wombat57

I've posted a few inputs and comments on the TK6 and track car gearing threads and after a some good feedback decided start a thread on my project. I currently have a '99 that I bought about 12 years ago with a blown (some kid ran it out of oil) stock engine and 5 speed. I put a 30k mile '03 VVT engine in it and have been running it as my daily, on the stock '99 ECU since then. Now it has about 130k on the engine and 240k on the chassis. It has an Ebay billy set on it with 450/275 springs, and FM sways, 15x7's. I'm now retired and have more time so have been gathering parts. Plans are first, a rods only turbo engine, at 275 hp or thereabouts, to work out bugs and get tune right, then buy a junkyard engine and build it fully forged. I have the following parts in my shop and am waiting on just a few more.

ZF8-HP45 (2) - bought them both out of a salvage yard in North Carolina, one w ~ 30k miles for $175, the second w ~ 60k miles for $150. If you do a Car-Part search for BMW 328I trans years 2012-2016, there are literally over 10,000 (no ****, 200 pages, at 50 listings per page) under $500. Gotta love that part of the project
Kraken low mount manifold, and DP, 3" pipe mufflers and resonators for exhaust, all the Kraken fittings
EFR 6758
1000cc injectors
fuel pump
Maxspeeding rods (hey, they were on sale!)
junkyard Audi red top coils
ME442 ECU with DBW option
CANchecked gauge

ordered and paid for, not yet here:
Domiworks ZF8-NB adapter and flex plate/ring gear. This is due in the next two weeks.

Not yet bought, and the next biggest chunk: Trans control unit (TCU)
Gasket set, sump baffle, oil pump gears, intercooler.

Re the -8HP. I have always driven manuals, and love them but also love the thought of a paddle shifted trans, and don't want to fight the various Miata versions. The Walter version is not cheap. After a lot of reading including the 7 sp DCT thread and looking at pricing and the sizes, I decided for me the 8HP was the way to go.

8 HP -45 is 300 ft lb capable, and a very reliable transmission.

More details: two main TCU's are available, the CANTCU, and TurboLamik TCU. CANTCU is used with the stock mechatronics in the trans, and custom software that allows connection to many commonly used ECU's - but not yet all. It uses the factory BMW software but can be tuned, and can be run basically almost slushbox auto to quick shift sport mode auto, or fully paddle shifted. The TurboLamik TCU requires disconnecting and re-soldering a board into the mechatronic unit, which seems scary, but many folks are doing it very successfully. The TL board has its own custom programming that allows tuning of all - or just about all - transmission shift controls. It can be run just like above - easy, sporty, or full manual.

The transmission itself is pretty cool because (I didn't know this and maybe all current modern autos do this) it has no pressure sensors inside, just PWM solenoids. Control algorithms in the built in (CANTCU) or replaced (TurboLamik) boards measure only relative speed deltas between input and output shafts, and compare that to throttle position, manifold pressure, and torque to tailor pressure with PWM solenoids to internal pistons that unload and load the clutches for shifts. So all shifts are clutch to clutch shifts, and engage or disengage different planetary gearsets. The planetary sets are STRONG.

I've just about convinced myself to go with the TurboLamik because I want throttle response. I hate soggy throttle response, and slow run down to idle. I've had an early 911 with a very light flywheel and my son built an E30 with a Franken 3.0 with a light flywheel - and to me, it transforms the character l of the car. However to get throttle response, the torque converter has to go, as it weighs about 8-10 lbs more than a stock Miata FW/clutch package, and the weight is more to the perimeter. So I am going to make a "TC less" version. It has been done already, and I owe many thanks to Steven Langaeker from FB,, somewhere in NorwSwediFinlandia and Darin George from FB at Motorsports Enterprises Racing in Cresson Tx., for letting me pick their brains. The CANTCU does not currently have the ability to run the trans without a TC.



