FD transmission shaft upgrade for 20b
 

there was a guy who upgraded his FD transmission shaft to custom made 300M shaft on his tracked FI 20b powered rx7 with wide rear stickies.

I couldn't locate his post with search. Do you guys know the outcome of the transmission? How long did it last? I am between T6060 vs. shaft upgrade right now... I used to pick up FD transmission for $150-200 but now they are becoming more rare and hard to find.

Thank you.

Also interested to know about this!!

Instead of one race and breaking it lasted about 6 and broke. In my opinion it is not the best solution as it is still weak. The t6060 is a newer better version of the t56 but will not fit as it is larger and will hit the tunnel.

I still think the t56 is the best solution . It is reasonably priced , good ratios, strong, and all the details on installation are well documented by a few member builds.

I think Liberty Transimissions does the FD upgrade. I think they offer a variety of options. There is a guy with a 20b on here that tracks it regularly with lots of power and big tires, I think his SN is "the wird".

I plan to go that route as well.

I heard directly from thewird, as racingdriver said, it broke after 5-6 track events. In other words, it's stronger than stock, but not the permanent solution. TwinCharged, thewird's transmission was the liberty transmission upgraded unit.

Yah, my transmission broke on the 5th track day. But for comparison, I broke 4 stock ones in 3-5 laps like clockwork before. So its definitely much stronger. I don't think the transmission would ever break on the street, you guys have to realize I'm running 335 hoosier slicks with a locking differential and beating the limit out of the car.

thewird

out of curiosity, what broke?

3rd gear like always.

thewird

Do you think that FD has the case twisting problem because it's mounted on a PPF? Do you think it would help with the twisting if you load the tail end of the transmission on a crossmember like an FC?

The problem is the shafts separating and gear strength which is why upgrading the the mainshaft and treating the gears helps. Preventing gearbox movement might help too I guess. But I've already decided on a 6 speed sequential gearbox so done with stock gearbox's.

To put things into perspective... The inside of the tire barely fits a finger between the coilover spring... Breaking on the track is different from breaking on the street

https://fbcdn-sphotos-e-a.akamaihd.n...86116115_o.jpg

thewird

jesus, that puts things into perspective. that rear tire is wider than my fat ass.

what sequential are you getting?

I mentioned case twisting because I thought it is the case twisting that separated the shafts which should separate the gear teeth and shear them.

Probably an Elite transmission which is rated for 550 ft/lbs.

thewird

I just spoke with Paul.. sounds like a nice guy. Did you get the 300M shaft or the 40** steel? Thanks in advance.

There is a company in poland makeing "bulletproof" gearboxes out of the fc/fd gearbox and even straight cut gears, dog engagement and so on....but they cost like a sequential box more or less

300M shaft.

thewird

How come you not running pettit flares on that beast?

I went the 5 speed OS Giken route. Do you think it will withstand the abuse of the 20b?

I can speak from experience. No. The strength of gear isn't the issue. Issue is the shaft bending and separating in the case which will shear the teeth of the gears, most commonly in the 3rd gear.

Bad new for all. Liberty makes the upgraded shaft but doesn't make it out of 300M material anymore. I wouldn't hesitate to do business with this company in the future though. Seems like very honest group of people. If Paul told me he's selling me the 300M shaft, I wouldn't have known the difference, but they were very transparent. They now make the shaft out of 40-- series steel which they claim is stronger than stock but not as strong as 300M. Price he quoted was around $500 for the shaft.

I think I'm growing on the idea of the Nissan swap. It handles upto 1000whp in a much heavier 370z with huge tires. It costs $500-700 used. I just have to work out its dimensions..

I would love to see a 350/370z trany adapter for a rotary, I have stripped 3rd gear 5 times so far. For the price it is a great transmission that has no problem being on the street or strip.

The 350/370 transmission is cheap yes, mostly because the syncros are so much shit they only last a few weeks if u shift above 7k rpm, the gear ratios are good thou so maybe if you can get the synchros beefed up it would fit our rev loveing engines better :-), the 370z even has a rev matching function that heel-toes for you and the sychros still give up all the time.
The second problem is easier to adress, you need an oilcooler to the gearbox since they overheat in notime then used at higher revs...
But yes the axels and gears are good.......
And how do i know this? I have owned 2 of those 350z and 5 gearboxes split between them

thanks, that's good info. Did you have CD008 or CD009 box? I thought CD009 box had triple synchros in all gears except for 4th.

To be honest i am not sure, this was in -09 and was done by the dealer that sold me the car (or well traded me for my evo) ...

You want the CD009. The CD008 (2003 through 2004.5) is no good and many with stock cars had to replace it. Which is why they changed it only 1.5 years after release.

well Nissan swap is going to be tougher than expected mostly because the starter is not mounted to the bellhousing... I would need to make a custom mount for the starter... just something to keep in mind for those considering this.