NC Autocross and Track Build

Passed my FE, so now I can add a job search to my list of activities. And hopefully a lot more time working on the car.

That axle popper tool is worth every cent, did the job easily. A few taps on the end with a 16 oz hammer and it easily took the axle from the diff, no damage.

My struggle with the hubs and bearings resulted in the uprights going to a shop for that job. I tried a slide hammer. Slide hammer and heat. Puller. Puller and heat. Puller, impact, and heat. Hub would not budge. So I sent them off and will hopefully have them back this week. It really sucks to get beaten though, those hubs/bearings ate my lunch for sure.

While I wait, I am continuing the roll bar install. Those holes have caused me even more issues. I thought I had drilled them pretty damn straight, but the ended up where the spacers will not sit flush due to the car's structure, so I am having to make some slots and adjustments to get them right. It is not much fun, it killed the dremel, so I have been using files instead. 

Still plotting the suspension mods, stay tuned...and covered with chips and cutting fluid.

Pulled the trigger on suspension mods. Going to continue with my hybrid 'Street' suspension for a couple years. Replacing the stock dampers with KYB's all around, new spring seats and shaft bushings. Good-win Racing bushings inbound.  In a few years I'll probably get Flyin Miata's package. Was over $150 less than any other option, important to save some $$ for the next item...

The exhaust. Since CO is going full CARB as of January, I decided to go ahead and get the exhaust for the car, since it will be hundreds less than the neutered CA version, and more powerful. RoadsterSport header, midpipe, and still deciding which single exhaust, Race or Street. Whichever one I get, I plan on getting the baffle just in case. My local autocross groups have pretty generous sound limits; even the loudest CAMC cars are nearly 10 dB under, so I am not too worried about that. Any exhaust in CO that increases volume over stock is illegal by the way. It is one of those laws that is mostly ignored unless you are purposely being irritating. 

Since the rear suspension is completely disassembled, I decided to the polyurethane bushings. It is the car modification I have gotten the most mixed messages about. Online, there are a lot of rather vocal folks who swear they'd never do it again because of the ride or the squeaking. Then there a lot of people who say it rides just as nice as a fresh rubber suspension or better. My conclusion is I will have to find out for myself. I plan on using the Teflon tape on the metal inserts as suggested on the forum here and a YouTube video. 

I am using the Energy Suspension kit with the black bushings. It was the best value, and beat everyone on price. They are also made in the USA, that is nice. I did measure all the rear ones I have taken out and the new ones do not have more metal relative to the old ones, thus they are all legal for Street Touring. I'll keep checking as I go along, and move to the front of the car. 

Roll bar is installed. I can't say enough about the quality and design of the Blackbird Fabworx NC RZ roll bar. It may be twice the price of the competing products in the market, but it integrates with car's structure very well, and uses some clever tricks to maximize the height of the main hoop and retain the folding soft top. The finish is very nice too, the silver powder coat looks even better in the car than I could have imagined.  The interior went back together ok, the instructions suggest putting the interior back together on the roll bar outside of the car. This is a great idea, because a lot less mess ends up in the car, and the work progresses much more quickly. The plastic is polypropylene, and very thin and soft. It trims easily with a sharp utility knife, and I used a thin Japanese style pull saw on the thicker pieces of plastic. 

Without a helmet, I'm a couple fingers under the roll bar in my driving position.

Helmet on, I'm still over about 1/4".

I have a seat drop kit on its way from Jass Performance by way of Moss Miata...that should buy me a couple inches. 

I also need to get some SFI padding for the roll bar, but I'm still enjoying looking at the powder coat 

Got the seat drop kit in. It was definitely a struggle getting everything to line up just so, it also doesn't help that the bolts from Jass Performance don't have a lead before the threads like the factory ones. 

The result:

I'm not exactly elated, I was hoping for more than the inch I got. But I am finally under the roll bar of a Miata with a helmet on, so that is a relief.

It is as good as I'm going to get without race seats, and as everyone here knows, that opens a major can of worms. I  have no desire to deal with that, it would easily add $1k to the car's build, and many weeks of work. 

