#miataupgrade

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Miata Update: 2014 Year End Catch-Up

Mileage: 86,000

Like all things, I had every intention of periodically updating this blog with everything I have been working on with respect to the Miata. The combination of my "next week" procrastination and the busy nature of the past few months resulted in 2014 coming to a close with out recoding many of the things I have done to and with the Miata.

This post will serve as a catch-all for the past five months, condensing all things Miata.

July:

First full autocross with the new suspension and stock wheels/tires.

The car was very predictable with a slight tendency toward oversteer during transitions. The all-season tires limited maximum grip and were not as sharp as I would like them to be, but performed as well as expected.

August:

With an autocross complete, it was clear that new tires were needed to fully utilize the suspension.

205/50-15 BFG Rivals mounted on 15x7 +20 Kosei K1s replaced the stock wheels. 

With the wider wheels and lower offset, a tab for the fender liners needed to be bent flat on the front wheels.

September:

First autocross with the new tires. Unfortunately, this event was quite wet. 

Event with wet tarmac, the rivals had more grip than the previous tires did in the dry. The current suspension setup (unchanged from installation) proved to be fairly prone to oversteer in the wet, limiting my confidence and how hard I could push the car around the course.

The stock steering wheel has always been a complaint of mine. It was too wide and thin for my taste and it was constantly fighting for space with my knees. I purchased a used Momo Corsa wheel on ebay and installed it with a hub adapter.

October:

The Miata's birthday rolled around October, 7th and I decided to get it a present in the form of a factory R-package front lip. I also purchased, plastidipped white, and installed a Rennmetal spec Miata two hook.

November:

Another autocross, this time in the dry. No pictures of the event, but the Miata performed very well. The new tires were amazing in the dry, allowing me to keep pushing the car harder on each run. This event left me with the feeling that there was much more left in the car, I just needed more experience to utilize the potential. The below shot show the new magnetic class and numbers I purchased.

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This brings us to today. There is more planned for 2015, but I will save that for specific topic posts. 2014 was a great year for the Miata and I hope to keep it going in 2015. 

2014 transformation (left to right)

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Kosei K1 15x7 +30

205/50-15 BFG Rivals

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Miata Upgrade: Catback Exhaust

Mileage: 85,000

In an effort to make driving the Miata a more enjoyable experience, I researched and purchased a catback exhaust. A lot of the aftermarket offerings for the Miata don't sound or look that great, so I had to take some time and find the best system for my needs. I decided on a lesser-known manufacturer: Yonaka. 

Less than a week after ordering, the exhaust arrived.

Everything seems well-built and high quality.

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Installation would have been a 1 hour deal, but the bolts that hold the original catback to the catalytic converter were rusted to their studs. They ended up snapping off the ends of the catalytic converter studs. 

Luckily, the broken catalytic converter studs had enough thread on them to allow the new nuts to be threaded on. The rest of the installation went smooth.

Old vs New:

After a few hundred miles I got around to making a quick video showing how it sounds. The video was taken on a cold start, so no high-rpm action but you can still get an idea of what it sounds like.

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http://youtu.be/-JWQfXiHCFs

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Miata Upgrade: Coil Over Upgrade

Part 5: Installation

With everything set to go, the installation process could begin.

With the Miata in the air, there is easy access to all suspension pieces.

Close-up of the front suspension.

Close-up of the rear suspension.

Front suspension out. I chose the "long bolt" method for removing the front shocks.

Comparison of the stock and replacement coil-overs (rear).

New shocks in place.

Installation: complete!

I guessed when setting the ride height, and ended up too low in the front and rear. The car rode OK, but was riding on the bump stops. I set the Konis to 1.5 turns in the front and 1 turn in the rear. 

Result after the first test drive:

Looking and driving much better. 

After a few test drives, the Miata was put on jack stands again to re-work the ride height (up 2 turns in the front and 2.5 in the rear) and to re-torque the suspension components.

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Miata Upgrade: Coil Over Upgrade

Part 4: Assembly

After cleaning, paining, and preparing the shocks, it was time to assemble them.

Here is everything set out and ready.

Assembly order for the rear shocks. Fronts are basically the same, using the shorter bump stop and stiffer springs.

Correct order of the spacer, bump stop, and upper spacer.

Finally, here is the shock fully assembled and ready to be installed.

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Miata Upgrade: Coil-Over Upgrade

Part 3: Bump Stop Upgrade

The bump stops that were on the shocks when I bought them were cut-down OEM pieces. They were too firm, too short, and broken so an alternative was needed. After a quick search on the miata forums,  Fat Cat Motorsports came up as the leader in aftermarket replacements. Custom spec'd for both the Konis and the Miata, the FCM kit should yield much improved ride and suspension behavior.

