Tremec TKX
 

lets see if this is going to be my transmission solution. Very similar ratios to the stock miata 5 speed, rated for 600 ft-lbs.



trans
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I always wanted to see someone with a TKO or TKX in a Miata. Very cool!
What engine requires such a strong trans?

His sig panel

Double check it goes into all gears, multiple shift forks like to engage when bounced around in transit. Had it happen to me, and apparently it's quite common. Fixed by unbolting that shiny 4-bolt plate, and sliding everything into neutral, but that's a bit difficult to access once installed.

yea there was a note in the box about that. shifts fine though.

That's interesting.
I'm very used to the BMW ZF 310/320 tansmissions and with a properly serviced shift linkage, they are very nice and strong boxes, especially the GS6-37BZ (I have one in my Z4 and a ZF320 in my E36).
Both can handle 450+ wtq all day, so is this more like a gear ratio thing?

I don't want to offend anyone, I'm just curious, because the ZF swap is very well documented and easy to do. I'm sure there is a good reason, please enlighten me =)

This is the setup I'm considering, what vendor did you get the trans/bell from?

The only downside on paper for one IMO is the RPM range they operate in, I'm curious how well they shift near the limit they supposedly have.
per Tremecs site.

I'd like to see how the fitment is compared to a Miata trans, in regards to tunnel clearance/exhaust and shifter position. Please post more info as you get it installed!

Good luck. :D

I've been eyeing the TKX as a replacement to my T-5z, which doesn't exactly enjoy shifting where I like to enjoy shifting. It'll also be nice to get away from the .63 5th gear (.8x available for the T5 aftermarket). I was hoping to go over a few questions with them at PRI but I don't see them on the exhibitor list. I need a shift offset of 23.700. My offset shifter gizmo works well but has a harmonic at lower RPMs. That and mechanical speedo interchanges, etc.

Looking forward to reading your experiences.

Also looking forward to hearing about your experience with it, especially how it shifts at high rpms. I've been thinking about putting a T-5 behind the Cosworth in my Capri, and this sounds like it might be just the ticket...

@fastivab6tg25mr is literally installing the same thing at the same time right now, also very interested to compare notes/feedback :likecat:

@Bronson M has one behind his LS and I think he really likes it.

Im planning to go with a TKX when I do my LS swap in the 24-25 off season.

Yep got one installed and boy I wish I had done it sooner. Cd009 was a massive mistake. The trans is a little rough around the edges, get a little snick from the syncros when cold, reverse isn't syncronised. Shifter feel is very ka-clunk and I mean that in the best way possible. It would never fly as an OEM trans but when you get mean to it, it just eats it up and shifts every time and does so super fast. I've only tested it up to 7200 but had no issues there. If you do have issues liberty will faceplate them for $1600. Bonus points that it weights right at 100lbs so much lighter than a t56.

Here's some video from my last event with it.

I am considering this for my k24 (future turbo) mainly because I’m in an exocet so any trans mount will be custom. As others mentioned in slightly concerned about 8k rpm shifts.

I would likely keep the k to Bp adapter plate and flywheel and then just do a Bp style bell housing.

what is everyone doing for a throw out bearing?

This is working well for me, you gotta get the shims right though

https://www.speedwaymotors.com/Chevy...MaAuGlEALw_wcB

Don't tell Tremec, but on a customers 13b with the bellhousing indexed to .001", he is shifting regularly at 8500-9000 rpm. It's all about stacked tolerances. This is on a non-faceplated box.

I logged .186 second shifts using flat shifts with syncros........ It's fucking fast

Im just now starting on this swap myself, except all the quicktime bell housings are on back order and from what i hear the dates typically get pushed back, so im attempting to make my own using an automatic bell housing. The automatic bell housing im using the center's runout is only .005 which is the max spec for the tremec so i have a few ideas that might make this im hoping atleast a pretty simple build. I might make my own thread though to go in depth with it.
Also curious what clutch your going with and what kind of slave/master setup?
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Which version of the TKX did you go with? How goes the install?

do you have any picture or measurement with the QuickTime on how far in the input shaft sits in relation of the front of the bell housing?

The quicktime housing is now discontinued and canceled my existing order. They told me at least 3200 to “custom make one” even though they have probably made this housing for 10 years or more now.

Wow I ordered the quick time from Summit. maybe I got the last one. Sombody should make one.

That’s the plan, I hope… I had an order in from summit when you made this post and was back ordered I eventually canceled it
snd just put it in at Holley not knowing how new stock was distributed figured I’d have quicker luck right through them… you very well did get the last one

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I have it mounted in the car and I'm keeping the PPF to mount it. ill take better pictures of my bracket when I take it out again. My motor is mounted ~ 1.6" aft of the stock location this was done by shifting the holes in the back of the PPF and offsetting the frame side motor mount brackets. The outboard hole in the TKX rear mount is pretty much exactly the same position as the aft trans mount hole in the miata just space it down and it gives you the correct location reference to create the rest of the connections. PPF works good and doesn't weigh much I saw no need to discrete mount the diff and trans. I bought an American Powertrain white lightening shifter with a 3" offset which I think will work OK with a further offset lever still need to work out shift boots though. Shaftmasters made me a custom aluminum driveshaft quick turn around.