The rear bushings are assembled into the links. I had to use a vise or a c-clamp to push everything together in most cases (better than standing on it like the guy in the video does). 

I have a beautiful 2.5" exhaust from Good Win Racing sitting in my garage now. I got the very large and heavy old muffler out, and the midpipe came in out in less than 10 minutes, I was even able to save the hanger on it too for some reason. The O2 sensors unplugged very easily, thank you to whoever designed those plugs. The header is a bit more difficult, I was able to get half the nuts off with tools I had, but I had to buy a socket/ratchet set that allows the stud to pass through the assembly, as I cannot get a deep wall socket onto these 4 remaining nuts. So hopefully that works...

The next step after removing the exhaust will be to drop the rear diff mount and change the bushings there, or take apart the front suspension. 

The pass through ratchet set from Harbor Freight did the trick. The sockets in the set will also fit into a 3/4" socket, so between my 3/4 deep and regular socket, my collection of extensions, the provided ratchet in the set, and my ratchets, I was able to get the old header out of the car. The new one went in after a thorough cleaning of the gasket with no issues at all. It looks really nice too.

I replaced all the boots on the five link rear suspension's ball joints, there are four on each side. I cleaned out as much grease as I could after removing the old boots which were cracking and beginning to tear. I regreased with my favorite Red Line grease, then put the smaller boots on with a 36 mm deep socket and c-clamp. The bigger boots installed nicely in the same way but with a 1 1/4" PVC pipe coupling instead of the socket. I really like Priority Mazda's online parts store, they are significantly less than my local dealer even with shipping (for small items only), and have made a good effort with the parts catalog on their website. That is where I bought the boots, and some other small parts.

The power mirrors in the car haven't worked since I got it, and the keyless entry switch on the driver's door was also not working. Mazda will sell the entire door handle assembly, but if you're willing to cut and splice the two wires that connect the 'request switch' as it is called, one from an RX-8 goes in nicely and at a big savings. I busted apart the driver's door this last weekend, replacing the power mirror switch and the request switch.

When inside the door, I discovered the car had received a decent set of aftermarket speakers. I had never seen an external crossover before, so I posted a picture of it in another part of this forum trying to figure out what it was.  The speakers were mounted using some now decaying hardboard aka masonite, so I remounted them on some thick boltaron sheet I had laying around, I also pulled the RH door card and remounted that speaker.  Everything worked including the mirrors when I powered it up. Not bad for a 13 year old convertible with every bell and whistle you could get on that car.

I also got all the shocks replaced with new rubber mounts and bumpstops. The most bumpstop I found is the chunk of red stuff in the picture below, shown next to the new bumpstop. The other three were just little bits of red dust...

The car is coming along ok. If I can beat this cold I have soon I will get up to the shop and get the bushings and diff mounts swapped.

I made a booboo when removing the LH upper control arm, a wrench slipped and dinged the hard metal brake line. I cannot get another complete line, so I will splice in a union and short new section of line. 

There is a 'Car Control Clinic' coming up in my area this month on the 21st, I think I may try to get the car back together by then, that would be a good shakedown and test of my modifications.

I got some high density padding added to the bar. I'd like to get a cover made for it soon, but this will have to do for now...

The struggle continued with the bushings. I visited my dad's garage about 1.5 hours away to use his shop press, it worked for exactly two of the eight bushings/shells I needed to get out. For the rest, there is no way to support them safely and press out the bushings, or the geometry of the part interferes with the press. One of the big problems is the bushings are flanged, so they can only go out one way.

I did some more research, and YouTube came through with a video showing how to use a gear puller to get the old bushings out. So I cut part of the flanges off to allow the puller jaws to rest on the control arm or diff mount, and what do you know, it actually worked.

Unfortunately my early attempts to carefully cut the bushing shells out of the right upper control arm compromised it, so I have a 'new' salvage one inbound from eBay in a few days.

