I'm considering adding a differential particularly a OS Giken unit (also open to Tomei) to my track focused NC, however, I had a few questions about the default factory settings and whether it would work for my particular application. Any insight would be much appreciated.

Background: my NC1 is primarily a track car (currently I participate in HPDE events with the intention of competing in TT or Time attack in the future). As of now, modifications to the car involve suspension (coilovers and sway bars), wheels and tires (200tw - RS-RR), however, in terms of power modifications, the car is approximately at stock power level (future plans include 2.5L swap). Note: the car currently has an open diff. In terms of driver experience, I’m at the point as a driver where I've developed enough to where I'm starting to push the limits of the car and would like to further improve my times. For comparative purposes, I'm within a few seconds of spec Miata lap times at MSRH, although this is not impressive, there are clear differences between spec Miata and my NC in terms of how early power can be applied, suspension handling characteristics and tires. Without considering upgrading suspension or running R-Compound tires, this has lead me to consider adding a diff. with the thought process being that it will allow me to get on the throttle earlier on corner exits. 

As for selecting a differential - I'm considering the OSG unit because from what I have read it is best suited for track use with the least amount of adverse handling characteristics compared to other options. I've considered going the factory OEM diff. route however, I want to future proof the car and not have to acquire another diff down the line should my build change and the OSG unit might be something that I can grow into as I continue to develop as a driver. I've also consider the Tomei unit as I've read that it will handle the power levels up to about 300hp. Any input here would be helpful as well.

In regards to the OSG diff, I have some concerns about the diff. particularly the default set up  from factory. Note: the OSG diff comes from factory as 1.5way ) Would it be necessary to further setup the OSG or would I be able to drive it with the factory default settings and still benefit from the diff for my application (<200hp) on track? Based on what I could find on the internet there is mixed feedback, certain individuals state that even with default set up, the diff will perform well on the Miata. Others albeit from an AutoX perspective have stated that the default settings from OSG have too much lock for stock Miata power levels. it's not exactly clear if this the case, if anyone with experience with this setup could chime in and provide insight, it would be tremendously helpful. If additional setup is required, what is the recommended settings for the diff for my application?

Super appreciative of any insight or suggestions for someone who is starting out!

Julian

https://www.mazdamotorsports.com/2019/08/21/spec-mx-5-the-kit-and-the-why/

 Hello
I have a 300whp 2.5L turbo miata nc with 2 oil coolers, bigger koyo radiator. Battery relocated... on ethanol

During drift day on my local track, I can manage temperatures (Hood is removed, I use the straight for cooldown, I don't drift continuously for 15 minutes,...)

On trackday, however, with winter temp (60°) I can't do more than 8-10 minutes. (coolant get above 240 and oil above 275)
Next step would be cutting the hood to I get a nice airflow thought the radiator. But I love my sleeper look and I would like to avoid that.

I wonder if some of you have removed their hood for trackday, and what are the cons...

I also plan to add a watersprayer. It would be hooked to a relay so everytime I do WOT I get some extra cooling effect

thanks for your inputs

I

The Talon advertising looks like they are supposed to be better, but am looking for real world experience

My personal experience - put my stock motor NA8 on the dyno with basically no mods and made 108whp.

I was under the impression that was kinda low, partially based on the (TT6?) guys all running ~128whp with apparently stock internals.

However, talking to a few guys in passing, they seem to have had similar ~110whp results. (Dyno Jet).

So for those of you that have been into TT / SM recently.....what's a reasonable number for a stock motor NA8 on say the 14deg timing trick and stock ECU?

Cheers,

I'm thinking of trying a more aggressive compound (XP12 or XP20?) and possibly adding a vent kit from Goodwin.  What are all the NC folks using for pads and rotors on stock calipers?  Any recommendations?

Also I scoped the engine and got these pictures. Is this just carbon build up or is their significant problems:

The front bumper and front fenders are cut, so I'll need to replace those. 

Rear bumper is also cut, but not sure what to do with the rear quarter panel. How does this work? Do I have to buy and entire quarter panel? Where would I even begin looking for one?

Wheels are Going Dekagram 15x10 ET25. On Maxxis VR-1 245/40/15. Can a wheel this size even fit under a fender? I might have to search around for a 15x9 

https://kmiata.com/blogs/news/game-changer-the-new-k24z3-swap-is-here

I've gathered all the parts for an Ecotec swap from EcotecMiata, and I think I'll stay the course since everything is currently in my garage and it seems be a pretty well proven swap at this point, but this seems like a pretty interesting option.

I'm curious to hear what others think?

www.partsgroup.com

www.planet-miata.com

www.treasurecoastmiata.com

I've come across the big named items: Xida Gen 2's, Flyin' Miata Fox Suspension, and Ohlins. I've been told Xidas is like Gods butter. Is there one from the bunch you recommend, or anything else that I haven't listed?

I’ll preface by saying I bought the car in April “as-is”, and just ran it as I found it, with the exception of stuff I needed to do to keep it running (Clutch, Lifter service, Brake fluid / caliper service, cooling system stuff, electrical gremlins, leaks, etc in addition to string alignments every other weekend).

Oh yeah, and the regular Miata stuff like a round of wheel bearings, tie rod ends, some ball joints etc.

Asking for feedback since I’ve basically been running “all the camber” at zero toe, and I appear to still wear the outer shoulder faster (much faster in some cases) than the inners.

Note: I think the guy had an extended lower ball joint on the front left, I’ve replaced the FR for play, haven’t addressed FL yet.

