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I have developed a transmission adapter for the 370Z 6 Speed MT transmission to bolt up to the 13B rear housing, and the assembly is now installed in a local time-attack vehicle that has undergone some serious upgrades in the drivetrain department as well as other areas. It will be going for testing in the following couple of weeks before the tracks close for the season.
The JK40C transmissions are relatively commonplace now. They are easy to locate, acquire, tear down, and inspect. They are extremely durable Warner style synchromesh transmissions that have beefy gears and have been good to some VQ35's turning 9000 RPM.
Here's a photo of the transmission mounted to the engine (or the engine mounted to the transmission, considering it's about 2 times the size )
The way the starter mounts is important for not hitting the frame rail, but I will post photos once it is tested and running. So far we HAVE gotten the car to start and idle with no odd sounds coming from any of the modifications we've made to the drivetrain.
I am posting here because I couldn't find a drivetrain section, and I've seen people attempt the V160/161, Supra Getrag, Z32, and T56 transmission adapters, but no one stepped up to develop a 370z trans, and they are relatively stout when compared to what's already available. Perhaps even overkill for most.
If anyone has any questions, concerns, feedback; please post away. I'm looking to make this kit available in the near future.
The current list of mods that are required to get such an item running in a car with a rotary motor isn't extremely extensive. It's pretty standard for a foreign transmission to be installed on a completely different engine:
Parts that I've engineered/fabricated
flywheel spacer and lock-plate disc
13B rear iron to 370z bell-housing adapter + custom flathead socket cap screws
13B manual to 370z bell housing starter adapter/mount
370Z throwout bearing spacer (recommended to upgrade throwout bearing)
Simple custom pilot bushing or modified nissan unit (very easy to modify)
Parts required from other sources
13B clutch disc (splines need to be changed to nissan/370z splines)
Driveshaft (custom) with 350/370z front yoke & mazda differential companion flange
Some more details:
Currently installed on previous record-holding time attack car
All parts were FARO ARM plotted with extremely high accuracy.
Starter requires very minor modification. It really takes about 5 minutes, and is better than buying a new starter.
Shifter position is "tunable" to a degree. It can be moved about 4 to 5 inches forward of where the factory Nissan 370z Shifter lever cup is situated on the transmission.
For the current installation, the factory shifter position is what the owner/driver of the car prefers, and we did not need to change its position. A car with factory seating position might need it moved forward.
Transmission is about 11.5 inches wide - transmission tunnel may require some "cold working" with a calibrated smashometer or variable-angle swing-press.
That's all I got for now.
It's running. Will be tested very soon. And then more details to follow.
Mods, please let me know where to move this if it's in the wrong place / against the rules. Thought you rotary guys might want to know someone is working on a 6 speed conversion that isn't made of glass and isn't half the price of a key of booger sugar, that's all!
Very cool to see another option besides the t56. I'm assuming we're talking about mounting in a FD?
Have any pictures of the trans tunnel modifications needed to fit?
How much does it weigh in comparison to the FD unit?
How do the ratios compare to the FD trans?
How is the feel/smoothness of the trans?
Can the shifter be made to fit to the stock FD shifter opening without modifying that metal work?
Very cool to see another option besides the t56. I'm assuming we're talking about mounting in a FD?
Have any pictures of the trans tunnel modifications needed to fit?
How much does it weigh in comparison to the FD unit?
How do the ratios compare to the FD trans?
How is the feel/smoothness of the trans?
Can the shifter be made to fit to the stock FD shifter opening without modifying that metal work?
assumption is wrong. it's mounted in an FC.
I will have to weigh the spare 370z box that I have when I get it back.
370Z 6sp Manual Ratios (same as late 350z and Nismo edition)
-- 1st: 3.794
-- 2nd: 2.324
-- 3rd: 1.624
-- 4th: 1.271
-- 5th: 1.000
-- 6th: 0.794
-- Reverse: 3.446
-- Final Drive: 3.692:1
These transmissions feel really smooth in comparison to old 80's transmissions- from which the FD trans is derived. The 350z/370z transmission is also a derivative of an older 80's trans- but with plenty of improvements in gear actuation, leverage on the forks, and engagement of the synchronizers. There are also many oiling improvements throughout the case.
You would have to drive a 370z if you'd like to compare. I can't say for you how it feels. Feel is subjective.
There was some required tapping with a hammer right near the butt end of the starter so that the solenoid would have enough room to clear the tunnel where it tapers inwards. It is slightly behind where the throttle pedal is, so it does not interfere with driver footing. I think the stock trans tunnel (on the FC, anyways) is too tight near where the middle starts to curve in, so it had to be split open up there. To be entirely honest, I wasn't there when the trans tunnel mods were made, so I'm not quite sure how much material was added/removed. I'll see if I can get a photo of that.
