Chickenwafer's Never Over Turbo 8 Build

[chickenwafer]

So I haven't been here in a while

Figured I could bump this with some updates:

First is I dyno'ed last weekend. After some issues with my boost controller my boost was seriously limited and I couldn't get boost to peak over 13.5psi

First run was on lower boost at 10.5psi or so:



Ended up with 317-rwhp and 287 ft-lbs of torque. After reviewing the logs of the run it turned out my knock sensor was picking up noise from the dyno rollers and pulling up to 10 degrees of timing at torque peak!!

I basically turned the knock sensor off, LOL, and did another run at 13.5psi, which was the max my GReddy E-01 was letting me do (I found up later I had it setup wrong, doh!)



330-rwhp and 326 ft-lbs of torque! Holy balls that's a lot of torque, haha.

That pull was at 13.5psi peak and trailing down to 9psi by 8,000 rpm. I also found out I was running a pretty high timing split so I was able to clean it up but I ran out of time on the dyno so I couldn't make a pull with the new map



So then the other day I was getting my boost controller settings figured out and tuning it on a back street. Was hitting 14psi by 3900rpm and it was feeling rather brutal! The spool was intensely quick. So I did a run, and boost was falling off slightly, so I pulled over and made adjustments, then went for another run....

I hit 14psi before 4k and started to spin tire a little, but like an idiot I stayed in the throttle and the tires hooked back up. BANG! My shifter popped out of 3rd gear and the transmission started making death noises...

I quickly clutched in and tried to shift into 4th, but it wouldn't. I coasted into a parking lot and after a minuet or so of frustration I was able to get it into a drive gear and limp the car home. Motor is fine, but transmission is pretty bad. I'm almost positive the shift fork for 3-4 is bent and all my syncro's are gone, LOL.

My trans has been an issue really for the last 10,000 miles, tho. It's grinded 2nd, 3rd and occasionally 4th. And about 1500 miles ago went I swapped fluid for Redline MT90 there was a shift detent ball stuck on the magnet of the drain plug. So I knew the tranny was a time bomb.

Plus these 6-speed Aisin gearboxes are just trash. Which is why I am considering doing an FD RX-7 5-speed gearbox swap.

The biggest hurdles of the FD gearbox are:
-Transmission is longer and shifter doesn't line up, but it's not off by much (about 4"). Apparently you can cut down the linkage and move the shifter forward by the amount required
-Obviously mounting locations are different. The stock 8 trans is mounted on the passenger side to the PPF and the FD trans is mounted on the driver side and bottom from what I have gathered. So custom mounts are required. I am going to keep the stock RX8 PPF.
-The RX8 is a push type clutch, FD is a pull type clutch? Or so I have gathered, maybe some people here can shed light on this...
-Custom driveshaft is required since the RX8 carbon fibre unit is too long and the FD unit is too short. I need a driveshaft roughly 13 inches longer than the FD d-shaft.

The Good news:
-Bellhousing bolts right up
-Uses the same 240mm flywheel and clutch combo like the RX8 so I don't need to swap any of that stuff (luckily too since I have a lightweight billet Fidanza fly and ACT Stage 2 clutch already)
-FD transmission is much stronger, cheaper, easier to find, easier to get rebuild kits, etc than the RX8 6-speed gearbox. I can pick up an FD trans all day long for about 1/3 to 1/4 of the cost of a used RX8 gearbox. So even if the initial cost of the swap is more expensive than just throwing another RX8 gearbox in, it will pay for itself once I don't blow anything LOL

So that is where I am at right now. I was also wondering if I could use the Re-Amemyia D1GP short shifter (don't see why not) and if it's a good shifter? FD guys? Here's a link: http://www.corksport.com/re-amemiya-...r-for-rx7.html

So I am still weighting options. I have a line a stock RX8 trans for $500 + Ship or I can pick up an FD trans for under $300 bucks. If anyone here is selling an FD trans and wan't to hook a brother up let me know! Haha. Even if someone has a completely BLOWN FD trans I will pay for shipping if you can send it to me so I can use it for mock-up and see if it's even worth it.

Thanks guys

[Rotary Inspired]

What about the Turbo 2 tranny? They are solid and are also a push type clutch. It will bolt up to the renny as well. I believe the Turbo 2 is slightly shorter. Cant remember I used to have 2 FD trannies and a t2 tranny side by side in the garage. My 8 tranny sucks as well. They are poorly built IMO. Good luck I bet the half shafts and diff are next.

