Yea the biggeest issue that led me away from the ND into the NC is the diff. There currently aren't any diff options for the ND that I'm aware of. The NC has the RX7 upgrade, the AAM and the 8.8. Not to mention the 5 bolt hubs, etc...

 

Yeah, I was definitely applying the TKX idea to my own personal application (<350whp). 7" ring gear should be fine with that amount of torque and from what I've seen, the NC diff mount is a little sturdier than the unreinforced NA/NB diff arms. Also I won't be launching the car basically ever.

I think the Fab9 kit makes sense for a lot of boosted track guys. The stronger NC2 transmissions are already known to give out after sustained track use at sub-200wtq levels. Obviously they can hold up to around 300wtq for shorter periods of time, but nobody really expects an NC2 6 speed to last over a season or two on a track car that's sitting in the ~300whp range. Yeah the TKX can hold way more power than the stock rear end, but similar to what rjacobs noted, the understressed trans will live a long happy life at or above that power level.

TL;DR: I think the Fab9 kit makes sense for a lot of the mid-power boosted track crowd, although I agree it might not sell in record numbers due to missing the high horsepower guys.

//threadjack kinda. Sorry.

 

I think the Fab9 kit would actually be better suited for the ND lol. That transmission breaks at stock power all the time, built replacements are 5k+ if you don't have a usable core, but I doubt the TKX ratios would work out very well with the crazy low ND rear end ratio.

 

If I was doing a high HP 4cyl turbo I would be a lot more serious on a BMW DCT... Keep the motor in the power band with lightning fast shifting.

The TKX is a great trans, but from what I have seen its a brute of a trans, which is ok for those of us that need 3rd and 4th gear like 90% of the time on track...

 

DCT has me intrigued as well. I believe Geauxmoto is running one in their K24-equipped NC.

I was surprised to see that a used DCT could be had for around $1,500. Definitely less than I would've guessed.

Edit: yeah Geauxmoto is already doing that swap.

 

Yea the trans IMO is the "cheap" part...

Adapter plate setup is same price as trans.

Then you have to run either a dedicated TCU like CANTCU or an ECU like the MaxxECU Race or Pro. MaxxECU looks good on paper, but has very little support unless you are a DIY tuner and there is a lot of talk on the facebook group about how the ECU isnt nearly as modern as the company would like you to believe... I think the dedicated CANTCU is the way to go as long as you run a main ECU that can transmit CAN which most can these days. Better be able to figure out how to tune it also or know somebody who has... thats not me personally...

Then there is a mounting setup.

Cooler setup... somebody makes a billet adapter to run -10 lines.

metal trans pan... again somebody is making a billet pan for them, cant remember who.

Then determine how you are going to convert from the BMW output yoke to your driveshaft of choice. Easiest is to get a shaft made with a BMW CV joint in it and stick with that on the trans side...

and then

and then

and then you're in it 6k+ at the end of the day to do it correctly.


FOR ME and an LS swap there were to many turn offs, the biggest being the tuning aspect and getting that working with my engine combo. I couldnt find anybody here in DFW metroplex who would say with certainty they could tune it and get everything functional at a high level. A few guys thought they could, but nobody really had experience and it was to much money and time to then find out its cludged together because we cant get the tuning right... Then, again, for my setup, I thought I was only going to use like gear 4-5-6 or maybe even just 4-5 or 5-6(cant remember) and I was like "thats a lot of work and expense for basically no upside". And in the NB the trans doesnt fit real well and lots of people say the trans pan hangs below the frame stiffener rails... thats a huge no go for me on a track car and I like to hop curbs...

Again, for a 350-400hp turbo 4 in an NC chassis, with the proper gear ratio in the rear end I think the BMW DCT would be a banger trans and totally worth the work... Im 99% certain the trans tunnel in the NC is far larger and higher up than in the NB so you dont run into pan to concrete clearance issues. If I was building an NC even with an LS I would also think long and hard on the DCT and would build my rear end ratio accordingly with either a 3.08 or a 2.73. Even my 3.31 is to "low" of a gear in that combo. The 8HP70 is also worth a look, but its even larger.