I don't know how this would fit in an FD chassis. I haven't worked on one. I don't come across them much.
The Time Attack car will be shooting for a reasonable 500. perhaps a little more. perhaps a little less. but that is the goal with a 13B Bridgey on drugs with a Comp CT4-6767 Turbo.
As for drift-car status, Any 350Z transmission that is marked as CD006 or later is suitable for smashing gears. In fact, the previous ones are notorious for 3rd gear synchro problems- but I have a friend who competes in a 350z drift car and has had not one issue with the 350z trans. It is an early trans too.
All the CD006 and later (JK40C is Considered CD009) are said to have the issue fixed, and the internal oil trough/baffle/slinger is much improved.
trying to post in this thread, but my posts are under review?
time attack car has yet to be dyno'd, but made 380 or so last time, and it has undergone big upgrades. shooting for 500-550 whp. would be a great trans for a drift car being that it's the later model JK40C/CD009 with the updates to them. Sound performance putting down 1250rwhp with multiple hard launch drag passes on these boxes.
I am curious to see how they handle high revs from a rotary motor in the 9000 rpm range, but there are vq35/37 hybridized motors that run close to that RPM and seem to handle the speed reasonably well.
I appreciate all the positive interest. The main reason why I haven't posted too many details are due to the final test that needs to be done.
Good news is, car moved under its own power and while the clutch engagement at low rpm is really "chattery", it's due to the pressure plate diaphragm weighing a ton, and not the kit construction. The car operated as it expected to. No harsh vibrations at low speed. No weird sounds.
Phase 1: Design - Completed
Phase 2: Implementation - Completed
Phase 3: Driving Test - Completed
Phase 4: Dyno / Agressive testing - Not Yet Completed.
Phase 5: Kit Pricing and Parts List - Not Yet Completed.
Dyno is all that's left (can't track test, as the season is over).
Also, I'm not too sure what the rules for selling/marketing parts are here, so I have refrained from producing any kit pricing as of yet or how to purchase it. Is there a code of ethics for that?
You can get listed as a vendor or open a group buy for a one time fee. It's a little sensitive, so PM a mod. You're on the right track. Best of luck. Excellent work.
Sorry for the long post ahead. Just want to add some info.
Keep in mind, it is a race car, so it wasn't done to keep any of the interior parts. The trans tunnel mods done on the time attack car using this setup are not the only way to go about modifying the tunnel. It looks pretty good and the transmission fits quite tight on the sides of the trans tunnel when tucked up under there, but the top of the tunnel was made flat to accommodate a new switch panel box / command center to operate the vehicle, so your own personal car's tunnel will look different when complete if you chose to do this modification.
The kit will not come with a transmission mount. Anyone who is capable of modifying the transmission tunnel can make a simple mount using the factory nissan bushing, and quite simply- I do not have access to FC or FD chassis cars that are close to stock to fabricate one that works. The owner of the car it is currently in chose to make a sturdy mount that ties into the frame rails and that was his decision. You will have to devise your own. It's a truly simple ordeal, either way. With the Nissan bushing it could work with just some 3/16 flat bar across the trans tunnel, and two ears pointing upward to put the through-bolt into the bushing. Or you could even buy the classic GM Transmission mount and use the flat-bar all the way across. It bolts up to the Z transmission fairly easily.
The area right beside the throttle pedal needed a brief 3 second meeting with a rubber mallet to allow the solenoid stud for the RX7 manual starter power wire to have ample room so that it does not arc to the chassis. There is still plenty of room between the pedal and the tunnel, and it does not intrude into any of the pedal arch area and fancy foot work is indeed possible. It's barely moved at all. I think you could drive with steel toed boots if you felt the need to. There is plenty of space after the required cold-working of that area.
The entire starter adapter and starter unit itself can be taken out of the car once the transmission is installed- which was very important to me when designing this kit. It is something that is necessary in the event of a starter failure or to diagnose clutch problems. The starter hole that needs to be cut out of the bell housing (very easy to do) also allows operators to inspect the throw-out bearing for fluid leaks- which is also a plus.
Due to the location of the starter in this kit, the CD009 or later (JK40C, JK40O) transmissions are the only tranmissions this works with as they do not have the clutch fork and slave cylinder on the outside of the trans- which is where the starter is. Those are the later transmissions from the HR 350z's and all 370z's. They can still be found for very low prices, barely used. And if you really want a new one from the dealership, they're roughly 40% of the price of a T56 Super Magnum. I am estimating that for the cost of a T56 Super Magnum alone (not including anything require to adapt and install it), you could have this Z transmission and adapter kit + your own custom driveshaft made- which is a huge plus as well and it is the reason for its existence as far as the time attack car goes.