Steven runs a drift E30, and Darin has built Miatas running these very trans's without a TC in track cars. I'm a bit concerned about clutch pack wear, but I think it won't be an issue because:
1) all of these cars start from a dead stop 10's of thousands of times with a torque converter. When they do that, they slip the first or second gear clutch packs until the clutch locks up, every single time. With a TC, the relative input/output speed delta allowed will be somewhat greater (how much?) because of TC slip, whereas without the TC, the clutch will lockup with no I/O speed delta, causing more wear. How much? Will it matter? Opinions differ.
2) take a look at the ratios below. First gear is damned near a granny gear. I think I'll be able to engage first gear clutch fully, just above idle and with a low inertia, roll on spinning tires then hit 2nd. So that could occur with very little first gear clutch slip. That's my theory and I'm sticking to it.
3) I've always been easy on manual clutches, and have never damaged a single one except that one when i was 16 in dad's Corvair van trying to pull my drunken buddies high centered station wagon back on the road. I think mechanical empathy will serve me well.



Interested folks can search the names above on FB in the ZF8 transmission swap and technical thread group, and see some of what they've done, and also the Zeroto60 guys in Australia on YT - they're doing a lot of both off road and hotrod sports cars using the TurboLamik controller. They've also developed a manual clutch actuator. I'll post more when I've made more progress.

HarryB

ZF8 is a kickass trans, much better than the usual DCTs. Looking forward to the next posts.

P.S. Did you have the chance to weight it yet?

Padlock

Thanks for making this thread. I should have made one when I posted about it in my build thread.

While I'm not in the position to be pulling the trigger on the swap for my car yet (yay scope creep!), this transmission has peaked my interest well over a year ago for the build direction that I have planned. Right now, CANTCU is leading the race IMO for the TCU to run given downshift and upshift smoothness and capability/adjustment. I don't have a strong desire to replace the mechatronic board for TL if other options are available. It's worth noting that for both TL and CANTCU controllers that they utilize estimated torque and throttle position via CANbus from the ECM to help control when shifts occur. Therefore, an ECM with CANbus capability is needed for TCU communication and DBW capability is required for downshifts as the TCU will send signal to have the ECM blip the throttle for a smooth rev-matched shift.

The TC-less install is intriguing and I'm sure it can work in track environment, but I foresee a lot of compromises in doing that with a car that sees street mileage (which mine will). Your second bullet point about your launch strategy seems like a miserable time if I was in traffic for example. Regardless, I'm looking forward to seeing how it works for you and I'm more than willing to eat my words if you prove me wrong. I just have zero desire to be an innovator or test dummy on something like this when I don't feel the TC will be that bad having driven other 8HP vehicles.

wombat57

Padlock - I'm hoping I'm 100% correct and you are not! :-) I have messaged Darin George at Motorsports Enterprises Racing on FB, and he said he got TurboLamik to do a bit of software that allows him to run TC-less. I hope to buy a copy of what he's using. Also, as far as I'm aware, the engine torque doesn't have to be used - I think MAP can be used also. He is running Haltech 1500's and I don't think he has torque, but does have TPS, and MAP. I could be wrong. He has tuned the PWM's to the clutches on his cars so they can do full power corner upshifts or downshifts under braking without chassis upset. The Aussies have a vid I'll try to find showing rolling off using manual clutch. Fingers crossed!

I have weights will try to post tonight with some dimensions.

Padlock

I look forward to the additional information that you share on the TC-less topic. I also hope you are right, but I'm very skeptical on that (until proven otherwise) is all. Being optimistic, at least one saving grace with our cars is that they are fairly light which is going to be incrementally easier on the clutches during slip activity.

