1997 Mazda MX-5 Miata Long Term Road Test - Maintenance

1997 Mazda MX-5 Miata Long-Term Road Test

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1997 Mazda MX-5 Miata: Busted Air Conditioning

October 11, 2013

1997 Mazda MX-5 Miata

Don't let that blue light fool you. Even though it's implying the air conditioning is turned on in our 1997 Mazda MX-5 Miata project car, trust me, the system definitely isn't producing any cold air.

Which is a fine thing to find out as you're driving home ahead of a hot southern California weekend.

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1997 Mazda MX-5 Miata: Power Restored

May 23, 2013

1997 Mazda MX-5 Miata

Holy crap. Project Miata's new catalytic converter has really reawakened this ol' tic-tac. To recap, the car had been feeling gradually less peppy, and finally the check engine light illuminated. At that point the car was also more detonation-sensitive than before and drivability had degraded a bit, too. But none of these aspects were overly prominent, just a collection of incremental nuances that I apathetically chalked up to age and hard use.

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1997 Mazda MX-5 Miata: Replacement Cat From Moss Miata

May 3, 2013

1997 Mazda MX-5 Miata

If you, like us, reside in California, you'll quickly find that replacing your catalytic converter is a thorny issue. The replacement cat has to carry an exemption order from CARB to be allowed for sale in California (a so-called "50-state" cat), and not all catalytic converter manufacturers bother to certify their cats thusly. As a result, choices can sometimes be slim, especially if you drive a car that wasn't sold in great numbers in CA.

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1997 Mazda MX-5 Miata: The Catalytic Converter Is Dead

May 1, 2013

2013 Tesla Model S

Project Miata's check engine light is illuminated. This is why.

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1997 Mazda MX-5 Miata: Pulling the Codes

April 30, 2013

1997 Mazda MX-5 Miata

Project Miata's check engine light is on. This is the code that came up: P0420.

P0420 is a catalyst efficiency code. This could mean that our cat's not functioning properly, or an oxygen sensor is on the fritz or even something else.

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1997 Mazda MX-5 Miata: Check Engine Light

April 29, 2013

1997 Mazda MX-5 Miata

While we've got a big upgrade in store for Project Miata. In the meantime, it continues to be driven. And, surprise, a check engine light.

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1997 Mazda Miata: Two Valve Stems, But Why?

February 13, 2013

1997 Mazda Miata

I first noticed that the alloy wheels on our Miata had two valve stems when we last tested it and I intended to do a little research to find out why.

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1997 Mazda MX-5 Miata: Fuel Economy Update for January

February 4, 2013

1997 Mazda MX-5 Miata

The plus side about building an engine offline (more info here, here and here) for Project Miata is that it avoids prolonged downtime for the car, so we can continue to use and enjoy it in parallel. Of course, this also means your hair's not on fire to slam the engine together and slap it in the car. It's been on the engine stand for several weeks, gradually being prepped as time allows.

In the meantime, during the month of January we drove Project Miata, our 1997 Mazda MX-5 Miata, about 600 miles. It uses some oil, some of which is oozing out of the tired old valve cover gasket and making for a grungy engine. Otherwise, it just runs and runs. During those four weeks the little green TicTac averaged 23.8 miles per gallon of 91 octane premium.

Not bad for a modified first-gen Miata.

Jason Kavanagh, Engineering Editor @ 140,650 miles.

Worst Fill MPG:9.6
Best Fill MPG: 26.5
Average Lifetime MPG:22.1
EPA MPG Rating (City/Highway Combined): 20 city/26 highway/22 combined
Best Range: 292.2 miles
Current Odometer: 140,650 miles

Note: Cars are sometimes refueled before their fuel tanks are nearly empty. As such, "best" and "worst" fuel economy entries above are not necessarily the result of an entire tank's worth of driving.

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1997 Mazda Miata: 140,000 miles

January 11, 2013

1997 Mazda Miata

Even though the number 225,308 is much more impressive than 140,000, the bigger number is in kilometers. And since we live in America, we hate the metric system. Take that, easy to use and accepted worldwide system of measurement!

Anyway, our 1997 Mazda Miata has defied the odds, as well as some friendly wagers around the office, and trucked through 140k on the odometer.

At this point in its life, our Miata still sports a Rotrex supercharger kit, Fat Cat coilovers, really nice 949 Racing 6UL wheels, Hankook Ventus R-s3s and a Blackbird Fabworx six-point roll bar. It might burn a little oil, but it's still a total rip.

Kurt Niebuhr, Photo Editor @ 225,308 km

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1997 Mazda MX-5 Miata: Screeeal

December 28, 2012

1997 Mazda MX-5 Miata

Cold engine, a bit of throttle and a whole lot of belt noise. Project Miata has been relatively trouble-free given its age, hard use and modifications but it (literally) sounds like it's time to check the accessory drive belt tension.

The Kraftwerks supercharger kit uses a Gates belt. It's racy blue and has a heavy dose of Kevlar in its construction. I know these fancy belts make more noise than standard off-the-rack belts, but what I heard that day was clearly a full-on belt squeal a la 1982 Oldsmobile Cutlass Supreme. So, no, there's no "ah, those blue Gates belts all do that" this time around.

Jason Kavanagh, Engineering Editor

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1997 Mazda MX-5 Miata: Chasing The Squish

November 29, 2012

An upcoming (likely floody) track weekend lit a fire under my backside to re-tackle Project Miata's brake pedal feel. 