VERY IMPORTANT: The motor can be removed and installed from over the rad support as most people usually do. I tend to prefer installing motors by removing the front sub-frame/engine cradle and raising/lowering the chassis onto the motor, but we opted to install it the conventional way to make sure it could be done- and it was done very easily.
I can get photos of the trans tunnel mods with the transmission IN the tunnel, but for most installations it will be up to the fabricator to make measurements and install.
I am trying to procure the fasteners required and all the hardware for a reasonable price and getting quotes for 5 - 10 sets of the machined items made as well. There are some uncommon fine-threaded fasteners that are necessary for proper alignment of the plate with the way it's designed, and I haven't found them for a decent price- but it's not a deal breaker. Still just shopping around to keep the kit cost lower.
A lift is being installed at the facility where the car currently resides, so once that is done I can get more photos. I will make some time to coordinate with my preferred machinist to see if I can get a quote for all the machined parts this week and perhaps visit the shop on the weekend to take interior shots of the tunnel.
Will try to update soon. If there is indeed enough serious interest, to lower the cost even further I would have to take some down-payments so that more kits can be produced to decrease overall cost for everyone, but I'm not thinking about that part right now and I want to get the important things sorted, like a high power dyno run at the very least.
The last thing I want to do is send everyone a bunk adapter kit and put 1 or even 10 cars out of commission.
IF THERE IS ANYTHING THAT I AM MISSING OR UNAWARE OF FOR FC/FD CHASSIS CARS THAT ARE COMMON MISTAKES FOR THESE TYPES OF ITEMS, PLEASE INFORM ME, I WOULD LIKE TO MAKE THIS KIT AS STRAIGHTFORWARD AS POSSIBLE WITH WHAT I HAVE ACCESS TO.
in the tunnel, have to trim the bulges for the trans mount to allow it to sit all the way but that is typical in T56 swaps also
will most likely need to do alittle trimming here but i have to get the shortened housing (brings center of shifter to 32" from bell housing) and get it mounted to the 2J first before i worry about that
Going by the burgundy 80's interior, am I correct in saying that's for an FC?
The front of the transmission sits a touch further back with the rotary installed, but it looks like the shift lever position is still quite comfortable with the modified extension housing and strike-rod linkage (which I have done on another car/swap that used this transmission, and it's fairly easy to do if you can weld aluminum).'
The facility with the Time Attack now has a hoist, so hopefully I can snag some more photos soon.
Yes, this is FC fitment. Also the trans will sit much further back when mounted to the engine this is just as far as it will go with the factory trans mount bulges in place. might fit if it was put into place from underneath the car but wouldnt pass those mounts when sliding the trans into the tunnel like i did.
Now that I recall, that is part of the reason why the car with the kit I put together had a mount fabricated that ties into the frame rails and holds the transmission up with two tabs in the center. The transmission is roughly 11.5" wide in that area, compared to the puny 8" wide factory trans casing.
We ended up putting the trans in from the top, which was as easy as any swap. It's best done with two people. One to guide the bottom of the trans the main seal protection cup slides against the ground. We just wrapped a shop-rag around it and once it was high enough, we put a short jack under it and rolled it back while lowering the engine at the same time to get the proper arch.
If removing the transmission mount bumps off the tunnel is all that's required aside from shortening the shifter linkage, that would be awesome.
I think that if I were to include a shifter shortening kit, it may drive the initial production costs way too far up for me to handle more than 1 order at a time. But we'll see soon enough. In a perfect world, the Z32 shifter would work- but it does not have a reverse lock-out function that is spring loaded like the Z33/34 transes do, and you can go from 5th to reverse quite easily without it.
I am also developing a shifter linkage that moves the entire unit FORWARD of the Z33/34 stock location/mount, but that is for another application and it's rather... involved. But it doesn't help any of the installs here unless maybe 4 rotor guys want to move the entire engine back a bit or something. I dunno.
The car is going to be dyno'd next Friday. I think it's ready for full power testing. I will get pictures of the setup and dyno results and we'll be looking out for any vibration or harmonics and all that stuff.
The starter mounts at the bottom driver (USDM) side of the RX7 trans bell housing, facing toward the front of the vehicle, as shown below. I've just been told it's an FC3S Turbo Trans. It came out of the Turbo FC3S that the CD009 trans is now installed into:
That is a N/A trans. You can tell by the lack of a removable bellhousing and a lack of a bottom cover plate. Further, you can tell it is an FC trans by the four mounting bolts on a ~45 degree angle to horizontal.
