The Full Frame

FEED 4.77 final drive review:

Getting the parts required for this has taken me around 3-4 months.

I bought the FEED gear used from Murix, great guy. He said it took him 3 months to get from Japan new.

$600

Can be bought new from http://www.mazdaparts.com for $677 plus probably $50 in shipping

http://www.mazdaparts.com/ProductDet…000-1156400947

or http://www.japanparts.com for $726

Then I had to get the Mazda bearing Kit, which are the two bearings for the main pinion, the two bearings for the axles, the three oil seals, and the crush washer.

Diff bearings- 011827350A (2ea) MSRP-56.80ea Website-45.44ea
Axle seals- P04327238A (2ea) MSRP-8.25ea Website-6.60ea
Pinion seal- RA0327165A MSRP-21.50 Website-17.20
Pinion Crush spacer- R00427171A MSRP-10.00 Website-8.00
Pinion bearing #1- 060427220 MSRP-35.45 Website-28.36
Pinion bearing #2- R00127210 MSRP-61.20 Website-48.96

$202

I got mine from http://www.onlinemazdaparts.com a forum vendor. They also have great prices on coils

Then The install is going to cost $500 (note, this is just for the gear install, if you cant remove the diff yourself then it will probably cost around $800 bucks for the whole thing)

So this is a bare minimum $1300 install. But realistically this will probably cost you around $1700.

The shop in town specializes in transmissions. They said that the fittment was perfect and the backlash, meshing and preload set itself on the first try.

Maybe a lot of you haven’t heard of this before, but the 4.77 gear shortens the gear ratios for all the gears (shorten meaning that any given gear will seem to last shorter in comparison to driving speed). So driving around in third gear at 3000 rpm, you will no longer be at 30 mph but rather at some lower speed. Its a ratio difference so its not like this just raises every rpm by 1000 for any given speed but rather it will vary with what gear it is in.

4.77 means that the drive shaft coming from the transmission has to turn this gear 4.77 times in order to turn the wheels once. This is raised from the stock 4.44 gearing. This functions the same way that the low gear functions on your car or on a bike. Its very easy to turn the pedals because torque is amplified by the gears but you need to turn them very quickly to go fast. Luckily the RX8’s rotary engine has revs to spare and rather meek low end grunt. So this seems like the perfect mod to trade some revs for raw acceleration, this will let the rx8 zip through the gears right into the power band and be able to put more power to the ground in general.

Top speed is limited to about 163 mph now as opposed to the 185 ish limit of 6th gear now. So at about 9K in sixth gear you will be at 163 mph.

This drive promises a noticeable increase in torque in every gear.

chattering in video is only from the camera bouncing up and down, there was no background noise in the cabin other than the exhaust
http://videos.streetfire.net/video/10a68352-4964-4a40-83ff-99ad014d0acc.htm

Review:

This is easily the best mod out there for the N/A rx8. I honestly couldn’t feel my flywheel upgrade that much, but this is like 4x the difference that the flywheel felt like!

Even though it is pricey it really gives a lot of grunt to the rx8, Pulls feel stronger in every gear.

At 70 mph in sixth revs were at 3900

at 80 revs are 4400

at 85 revs are 4750

It is harder to drive though, engine braking is MUCH more pronounced. So I don’t really recommend this for someone who isn’t already well acquainted with rev-matching and smooth shifts.

Engine feels a lot more responsive and I can definitely notice MUCH more pull.

The gear is very silent, there are no abnormal noises from the differential. The gear is well made.

this easily tops my list for the best power mod to do for the RX8, really gives the car back some pull, makes it more fun to drive because it feels even more revvy than it already is.

Ground was wet outside so I couldn’t really do any serious starts because I wasn’t getting any traction in 1st gear.

It feels good, I’m very pleased with how this mod turned out and I will post some RX8 vs RX8 comparison vids when my buddy gets his out of the shop.

Overall, this makes my mod recommendation list:

1. Lightweight wheels
2. FINAL DRIVE
3. RP short shifter
4. AP pulley
5. coilovers & swaybars
6. flywheel
7. REVi + duct
8. test pipe + exhaust
9. mazmart water pump, gauges, koyo radiator, battery relocation, grounding kit, strut tower bars.

It Really is the best mod out there aside from some wheels <17 lbs (cause those help you not only in acceleration but also steering and braking)