As mentioned many times previously, its pedal is rather soft. Always has been. Moreso than in any of the countless Miatas I've driven over the years. It's not that scary squishy pedal you get when there's air in the lines, it just has a very gentle ramp into actual braking force. And that's despite numerous brake bleeds (including cycling the ABS unit) and several pad changes. The calipers are in good shape and function normally, there are no leaks, pedal free play is about one millimeter, and it has stainless braided lines. Full ABS braking capability is still available when called upon. 

That leaves the master cylinder. 

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1997 Mazda MX-5 Miata: Rotaries Are Good For Something After All

November 27, 2012

1997 Mazda MX-5 Miata

We're not swapping a rotary into Project Miata, but we are in a very small way taking advantage of its bigger brother's infamous thirst.

If your Miata is turbocharged or supercharged, its fuel system is flowing a significantly higher fuel flow rate than stock. Fuel flow rate scales (roughly) proportionally to power -- increase the power by 50% and you increase the fuel flow rate by 50%. And all of it passes through the filter. From a filter design standpoint, higher fuel flow rates require more filtration media, which are those pleats of paper wadded up inside every filter canister. Manufacturers don't like to put any more filtration media into a filter than they need to because, hey, that stuff costs money. 

So what happens when you put 171 hp worth of fuel through a 100-hp filter? Hard to say without measuring, but its a good guess that the pressure drop of the fuel across the filter increases significantly. Higher pressure drop means the fuel pump has to work harder than it really needs to.

I have no idea when the previous owner of Project Miata last replaced the filter, which means it was time to replace the filter. In doing so, I wanted to find a filter that at least matches our modified car's horsepower and looked like it can be made to fit with minimal effort. Effort sucks. Being savvy with part interchanges is awesome. 

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1997 Mazda MX-5 Miata: DIY NB2 Coil On Plug Option

November 23, 2012

1997 Mazda MX-5 Miata

If you're installing an '01-'05 Miata engine (aka NB2) into an earlier chassis, one of the things you'll have to deal with are the coils. The NB2's VVT hardware precludes mounting the earlier coils in the usual spot at the back of the head. You can adapt the stock NB2 coil-near-plug hardware to the earlier harness, but these coils are generally considered the weakest of the NA/NB coils (themselves not much to write home about), so if you're planning on boosting you may find that you'll need some kind of other solution. 

Beyond the jump is some kind of other solution.

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1997 Mazda MX-5 Miata: Electronic Surprise

October 18, 2012

1997 Mazda Miata

Project Miata was recently sidelined by a electronic surprise, courtesy not of a rodent per se, but of a squirrelly little bastard nonetheless.

Here's how it went down. During Project Miata's seat installation, Moti of Blackbird Fabworx needed to use the welder, natch. He disconnected the car's battery (his normal welding-on-a-car protocol) and went to work.

When the work was complete, he reconnected the battery and discovered the car wouldn't start. There was power, but no crank from the starter or even a click from the solenoid. Moti surmised it had something to with an immobilizer and so called me to ask how to disable it.

"Uh, immobilizer?" was my reply.

It turns out Project Miata indeed had an aftermarket immobilizer/alarm installed at the behest of the previous (original) owner. Said owner neglected to inform us of its existence at the time of purchase, probably because he'd forgotten it was there. The alarm horn was long gone, but the starter interlock remained. Dormant. Waiting. And disconnecting the battery was its signal to awaken (I swear I've disconnected this car's battery before... haven't I?).

No problem, I said, I'll just pop over to your shop, locate and disconnect the wiring to the immobilizer and drive the car away.

Silly me. When I removed the kick panel beneath the steering column I was confronted by the most insane rat's nest of wires I've ever seen in a car. Knots of wires, loops, bad splices, bare wire ends dangling about, mystery black boxes, taped-off cut wires... just a ghastly, godforsaken hellish nightmare of cheap '90s electronics installed -- apparently -- by an amphetamine-fueled bonobo. It was like peering into David Lynch's mind.

It was hopeless to even attempt to figure out how to euthanize the wiring disaster. But maybe there was a workaround, a way to get the car started without removing the immobilizer -- a push start. Sure enough, push starting the car in gear and popping the clutch brought the engine to life, with one caveat -- all of the exterior lights were flashing. Of course the immobilizer people thought of this; they created this stuff back when there was something called the manual transmission.

So I drove 25 miles from Blackbird Fabworx down to our studio in Marina Del Rey with the lights flashing the whole way. Nobody even blinked, not even the cop car I passed on the freeway.

Once parked, it'd have to be push started again, so whomever was going to remove this immobilizer -- not me -- would have to come to us. After several logistical snafus, our guy Rex was able to convince Richard Dang, a talented wiring guru friend that happens to work at Al & Ed's in West Hollywood, to come over after hours and remove the mess and restore the car's normalcy.

Now, Richard has seen a few wires in his day. So when he exclaimed, "Holy sh#t! Who did this?" while holding up the giant electronic tumor he'd just excised from the Miata's dashboard, you know it was bad.

Jason Kavanagh, Engineering Editor

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1997 Mazda MX-5 Miata: Blackbird Fabworx Is Replacing The Seat

October 12, 2012

1997 Mazda Miata

Who is this man and what is he doing? Well, yes, you're right -- the title does sort of give it away...

That's Moti of Blackbird Fabworx. The same Moti, in fact, that was behind Project Miata's GT3 6-point roll bar (Part One, and Part Two).