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The quick time had a lot of strange stuff about it that didn't really seem fully worked out. it comes with a huge heavy block plate that that extends further out and has extra bolts. I didn't see a need for it I'm using the stock plate and trimed down the Quicktime flange to the stock demensions so it would clear the exhaust and it also took a bit of weight off. I'm going to use a Tilton hydraulic throw out bearing with a tilton 7.25 twin clutch and clutch master cylinder. The belhousing comes with a window and a post for a pivot ball for the stock clutch fork but no provisions for mounting a slave cylinder which is strange.

spec is supposedly making me a billet 215mm single disk that they claim 600ftlb I’ll wait and see, and also was going with a tilton adjustable, my worry was clutch hydraulics, what spec master did you get. With the short Miata pedal throw I got a 13/16 size master but I have a feeling it’s going to be super stiff. It’s hard to use the 3/4 1.4” of stroke recommended by tilton as stock pedal comes in at like .88” of stroke at the master.

Using a 3/4" tilton as recommended for the clutch and hydraulic TO bearing combo as recommended by Tilton. stock pedal ratio is right in the range recommended as well and it says right in the instructions theoretical max stroke at the master cylinder will be 0.73". with this combo.

I tried a 1.6l size Spec clutch years ago that was rated for over 400 ft lbs. I think it was the stage 3+ initially with the light weight pressure plate that had an aluminum ring with a steel friction surface like an aluminum flywheel. It was the worst engaging clutch I ever drove including 5.5" multi disks. basically had to spin the tires to get it rolling. The pressure plate warped to shit in no time and spec replaced it with the heavy plate I thought it might fix the engagement issue if the pressure plate wasn't warped but it didn't. Also the clutch started slipping under full load in higher gears. I gave up and went to a ACT ZM1XT pressure plate and I have used both sprung and unspring disks with it. It is rated at just 350 ft lbs but I think they are conservative in their rating. the sprung centers springs would eventually fail but with a solid disk I had no problems lasts a long time and engagement is nice and smooth used it for years.

I have a 949 twin in with organigc discs in another car and love it but decided to go Tilton with this build mostly because of parts availability it also fits on the 949 twin flywheel.

yeah hopefully this isn’t that bad but guess I’ll see m, this was a 1.8 size clutch though, if that doesn’t work out I was just going to get a comp disk resplined for the tkx and just keep using my fm2 for a short term solution, I talked to one guy that said they used a clutch masters twin disk with this setup before. And I’ll have to re read the manual, I know I spent a ton of time trying to get the right size master but I suppose I could be blind and missed that part, even went as far as messaging Tilton who showed me the math on calculating it. Are you using a tilton clutch too it sounds like might be why they had a little more data on what to use then vs my case. I was just reading the manuals for the hydraulic throw out, is that all you were reading or have different instructions? I might have to re think and go with a 3/4 master then. Guessing a wilwood 3/4 is going to be basically the same as a tilton 3/4 for the most part.

I also have driven a 949 twin with ceramic discs and had no problems with it. pretty sure their sourced from Competition Clutch. The 949 twin flywheel has the same part number on the box as competition clutch and its cheaper through 949 but I think the disk thicknesses 949 uses are different and might be sourced elsewhere. I liked tilton because the parts were off the shelf and always in stock from multiple suppliers. I chose the High pedal ratio Buff spring and cerametalic discs which rates at 480 ft-lbs. high pedal ratio over Ultra high sacrifices some engagement slip for longer and more consistent grab feel. I have no experience with either so Im taking a guess which I would prefer.

The 949 twin with organic discs tends to wear the discs out requires some periodic pedal height adjustment and we only get about 2 seasons out of the discs auto crossing a CSP car with it before it needs new discs. The engagement is nice plenty streetable but it is so light of assembly that if you are trying to hard launch it there is generally some wheel spin involved to keep from bogging. From what I understand the ceremetalic wear much more slowly. I didn't notice the ceramatalic discs really being that much different in the way they grab when I drove a car with them in it. I think we might switch to those.

Now that i reread your previous post sounds that might be kinda similar to what they are making me, pitched it as a single disk version of their 215mm bmw n54 twin disk cover on a Miata aluminum flywheel using a 3+ disk or any disk stage i wanted that would be good for around 600ftlb which i expect ill eventually drop down to a less agressive disk as I wont be making 600ftlb anytime soon out of a bp, Its a bit trial by fire I suppose and never learn until you try it. I much like the idea of both surfaces being replaceable to keep the cost down on rebuilds so i dont feel so bad beating on it. Car was going to be kind of an all round street car and will see a fair bit of drag racing. Excuse me for sounding like a noob here but it sounds like to me you specced a clutch to have less of a disengagement distance so thats how you can get away with a smaller master/pedal stroke is what you mean by "high pedal ratio buff spring".

also what ratio tkx did you go with and what diff ratio?

