Basic Spec Miata Maintenance Guide

This list was put together as a guide along the lines of: “Are you new to Spec Miata? Check out this list to see what has worked for me”. This is intended as a starting point for those new to the class who want to put on a somewhat serious, but fun effort, while keeping to a tight budget.

General maintenance of track cars is one of those really interesting subjects to ask for advice. If you ask 5 people, you’ll get 10 different answers, 9 of which are based loosely on what someone read on some forum.

In general, I fall very far on the side of “deferred maintenance” and “try cheap parts first until they fail”. Partially to be a test-mule for this site, part because I’m stubborn, and part to spite those that do too much and love to brag about it. Obviously, your mileage may vary, but I’d expect it will be fine. There are MANY in the class who have hour meters in their cars and have long punch-lists to preventively replace items at certain intervals. If they have the willpower and budget to do so, great for them. To me, most of that is wasteful. As I’ve written elsewhere: Following these general guidelines, I’ve finished every race I’ve started in my 5 years of racing. I’ve managed to run upper-midpack in a region averaging 19 cars per race. For me that’s enough evidence that this list works.

If you are simply looking for advice on prepping your Track Day Miata, this information can also work well for you. Track day driving is generally not as rough as racing, but usually with much more time on track per day. Consumable use may be similar but wear items (like hubs/fluids) often can go longer. However, as soon as you begin modifying your car outside the realm of Spec Miata other issues may begin to arise. Wider, Stickier tires and aero will lead to more issues with bearings and hubs (There are upgraded options but most are still very expensive at this time). With more power you may have excessive brake wear or cooling issues, etc.


Fluids:

Oil & Filter: Replace every other race weekend: I’ve been running either Rotella t5 and t6 15w40.

Trans Fluid: I have been doing it once every 2 seasons, but lately it’s becoming harder to shift after a full season so my next interval will be 1 season. I use the ford synthetic XT-M5-Q. I’m still using the same transmission my car came with (5 years use by me). I bought the basic 5x racing shifter rebuild kit when I first got the car. 

Diff Fluid (Torsen)– Once every 2 seasons, sometimes longer. I use cheap synthetic fluid (Mobil 1) from the parts store (75w90)… Torsens aren’t picky.

Coolant: I run distilled water with water wetter and maybe just a splash of antifreeze during the summer. Make sure to swap to 50/50 antifreeze/distilled water for storage when the season is over (In cold climates). 

Gas: I run 93 octane. Timing is set pretty aggressively, on a hot day I imagine it could have some premature detonation with lower octane, but I haven’t tested. 93 is an easy button. I do bring two or three 5-gallon cans (I like Scribner as they are one of the cheaper options). Depending on the track and how much they mark up gas (and availability) I’ll buy there or at outside stations. 

Clutch Fluid: Clutch fluid quickly darkens but doesn’t have a hard job. I use whatever bottle of DOT3 is on my shelf and only really bother to flush if/when the slave cylinder gives out. 

Brakes:

BrakePads: I’m a fan of Hawk DTC 60 in the front and 30 in the rear. They’re easy to bed and have always been reliable and consistent for me. Hawk’s generous contingency makes me like them even more. Front pads usually last 2/3rds a season. Rears last two years easily. To be honest, I don’t even remember how old my current rear pads are. 

Brake Rotors: The cheapest I can find that week, usually on RockAuto, sometimes Amazon. Not kidding here: No premium rotors, no slotted stuff, just plain blank rotors. Many drivers replace fronts annually, I do mine after 1.5-2 seasons. My rears are currently 3 seasons old, and I’ll likely keep them for another.

Brake Fluid: I do a quick bleed after every event to refresh the fluid at the calipers. If I don’t, the heat from the front brakes builds up tiny air spots and leads to the rears locking up earlier than the fronts. I do a full bleed once a season. ~$15/qt ATE fluid works fine for me.

Backing Plates: I removed the brake dust shield/backing plates for the front and rear. It makes various jobs easier and I haven’t noticed any adverse effects. 

Calipers: Parts store remans have worked fine for me. I gutted the rear caliper e-brake mechanism by blowing out the piston and removing the piece on the back side of the piston. I clean+lube the pins and sliders at least twice a season. I run the metal sliders but not the spring clips.

Setup:

Alignments: (Big post coming for my homebrew alignment rig as well.. I’m about $200 invested into it Total) – I do a string alignment pre-season and quickly check the car with toe plates after every event, sometimes during if the car feels off or I hit something. I’ll tweak what I can with toe-plates as long as I can, but usually end up setting up the full alignment rig again mid season once things get out of whack. Marking your alignment bolts can go a long way as you’ll get a clue which corner is off (since Toe plates tell you total, not per side). 