This time, he's helping to install a new seat in Project Miata; a long, long overdue mod. And by "helping" I mean "doing all of the work."

More to come.

Jason Kavanagh, Engineering Editor

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1997 Mazda MX-5 Miata: Assembly By Keegan Engineering, Pt. II

September 4, 2012

1997 Mazda Miata

The role of proper hardware in an engine build is paramount, but the role of proper assembly is just as critical, and often understated. A few thousandths of an inch in the assembly of a high-performance engine separates a reliable, high performing engine from one that, well, isn't.

That's why we left the assembly of Project Miata's heart transplant, a 1.9-ish-liter long-rod VVT Mazda BP, to the pros at Keegan Engineering. We delved into the nuances of their work a bit in a recent short block setup entry.

Across the jump are a lot more insights provided by Keegan as the build process progressed. (I originally planned for this entry to get into the head, but I realized I had such a surplus of short block assembly notes that the head will have to wait for now!)

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1997 Mazda Miata: +1

July 30, 2012


After a very, very odd day of transporting and photographing cars, I wound up with our Miata and an hour long drive home. But as I stuffed myself over the bars, into the seat and fired up the motor, I heard the tell-tale clicking of the valves. As I was already at a gas station, I popped out and checked the oil. Sure enough, it was down a quart so after a few bucks and a few minutes, the oil was back up to level and I hit the road, sans radio.

Kurt Niebuhr, Photo Editor @ 137,820 miles

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1997 Mazda Miata: Two Screws and A Twist

July 13, 2012


It what, I think, was the easiest bulb replacement I've ever done, I said goodbye to the old left front parking light blub on our Miata and hello to the new one.

And when I say it took me longer to grab my camera, and take the picture than it did to change the bulb, I'm not exaggerating. I love simple cars.

Kurt Niebuhr, Photo Editor @ 137,802 miles

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1997 Mazda Miata: Trip Out, Man

July 11, 2012


So there I am, standing behind a taco stand gazing at the trunk of the Miata hoping we never get the thing repainted.

Stare at it long enough and it gets all three dimensional, I swear.

Kurt Niebuhr, Photo Editor @ 137,801 miles

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1997 Mazda MX-5 Miata: Rattle Patrol, Driveshaft Edition

June 27, 2012


Sometimes you can locate and solve a weird noise in a car with a torx bit, a ratchet and three minutes. Then there are the noises that are more elusive.

*Updated* - more accurate intel inside

A few weeks ago Project Miata developed a very subtle skrik-skrik-skrik in certain driving conditions. In the space of a week or so it grew obnoxious, and the conditions more obvious -- the noise was happening in gear, clutch engaged, on the overrun (or while in reverse), and was not coincident with wheel speed. To me this was the telltale of a bum u-joint. U-joints on Miatas are not serviceable, so the whole driveshaft would need to be swapped.

Flyin Miata Salvage had on hand a 58k-mile driveshaft from an '04 Miata, and into the mail it went. A couple of days later I put the Miata up on our Rotary Lift to get busy. 

Replacing a Miata's driveshaft is cake -- drop the underbody brace (six bolts; it's already removed in the lead shot), remove the O2 sensor, drop the exhaust, then it's just four bolts at the diff and the driveshaft practically falls out.

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1997 Mazda MX-5 Miata: Rattle Patrol

June 19, 2012


Project Miata has plenty of rattles and squeaks. Lately, though, there have been more noises than usual, particularly related to the hardtop. So while it was in my driveway for a once-over, I went on safari. 

For starters, the striker plate (the thing on the windshield header that the hardtop clasps onto) on the driver's side was missing one bolt, and the other had backed out halfway. Aha. They're T40 torx head metric bolts, not quite unicorns but certainly won't find them at Home Depot Motorsports. Not to worry. I found the missing bolt stowed away under the seat. 

Add a stiffer suspension to an old floppy car and then drive it for as hard as possible on murderous roads for thousands of miles and bash it over the kerbs of a few roadcourses and you, too, can expect to find hardware under your seat.

Jason Kavanagh, Engineering Editor @ 137,576 miles.

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1997 Mazda MX-5 Miata: Exfoliated

June 18, 2012


Considering its age and the hard use Project Miata, our 1997 Mazda MX-5 Miata, gets, it was time for a little TLC. So on Sunday I washed, clayed and waxed it and in the process remembered how much I dislike detailing cars, even ones with minimal surface area like the Miata. The hours consumed, the tedium, the subsequent fear of birds defecating anywhere within a three block radius.

Ah well. It does look better now; a bit of gloss returned to the coat and many tiny scratches and blemishes ironed out thanks to the clay bar, aka magic eraser. If you've not used a clay bar, give it a shot -- the smoothness it imparts makes the wax go on and off sooo much easier. 

Its decklid is beyond any kind of hope, but waxed it anyway in a (probably futile) attempt to stem the rate of oxidation. After all, a little patina on a well-exercised car is good provided it doesn't evolve into neglect.

Jason Kavanagh, Engineering Editor @ 137,576 miles.

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1997 Mazda MX-5 Miata: In The Zone

May 09, 2012


Threw Project Miata on the scales to recheck the corner weights. I use the corner weighting technique outlined here

Our little green hoopty has been pounded on for thousands of miles so I was curious if any settling or preload had occurred due to spring set or bushing deformation or other malady. 

