ZDan

Hi! This site was recommended to me by BRZ brevren at ft86club.com.
I'm looking to get into something smaller and lighter-weight for street and for time trials competition with COMSCC. ND2 looks about perfect! Currently looking at used Club and GT(S) cars for LSD. Plan to get a roll bar (Hard Dog?), coilovers (~10kg/6kg), and either lowering the stock seat or getting a semi-race-seat that can be used with stock 3-point belts.

Anyway, I'll be searching around this place but welcome any info on what must be done to these cars for reliable tracking at 10/10ths on Yok A052s, but for no more than ~15 minutes at a time. A few Qs:
1. is transmission really made of glass and if so any fixes?
2. are trans and diff coolers required or is it OK to run good synth fluids and change often?
3. anything else I should know about before hitting the track?

Thanks!

curly

iTrader: (25)

They are indeed glass, fix is the newer sequential out of the cup car, or some guys put NC transmissions in. There are some fixes like stud kits and built gear sets, but all with questionable results afaik.

There’s not much else wrong them for track cars, just avoid the RF due to roll bar comparability, good pads, tires, and like you said suspension.

ZDan

Thanks!
Yeah, initially was thinking RF because looks kick-***. But is heavier, with added weight up high, more $$$, and roll bar defeats convertible (not that I'm a convertible guy...). Wish they'd just make a fixed-roof-coupe...

Anyway sounds goot! I'll ensure good synth GL-4 in trans, GL-5 in diff (assuming those are specified grades), and as for the trans will see how long it lasts and go from there.
How long *do* they last? I do about 12 track days per year, less than 1 hr track time per day so <12 hrs track time per year. Also I'm not banging off no-lift upshifts, pretty gentle shifting (I think).

curly

iTrader: (25)

I work at a motorsports shop, we've had one cup car (non sequential) that lost most of the case bolts during an 8 hour enduro, but didn't break, we've turbo charged and supercharged a few street cars that haven't blown up (as far as I know), and we've had one track day car like you plan on building blow up during track days, I don't think he did more than 12/year, or more than an hour/day. So they're sort of hit or miss, but others with more experience may chime in.

It's a lot like some of the WRX transmissions, everyone says they're glass, yet you still see them driving around everywhere.

ZDan

Failure mode is that the case bolts come loose? Preventable with Loctite maybe? Hmmm...
Test-drove a black one yesterday, fun! Holding out for Soul Red...

curly

iTrader: (25)

No, studs are stronger since you’re torquing only the nut, not the entire shaft. https://flyinmiata.com/products/nd-s...-case-stud-kit

ZDan

If the bolts are coming loose under track usage, I can see how added flex could lead to gearbox failure. This mod seems like a no-brainer. Higher-strength studs with nuts, torqued a bit more >> lonnnnggg-*** bolts...

rjacobs

ND2 should ALL have the V5 transmission. Much less failure prone than the earlier trans...

As was said Mazda Motorsports sells a stud kit for it. The case flex is the issue...

Along with the studs, motor mounts and a rear diff mount will help out to keep the spaghetti noodle affect from happening. Rear diff mount on my ND2 made a HUGE difference. Before I installed it the shifter moved around all ***** nilly over any bump... after, I would say 85% improvement. Had I kept the car I would have put some AWR engine mounts on it.

As far as what to buy, I bought a Club BBR and then swapped out the wheels, suspension and Brembo's... I was about to swap out the Recaro's for a proper track seat also. So IMO if you are buying for a "track" car, just get a sport, plan to upgrade everything else and throw a OS Giken in the rear end... I wish I had saved the 5k I spend on the upgrade to club BBR and just spent it on aftermarket...

And the BBFW roll bar is superior to the Hard Dog IMO...

e1_griego

I thought the dual mass flywheel of the ND2 was what was keeping things together.

Out of the folks I know with ND2 from autocross, I haven't seen any break the trans. Plenty of ND1s broken though.

rjacobs

I think its part of it. And I believe it has torque cut on shifts.

Most of it is trying to keep shock loads on the trans down.

I think MOST of what Walter motorsports found was gears with bad mesh would come apart when the case would flex under loads. So whatever you can do to keep the drivetrain shocks down will keep everything from flexing and in theory help out.

ZDan

Muchas gracias! If '19 has no downsides vs. '20+ that opens up some lower-price options...

Yeah, stud kit + stiffer diff and motor mounts sound like good ideas to minimize squirm, added to list of mods...

Yeah, that might be an option for me... Less $$$ and better lsd!
Car will be tracked and time-trialed but still 90% street, looking to keep factory 3-point belts, airbag functionality, and headrest speakers if possible. Factory Recaros should address my concerns over the lack of lateral support from the "normal" cloth/leather seats. Just wish there were more out there to choose from! Would not go to a real race seat, but something like Cobra Nogaro would probably work for me...

Depending on the deal, I could go with BBR (possibly acceptable seat for road & track), GT (quieter top for road trips to "away" tracks), Club (lsd), and Sport (less $$$, better aftermarket diff)

Seems to be the consensus... If they are in stock and ready to ship I'll go that route but time may be of the essence.

Thanks again, great info!