Posting this build thread for reference as he's an active member planning an Emtron ECU with CANTCU on a big boi 8HP70. He's probably the closest to any of us to having it completed with a car expected to be running in a few months. He just got trans mounted up a couple weeks ago.
https://www.miataturbo.net/build-thr...sweden-108923/

wombat57

I'm a dummy - just posted this in his thread. Cut and pasted back here. Some rough dims, zf8-45.

lgth ~ 28.5"
bell hsg dia ~ 13.75
4" back from bell hsg face ~ 12.25 dia, but taller (dont have that dim.
8" from bell hsg face to ~ 20" from face, approx 10.5 dia

weights below assume 35 lb flyw/pp assy for manuals and same for ZF8 TC (I cheated slightly - the TC weighed 36 lbs ) and are based on quick Google for manuals, and me plus parts and bath scale for ZF8, and I assumed 15 lbs for the TC less ZF adapter. I'll try to get some pics w a tape measure so dims are a bit more clear.

wombat57

btw Padlock - off topic but how is the NVH in your 99 with the K24A2? Those are awesome engines.

Padlock

I wouldn't consider the NVH bad, but its definitely worse than anything you get a on a BP powerplant. Poly engine mounts and the necessity to delete the balance shafts on the k24 swap by design will create more vibrations. Early on in the swap, I noted multiple rattles on the interior/exterior that I haven't had before, but pretty much all of them were around idle. I have found that by raising the idle speed 100rpm to change/raise the resonant idle frequency and by using some adhesive backed foam tape in a few key areas, I was able to minimize almost all the rattles. While driving, I don't notice too much at all. On track, you can tell the vibration is there at high rpm, but in that environment the vibration and sound is just part of the experience/feel of the car... There's other solutions to some things but I don't want to derail this thread too much...

As it relates to this thread, the vibration of the k24 is one of my concerns with a TC-less ZF8 trans. It is a known issue on BMW DCT transmissions that a dampened flywheel is pretty much a requirement, otherwise the vibrations on an inline 4, which are much more aggressive than BMW inline 6's, will destroy clutch baskets. SuperK (video below) is a car built by a local shop to me, and that car has been absolutely plagued with issues on the transmission side of things as I've stayed in touch with Andy from ASM on it. While I know the ZF8 is different in design than the DCT, the concerns that I have long term about removing a TC (which is effectively a damper when unlocked) is still real. The SuperK build does inspire me to keep pushing down the ZF8 path though, because if I can get 90% of that performance with the much cheaper ZF8, it looks like a phenomenal time to drive... especially considering my car would be ~500lbs less than SuperK.

wombat57

Yeah Langaeker from Sweden( I think) has just a solid hub, with a BMW diesel, but Darin uses what looks like a Miata spring hub clutch disk welded into the adapter. TBH I’m still a bit on the fence cuz of the things we’ve discussed.

wombat57

I'm still researching and mulling this TC-less thing over, and trying to use my old Engineering brain and some logic (haha right?) to make a decision on it.

One of the things I'm still trying to find out is how many plates and discs are in each clutch pack of the ZF8 vs DCT, and whether the DCT launches with both clutch packs or only one. I think because of its design it is only possible for it to launch with one. And I think this is good info to infer from.

I was fortunate enough to partake in the Porsche driver experience at Barber several years back. It was a great day, and one of the first things we did was to "get used to the cars" - a full throttle launch thru 1st and second gear followed by full effort braking, in a 911 Carrera with DCT. 4 guys in our group, one car. Launch, (slap pedal to the floor) run to redline in 1st and 2nd, hammer brakes, u-turn to start, climb out, the next guy does it, lather rinse repeat. I think we ran thru the exercise 4 times. I think there were 5 groups of guys doing this and I never saw them change out the car. Never felt a difference in clutch take up or slip at all. The DCT has two wet clutch packs. They are not visually significantly different from the ZF8 clutch packs.
There are definitely multi plate wet clutches in almost all common superbikes. I think the Ducs used to be dry multi-plates, but they may be wet now. These bikes have (1) multi plate clutch stack, and guys beat the living dudu out of them all the time. I have never abused a clutch like guys doing burnouts or drag racing bikes.