(You can ignore the measurements in the 1st pic - just note Camber and ride height - then toe (as close to zero as I cared to get it) translated in the 2nd pic:

I assumed that with me in the car, the ride heights would level out a little bit, I actually don’t know what they are with driver seated.

I’ll start with the “bad” - 205 RE71R’s on 15x7’s running about 34psi Hot.

- 1st weekend (new) I noticed the majority of the wear on the outer shoulders.  So I flipped them on the wheels (side to side) and swapped front to back (i.e. the “good tread” was now back on the outside, and in the rear).  Pics (Rears, Fronts):

So after the tire rotation, I ran them a 2nd weekend.  Looks like the transits are continuing to punish the inner shoulders, but overall track use seems to continue to wear the outer shoulders more quickly:

Pics (All, Rear, Front):

Not going to run these again, although history would say that outer shoulders are taking the beating, the insides are now a bit too sketchy.

For reference, I ran Star Specs in the same size, at the same pressures and alignment setup, for about (9x days) + ~1,800 transit miles, and they are less worn.  (~12-13 track hours).

RE71R’s about (4x) days + ~700 transit miles. (~5-6 track hours).

Star Specs: (Also rotated / swapped them once or twice):

So is it pressures?  I say I’ve ran everything at about 34psi Hot (~28psi cold), but some sessions that was 36-38psi initially, and I was taking pressure out as the day warmed up.  They’re sitting at 28psi now.

I was dropping pressures so that they wouldn’t get “greasy” after ~2-4 laps pushing.  Initially at higher pressures, I was doing “cool down” laps once or twice a session.

I generally “over-drive” the tire a little, I like to have the car move around a little (probably see that from 1st weekend’s rear tires) / straddle either side of “the edge” once the car is set in a corner.  I’m also an amateur, so that’s all subjective.  Is the wear all in driving “style”?

I’m running 1:57 in both directions at MSR-H, or about 1:59-2:00 with an instructor riding along.  I had a (Miata guy) instructor drive the car for a session, and he ran 2:00 with me right seat, then dropped me and went out alone, but hit traffic and couldn’t get a clean lap to compare.

I’m “easy” on the brakes into the corners, but I think corner speeds are ok.  The instructor mentioned above was later on the brakes than I was, but I’m taking that approach to get the car set up into the corner at the “level” I’m currently driving.  Corner speeds seem to still be ok?

For Reference (for driving style / inputs, corner speed references, etc.) - runs I think we’re all in “yellow” PCA / Drivers Edge etc.

MSR-H CW (1st weekend in the car):

MSR-H CCW:

User inputs, also MSR-H CW (on Star Specs):

For reference - MSR-C 1.7 CW after a little rain - had removed a rear subframe brace to zero toe, and the car was more “under-steer’y“ than I like:

For reference - MSR-H 3.1 CCW 2nd weekend in the car:

So is it me?

Alignment?  Pressures?

Wheel width?

Cheers,

- Jonathan 

Has anyone installed a ~15 gallon fuel cell into a NC Miata?

Looks like a huge pain due to how the exhaust is routed?

If we get a Miata for chump we need a fuel cell to increase our fuel capactiy, the 12.7 gal is on the low side.

What do you think about buying a former playboy cup for chump or WRL?

Seems like they could be a good base to build from?

Typical car, https://www.racingjunk.com/Road-Club-Racing/183199584/2006-MX-5-T4-Car.html?category_id=&search=mx-5&quickSearch=1&np_offset=1&from=search

I'm sure the super competitive SM guys are on top of their clearances, but would the miata track rats care about 1-2 thousandths? on the intake side, that's like 25% of the spec clearance...

I've looked around online for the special tool that Mazda sold that would allow shim removal with cams in place, but good luck finding one. Shims seem hard to find. Anyone have a bead on where to get the special tool and or the valve shims? Anyone willing to rent (with a deposit) an internet rando like me the special shim tool if you have one?

Going to start Travis in an NA H2R challenge car.  Hope to get the same information we get in his Tag Kart.

What do you think about NC miatas in chump? 

They are 400pts so you could do:

40 pts gc coil overs (non adjust)

20 pts sway

25 pts header

At Harris Hill it would have to do 1.28-1.29 to be competitive. Not sure about COTA, maybe 2.45? (Fastest chump was a frsnkenstein civic doing 2.42)

This would be on RS4 or similar 200tw tire. (Dont think the re71 would last a race)

And a good driver.

It was back on track the next morning.

I want to keep my 2013 Club legal for STR class autocross, so my first set of wheels will be 17x9 with 245 width tires.  At my present low level of track experience, it probably doesn't matter much what size wheels and tires I use.  But some time down the line when it makes sense to do so, I might spring for another set of wheels and tires for track use if 17x9 with 245s aren't ideal.

Driver side only

I saw an older thread on another forum talking about how to trick the seat weight sensors. 

https://forum.miata.net/vb/showthread.php?t=614984

I assume that is to allow the steering wheel airbag to function, rather than to just keep the dash warning light off.  Is that correct?

And putting 2k ohm resistors into the side air bag circuit to keep that idiot light off.

The contingency changes alone are massive. SM 2.0 on the way...

https://www.roadandtrack.com/new-cars/future-cars/a19717774/theres-more-to-the-2019-miata-than-a-more-powerful-engine/

https://www.autoblog.com/2018/04/09/181-horsepower-2019-mazda-mx-5-miata-chat/

https://drivemag.com/news/2019-mazda-mx-5-miata-specs-partially-leak-online

Spark Notes:

• Jump to 181 hp / 151 tq
• Dual mass fly-wheel
• Drops CD-player
• Telescoping steering wheel
• Rear view camera
• Other tech nannies

Any suggestions on vendors for Carbotech?