The good news is I can begin reassembly of the car, I am beyond thrilled to actually start putting pieces back on the car now.

I just picked up the prht version of your car. Great colors. 

In reply to amg_rx7 (Forum Supporter) :

Excellent! One of the guys in my area has a PRHT like yours running a supercharger and a bunch of other mods, it is faster than my car will ever be that is for sure. It is a great color I think, it is growing on me more and more.

The brake line problem has grown into a much bigger problem...the brake line in the car will not flare, it is too hard and keeps getting pushed out of the tool no matter how hard I tighten the tool. I carefully cut the line without a tubing cutter (those work harden the crap out of the metal), but still no luck.

So now I have a roll of nickel copper brake line coming and I will have to fab a new line. 

The good news is I did get the bushings installed including in my 'new' salvage UCA. I got the diff installed, rear subframe remounted, rear axles in, and the 10 links assembled. On the RH side I tried doing the ball joints first, then the bushings, it got done but the last one was an absolute bear and took me nearly an hour to get it aligned enough for a bolt to go through. So on the LH side, I did the bushings first and then the ball joints. The last one only took 30", so it was a small improvement I guess. My RX-8 sway bar mounted painlessly too. 

Last, I got the Goodwin Racing midpipe installed, including the O2 sensors and the extension cables. Mounted up the new Roadster Sport Street Single exhaust too. After bleeding the power steering rack, I decided to fire up the car since it hasn't been started since August. It started right up, with the typical rough running for a little bit that you get in this car after the battery has been disconnected for a while. I restarted it after topping up the power steering, and it ran perfectly, no codes or anything. The new exhaust sounds a little better, everyone online keeps saying that particular header/midpipe/muffler combo is loud, but at least in my garage it seemed pretty reasonable.

Next step is getting the RH front suspension and spindle back together, hopefully this afternoon. Then I just have the brake line to make and then get the LH front back together. I also got some Hawk HP+ pads to throw in the brakes, and then I can think about sticking the wheels back on and finally getting this car back on the ground.

Took me few hours to get the brake line run, so far so good. I also finished the suspension installation, and got all the plastic pieces on the bottom of the car again.

Slapped the Hawk pads in, cleaned and greased the caliper pins, bled the brakes, and slapped the wheels on.

47 degrees is warm enough for a drive with the top down right? Any way, so far everything is working well. I bedded the pads, they are kinda noisy cold but bite hard (and dust a lot) when the heat up a little. 

The exhaust sounds good, it sounds very nice, not 'ricer' at all. I for sure wouldn't want it any louder though, I hear they mellow a tad after 1500 miles or so and I look forward to that. I have the extra baffle installed too...

What's next? A visit to the alignment shop. Maybe an autocross in a couple weeks too!

Visited the alignment shop today. If you're in the Colorado Springs vicinity, Shogun SpeedShop is pretty great. They also do dyno work and engine tuning as well. The alignment was priced well and done quickly, and based on the cars on their Facebook pages I had zero concern turning over a low car to them...

I used the numbers Brian Goodwin suggested on his forum to a customer at a stock ride height that wanted an autocross alignment, since I am running that height also. 

Front camber: max possible, usually works out to around -1.0 deg

Front caster: whatever it comes out to once camber is set, usually around 5 deg.

Front toe: 0

Rear camber: negative, about half a degree less than the fronts

Rear toe: 1/16" in on each side

Of course YMMV, and mine did a little. They were able to get around -1.0 deg camber on the fronts, 0 toe, and caster came out just under 5 deg. They set the rears around -0.6, with the 1/16" toe in on each side. 

As a reminder, my current suspension setup is this:

KYB Gas-a-justs front and rear, stock springs. I do not have the 'sport' springs either, my car was the GT package without the Sport Suspension. Front sway is stock, and the rear is a 'yellow dot' from an RX-8. The stock rear sway is a dainty 11 mm in diameter, the RX-8 piece is 16.5 mm (measured). 