Without making a single adjustment, the corner weights (with me in the seat) were fewer than five pounds off the target. 

Easiest corner-weighting job ever.

Jason Kavanagh, Engineering Editor

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1997 Mazda Miata: Self Tech

March 31, 2012


Before you attend a track day, it's in your best interest, as well as the others who will be on track around you, to give your car a good going over. Being spoiled with a Rotary Lift makes this easy. So with Miata Meister Jay Kavanagh looking over my shoulder, I had a good look in, under and around Project Rattle Can.

As everything was in good working order, Jay wanted to tackle a nagging issue having to do with the brakes.

Click on through...

For a while now, brake pedal travel has been on the long-ish side. While the braking force is still there, the extra half inch or so of distance has been bugging Jay. With the master cylinder and all the brake lines looking a-ok, our friends at StopTech suggested that tapered pads might be to blame. And, as long as the car was already up on the lift...

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1997 Mazda Miata: Rattlecan

March 27, 2012


I got the opportunity to take our Project Miata out for a good spin through the Santa Monica Mountains. Normally I'm driving it home in traffic. This time I had an open twisty road. Going up the hills and through the turns I had a blast.

It wasn't until I was working my way back down the hill that I ran into trouble.

I was stuck behind a really, I mean REALLY, slow driver. On these narrow roads there are no pull offs, no alternate routes. Misery.

It was then, while using the gearing as a brake that I noticed an unsettling rattle coming from what I expected to be the exhaust pipes. It was the kind of piercing rattle that made your teeth itch. It sounded as if the pipes were vibrating on some suspension component during each sharp spool down of the revs. I tried to use the brake more often, but I still had to use the gearing with wuss in the Explorer ahead of me. By the time I got to the bottom of the hill, I just wanted to get out the car for some relief.

I got to a beach parking lot at the bottom of the hill and pulled in. With my cell phone flashlight app, I inspected the under bits. I looked for what I thought might cause the sonic terror, but I didn't see anything. Though at the same time, I'm not especially mechanically inclined.

I think this is part and parcel for a "project" car. Especially one we sourced so cheaply. Though it is fun to drive in my opinion, it needs a caretaker with greater compassion than I can provide.

Scott Jacobs, Sr. Mgr, Photography

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1997 Mazda MX-5 Miata: Hate That

March 05, 2012

Miata_windshield star.jpg

Yep. Such a butt-puckering sound, too. "Clink!" And you know. You know from the tone, the density of the sound, you know about how bad your windshield is going to look, even at night when you can't see it very well while driving. When the sun came up, this didn't turn out too bad. But bad enough to remain pissed off at the jerky we believe kicked up the object, and want to work the DMV records to find his car and smear poo on it.  

So, loyal ILLTRTB reader, what say you? Many of you are critical of our maintenance decisions. Do we Safe-Lite fill it now? Wait for it to spider and get new glass? Claim eminent domain and seize the windshield from Monticello's Miata? Personally, I think it's time for a sheet of Lexan, broken in with some laps at Willow Springs.

Dan Frio, Automotive Editor

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1997 Mazda MX-5 Miata: Now That's a Racket!

February 09, 2012


The other night I got stuck in some pretty awful traffic. It ended up taking almost 30 minutes to get home from the supermarket, which was only a mile away. Besides fearing that my pint of Ben & Jerry's was turning into a milkshake in the trunk, the cabin started getting a little hot and stuffy. So, I hit the AC button.

A cacophony of rattling and belt noise sprung from under the hood. "Well, that's not good," I said. I tried it once more and left it on for a few seconds, but the racket continued. Alright, time for the windows.

It was so loud and rough, it reminded me of this:

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1997 Mazda MX-5 Miata: The Three-Pedal Dance

February 08, 2012


I love manual transmissions. I love mastering a heel-toe downshift so that's it's only heard, not felt. But I'm having a little difficulty with our little Miata.

It's not the pedal placement, no, that's perfect; it's the brake pedal stroke. Even though our Miata has steel-braided brake lines, the pedal feels a little squishy (technical term, I know). I was taught that the brake should be adjusted so that a "7" pedal (a 1 pedal is just barely dragging the pads and a 10 pedal is full panic OMG braking) would bring the brake and gas pedal even. That'll allow for an easy throttle blip between gears as you're braking before turn-in.

As it is, our Miata's pedals are on the same plane with only a "4" pedal. If I'm not careful, I'll hit both pedals at the same time. It also means heel-toeing is awkward and difficult. I'm not sure if we need to bleed the brakes or if there's an adjustment available, but it can sure use some sort of a fix.

Mark Takahashi, Automotive Editor

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1997 Mazda Miata: Tuned By JKav

January 26, 2012


I put the key to our Miata back on the big board yesterday.  My two-week stint is over. In hindsight, it was (as well as fir any other editor who drives it) a pretty sweet deal.

I got to blast around in a modified Miata that I didn't have to do anything for. No scouring ads and wasting time looking for a used Miata (OK, I've actually done that before; I owned a '97 Miata M Edition just like ours for a few years). No late nights, bleary eyed, reading stale Miata forum posts on the Internet. No wrenching on my own accord trying to install aftermarket parts that just don't quite fit, or fix things that are breaking/not working on a 15-year-old car.

Basically, it was like renting it for two weeks. Then I got to give it back with a list of a few nettlesome things that need attention.

So a tip of my hat to fellow editor Kavanagh, who's been the Miata's handler since inception. He's done a great job with this car.

