FS: 1999 NB Miata FMII (N. Fla) - $10k obo

With my daughter headed off to college this fall, I am thinning my herd. This is a super fun car to drive and will make an awesome street/auto-x/track car for someone.

1999 Miata – silver on black

~118xxx miles

VIN: JM1NB3534X0115005

Overall condition is very good

Clear title, in hand

Body:

Hardtop – professionally wrapped

Side mirrors wrapped too, but wrap is failing

Brand new Robbins canvas soft top, zippered glass window (has never once seen rain)

Extra hood (red paint - rough) with Singular motorsport hood vents

Interior:

Twin Sparco “Junior” model fixed back seats

Planted seat brackets (driver seat on factory sliders for adjustability)

Blackbird Fabworx single diagonal roll bar – powder coated orange

Twin 5 point harnesses

New radio and front speakers (radio currently removed to make way for gauges)

Autometer boost gauge

Oil temperature gauge (not installed)

AEM wideband O2 gauge

A/C was removed by PO (ordered a complete A/C kit from Treasure Coast, still sitting in a box)

Suspension/wheels/tires:

KYB AGX shocks

First gen Flyin’ Miata lowering springs

Flyin’ Miata solid front sway bar

949 6UL 15x8 wheels (Beryllium) – nearly new

949 aluminum lug nuts

Kumho Ecsta V720 (205/50/15) – less than 2,000 miles

Factory viscous LSD

Extra set of wheels (13x8 Rota RB)

Engine/transmission:

Original motor

Flyin’ Miata FMII turbo kit

GT2554r turbo

Intercooler silicone piping

Downpipe

Intake and turbo heat shield

Greddy BOV

Stainless steel coolant and oil lines

Coolant re-route kit

CSF aluminum radiator from 949

Setrab oil cooler (not installed) with Flyin’ Miata steering rack mount

Stock clutch w/ ~7,000 miles

(Picture is before new soft top was installed)

Could be a pretty killer deal for someone. What ECU?

Keith Tanner said:

Could be a pretty killer deal for someone. What ECU?

Shoot. Totally forgot to list that. It’s running a Megasquirt PnP. 

Doesn't '99 models have Torsen and not  viscous LSD?

jharry3 said:

Doesn't '99 models have Torsen and not  viscous LSD?

Yeah, the viscous is only found on the 90-93s.  After that it was Torsen (referred to as "type-1") from 94-95, then the "type-2" with slightly different lock up from 95ish+ to the end of the NBs, if I recall.

Nice car, and sounds like a fair price!

Hmm. The previous owner definitely told me viscous. Is there a reliable method to determine the type?

A viscous will have two piece axles with different flanges on each side of the diff. But it's really unlikely someone retrofitted one. More likely would be a retrofitted clutch pack.

You could jack up the back of the car and turn one wheel by hand. If the opposite wheel turns the opposite direction, it's either a Torsen or an open. If it turns the same direction, it's a clutch pack. I honestly don't recall exactly what a VLSD will do at hand-turning speeds, but you have a visual check for that unlikely scenario.

FYI, and this may only matter to Flyin' Miata - if it's identified as an FM II, that should mean it's running an ECU from FM which means Link, Hydra or FM 221. We never sold an FM II with a Megasquirt. If it's paired with a Voodoo Box, it's a Voodoo II. We sell the hardware as a no-electronics kit and people often pair that with a Megasquirt, but FM won't support the ECU in that case. Just so future owners know.

The GT2554 combined with decent compression will make this a responsive little critter, very similar to my own personal car. It'll never be a dyno hero but it'll be fun on the street and probably quite effective on the autox course.

dyintorace said:

Hmm. The previous owner definitely told me viscous. Is there a reliable method to determine the type?

They were just trying to dazzle you with vocab words :)

It's a type 2 torsen if you have an lsd, which I'm sure you can determine from your burnout.

Keith Tanner said:

A viscous will have two piece axles with different flanges on each side of the diff. But it's really unlikely someone retrofitted one. More likely would be a retrofitted clutch pack.

You could jack up the back of the car and turn one wheel by hand. If the opposite wheel turns the opposite direction, it's either a Torsen or an open. If it turns the same direction, it's a clutch pack. I honestly don't recall exactly what a VLSD will do at hand-turning speeds, but you have a visual check for that unlikely scenario.

FYI, and this may only matter to Flyin' Miata - if it's identified as an FM II, that should mean it's running an ECU from FM which means Link, Hydra or FM 221. We never sold an FM II with a Megasquirt. If it's paired with a Voodoo Box, it's a Voodoo II. We sell the hardware as a no-electronics kit and people often pair that with a Megasquirt, but FM won't support the ECU in that case. Just so future owners know.

The GT2554 combined with decent compression will make this a responsive little critter, very similar to my own personal car. It'll never be a dyno hero but it'll be fun on the street and probably quite effective on the autox course.

Thanks Keith - It is definitely running a MS PnP. And you're right, it is quick and loads of fun. Someone will have a blast with it.