The ZF8 utilizes three multi plate stacks to transfer torque to first gear - clutches A & B are actually brakes, and clutch C is a rotating clutch. I think the Turbo Lamik will allow all to be energized simultaneously but maybe not. If it does, it should be capable of launching like the DCT or nearly so, with negligible wear. Even if it does not, it may be ok, because if it only uses one clutch pack to start off in 1st, and the DCT only uses 1, maybe it is still the same sort of capability. Both are ZF8 * DCT are full oil bath, with an oil cooler. The DCT does sometimes slip both clutches at once on purpose, but from this I'm inferring it is impossible to use both to launch from, which to me is another good indicator of how much abuse a single multi disc oil bath clutch pack can take. From the 911UK forum, by member 911Time, in March of '22, in his excellent DCT article: "If the vehicle is travelling along in a steady state, on a light throttle, in one of the lower 3 gears (which have the widest spacing of gear ratios) and the TCU determines that none of the current ratios offers the best efficiency, it can effectively run two gears at once. By engaging both clutches lightly and slipping them, it's possible to provide an intermediate ratio, that better suits the state of the vehicle and thereby maximizes efficiency."

I've cut apart the ZF8-45 TC. It has a double steel, one disc lockup clutch. There is no significant wear on the disc. Its piston is about 30 sq inches, w about 250 psi operating pressure, so ~ 7500 psi clamp pressure. The other clutches are all multi disc - from the sections I've seen the min no of clutch discs is 4 on one clutch and 5 or 6 on the others. Looks like 6 on clutch C. Much less piston area, much more disc area. Kind of hard to estimate their piston areas.

You Tube

- go to about 7 mins.

that is an 8speed.au vid showing a clutch emulation easing off, albeit with a TC. Still seems to me if it can work with TC, it can work without. Easing off is just slipping the clutches, with or without TC.

inputs/thoughts welcome.

Padlock

Logic seems sound, but it's probably also worth noting that TurboLamik is the only software available to support that type of clutch feature. It requires replacing the mechatronics board AND it's been known to be good for mostly drag racing and drifting due to relatively harsh downshifts. That isn't to say that a software revision couldn't address that in the future, but I can only speak to what I read about now on the facebook groups. Until the downshifting issue is resolved, I can't take this controller seriously for road racing application regardless of the other features that it offers.

CANTCU, in comparison, has very well reviewed shifting both up and down (great for road course use). It does not require a mechatronics board change, and you give up the ability to have a transbrake or clutch pedal.

One of the multiple guys I've chatted with on the topic with a turbo K24 NC has recently made the switch from Turbolamik to CANTCU for smooth downshifts alone. He hasn't posted much publicly about it, but there are a few private group videos on facebook showcasing some of the differences. Here was his car when on Turbolamik software and the reasons why this 8HP swap thread exists. Those upshifts shifts are crispy. Tune in around the 50 second mark

engineered2win

A DCT only uses 1 clutch for launch. The gears are separated even/odd, so odd # gears are on clutch 1 and even on clutch 2. The idea being that you're always shifting sequentially and thus are able to prep for the next gear without interrupting torque transfer and then transition between the clutches. Otherwise, if you wanted to skip gears and say go from 2nd to 4th it would basically operate as a single clutch and would drive like a bucket of crap. Think old early 2000's single clutch transmissions.