Brent Romans, Senior Automotive Editor

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1997 Mazda Miata: Not Quite House Trained

January 20, 2012


The Miata has been piddling on my driveway. At first I thought it might be power steering fluid (Jay had told me it might leak a little due to the supercharger install) but it wasn't the right color. Further inspection revealed it to be coolant.

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1997 Mazda Miata: Everything We've Done So Far

January 13, 2012


I'll be driving our Miata for the next two weeks. It's actually the first time I've been in it since we got it way back in November of 2010. I wanted to familiarize myself with all we've done (well, Jay's done) and when. So I looked at all our posts and cataloged the modifications. If you'd similarly like a recap, hit the jump.

November 2010
It lives! The introduction to our green 1997, not to be confused with the white 1994. The suspension bits from the '94 were installed.

December 2010
A Kraftwerks supercharger was installed. Two-part series, here and here. Also, new stainless steel brake lines and fresh gear oil.

January 2011
This was a big month. Jay removed the fabric top and installed the black hard top. The Miata also hit up the dyno, got a new Momo steering wheel and gained its upgraded wheel package, the 6UL wheels and Hankook Ventus RS-3 tires.

March 2011
Track tested. The driver seat went to Oldham's Upholstery Services, LLC, for modification. We also had the new Flyin' Miata clutch and flywheel installed.

June 2011
A Blackbird Fabworx six-point roll bar was installed.

August 2011
Minor mechanical updates, plus Jay installed a new Flyin' Miata cross-flow radiator.

Brent Romans, Senior Automotive Editor

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1997 Mazda MX-5 Miata: Back In Action

January 11, 2012


Previously, Project Miata would sit as editors didn't want to deal with its finicky belt. To recap, when you put a roll bar in a Miata the belt guides point more inward than usual. This has a couple of side effects that, in our case, were making the belt a hassle to deal with for most normal people. 

Then the car just sat - we were slammed with other work, then the holidays happened, the dog ate my homework. Recently though, Blackbird Fabworx put a simple fix on the seatbelt guide (trimmed the plastic ear that was promoting belt foldage). I've driven it quite a bit and it seems to have done the trick. 

By the way, the cooler temps of winter have perked up the car's poke. Feels like it pulls with a bit more enthusiasm these days. It's still got far more grip than grunt, though.

Speaking of which, we're making headway on the next phase of Project Miata's metamorphosis. The engine bits are coming together nicely, and before long Keegan Engineering will have their hands full. Will attempt to put together some tech pieces soon to explain in more depth the whats, whys and hows of the engine program.

--Jason Kavanagh, Engineering Editor

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1997 Mazda Miata: I Guilty

November 30, 2011


Mike found something horrible in the Miata. He wasn't sure what it was. A toenail from a monster? 

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1997 Mazda MX-5 Miata: The Next Level

October 06, 2011


Project-wise, it's been pretty quiet around this little green tictac lately. Let's see, I changed Project Miata's oil last week. Thrilling. Oh yeah, the a/c stopped working temporarily until I replaced a blown condenser fan fuse (the higher current draw of the new fans are likely the factor here, but so far so good with the new fuse, which has lasted 10x longer than the old one). So exciting.

Blah blah blah. Time to turn the wick up on this project thing. I've been talking to some peeps and we've hashed out a plan. It involves dragging the Miata's BP engine into the 21st century in keeping with the car's dual purpose intent.

The idea is to maximize the area under the curve and to do it as reliably as possible. Also, to keep it real it has to be done on pump gas, and around here that means 91 octane. An LSx swap is certainly one valid approach to this, but the wholesale changes involved would result in perpetual downtime and too many extra pounds in the nose for my liking. Besides, I'm of the mind that there's life yet in the Mazda BP engine.

Making power on 91 then becomes an exercise in maximizing flow and managing the knock threshold. Decisions cascade from those notions. There's no hard power target, but 300 hp would be excessive so let's size things up around that and see what happens.

We'll start with the version of BP with the most potential -- the one that came in Miatas built from 2001 to 2005. Compared to the one in our '97, these later BPs had a better head and packed variable valve timing on the intake cam. VVT allows overlap to be dialed in when intake pressure is high relative to exhaust pressure, and then dialed out as exhaust manifold pressure rises. This broadens the powerband and staves off detonation.

Originally the VVT BP engines had high compression, something like 10:1. This is incompatible with 91 octane when we're talking about the kind of boost that will make Oldham happy. Also, the stock rods tend to fold like a map when pushed hard.

Since new reciprocating components are needed anyway, we're taking this opportunity to add a twist -- a long connecting rod layout. The required piston and rod geometries to achieve this are being worked up by JE Pistons and Mil-Spec, respectively. Keegan Engineering will mastermind the head specifications and engine assembly, an area that is deceptively critical for performance. Similarly, we're working with the big brains at Apex Speed Technology on engine management and tuning.

Then there's the happy spinny thing to be mounted in the exhaust necessary to achieve the required flow. I have ideas around this, though details are TBD.

Lots more to come, as some of these bits are already trickling in. Should be a fun ride.

--Jason Kavanagh, Engineering Editor

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1997 Mazda MX-5 Miata: Curing The Overheating

August 30, 2011

1997 Mazda MX-5 Miata: Curing The Overheating 

Perhaps the most weaksauce portion of a first-generation Miata is its cooling system. Even stock, the fundamentally compromised cooling system layout can mean overheating in adverse climates. That, and a sweaty crotch.  

