.diversifiedcryogenics.com...rtspricing.htm

 

Or you can take it to porterfield Brakes in Costa Mesa.

 

hmmm maybe i should've asked if anyone has used a company that can do this....don't want to use someone (far away no less) and not be sure of their reliablility. etc. etc.

geuss i'll have to do some research. thanks for pointing me in some directions guys

 

Ok, I've got some pretty basic questions that need answering...

1) I have a 2004 M6 RX-8. That means the stock rear-end gears are 4.444, correct?

2) Higher gears, such as 4.778 would yield faster acceleration, correct?

3) Lower gears, such as 4.10 would yield slower acceleration, correct?

4) Is there anything special about our rear-end, that would make the swap any harder compared to the swap in say the rear end of a Mustang or Camaro? Will my performance shop have to do anything special if I buy the new ring and pinion, throw it and the car at them?

 

Yep

Yep

Yes

Easier than the Mustang or Camaro since the pumpkin is much smaller and lighter. Install of the R&P is the same, same shim kit.

 

^ Hey Slick where you able to get a 4.778 gear yet?

 

Just ordered from Kia $325 w/ shipping, comes in next week... Found a few Sportages in the salvage yards but the prices were for the entire front pumpkin at $350 the lowest.

Called Fountainhead Cryogenic Processing for treating the 4.778 ring and pinion, $5/lbs. Good insurance for the price.



Rick Heasel who resells the Kia 4.778 gears for the S2000 folks just gets them polydynned.

Anybody got a parts diagram for the RX-8 pumpkin? I also need the torque specs.

 

must resist....

 

^i know what you mean

 

Not all of them.....Australian auto RX-8's have a 4.300 diff ratio.

 

hey slick did you get that service manual link yet (for the parts guide torque specs)