WonkoTheSane said:

dyintorace said:

Hmm. The previous owner definitely told me viscous. Is there a reliable method to determine the type?

They were just trying to dazzle you with vocab words :)

It's a type 2 torsen if you have an lsd, which I'm sure you can determine from your burnout.

I'll see how it behaves under those circumstances!

I’ve seen this car. It’s a good one. 

And dyntorace is top notch. 

Good buy. 

Keith Tanner said:

A viscous will have two piece axles with different flanges on each side of the diff. But it's really unlikely someone retrofitted one. More likely would be a retrofitted clutch pack.

...

I honestly don't recall exactly what a VLSD will do at hand-turning speeds, but you have a visual check for that unlikely scenario.

It's been a while, but I'm 99% confident that a viscous will act like an open under all testing (hand turning, burnout, etc, etc, etc) until it gets a little heat into it.  According to what I've put together from reading some of the engineering testing and such, most of the time that people replace them because "they're worn out," it turns out that the people just never really use them in the right environment to heat them up enough.  It takes longer than you think of that differential action to really work, so if your car is cold and you do a single autocross run (30-60 seconds), the diff will juuuusssssttt barely be starting to work as an LSD.   When they're up to temp in track use and such, they work fairly well until they spontaneously fail because they're tiny little diffs.  We have one on the Champcar.

That's what I was wondering as well. They slip and grip. I don't think they need a lot of heat to work, but even when they're fully engaged they just don't transfer that much torque.

The factory manual tests the function of the VLSD in the following manner:

• turn off the engine (thanks guys) and put the car in reverse
• put the car on jackstands
• release the parking brake (seriously, they have a low opinion of mechanics but I can kinda see where they're coming from)
• using a torque wrench on a wheel nut, measure the time it takes to turn the wheel 90* while applying the specified torque
• Specified torque is 11 ft-lb, specified time is 4.0 seconds minimum.

That implies that the viscous fluid really starts work immediately, which it should or it wouldn't be useful at all. No mention as to what the other wheel is doing at this time.

Keith Tanner said:

That's what I was wondering as well. They slip and grip. I don't think they need a lot of heat to work, but even when they're fully engaged they just don't transfer that much torque.

The factory manual tests the function of the VLSD in the following manner:

• turn off the engine (thanks guys) and put the car in reverse
• put the car on jackstands
• release the parking brake (seriously, they have a low opinion of mechanics but I can kinda see where they're coming from)
• using a torque wrench on a wheel nut, measure the time it takes to turn the wheel 90* while applying the specified torque
• Specified torque is 11 ft-lb, specified time is 4.0 seconds minimum.

That implies that the viscous fluid really starts work immediately, which it should or it wouldn't be useful at all. No mention as to what the other wheel is doing at this time.

Huh, fair enough..

Luckily, google was my friend and brought up this post by Lance Schall, which references the original SAE papers I recall reading years ago:  https://forum.miata.net/vb/showthread.php?t=360565

Here's his synopses of the relevant part:

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It turns out that the plate tabs twist and shift axially giving rise to all sorts of interesting phenomenon with fluid phase changes, bulk pressure, dissolved air, Coulomb friction, blah blah blah (see SAE 2004-01-0867 - Mohan). The short story is the VLSD differential enters an operating phase Mohan calls "Self-induced Torque Amplification" (STA). This is also described by engineers working with Nissan, Takemura and Niikura, although they call it "hump" (SAE 900558).

In any case, the VLSD has 3 phases. First is initial viscous dissipation where the oil heats and viscosity drops. The VLSD transmits less torque. This is the operation you can measure with a torque wrench as outlined in the Shop Manual and gives rise to the idea that the VLSD is lame. As the fluid heats, the transmitted torque levels and at last in the final phase, as the fluid temperature exceeds 200 C, the torque graph shoots up, with a very steep slope, to transmit 300-400 ft-lbs or more. The ability of the VLSD to transmit this torque will continue as long as the high shear rates are present. To achieve this temperature, the VLSD may have to be subjected to high shear rates for several minutes. Clearly, this is not accomplished at an autocross or even, perhaps, on the track. So, the poor reputation of the VLSD for typical Miata performance applications is supported by the scientific explanation. However, this continuous shearing may be experienced in off-road center differentials and, indeed, Mohan worked for New Venture Gear and viscous differential are still found on 4x4 vehicles here and there.

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Either way, this in no way, shape or form helps DYINTORACE sell his awesome car :)

So I finally had time to go spend some time with the Miata yesterday. Between dropping our daughter off at college and then hosting an 80th birthday party for my dad, the last few weeks have been crazy.

I jacked the car up in the rear in order to spin one wheel. When doing so, the other wheel did absolutely nothing. :(

I also took pictures of the rear end, thinking those might help.

Suspension shot for good measure.

Also comes with a spare 1.8L motor of unknown condition and a complete FM timing belt change kit, with tool.

Bump.

Happy to entertain conversations regarding the car.

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