If you then stick an intercooler and a heat exhanger for the supercharger's magic fluid in front of the radiator and make a bunch more power, well, you can guess how much that helps.

The best approach to licking Project Miata's overheating conundrum comprises many facets. Hit the jump.   

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1997 Mazda MX-5 Miata: Sticky Belt

August 25, 2011


So here's a problem. The seatbelt hanger which rotates to accommodate different sized people as the seatbelt deploys is limited in its range of motion by our Fabworx roll bar.

The result is that the belt passes through the hanger at an awkward angle which causes it to bind, stick and eventually stop retracting. In fact, when I got in the car last night it was dangling loose onto the seat. Feeding it carefully through the hanger will make it retract, but it's a job that takes a few minutes.

Last time I checked a loose belt isn't a safe belt.

The solution doesn't seem to be simple or cheap (although resident Miata Magician Jay Kav is an expert at finding simple solutions to Miata problems). Harnesses won't work with the currrent seats so perhaps harnesses and seats will be a necessity.

Either way, this is something we'll be dealing with soon.

Josh Jacquot, Senior editor

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1997 Mazda MX-5 Miata: Wrench-Turning Update

August 15, 2011


Project Miata spent some downtime in the Edmunds HQ garage while I traveled here and there. If you recall, its clutch hydraulics took a crap a couple weeks ago. That's all sorted now that I've swapped out the clutch master and slave (the culprit turned out to be the slave) on the bottom floor of the dim, stuffy, underground parking area.

Now it's time to address the lame-ass cooling system, which is what's happening in the lead shot. I've got plenty more to share on that subject, but right now I've gotta locate a tight-radius silicone elbow. Stay tuned.

Jason Kavanagh, Engineering Editor @ 132k miles.

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1997 Mazda MX-5 Miata: The Beauty Of Dual-Purpose Cars, Pt. II

July 13, 2011


Remember a few weeks back I observed some pinging in Project Miata, and did the only thing I could which was to retard the ignition timing? Of course you do. It solved the ping, no doubt. No amount of flogging, flooring, or otherwise hooliganistic behavior will elicit that hamstring-jerking rattle of detonation.

Success. Right?

Partially. Recall that retarding an engine's ignition timing means that more of the combustion event occurs while the hot, burning mess is escaping through the exhaust valves. This, in turn raises exhaust gas temperature (EGT).

Who cares, right? Your ass cares. Higher EGT means higher cylinder head temperatures, which places extra demand on the engine's cooling system. If your cooling system is in a Miata then it inherently sucks to begin with. A couple degrees of ignition retard alone aren't enough to send things into a tailspin, but throw an intercooler in front of the radiator and add hot weather and you've got a recipe for a swampy ass.

Which was precisely the situation I found myself in as we crept along in traffic, just before making the decision to bail on Highway 101. The ambient air was in the low 80s-degrees F, with some humidity. The needle of Project Miata's temperature gauge crept off its usual "11:30" position over to the 12:30 position, and if you've been a regular reader of Project Miata, you know that this is not a good sign. Immediately I shut off the aircon and entered a staredown contest with the temp gauge.

It recovered. But this didn't bode well. The weather at this point isn't nearly as hot as it will be later when climbing the Tejon Pass (a long, long grade that ascends to the high desert), nor as dry, nor is the air as thin here at 670 feet above sea level as it will be when we exit I-5 at Frazier Park (4600 feet). And a big chunk of the drive from that point is literally through the middle of the desert until we reach Highway 101, or about, oh, 140 miles.

To date Project Miata has seen loads of hard driving, but always in pre-summer conditions and always around sea level. The cooling system is in good nick; all ducting in place, t-stat functions normally, the radiator was replaced with one of those thicker stock replacement jobs shortly before we bought the car, the cap holds pressure and it's topped up with 60/40 water/glycol.

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1997 Mazda MX-5 Miata: The Beauty Of Dual-Purpose Cars

July 12, 2011


It was one of those trips I used to take monthly. My friends and I would pack up our cars with tools, various spares, a helmet and a set of R-compound tires and then hit some of the best driving roads in California on our way to a track day. Being in southern California, we're blessed to have several road courses within easy striking distance.

We'd drive hard, compare notes, tell lies, talk smack, joke around, eat bad track food, discuss the nuances of our digestive tracts. Sometimes there would be mechanical drama along the way. But it was always fun.

Somehow along the way these trips dwindled into annual events, maybe. Life got in the way. Racing, too, as competing in a half-dozen or more crapcan endurance races a year leaves little time (or desire) for hotlapping days.

When the last-minute call for a track day at Laguna Seca came in, my gang of fools decided we were long overdue for such a trip. The road beckoned.

We mapped out a route that had us taking 101 North and then picking up Route 33 in Ojai, across Route 58 back to Highway 101, and then jumping off at Carmel Valley Road, which spits us out nearly at Laguna Seca's front gate. If you've ever driven these roads, you know how badass they are. If not, well, they're badass.

Mike has his '99 Miata, and Dan's got a Lotus Exige that wears R-compounds exclusively. As for me, Project Miata's dual-purpose intent makes it ideal for such badassery. It's got the right balance of compliance and control and comfort and capability to swallow bumpy, broken roads and smooth track tarmac in equal measure. With only some minor wrench-turning before the trip, I could roll up to the track and not have to change a single tire or brake pad the entire time.