This wasn’t super necessary in the past but my region has gotten much more competitive lately and I’m working harder to get/stay towards the front, keeping a good alignment is a big deal.

In an attempt to minimize my horsepower disadvantage, I run as close to 0 toe as I can for both front and rear. My camber targets always change but I am currently running 3.6 degrees in the front and 3.2 in the rear. There are plenty of competitive drivers who do track-specific setups, I do not. 

I do not have a standard replacement interval for the alignment bolts, but as they age they are more prone to slipping. If yours are original, replace them. Always have spares if one decides to start slipping on you. Once you get your alignment set, mark the bolt positions so you can easily check (and fix) at the track in a pinch. 

Tire Pressures: Note: I am VERY lazy with tire pressures. I’ve had weekends where I forgot to even take the tire gauge out until Sunday. I’ll adjust individual tires a bit based on track configuration and temps, but I’d say 28psi is my general starting point.

Sway Bars: Since the move to Penskes, I’ve been happy running without the rear sway bar (by removing one endlink bolt from the driver side endlink and zip-tying it up to the bar). With the Bilsteins I would run the rear bar on soft until the tires got to around 12 heat cycles, then remove it for the rest of the tire’s life. For me, As the tires age the car was slightly easier to drive without the rear bar, though a hair less quick.

Rain: There are plenty of people with a lot of tricks to run better in the rain, I’m lazy and don’t do much. First: I don’t put rain tires on until it is VERY wet, with standing water all over the track. RR’s do surprisingly well on a damp and drying track. I remove the rear sway bar (if it’s not already off). Removing the front is popular but I don’t. When I do use the RA1’s, (in heavy rain) I run them very low, around 20-25 psi.

Maintenance:

Front Hubs: I give the wheel an up-down shake any time the car is up in the air… I usually have to replace the left side mid-season, and at the end of the season I remove, inspect, and repack the ones on the car. Some years they’re both trash at the end of the season, some years they are fine. I run cheap GMB hubs, but did recently get a set of good condition OEM hubs to try once these wear out… repacking front bearings with good grease is essential (Redline grease is okay, as is NEO, but it is expensive). Many swear that front hubs should be removed and repacked ANY time they are run in the rain as some amount of water WILL get in them and contaminate the grease.

When shopping for hubs/bearings, beware the “Bad” overly machined hubs, known for breaking in half either at the stud holes or across the machined surface… leading to a catastrophic failure (your wheel falling from the car at speed). If you have the front brake backing plates removed, it is very easy to inspect the rear surface of the hub for cracks.  

Rear hubs: Pretty maintenance free provided you don’t hit anything. I did mine “preventatively” 2 years ago, and they sure did look to be original to the car (On a ’96 that had been raced since 2008).

Wheel Studs and Lug nuts: I run cheap studs from 1320 performance’s Ebay store. Dfuser Motorsports just released their own version, they are the most affordable option, and look great. Generic open ended lugnuts from amazon too. All have performed as hoped. 

Axles: As long as the boots are good, they’re usually good. They rarely fail. 

Bushings: I’ve been running on original bushings. They may not be ideal, but they aren’t currently falling out either. Replacing (With OE, from Mazda) is on my list… but it’s pretty far down. I do NOT have the allowed offset upper control arm bushings. I’ve heard of (And seen) too many people having issues with them, I run the extended lower balljoints for added camber.

Ball Joints: Nothing special for me here. Watch for movement and keep an eye on the boots, replace UCA balljoint boots if they look ripped as they aren’t super high stress. If boots go bad on lowers, replace the balljoint.

I have been running the extended lower balljoints for years without any issue. While they have been reliable, I still keep a second set as backup incase I need to replace one at the track. Since they are such a niche part, if one fails at the track you won’t be able to head to autozone and get one. 

Engine Maintenance: 

Spark Plugs: I replace my plugs every two years with midrange parts-counter items.

Wires: I replaced them when I bought the car ~5 years ago. 

Air Filter: I use a midrange parts-store filter. I run them for two years and check/blow it out mid-season.

Motor Mounts: I installed MazdaComp motor mounts. Stock mounts get torn up and fail quickly with SM abuse. The Comp mounts have done fine for the last 4 years.

Radiator: For years I raced with a $100 generic “Aluminum racing radiator” from eBay, and it functioned flawlessly. As my region gets more competitive and we’re running entire races literally nose-to-tail, I’m having issues with temps climbing when running in multi-car drafts. I will likely be upgrading to the East Street Racing radiator.

Tires:

I run with NASA, where the Toyo RR is the dry tire. I have no intention of trying the Hoosier SM tire that SCCA runs as they cost more and are competitive for WAY fewer heat cycles. 

