Initial prep for life as a novice driven track car
So the NC Mazda Miata came to me with a bunch of things done right, and then whole heaps of things done stupid. The previous owner displayed wild incompetence in a whole lot of their work. For example, the seats had clearly been removed as part of him replacing the soft top. During that process, he managed to cross thread nearly all of the bolts in the rear and then proceeded to just crank them down as far as he could... which in the case of the passenger seat was halfway, and in the case of the drivers seat one side entirely lost all of it's threads and was just decorative at that point.
Needless to say, there was a lot of basic stuff to sort out, along with a lot of upgrades needed to sort out the car.
Roll bar install
So the first major task that needed tackling was installing the rollbar. The factor hoops are not workable, both in height, and in general not being as robust as they should be for safety.
We went with Blackbird Fabworks RZ rollbar for the NC Miata. The choice was mostly due to them being certified by many racing organizations, and thus seemed like the safest choice. It did not hurt that I was able to drive over to their business to pick them up as well.
Installation was... a nightmare. Directions were not nearly as clear as they could have been, and some of the requires of the job were almost entirely unreasonable to pull off. Fortunately, in the end, the job was completed and while a few aspects were not to the best requirements of the directions, this rollbar is such extreme overkill, it is a very important safety update.
The bar does allow the planned first driver of the car at 5'8" of height to pass the "broomstick test" with their helmet on. Unfortunately, at 5'10", I am unable to pass the broomstick test with my helmet on. Lowering the seat 2.5" should work for me, and in general get our weight lower in the car.
Cooling System Fixes
When inquiring about known problematic areas for these NC miatas, the first mention is nearly always the stock expansion tank. These are made of plastic, and are a pressurized unit. Thus, any cracking that might occur in them is compounded by the pressure the unit is under, and when the unit fails as it is pressurized it will cause rapid boiling of your formerly pressurized coolant along with quickly dump all of the fluid out of your car. This can lead to rapid engine failure.
I swapped the expansion tank out for the Moroso unit. This was a VERY easy task. Dumping the coolant out several times to switch the entire setup over to water + water wetter however, was not nearly as smooth of a task.
Lastly, I removed some items from the engine bay to make room for additional airflow. I also added a few holes to the radiator shroud to allow further airflow through. This car is not a sit in traffic car or idle around pointlessly car, you simply get in it and go! These NC Miatas are also renowned for coming very stuffed up in the front from the factory. Companies infact make a notable amount of kits for relocating items in the engine bay to increase airflow under hood. Some of the aspects of those kits will likely be implemented into this car.
245 Grippy Tires
One of the biggest head scratches for the way this car was setup is that it came with road racing coilovers and wide wheels, yet had 500TW all season tires that were even winter snow rated. The previous owner clearly wanted that cool car look, but then didn't want to pay the price it takes to have low tread wear high grip tires.
Given my positive experiences with Federal 595RS-RR tires, I decided to get a set for this car in 245/35R17 sizing. The tires went on without much drama, but man oh man is it a SNUG fit! I even got the fenders rolled, and the fitment is still aggressive up front, to the point I think 235's may be better up front and run it staggered with 245's in the rear. Or, just modify the front to have fender falirs to fit the 245s.
With these new tires up front, the car handles noticably different. WIth those stupid 500tw tires on the car I could get the car to understeer and then attempt to snap oversteer just pushing it hard onto an onramp. They also gave way silently, not even squealing when sliding. These 200TW Federal 595RS-RR's however instantly yielded dividens. I now cannot reasonably acheive the limit of these tires with very spirited and aggresive manuevering on the street. While I'm sure the limit can and will be found at the track, on the street there's simply no kill like overkill to ensure you're always in maximum control.
General maintenance / Repairs
Lastly, there were a bunch of general things to handle on this car that aren't terribly sexy to describe or photo worthy. The brake pads were upgraded for EBC Street/Track pads, and I have to say they seem to be pretty darn good with a mild initial bite that gets quite aggressive qutie fast. The oil was changed out for 5w30 both as it likely needed a change, and I wanted to run a heavier oil to try and handle the expected high oil temperatures of driving this car around for 20-30 minutes at a time at high RPMS and maximum power loads.
Beyond this, I spent a lot of time discovering stupidity on the part of the previous owner and remedying it. The stripped bolts on the seats required I chased all of the threads and even go so far as to helicoil one set of threads back into place. The car is definitely much safer than the condition in which we received it due to all of these fixes, but is definitely a car that came to me with some notable silly issues. Fortunately, the bones of the car all seem fine, even if a bonehead owned it for a while.