First a brake bleed, then pads. Its Stoptech 309 brake pads are some of the best pads I've encountered for hard street driving and day-to-day livability. I even use them on our championship-winning Eyesore Racing FrankenMiata LeMons race car, where they've shone.

Our green wine-and-cheese-mobile is heavier than the FrankenMiata, though, and doesn't have anything approaching that car's advanced brake cooling scheme which consists of deleted bodywork. For Project Miata I wanted pads with a higher maximum operating temperature to withstand track use, but still have enough thermal range to work on the road to and from the track.

A last-minute call to Cobalt Friction Technologies landed a pair of XR3 front pads on my doorstep. Normally they'd match these with XR5 rear pads on a Miata such as this, but they were fresh out of XR5s. Still, the XR3s have similar-enough torque output to the existing rear pads that there won't be any brake bias issues.

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1997 Mazda MX-5 Miata: Ping

May 29, 2011


Lately, if you give Project Miata a proper dose of throttle after it has had a good long heatsoak in, say, LA traffic, it'll ping. Not just one sporadic event, but several pings scattered through the midrange and up into the red.

When you hear detonation in a car like this, you should back off the throttle, stat. This is how I'm wired, but in this particular instance I had to grit my teeth and stay in it for the duration of the gear.

I did what I could to remedy the ping once I returned home.

I used this:

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1997 Mazda Miata: Need to Keep an Eye on That Oil

May 12, 2011


I was alerted by our resident Miata mechanic that our '97 hardtop has a slight thirst for oil. So after taking it for a spin I pulled it into my Miata-sized garage to give it a little love. I had stopped and checked the oil during my drive and sure enough it was a bit low.

I can't say that I'm surprised. You really have to ring this thing's neck to have fun even with the supercharger. And when you're talking about a tired old, four-cylinder, its bound to use more oil than your average Corolla.

Didn't stop me from having a great time driving it though. It's easy to forget how enjoyable it is to drive a light car with some decent power. Those big meats don't hurt either. I even like the Oldham seat update. Only thing that still bothers me about this car is the shifter as I fumbled into third more than a few times. Nothing a little more practice wouldn't fix I'm sure.

Ed Hellwig, Editor

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1997 Mazda MX-5 Miata: HVAC Mode Slider Stuck

March 18, 2011

hvac stuck 717.JPG 

Hmph. Well, I usually just leave it set to vents-and-feet anyway. So there.

The slider is jammed in the position you see above, so I crammed my torso into the driver's footwell to see what is amiss among Project Miata's various cables and rod linkages that regulate the direction of the breeze. Found nothing obvious in the time it took for my bum shoulder to really get pissed off, which is about thirty seconds. A problem for another day. Or another person.

In other, less-pedestrian news, I installed a Flyin Miata clutch and flywheel this week. And I'm likin' it. More on that later.

Jason Kavanagh, Engineering Editor @ 130,045 miles.

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1997 Mazda MX-5 Miata: Personal Hygiene

January 31, 2011


Not sure if you're aware of this, but there's a whole industry devoted to just making your car clean.

There are washes and treatments, lotions and potions -- all designed to keep your car looking good. You don't even have to do it yourself, as there are these big places where people will do it for you. They are called "car washes." 

It kind of makes you wonder how our poor old Miata ever got to looking so bad.  How many years did it suffer, parked in the back of some apartment without even a carport to keep off the sun? And yet it's never too late for cleanliness. Even in its worn and sun-bleached state, the Mazda still seems to sparkle once it's been to the car wash.

It's not that a little cleaning makes a car look like new. (This Miata will never look new again, no matter how hard you rub on it.) But when a car is clean, it seems like it's been prepared just for you. The connection is a little stronger in some special way. Even when you're just at the car wash and they tell you that your car is ready, it just seems like your relationship with the car is a little more personal.

It's always tempting to dismiss all that car wash stuff, those weird concoctions of chemicals that seem like patent medicine. Totally not worth the money. And yet if you keep thinking you're too smart to squander your money on such frivolous stuff, pretty soon your car starts looking as bad as this poor old Miata. So instead of saving money, you've actually squandered the intrinsic value of your car. 

So go to a car wash, maybe go off your usual menu and get something special, maybe a clay bar treatment and some good wax.  

Michael Jordan, Executive Editor, Edmunds.com @ 124,711 miles.  

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1997 Mazda MX-5 Miata: Stoptech Stainless Brake Lines and Fresh Gear Juice

December 23, 2010

stoptech stainless brake line front.jpg 

I took the opportunity recently to flush out Project Miata's fluids of unknown provenance and install a set of Stoptech braided stainless brake lines. For the geeky deets, hit the jump.

Gear Oil Gotchas

Be careful when choosing gear oil. It is categorized into different performance classes, known as API Categories. Mazda specifies API GL-4 for the Miata transmission. But, hey, check out this API GL-5 stuff. Bigger is better, so GL-5 must be one number better than GL-4, right? Wrong.

GL-5 oils have much higher concentrations of extreme pressure additives that make them suitable for use with the low speeds and high torque levels experienced by the ring and pinion in your differential. This sounds like the hot setup for the manual gearbox behind a highly modified engine, except that GL-5 oils lack the friction modifiers needed for the gearbox's synchros to operate correctly. Simply put, using a GL-5 oil in the Miata's gearbox will eventually turn the synchros into Captain Crunch.

