irishrx7

First up I'm sure these questions have been answered already but I've searched and came back with notting. Here's the deal. I'm building a FD race car with a 13b pp motor in and around the 300 hp Mark and 1000kg. I want to put in a dog box with nice low ratios to get the most out of the PP motor but I'm not going to have the funds to go down this route so that's what led me to the rx8 box option. I know the bolt pattern of the bell housing is the same but the gear lever will be alot further forward than the FD box. I've heard the mx5 version of the rx8 box has a gear lever set up that would be better suited to original position of the FD lever?

The engine I'm running has a FD fidanza aluminium flywheel that takes a a 7.25 inch clutch assembly. What type clutch/plate will I need to use for it to be compatible with the 8 box?

I will not be running the ppf frame in the car instead I have the rear diff mouted solid to the chassis so I'll just be making up some bracket to solid mount the gearbox to the chassis. Should be easy enough on that side of things. I'll be running hopefully a 5.1 rear end but again on funds I might end up using a 4.777 as they are far far cheaper.



Any info or help on this would be much apriciated.


Link to the build tread that I will try update when I get home from work.
https://www.rx7club.com/showthread.php?t=962459

Shane

DaleClark

iTrader: (55)

No one has really done it since in a standard car it's far from a bolt-in. Also, the RX-8 6-speed is supposed to be a good deal less robust than the FD 5-speed. Big consideration would be how much power you're making.

The length of the transmission is pretty close so the shift lever will be in the ballpark I believe.

The clutch and flywheel will also be weird, as will the clutch hydraulics. Also will probably need a custom driveshaft.

Dale

irishrx7

The power level as above will be in and around the 300 Mark and the torque quite low. I'm not to worried about the Strength as it won't be getting launched hard and the car itself is quite light.

On the clutch hydraulics side of thing the car has a pedal box with a dedicated master cylinder. Is the rx8 box a push or pull type?

I have a crowed lined up to alter a rx8 shaft to suit.

Thanks for the reply.

7dust

iTrader: (14)

I know the RX8 uses the same sized clutch and pressure plate as the FC turbo. They are the exact same part numbers if using ACT clutch. These will bolt right up to an FD flywheel.

Aside from converting to a push type clutch, that end of the swap should be easy.

Prôdigy2nd

iTrader: (3)

A Japanese company made a converter kit, to go from the FD Pull, to a push type... I forget which company though... A quick search around RHDjapan may yield some results...

I think a strengthened 6 spd woukd be awesome for a cruiser/highway car...

Track car though I think you would be switching gears too much...


J.

7dust

iTrader: (14)

If you switch transmissions, you don't need a push pull converter.

The push or pull shift fork design is transmission specific, not engine specific.

I have an RX8 and I can count the number of times Ive used 5th gear on one hand. I usually just go right from 4th into 6th. I think Mazda made the RX8 6 speed just because it seems like a selling point until you figure out how unnecessary it is.

I personally wouldn't put an RX8 transmission in an FD because I don't think its much of an upgrade and its probably gonna suck.

nlsolja123

Anyone ever do this ? I can't find the person who did but kept breaking them.