[My5ABaby]

From rx7club.com and user RXgirl7

for those of you who know me, i have been thinking about putting a miata transmission into my 89 GTU. i know this swap is common on race cars, but i have never heared of it being done on a daily driven car before(i serched, but i may have missed something). my car has a bone stock S5 motor(22k miles, running strong)and a stock exhaust system. i chose the miatabox because the gears are closer.
i picked up the transmission for $125, used from japan in excelent condition. no gears or synchros had to be replaced.
i decided to go with a racingbeat race pressure plate, and a racingbeat aluminium flywheel. i also installed a competition tranny mount at the same time. i am also running NEO synthetic 75w-90 in the new transmission. installation was done by John at Mazdatrix(thank you!)and the transmission was done by Brian Fields(thanks!)located right behind Mazdatrix.
in order to install the miatabox in an FC, the imput shaft has to be modified by a machinist, and the miata gears need to be inserted into an FC case.
the miata transmission has a very tall first gear, and it was assumed that driving the car on the street in stop and go traffic would be tricky. as soon as i drove the car around the block, all my apprehensions dissapeared. it is extreamly easy to drive the car, starts and hills feel about the same as they did with the stock setup. driving the car around town is a blast. it revs up quickly due to the flywheel, and i can ACCELERATE in 5th gear!
i took the car to Streets of Willow on saturday, and it was absoloutly a blast to drive. i have driven on that track before with my stock transmission, and the difference was quite noticable. 2nd and 3rd gear are much closer, and the car feels more spirited, zippy, and responsive than ever before.
top end in 5th gear is somewhat reduced(155mph @7500rpm)but 5th gear feels much stronger and more responsive. i would say it feels sort of like a 4th gear.
i had a Mazdatrix short shifter installed on my stock tranny, and it was quiet as a mouse. after we installed it on the new tranny, it rattles like a mofo, which has lead us to conclude that shifter rattle is specific to each transmission. more on this topic can be found on the Mazdatrix website.
everyone who has driven the car has given me positive feedback, and the car is an absoloute BLAST to drive. the results completly exceeded my expectations. in my opinion, there is absoloutly no downside to this swap. i would definatly reccomend this swap to almost anyone with an FC. the transmission has completly woken up my motor.