Some modern manual gearboxes however can live happily with GL-5. Your owner's manual will tell you.

Redline MT-90 is GL-4 oil. It's synthetic, so it ought to tolerate higher temperatures better than non-synth stuff. Same goes for the Redline GL-5 gear oil I spurted into the diff. Both are 75W90 viscosity, same as the OEM specifications. The conventional wisdom that 'thicker is better' for performance cars really doesn't hold much weight (har har) with respect to modern oil formulations.

Stoptech Braided Stainless Brake Lines

It's true that braided stainless steel brake lines expand much less than the stock rubber ones and that this translates into better brake pedal feel. However, replacing the brake lines in Project Miata is as much about safety as it is performance. Brake lines do fail, and the older they are the more prone they are to degradation.

The car has 127k miles, and the original brake lines have lost much of their original compliance. The last thing I want is for some crusty old stock rubber brake line to spring a leak in the braking zone of turn two at Laguna Seca. Enter Stoptech stainless steel brake lines.

Stoptech's brake lines are a PTFE inner sleeve surrounded by a snug-fitting stainless steel braided sheath that resists the expansion caused high brake line pressures. Atop the braiding is a clear plastic coating that prevents the stainless braid from chewing through anything it comes in contact with (if the line rubs anything on the suspension then they're been installed incorrectly anyway).

At the ends of each line is a hefty strain relief and plated steel fittings and new copper crush washers for the banjo fittings. All robust-looking stuff. The Stoptech lines are DOT-compliant, too, each line being subjected to a 4500 psi leak test before being packaged up. The only thing that's missing from the Stoptech lines is an orientation tab on the fitting at the caliper end (the stock ones have this), so you just have to take some care to ensure you've aligned the fitting properly before and after torquing the banjo bolt. No big deal at all.

During threshold braking, Miata brakes have a tendency to be difficult unlock once you've locked one up (exacerbated by too much front brake bias, particularly in the early cars sans ABS). This is due to compliance elsewhere in the system -- flexy calipers are the likely culprit. The stainless lines won't cure it, but they will reduce a bit of that hysteresis in addition to the peace of mind they provide.

Jason Kavanagh, Engineering Editor

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1997 Mazda MX-5 Miata: Dripping But Driven

December 21, 2010

trunk leak.JPG  

Yeah, the trunk gets damp, but that just proves that Project Miata, our longterm 1997 Mazda MX-5 Miata, is being driven despite the deluge we've been experiencing here in LA for the past week or so.

First, that leak. Then the driving with the supercharger.

My esteemed colleague Ms Pardilla mentioned earlier that the Miata thinks it's a Cruze. For those readers that for some reason don't read every word we write here at the gilded IL halls, the trunk of the Cruze leaked early on and apparently passed this bad habit down to our lowly Miata.

Some experimentation with a pot (that's A pot, you fiends) of water showed that the leak is centered right above where the spare tire lives (see lead pic). Pouring water down the softtop triggers the drip, so either the softtop's rain rail is cracked or misinstalled, or the car's drain channels are plugged. 

Regardless, the top's got to come out to resolve it. If you've read my previous diatribes regarding Miata softtops, you know I'm no fan, and this is yet another reason softtops suck. This will be my excuse for perma-installing the hardtop when I'm finally in town long enough to remove the soft and install the hard.

Much more exciting than that, though, is the Kraftwerks supercharger kit. It's given the Miata's rather trucky 1.8-liter BP engine a more urgent character and a much-needed heaping of beans. It's definitely not a bottom-end grunter like you'd expect from a Roots blower, though there is a bit more low-end sauce than before.

Nor is it some high-strung, peaky thing. Lay into the throttle and the shove builds linearly as the revs pile on. Unlike a stock Miata, acceleration is now more than adequate for passing maneuvers, and we've taken a few people by surprise on LA's ever-present onramp drag races.

Finally, thanks to the supercharger, the engine is not totally overshadowed by the capabilities of the chassis around it. A degree of balance has been brought to Project Miata's equation. Speaking of balance, the linear response from the go pedal makes the car a cinch to balance using the throttle, provided you've got the revs dialed up. You can meter out or reign in the power in a predictable fashion. It's now a sharper tool for driving.

It's actually worth revving it to redline now, the way a sports car should be.

Jason Kavanagh, Engineering Editor

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1997 Mazda MX-5 Miata: Project Miata Lives

November 24, 2010


In 1994, Mazda introduced that nadir of Miata-ness, the special edition M-Edition, which persisted like a lingering sore through the '97 model year at which point Mazda mercifully euthanised the concept.

Essentially loaded Miatas with different paint, trim and hideous chrome wheels, the M-Edition was that shameless money-grab by automakers -- the badge and sticker job. M-Editions were the poodle chariots of Miatas. The wine-and-cheese version. They were given names like Fifi by the kind of people that name their cars.

They're also a goldmine for hardcore Miata enthusiasts.

Say what?

If you're befuddled, good. And I swear I'll tie this in to Project Miata, but you'll have to hit the jump first.

Being loaded, all M-Editions packing a manual gearbox also came equipped with a Torsen limited-slip differential. Meaning that unlike other trim levels, there are no questions or guesswork when you find one for sale in the classifieds or craigslist -- stick equals Torsen.

And being the range-topping frilly-frill version, M-Editions tended to be bought by affluent (read: older) buyers that maintained their cars well and drove them only as hard as they needed to get to bingo night on time.

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Past Long-Term Road Tests