 

My day job was running a robotics engineering group as the engineering manager, so the CAN tuning and wiring doesn't worry me. As long as the mechanical side is solid. For track only I think the TKX is the way to go, but I think the DCT will be more street friendly and also better for autocross. I think either could work. I talked to GEAUXMOTO and they were hot on the 8HP and have a kit for it with paddle shifting steering wheel and the whole bit, but I've never driven one, and I think they are even heavier than the DCT, which is already 50+lbs heavier than the TKX.

I have a line on a dry sump ls7, fully built, for an extreamly good price as well, so evaluating if I want to do that. More motor than I really want / need, but....

 

The DCT is like 140-150lbs. I think the 8HP is like 190lbs.

The CANTCU and wiring setup from Domiworks is pretty plug and play. The tuning side is a bit different. I can do basically any mechanical work, but tuning and wiring/electrical to me is not in my wheel house.


The only thing on the LS7 I would want to be sure of is the oil pan will clear the sub-frame, specifically the steering rack. If the oil pan wont fit then any advantage of a "dry sump" LS7 is out the window. Also make sure you can fit the tank as the OEM tanks are pretty tall because they have a small diameter. Not sure on converting to a different tank thats shorter and larger diameter. The "dry sump" LS7 is kinda half assed dry sump anyway.

 

Agreed. THe stock dry sump is barely a dry sump, but you can just use a larger diameter / short tank, but it needs to go in the trunk, which is a fairly large bummer. You can cut down an Aviad LS7 pan to be very shallow to clear a steering rack. I did that in an Rx7 I built. It just has to clear the crank basically. The nice thing though is there is no external belt and pump to fit or worry about.

The weight of the 8HP kinda puts it out for me. Just too heavy, and the DCT would also just be super cool. I had a F80 M3 with one, and a Porsche with a PDK and it is faster on track for sure.

I'm in Copenhagen for an Ironman on Sunday and then back home. After I get back I can start.

 

Yea if you understand what you are up against. The 4.125 stroke stuff also can cause issues with the low clearance pans. I think the pan I am running Kevko recommends max 4" stroke. Im only running 3.268 stroke on a 4.8 crank so plenty of clearance.

I was quite against running a dry sump tank in the trunk, although plenty of people do it. I just didnt want like 20+ feet of -10 lines and all that oil to deal with. Seemed like a nightmare. I think my wet sump recipe should keep the motor happy. Ill see if I fill my catch can quickly then it probably didnt work LOL.

You've seen my spread sheet(I think, I never got confirmation you received it) so you kinda can piece together what I am spending on building a motor from absolute scratch vs. whatever you are thinking of buying.

 

I posted this way back in the start of my ZF8 swap thread - the ZF8-45's are literally cheap as dirt - have a 33k mile one and an 82k mile one for the princely total sum of $425. Weights of the -45 are:

182lbs w TC, 154 without.

TKX w clutch & flw ~ 135
T56 ~ 160.

so for me, with, (I think) sim ECU/TCU tuning and cost issues, rear axle ratio issues, the availability and price of the ZF8 are still my go to.
.
I think the fit into NA/NB is going to be a cut and fit for either the -8 or DCT.

I'm interested in any fit up info etc, esp NA/NB/s.

Wombat

 

PS - re weight - I'm a 195 lb fat ***. I need to be 175. That will make the difference right there. How many of you are focused on the wrong thing?

 

I dropped from 215 to 155. you can do it.

 

The 8hp45 only is rated for 330ftlb though, so not really comparable. You'd really need the 8hp90 (664ftlbs) to compare, and then it's a fair bit heavier still.

 

Both "fit" in the NA/NB chassis... both hang pretty low, generally below the frame stiffener rails. I dont think its as easy as saying "well just open up the tunnel and raise the trans" because then you are raising the motor also which then causes other issues probably the least of which is hood clearance. Exhaust fitment with either gets "iffy". And a few other issues.

There is a reason not many people with NA/NB's have done them and the couple I know that did have since swapped out for something else.

 

I don't really have much to contribute other than to say I also live near Aliso Viejo (technically, just over La Paz in Laguna Niguel). We should get a south OC miataturbo meetup going!
Sounds like you're set on the LS path, but for 400whp, have you thought about a GM Ecotec swap? The LNJ/F is a pretty solid engine, easy to find, still get that 4 cylinder character (personally not a fan of how lazy most LS engines feel, even having driven one in an exocet), and fun turbo noises. Relatively good trans options that don't require a bunch of R&D.