The general Toyo RR usable life guidelines I follow are: Heat Cycle 1 through around 12 the Toyo RR’s are their fastest. From there, they are pretty consistent until the low 20’s. Much beyond that, they get a bit tougher to drive. These numbers vary a bit between tracks. NJMP likes fresh rubber, but at Watkins Glen I don’t see much difference between 5 and 20 heat cycle tires. With my recent alignment numbers I’ve had tires age and compound out before they cord. 

Used “scrub” tires are a great way to cut tire costs. They work well when you start racing, but as you get more competitive the subtle difference in drivability gets more frustrating. The Toyos don’t get much slower as they age but as they get tricker to drive, my average lap times get slower. 

 In my current operation I save up contingency money towards buying one set of fresh Toyo RR’s per season, then buy a cheap set of 8-10HC Toyos as my “Scrubs”. It has been a good mix of staying competitive while keeping to a tight budget. Running competitively on Hoosier SM7.5’s would cost me a lot more. 

For Wet, we run Toyo RA1’s. They don’t get used too often, and when they do it’s so wet that they don’t wear much. I replaced my last set when they hit 10 years old… They looked brand new and performed well on their final outing. I bought my current set used, with some wear, but they are one year old… I plan on keeping them for a while. 

The Wheel+Tire Pile: I have 4+ sets of wheels & tires for the Miata.

Set 1: My “Good” competition tires. 

Set 2:  My “Scrub” practice tires.

Set 3: My Rain tires 

Set 4: My “Winter Storage (very old) tires on VERY bent old wheels that I got exceptionally cheap. Stock wheels also work fine for this job.

Bonus: I have one extra wheel mounted with a decent scrub tire. I usually bring it to the track as an extra spare for myself or others.

Wheels: I run TR Motorsports C1M wheels because they look good and were the cheapest option when I was building up a stockpile. The market has shifted a bit in price and availability. Most of my current wheels are 5 years old. I inspect them pretty regularly but have never had a crack or failure. 


I’ll add more items as I think of them. If there is anything I missed, or something else that you’d like to see, let me know!


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9 thoughts on “Basic Spec Miata Maintenance Guide

  1. What about timing belt replacement? I am doing HPDE events with no idea how old the belt is. Thanks

    1. Great Question! There are some who do think timing belts see extreme conditions in a race car, and will regularly inspect and re-tension them, but I’ve been hands-off with mine. In my experience, the water pump has always failed first, so I’ve replaced them in my HPDE days as part of the water pump job.
      I will say, I’ve gone 5 seasons racing on an unknown-age belt. Miatas are non-interference engines so if it does pop, you’ll need a tow but you won’t ding the valves, so that’s good.

    1. Edit: Whoops, I read your question as “Motors” not “Rotors”… Info still stands, though irrelevant.

      I wouldn’t say it’s often enough to be planned. For HPDE I ran the original motor until around 180k. At that point it was running fine but smoking so I dropped in a $500 junkyard engine with about 110k and ran that until I sold the car.
      With the Spec Miata, after 5 years, it still has the junkyard engine that I bought it with. I haven’t done so much as take the valve cover off. Just dynoed 115hp last month. I had planned on getting a fresh built cylinder head for it, but I found a killer deal on a used pro build engine that’s going in over the winter.

    2. Great question. Rears I do every two or three seasons. I can see doing fronts yearly, I usually do them every 1.5-2 season though.

  2. Regarding Dfuser wheel studs. It looks like they claim a class 10.9 rating, which means a minimum tensile strength of 1040 MPa or 150,000 psi (they have the unit wrong on their webpage). ARP claims a rating of better than 190,000 psi, which surpasses the spec for a class 12.9 bolt. Now, the Dfuser wheel studs are cheaper but they also have a 22% lower tensile strength.
    For the E30 I always went with at least class 12.9 wheel studs but I have no reliable data if that really makes a difference in real world.

    1. The ARP studs indeed claim to be stronger. However in our application I couldn’t find ANY examples of stud failures with any kind of stud. While aftermarket studs are a popular upgrade, there are still many drivers who are running with old OEM studs, and many who run unknown studs in cheap aftermarket replacement hubs.

      It is my understanding that 10.9 is the standard for OEM wheel studs.

      I understand some applications do see regular stud failures, but Miatas do not.

      So to me, this seems like we have a scenario similar to this: If 12″ of dirt will stop a bullet (minimal strength for studs to not fail). The Dfuser studs may be something like 24″. Would you pay DOUBLE to do 30″? (ARP).

      100% your call, and I won’t judge if you choose to pay for the stronger versions, I just do not see the need.

      1. I have seen two cases in Spec E30 where wheel studs sheared off so this was a high enough occurrence to trigger my attention. Good to know that the SMs are not as harsh on them.The trick (or difficulty) is always how to quantify or rationalize choices.

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