I'm on the fence weather I'm going to use a 4.30 or a 4.10 diff. leaning towards 4.10. It's the tremec TKX version with a .81 fifth. How fast I can go in second gear is important to me for autocross. otherwise I might run a 3.90 for track use. I've outocrossed it with a Quaife wide with a 4.77 and a 6 speed 3.636. which is pretty good. Stock 5 speed with a 3.909 was too tall of second gear for autocross. For autocross I rev the shit out of it 8600 rpm + to make the most of second gear off corners and avoid shifting to third. more recently though Ive been on the rev limiter a bit much on several courses so maybe time to bump it up a little. Ill probably keep a 3.90 in the quiver to swap in when needed for like Crows Landing California or road courses.

I went with the same one, I’m a little worried the 2.87 first will make launches hard but I didn’t want 4th to 5th be a huge drop in case I did ever need to grab 5th in power, I don’t care about going 170mph in a Miata nor do I care about cruising rpm. I’m prolly gona stick with 4.10s for now but I’m going 8.8 one of these days with probably the same ratio, whether it goes in with the tkx at first or not is up in the air but I do already have the diff but might just stick with the 4.10 torsen for a little while and take my time rebuilding the diff and subframe mounts and everything. If only the .81 5th tkx had a shorter first gear it would match a 5 speed quite well. I’m not sure how much the taller first affects it in the real world I might be over thinking it but I already have it sitting in my floor so just gotta wait and find out.

yea might be better if fist was a little lower but my experiance is that we launched better with the Quaife wide 4.77 combo than the miata 6 speed with a 3.636. first gear with the 6 speed is silly low end up grabbing second almost instantly. I got the first gear shift point with the TKX 4.10 as being just 1.2 MPh faster than with the Quaife wide 4.777. and for what its worth the Quaife wasn't really any stronger than a stock 6 speed. Even with a 3.636 and the 6 speed there wasn't a single road course track that I used second gear for on track. Im leaning towards using 4.10 for autocross 3.90 for track with the TKX.

Did you index/check the bellhousing with it bolted on if so did it line up very good? I wasn't really able to find any offset dowels incase my diy housing needs any per whatever engine block it gets bolted to in the end. Got a little work done on it, basically all the milling stuff out of the way now just on to centering and welding and drawing out the pattern for the tkx and tapping holes and what not but thats the last step.
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Please keep us updated on how it goes, I'm sourcing a 1990 auto trans bellhousing and hoping that you can make this work since the quicktime option is no longer there.

i posted a bit more in my thread on here aswell if you wanted to check it out, just got the housing welded to the plate, certainly has its challenges

The welds kind of turned out like total crap, im sure the cast aluminum thats spent the last 30 years soaking in oil didnt help and my 200a welder certainly wasnt enough but made do with what i had. Keeping the center within spec when welding was a total pain in the ass aswell as flat. I decked it on my mini mill but that thing has its own set of limitations and it seems kinda decent then bolt it to the motor and its way outta spec again, have to play with shimming tonight i think. I Believe id go about this in different order next time if i had to make one, rough everything then weld the plate then bore it to spec.. The whole challenge here is keeping it under the .005" center runout and .002 Parallelism without having to make offset dowels which again... An Entirely new rabbit hole ive yet to explore. Every motor is going to be a bit different, i think in the case of the engine i was mocking with the oil pan is what's holding the one side higher, since half the bell housing bolts go to the pan, if it isnt aligned itll throw it out too. Id be curious if OP had good alignment the first time or if you were able to find any offset Dowels or had to make any or just sent it as is?

Oh and it doesn't have to be an auto housing, one cut off a 5 speed will do just as good too id imagine i just had an auto laying around and just didnt have to cut it, Im not sure about the actual metal thickness tho if the auto or manual has more meat on it ive never cut a 5 speed one off to look.

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i got my tkx swap running and driving, curious if you got yours goin if so do you get much chatter on decel? Ive spent days trying to track down this noise and make sure its nothing bad even to the point of swapping to my spare torsen to no change... at this point i think its gear chatter in the trans, i run a decently light clutch and flywheel

Yep, drivetrain noises "changed" with mine. I already had some gear whine from the getrag and light clutch/flywheel but it got a bit louder in lower gears with the TKX. Pretty quiet in higher gears.

I wouldn’t call mine a whine it’s more like rocks in a blender on decel in 1-4 1500-3500rpm ish but everything I find is it’s just gear chatter/rollover

is it at decel by chance, video is what I’m experiencing, haven’t ran into this before trying to make sure it’s not hurting itself or something is wrong or if it’s just normal rollover noise.

Yep decel, mainly in lower gears and that's exactly gear whine.....has some gravel to it

cool so I’m likely not grenading my shit and it’s just gear rollover/chatter/whine lol. Sorry I picture whine as a high pitch squeel or acceleration whine and this was yeah I’d also call it whine with a bit of gravel lol