Mazda Rotary Club

Cars by Model Type => 2nd generation RX-7's => Topic started by: m1tch on July 20, 2008, 10:23:35 PM

Title: FC gearbox help
Post by: m1tch on July 20, 2008, 10:23:35 PM
Hey guys, I just need to ask a few things about gearboxes, I know the FC box is rated to about 500bhp (which is nice) but recently I have had some juddering whilst driving, here are a few ideas:

1. something wrong with the idle screw
2. Gearbox is worn and partly coming in and out of gears
3. car is still warming up (ie when the car pops the car will judder slightly)
4. Something else lol

I was recently thinking about installing an overdrive unit, or researching further into overdrive units to get better GT milage cause when driving im either in town/fast road using the first 4 gears, or in 5th with the cruise control on.

I was also thinking that if the gearbox was on the way out I could perhaps get a gearbox reconditioned and possibly get a different 5th gear cut and fitted to it?

I know that for some subaru owners they get a dog cut 3rd gear so that it doesn\'t pop the gearbox, but I was thinking of making 5th gear (which is only used for cruising and motorway stuff) longer so it could rev at say 1,500-2,000 rpm instead of nearly 3000rpm at 70. For overtaking on the motorway I would just drop to 4th and overtake.

What do you think I should do?
Title: FC gearbox help
Post by: L18M on July 21, 2008, 01:17:07 AM
Hey, when do u get your juddering..? is it when your driving at some speed in straight line or when your pulling off and turning at the same time.

i have the prob of car juddering when i have the wheel turned (even a little bit) and pulling out. in a straight line its fine. but for me i think my lsd is f**ked (tho i been told by some ppl that its jus the lsd doing its job?!)
saying that.. i think i need a new clutch soon also n maybe a clutch release bearing.
maybe gearbox also as the gears kinda klinks when changing gear n its bit hard to change gears at times.

if need new gear box i read some places that some ppl put a 5th from an fd as its slightly better for fuel when cruising at 70.

hope this gives you some idea and im not jus going round in circles.
Title: FC gearbox help
Post by: m1tch on July 21, 2008, 09:05:18 PM
Hmm im thinking it might be the dashpot, but that means taking the IC off :( arg lol

would an FD box fit an FC?
Title: FC gearbox help
Post by: TiddlesRX7 on July 21, 2008, 10:26:25 PM
Quotewould an FD box fit an FC?
I don\'t believe it fits from what i\'ve read on here.
Title: FC gearbox help
Post by: dthebuk on July 22, 2008, 08:45:25 PM
could it be the crank angle sensor. My friends car sometimes juddered and it turned out to be the sensor. but this was a corsa...