Here are the bump stops that were included with the shocks. 

Short, hacked, and broken, the modified OEM pieces needed to go.

The sport Koni kit from FCM will be taking their place.

Here is the kit in detail. The left two stops are for the front (36mm) and the right two are for the rear (46mm). The kit also includes four 9mm spacers that will be placed under the bump stop to help protect the shock from bottoming out, as well as four 3mm spacers to be placed between the stops and the top hats.

Finally, a comparison between the old and new rear stops.

In part four of this series, we will visit the refreshed shock assembly and see how they turned out. 

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Miata Upgrade: Coil-Over Upgrade

Part 2: Preparation and Painting

Goals: 

Remove rust and loose paint

Clean and primer prepared surface

Paint the shock bodies with the original color

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Shocks

The first step is to mask off the threaded collar and shock shaft.

Next, I need to asses the situation and begin sanding down the rust and loose paint.

After sanding is complete, I need to clean the loose paint and rust from the shock body.

Once the surface is clean, priming is next.

After two coats of primer, the shocks were left overnight to completely dry.

Plastikote school bus yellow is a very close match for the yellow on Konis.

First coat

Second coat

Third and final coat.

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Top Hats

Original condition. Next step is to sand the rust off and prepare the top hats for primer.

After two coats of primer, three coats of black enamel paint finishes the restoration.

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Results

In part three, I will go over the bump stop upgrade.

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Miata Upgrade: Coil-Over Upgrade

Part 1: Overview and Plan

The time has come for the Miata to get some serious upgrade love. The first thing I wanted to change about my Miata was the tired shocks and springs. The car felt good during normal driving, but when pushed exhibited confidence-shaking body roll. Add that to the fact that NA/NB Miatas have very little suspension travel and rock hard bump stops, it was time to make some changes. 

My initial plans were this:

Replace stock shocks and springs with a reputable aftermarket alternative

Replace bump stops to gain travel and improve handling characteristics when transitioning from regular travel to bump stop contact

To expand on my plans, the replacement suspension needed to fulfill the following 

Lower the Miata (goal is 12-12.5" fender to hub), bonus for height adjustability

Good match between shocks and springs to provide excellent handling performance

Good street manners (limit handling is priority one, but the ride has to be decent), bonus for adjustable dampening

With the guidelines set, I began my search. Due to the Miata's popularity, there is a massive number of aftermarket shocks, springs, and coil-over kits available. Pricing for these kits range from $400 to over $2,000. I wanted to keep my cost as close to or below $800 as possible. I won't go into detail, but I used the Miata.net and miataturbo.net forums for a few months trying to decided what suspension was right for me. I originally settled on the (as of this writing) unreleased 949 racing TECNA entry coil-over. It was targeting the entry-level coil-over market focusing on great ride quality and overall solid construction. With that in mind, I setup a craigslist watch to see if any used suspension components would become available while I waited for the TECNA's to become available. A few weeks later an ad was posted for "Bilstein shocks with ground control sleeves and springs". 

Here is what I was looking at:

As with any craigslist item, there is a certain amount of questioning that needs to be done to figure out what exactly the person listing that item actually has. I wanted to know spring rates and how old the shocks were. The responses were strange. The lister stated that the shocks had only seen 7,000 street miles and a few track days. I would buy that, except for the amount of rust on the shocks. The answer to the spring rate question was very questionable. He quoted 600 in/lbs front and 63 in/lbs in the rear. At this point I knew the owner had no idea what this suspension was and his responses could not be trusted. For those of you confused at this point, 600 in/lbs spring rate is a little less than four times the stock spring rate (potentially too stiff for the shocks) and a 63 in/lb rear spring rate is less than the stock rear spring rate (unbelievably soft).

I eventually met the individual selling the shocks in person and got to take a close look at what I was dealing with. My observations are listed in the order I came across them:

The shocks are Koni adjustables and not Bilsteins (there was a Koni sticker and Koni imprints on all shocks) - GOOD

The front spring rate is 450 in/lbs, not 600 in/lbs - GOOD

The rear spring rate is 63 mm/kg (around 300 in/lb), not 63 in/lb  - GOOD

The rust looks to be all surface rust and the shocks look to be in good condition. They all compress and rebound correctly. - GOOD

The shocks had stock bump stops that were cut and reused - BAD

After a good looking over and a few minutes of haggling, I decided to take a chance on the suspension. 

Next Steps

Once home I decided to make a game plan around what I wanted to do to prepare the suspension for installation. I really just wanted to get rid of the rust, change out the bump stops and throw them on the car. 

The next fours parts in this series will cover the following:

Preparation and Painting

Bump Stop Upgrade

Assembly

Installation

I will end the first part of this series with some more detailed pictures of the suspension before any work was done.