The car drives really nice now. It isn't 'nervous' or 'darty' at all, but turn in is more quick and sharp than any other car I have ever driven, even the NB I owned, which was rocking aFlyin' Miata's excellent springs and Tockico shocks, Toyo T1Rs, and an aggressive alignment.

The other thing that is hard for me to explain is related to the suspension bushings. The NC previously, and my Impreza daily all have this 'spring loaded' 'return to neutral' feeling, but now the NC when it pivots into a turn, it feels like it wants to stay there until you tell it otherwise. It feels different, takes a little getting used to for sure. It feels more stable than the old setup for some reason.

I have registered for an autocross in less than two weeks. Hopefully it takes place under our increasing restrictions here in CO, there other big 'if' is the weather.

Have a happy Thanksgiving. I am certainly thankful for a car that turned out as I had dreamed it up. It is kind of surreal to walk out into my garage and see a safe, well prepared, theoretically competitive, and just damn good looking car sitting there, and realize it is mine. I am so very thankful.

So far the autox on Sunday is a go, weather forecast looks great with a high around 55 deg F.  35 drivers registered so far... I am cautiously optimistic.

Edit: Family issue came up, gonna have to punt on car fun this weekend.

I finally sat down and dumped all the bushing measurements into a spreadsheet, both the oem and the new ones from Energy Suspension. Why do I care?

The Solo rules, 14.8.B states "...In a replacement bushing, the amount of metal relative to the amount of non-metallic material may not be increased..."

So as long as I don't increase the amount of metal in there, I am good to go. I passed, there's one that is few thousandths away, but they all make it. Can I guarantee your bushing kit and your car will be the same? No, but there's a good chance it will make it too.

Next autocross is in late January, hopefully the kid will behave so I can make it to that and give this thing a good test...

I accidentally deleted the last post  Basically I got the Federal 595RS-RRs on the car and it is waaay better than the 205 size all seasons, even rides better. The Federals do make a bit of road noise, but the header kind of covers it up...

Anyway, I have gotten underway in the local autocross season. I attended a school at the beginning of the month, and my first event with the modified car and the new tires last weekend. 

It was pretty cold and occasionally damp, I still had fun. I PAXed at 72 out of 76 and got 4 out 5 in my class, got a long way to go. Here's my best run, helpful ideas welcome. My current takeaways are to A. look further ahead and B. smoother transitions in steering throttle and brake. I am spending a lot of time in the sim working on that this week and next week, next autocross is the Saturday after next.

Run 4 of 5, fastest for me that day

Ran my second event of the season. Still on the struggle bus, but improving slightly, PAXed 5% higher and was only 7 seconds behind the leader instead of ten.

I felt like I did a lot better on smoother transitions as mentioned above, and also getting a bit tighter to the inside of most of the course. Still not looking far enough ahead, that one is pretty tough to work on. I feel like I'd do better with it in VR in the sim, but gonna be stuck with my gaming laptop and the tv until silicon prices come back to earth.

Run 4 of 4, my best of the event

Third event down, now in the bottom 20% instead of the bottom 10% by PAX. Now only 3 seconds behind the leader. I wasn't dead last either, finished fifth out six. Long ways to go yet...

Finally got the exhaust in front a sound meter, every run was 78 dB with one at 80 dB. That was running the RS street single with no extra baffle. My club's most strictly controlled site is 93 dB, so I think I'm gonna be alright 

Run 5 of 5, last one fast one

Almost lost it in the slalom, need to work on some more smoothness there, and tidy up some of the corners, left a lot of time out there. 

Looked like fun.  The more you do it, the faster you will get,.

What are the plans for 2022? Any further modifications or drive it as is this year and continue to develop the nut behind the wheel? 

Any further impression on the poly bushings? Have you managed to keep the squeaks at bay? 

I ran one track event late last year and decided it would be wise to order the Blackbird Fabworx RZ roll-bar today to be ready for a track day in May.  Of the four cars I have had on track it is the quickest and I certainly have room to grow with it as currently equipped. It has been competitive at the local level in STR the past two years but (2) ND's are planning to join the fun this season so its time at the top will come to an end