So you're set up for the small diameter (non turbo) flywheel/starter and 225mm clutch? (This is increasingly relevant to my interests)
Peejay, the photo I posted was just off some website to show the starter location, not a photo of the actual transmission. I specifically said in post #3 (https://www.rx7club.com/rotary-car-p.../#post11978869) that is is for an FC. And in the post prior to your response- just above the photo, I specified that it was an FC3S Turbo Trans.
The car it came out of was equipped form factory as a Turbo II. It has a Turbo II flywheel (aftermarket, but shouldn't change anything), and an aftermarket clutch disc and pressure plate made for a Turbo II, but with the clutch disc splined 24T for Nissan transmissions (virtually all the same).
Now that I think of it (Being a Nissan/Datsun guy), it's possible to get away with buying a pressure plate for an RX7 Turbo II or using your current aftermarket one if you have a Turbo II kit, and using any 240mm Nissan 24T splined disc from the S130 280zx Turbo, Early (84-86) Z31 300ZX Turbo, or t he N/A Z32 300ZX (Non-Turbo), as they are all 240mm. I should have one laying around that I can verify this with, but I would need to locate another Turbo II pressure plate and flywheel to see if the clutch disc hub will be clear of obstruction on both sides. It would make this whole ordeal about 300-500 dollars cheaper for anyone who wishes to swap to this transmission but has a good working high torque capacity clutch kit installed already. I will try to confirm these suspicions and post photos.
Sorry for the confusion, The trans I was referring to is actually the one on the right, posted here:
Would be appreciated if a Mod could remove the other photo I posted to avoid confusion for anyone just skimming through.
Information is good. I can sympathize with not being 100% on board with the history and the weirdnesses of the different transmissions used. Mazda changed a lot of things around over the years.
It probably would be just fine to use a Nissan 240mm disk in a Turbo II pressure plate. Note that Turbo II and FD are the same diameter but different clutches, the FD has a pull style unit and the Turbo II has a normal one. Another one of those cross-swapping gotchas to look out for.
I mean, a 3-liter Ranger disk is used to mate a nonturbo (225mm) clutch to a Turbo II (23 spline) transmission, if you have an RX-3/4/5 bellhousing to mate up with the trans... since those cars had N/A sized flywheels (starter position, starter position!) but the same trans design as the TII/FD...
I'm still interested. I could always just use a topmount RX-3 starter and cut a pocket to fit as necessary... all rotaries up to 1992 have the mounts for the starter that Mazda stopped using in 1974.
(The *reason* why I am interested is the AWD version of those transmissions from the Infinitis. Which uses a computer controlled clutch pack to the front instead of a center diff. Which is the setup I would want.)
I'm still interested. I could always just use a topmount RX-3 starter and cut a pocket to fit as necessary... all rotaries up to 1992 have the mounts for the starter that Mazda stopped using in 1974.
(The *reason* why I am interested is the AWD version of those transmissions from the Infinitis. Which uses a computer controlled clutch pack to the front instead of a center diff. Which is the setup I would want.)
if you intend to do that with the RX-3 top mount starter, it would require offsetting it to the rear of the car by 1/2 inch, as the flywheel has has a spacer that moves it 1/2 inch further backward. The common method (when installing this box on some other engines) of removing 1/2 from the bell housing leaves an unsafe amount of clutch disc spline engagement for the this Turbo II or 13B setup. When making driveline components fit together, I like to always get full engagement on the sleeved portion (female) of splined components. Not adhering to that detail makes for interesting twists on splined sections that can cause binding or simply make it non-reusable if it ever has to be pried off. Repairing an input shaft every time you have to do the clutch doesn't seem efficient or fair to a consumer, in my opinion.
With your proposed starter modification, the only issue I see would be the top two bolts that fasten the bell housing to the adapter are close together, and the flange and snout on the RX-3 starter may come in contact with them, or simply not allow the starter to be used without removing them. A considerable amount of material would have to be removed from the top and you might lose fasteners. One way around this would be to make a flange/plate that you can weld to the top of the transmission if you remove those two bolts, and find a way to affix it so that when you bolt the starter, the rear two starter mount bolts will take care of keeping the transmission tight to the adapter up there. This would be a simple fix for that issue.
On the starter adapter I've developed with the owner of the car, there is still bell housing cutting, but all bolts are retained, and even the entire bell housing flange perimeter is retained.
As far as the G37x transmissions- I can't say that I've seen one in person or in photos. I thought they were only available in auto, so I never paid any mind to it.
10-12-15, 02:06 AM
JK40C/CD009 Transmission from 370Z on 13B
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