If you're running FD transmission in RX8, please help..
 

For those that's running FD tranny in our RX8, are you using RX8 master cylinder with FD slave without issues? My clutch holds fine in boost, but it's not disengaging all the way which makes shifting difficult. I took the tranny down, and everything is fine. Lines are bled properly. Only thing I can think of now is maybe RX8 master cylinder displaces less fluid than RX7 master cylinder. Before I switch out the master cylinders, I just wanted to ask whether anyone is using RX8 master with FD slave cylinder without issues. Thanks in advance!

I'm using the JDM5 speed which is same trans but set up for an 8. There is a thread somewhere about taking the bell housing and shift housing off the jdm 5 spd and fitting it to the FD trans.
Dunno if that helps but ............ it's all i got :)

This is my buddies 20B setup (a few years old but still the same), he is running an FD trans (after blowing many RX8 trans back in the day) with the RX-8 clutch and brake master cylinder.

http://www.flickr.com/photos/9krpmrx8/4573697396/
Recent Pic.

http://www.flickr.com/photos/9krpmrx8/10568172266/

is this JDM 5spd for RX8 or RX7? If it's RX7 transmission, are you still using RX8 master cylinder?

It's for the RX8 - so rx8 master and slave cyl.

9krpm, thanks! That answers it. I guess hunt continues.

I'm assuming you meant RX7 tranny & clutch, right? Does he have any issues with shifting?

As far as I know it a US spec FD trans. I think he had it built though for durability. I can ask him tomorrow if you want?

That would be awesome. Thanks man. btw, I'll be in TX next month!! :)

He has tracked this car many times very hard and the FD trans has held up very well. The car is not just for show despite it's looks, he drives it hard when he is not tracking his R35 GTR.

I assume it's working well, and that answers the question. Thanks! Maybe I should drive over to San Antonio lol

Yeah it's been working well, he has had this setup for years already. We would be glad to have you man, just give me a heads up.

The RX8 uses a push slave/clutch and the FD3 uses a pull slave/clutch. Essentially they work in opposite directions. The people running the RX8 5 SPD version/conversion do not have the same situation. Thought there was a thread on here where some guy went to all the trouble to modify the shifter housing on an fd3 5-spd so that he could use it in the RX8/Renesis and have the shifter line up properly. It was kind of a back yard cluster job. It didn't pop up immediately in a search though. Not sure if he ever got it to work properly.

Here is the info on the RX8 5-SPD version/conversion, essentially taking the RX8 5-spd bellhousing and tail housing allows the FD3 main case & shaft assy to bolt in behind a Renesis as a direct replacement to the factory 6-spd. Maybe the RX8 5-spd bell housing with a push type clutch and RX8 slave & fork assy would be the answer for you. Only just a guess though.

http://www.rx8club.com/series-i-majo...setups-225750/


And this for people who maybe don't understand how the FD pull clutch type is different from the RX8 push clutch

Stick, from what I remeber you were using a fc transmission weren't you?

thanks for the replies.

team, sadly, I just bought a new exedy twin clutch, so I really want to make pull type work. If I can't, I will do the 5 spd bellhousing.

dznut, it took me awhile to sort things out, but I'm using FD front housing, FD transmission, and FC TII rear housing. I may just change the entire thing to FC TII or T56 when this transmission dies or when I need new clutch, but it hasn't broken yet. I think as long as you don't launch it, FD tranny is quite capable.

I found out master clutch cylinders for RX7 and RX8 both have 5/8" bore. Does anyone know the stroke? I'm trying to figure out whether RX8 and RX7 masters clutch cylinders are different in stroke. If RX7 has a longer stroke, I can then add larger diameter master clutch cylinder and hopefully be able to disengage the clutch completely.

Are you sure the clutch pedal is adjusted to get max stroke? It has quite a bit of adjustment available. You would want to adjust the pedal height to a higher position then adjust the rod between the pedal and the master to lengthen it and take up the slack from the created by the pedal height change.

With the higher pedal and the rod adjusted for it you will be gaining master stroke which in turn will be engaging the pressure plate further.


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yea, it's been adjusted to the max. Pedal connection is at the very end of the master cylinder rod. I just can't disengage the clutch entirely. I've been trouble shooting at the rx7 forum, and it seems subtle clutch fork failure is to blame. but since that requires taking tranny down again, I am going to try to change the master cylinder first since I haven't changed mine since I bought the car. If you have some suggestions, I have all weekend to troubleshoot! :)

You can do what Matt did: https://www.rx8club.com/frankenstein...4/#post4405948

I fixed this today and I thought to post it for anyone looking to use FD transmission with FD slave cylinder with RX8 master cylinder.

For single plate clutch = RX8 master cylinder will work fine.
For twin plate clutch = RX8 master cylinder doesn't move enough volume to disengage twin plate completely.

You need to install .75 Wilwood remote reservoir master brake/clutch cylinder. Pedal will feel very stiff because you're moving more volume, but you'll be able to disengage the clutch completely. In retrospect, I think I could have gotten away with .70 master cylinder which will give you relatively softer clutch feel, but I don't know if that would've moved enough volume to disengage twin disc. I can report that 0.75 works just fine.

Glad to see you got this resolved.



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thanks! I also wanted to add that Wilwood remote reservoir masters are almost direct bolt-on's. All you have to do is get a stepper drill bit and drill out the center hole little larger. Bolts otherwise line up perfectly. With them being almost the same price as the RX8 OEM ones and available in different sizes to suit your needs (they also got one that is same exact size as the OEM RX8 cylinder), if you were daring, you could try these when your stock one goes to the floor again.

here's the pic of the wilwood cylinder.