I had to look this up. We weren't aware of anyone using this "feature", but it is highly atypical of DCT's. I discussed it with a transmission hardware chief engineer and we don't really understand why you would do such a thing other than "those crazy Germans." It's highly inefficient, as you're using a lot of clutch slip on both clutches, which just generates heat in the clutches and the oil. And the amount of slip would be why it's limited to low speed/load operation, since you're limited on clutch torque capacity in this state. If you were to fully lock up both clutches it would essentially be a trans brake as you have 2 gears engaged, so there's some fundamental limit of drive force in this condition.
Fuel economy is out since efficiency is key, and thusly emissions. Probably not a driveability benefit, since it's pretty standard to use 'microslip' where you would have only 1 gear engaged and slip the clutch ~3-10% to smooth out the torque fluctuations (like an unlocked torque converter effect). Maybe NVH to get the engine out of some resonance area? Regardless it's an edge case and not the norm.

jpreston

iTrader: (4)

I've been looking hard at the ZF8 and Ford 10r80 for a while now. I started following Darin's team (Rapscallion Motorsports, previously MER-- and I'm told Darin no longer works there) last fall when I found out they were running ZF8s in their WRL enduro NCs. They had a rental seat open up for WRL COTA in December and I decided **** it, why not. Good opportunity to experience the trans in real life AND finally get to drive COTA before doing the swap in my car and possibly regretting it.

Both cars were running Haltech Elite 1500, Turbolamik, and torque converter that weekend. They'd been testing the TC delete the week before COTA but didn't have it ready for full enduro use yet and put the converter back in. The upshifts weren't as crisp/firm as I expected but it wouldn't surprise me if that was intentional for enduro longevity. The downshifts were very smooth except for one spot in the esses, and after I told Darin about it he made a change to the settings (I think the haltech auto-blip, not the lamik settings) and it was great the rest of the weekend. Could downshift mid-corner basically anywhere without upsetting the car. My biggest and only real complaint about the trans was that it was set up way too far on the conservative/safe side for when it would allow downshifts. Any time I needed to go down more than 1 gear I'd have to just keep pulling the paddle and watching the gear display until it got to the gear I wanted, even when I knew the RPM had dropped far enough to allow a safe downshift. I don't know any reason why this would be a limitation in the hardware and I think it was purely in the turbolamik programming-- again, maybe intentionally because these are rental enduro cars.

I still haven't decided what I want to do. I keep going back and forth between ZF8 swapping my turbo NC, building an RX8 with a mustang ecoboost/10r80 swap, or just building an ecoboost/10r80 mustang. I bought a 2020 ecoboost/10r80 mustang daily driver that I've taken to the track twice now and it was surprisingly fast and handled great, even at full street weight of 3800lb with driver and stock mag-ride shocks and springs. The 10r80 upshifts are HARD and fast when in track mode. I imagine the ZF8 could be as good or almost as good, but there are 3 generations of ZF8 and I think they made improvements to shift speed with each generation so I dunno if you could get an early ZF8 to shift as fast as the 10r80. It has the same downshift command problem as the Rapscallion car, but HP Tuners has a lot of adjustability in those settings and the one change that I've made so far made a big difference.

jpreston

iTrader: (4)

Also worth noting: they said they lost about 25hp going from the stock manual trans to the ZF8. They were hoping to get a lot of that back with the TC delete but it only made a small difference.

COTA was my first ever rental experience but Rapscallion was a great team to run with. Would definitely recommend them to anyone else.

wombat57

And thx Padlock - all good info. I watched Law’s NC vids - thing is badass. Domiworks finally got starter ring gear so he’s supposed to ship this week!

Padlock

Thanks for the feedback Jeff. That's insightful. Do you know if the 8HP swapped NC's had trans coolers on them and if so, which ones?

jpreston

iTrader: (4)

They had a custom radiator/oil/trans cooler setup that worked really well. Coolant temp is the only one I remember seeing on the dash and it was right around 190 all weekend. I think I saw trans temp at one point and it was also nowhere close to overheating.

chuckieho

That’s a huge loss, do you know their ballpark before/after power numbers?

jpreston

iTrader: (4)

They just run basic 2.5 swaps with cams afaik so I'd guess 190-195whp before and 165-170whp after.

chuckieho

Is that a typical HP loss? Was the lower HP something that you noticed, or was the faster shifting good enough to offset that?