[Whizbang]

chickenwafer... +1 for odd ball usernames.

great project btw!

[Max777]

Originally Posted by theorie

nice work man!!!

my only gripe is the lambo doors...lose those rice-hinges and you're good to go.

that is your opinion. The owner of the car might highly enjoy them, and as shocking as it may be, not everyone thinks the same as you do. As a matter of fact, lambo doors can be very tastefully done, such as on this car.

[WE3RX7]

I second the T2 trans. Just as strong, and if you get a USDM actually has a decent overdrive for fuel economy (if you care, if not.. go JDM as the gearing on 4th and 5th are much closer).

It would be the same if not an easier swap than the FD trans and parts are just THAT much cheaper for T2 stuff.


The RX8 6spd actually isnt a bad trans, it has a weak point (the ball you referred to) which can actually be modified and never cause a problem again. I'm not sure but I'm wondering mazda fixed the issue on the newer trans... I'll have to do some research. It should hold 400lb ft of torque though once modified.

[chickenwafer]

Yeah the 2009 transmission is much beefier (how much we're still not sure no one is really pushing them yet) but it isn't a bolt-in swap, and since it's so new you can't find any used. Brand new from Mazda it's over $3500 if I recall correctly.

Do you know the modifications to beef up the RX-8 6-speed? Or at the very least a company doing this? I haven't heard of it yet. I also know the shift forks are VERY fragile in this transmission as well.

I am actually leaning to the S4 T2 over the FD transmission. If my research serves me right the S5 Turbo and FD transmissions are basically the same thing but with a slightly different 5th gear? But the same case, and gears up to 5th.

So after more research this is what I have found:

Updates:
-The clutch release isn't an issue. The 8 gearbox is a push type clutch and the RX-7 5-speed turbo gearboxes are pull type clutches, but since I'm swapping transmissions none of this matters. I just need the clutch slave cylinder and it's a bolt in.
-The S4 transmission can have its linkage cut down and shortened by 4 1/2" so the shifter will line up with the factory RX-8 shifter opening in the console. Very good news and the main reason I am leaning to the S4 Turbo trans
-The driveshaft needs to be approx 12.5" longer than the RX-7 driveshaft.
-I will need the clutch slave cylinder and the RX-7 Turbo/Automatic transmission starter motor
-Custom mounting brackets are required or a custom PPF ($$)

But right now I am still thinking I may just throw in another 8 gearbox and play my cards, shift like a grandma and hope all goes well. IF that one goes then I'm definitely going RX-7 transmission. Right now it's more of a timing issues- I would get my 8 back on the road MUCH quicker just throwing in the 8 tranny otherwise with doing the RX-7 5-speed swap it's probably going to take me all winter to do it LOL

[speedjunkie]

Actually he sold this car a few months ago and got an FD.

[BMW.Nick]

I have never liked RX8's but this was an impressive build!

[MrsJoff]

Chickenwafer bought an FD? There is no way he could fit into an FD. I won't believe it until I see a picture of him in the car.

How you doing Chickenwafer? It is going to be 112 degrees Monday, be glad you left the desert!

Lynn

[speedjunkie]

Actually I'm about the same height as him and I have an FD too lol. He still fits a little tighter in it than I do though haha.

He said he doesn't really get on here much anymore, but I did tell him about this thread so maybe he'll stop by at some point. Last time I saw him he was doing well.

I guess the name of this thread should probably change again huh? LOL

[chickenwafer]

Originally Posted by MrsJoff

Chickenwafer bought an FD? There is no way he could fit into an FD. I won't believe it until I see a picture of him in the car.

How you doing Chickenwafer? It is going to be 112 degrees Monday, be glad you left the desert!

Lynn

Hey Joff and Lynn!

Yeah, I have an FD now! I hate to say it, but I should have done it YEARS ago! Really in love with the car.

It's a tight fit, being 6'6" isn't always a good thing. I have an aftermarket small steering wheel and an NRG quick release on the hub. Makes fitting MUCH easier. My FD is a touring model, so it has the sunroof, wish I would have got an R1 so I wouldn't have the roof but oh wells. FD's in Colorado are slim pickins!

Not missing the heat at all! But the snow kind of sucks. At least it gives me downtime to have the FD tucked away in the garage so I can complete some winter projects.

The RX-8 was a great ride, but we all have to move on.