The Miata experience: his and hers.

That is an interesting interior color combination., don't think I've seen it before. Congrats on the buy, looks really good - and with only 33k, it should!

P.S. Still on the stock expansion tank I guess?

In reply to Piguin :

Yes, still 100% stock.  I will definitely address the expansion tank in due time... looked good when I was inspecting the car this morning, though.  First mod will probably have to be the stereo.  I forgot how bad the stock NC head unit was, and no bluetooth or USB interface.

Washed the NC and took it on a breakfast drive this morning.  Just as good a street Miata as I remember...  quieter and more powerful than an NB, and the power hardtop is just fantastic.

I realized today that it's anniversary week for our NA... we've owned it 13 years now... it's come a long way!

About a month ago, I tested the NA at the local AutoX to see if my CPS wiring fix had worked.  I didn't have any cutouts, but the logs still showed a couple of signal errors.  I pulled the CPS connector apart, and put a slight crimp in the female side of the connectors for a tighter fit over the pins.  A street test drive showed zero CPS trigger errors.  Yesterday, I ran the local AutoX again, and again, did not have any cutouts.  Going to pull the logs today and check for CPS trigger errors.

As much as I enjoy the driving at AutoX, it was a pretty miserable day.  9 hours for 6 minutes of driving.  I was in the second run group this time, so 3 hours standing in the sun at 95* chasing cones before driving.  Sitting in the grid between runs choking on the exhaust of the two carbureted cars I was gridded next to (which they left running the entire time in grid).  And roasting in the car...  if not for my coolshirt, I'm not sure I would have been in any shape to drive.  Of course, a caged/harness car doesn't help...  the time between runs was just short enough to make getting in/out of the car impractical.  Ugh...

In any case, the car ran well and I put up respectable times.  Still waiting for results to be posted, and I need to look at the data.  I think I got my first run on video this time...

AutoX results posted, logs pulled...

No trigger errors while on course!  I did have a few trigger errors when the idle drooped, I think when I nearly stalled the car a couple of times coming on/off grid.  Still getting used to the clutch when idling around the pits.  All trigger errors occurred at RPMs below idle speed... I think the errors were more related to nearly stalling than an electrical issue.  

Came 9th fastest overall of 45 cars, 2.1 seconds off FTD (CAM-S C5 'Vette).  Plenty happy with that.

Max speed on course, a reality bending 47mph....  Max sustained lateral g's in the 1.0 range... definitely low grip compared to the track!

Only got one run on video, and it started late... camera was giving me a power fault, have to figure out what's going on.  First and slowest run...

Finished up a few small projects on the new NC this week.

First up was getting rid of the OEM head unit, which was pretty useless.  I picked out an Alpine head unit that would provide hands free phone, satellite radio and would work with the stock steering wheel controls and a backup camera.  I retained the factory Bose amp and speakers.  Stereo installs are both easier than they've ever been, and frustrating.  The plug/play harnesses make things pretty easy, but trying to figure out feature sets on the head units can be headache inducing.  I finally picked the Alpine because it does most of what I want, one particular feature being able to adjust the lighting for both night and day.  In a rural environment at night, a too bright stereo is just infuriating.  What I didn't realize was that while the brightness is programmable, it didn't have a 'dimmer' input wire so it knows when the lights are activated (night) and you have to switch day/night mode manually... WTH??  Stereos have been coming with dimmer wires since the 1990s!  The other goofy feature I didn't discover until opening the box is it had a GPS antenna.  No GPS, no NAV... so what's it for?   It's for the clock!  The clock sets the time automatically via GPS and you CANNOT set it manually.  You can only set the time zone.  WTH???  Who thought that was a good idea?  Anyway, I got it installed and everything working and it sounds good.  

Next up was a couple of exterior mods to sharpen up the NC's 'bar of soap' looks.  I added an eBay copy of the NLA factory Appearance Package 'air dam', and a small decklid spoiler, which I had painted to match.  Easy install, and spices up the looks just a tiny bit.

Last for today was an ongoing project on the truck.  Now that we're back in a rural area, night and early morning travels risk encounters with the local fauna.  A couple of weeks ago I ordered a bull bar for the truck.  It came in a funny looking box...

It was a simple install, and only took about an hour to get it on the truck.

I know these aren't a big help in deflecting animal impacts, but the secondary purpose was to provide a mounting location for some portable daylight.  I picked up a couple of Hella "ValueFit" LEDs, one in pencil beam, one driving beam.  In the past, I've really liked the Hella 550 series, but I wanted to try some LEDs.  I almost bought a set of Rallye 3003 LEDs, but these were less than half the price, so I decided to give them a try.  Our RV is desperately in need of some added lighting, so may also get a set if I like them. 

Got them mounted up and the wires run into the engine compartment.  Still need to wire up the relay and set up a switch in the cab.  They will be wired to come on with the high beams and have a switch so they can be completely turned off.

Shop is crowded today...

Did a couple of minor projects on the NC this morning...

First up was the exhaust.  Goodwin Roadstersport mid-pipe with hemholtz resonator, and Super Q muffler.  Gotta love working on newer cars with a lift... quick and easy.

Stock:

Exhaust out

New mid-pipe in

And done...

It reminds me of the stock Euro exhaust on my E36... still very civilized, but you know you're driving something a little sporty.  Also lighter than the parts that came out, which is always nice.

Next up was the coolant expansion tank.  The stock plastic tanks are a known failure point as they age, and will cause a near instant overheat if they fail.  The stocker looked OK, but not taking any chances, so I replaced it with a Moroso unit.  Another easy swap.

Stock part

This morning I said goodbye to our NB, and saw it off on its journey to a new GRM home.  I took the chance to take a family photo before the truck arrived...

Sorry for the dark pic... the sun was just coming up.  I expected the transporter early... which I needn't have worried about.  I later found out he was supposed to arrive at 9am, but then got lost thanks to his dispatcher giving him incorrect info, so the car got loaded up around 10am.

The NB has been a great project and I'm sure it will bring many smiles at its new home.

Had a great day at the track yesterday (FINALY!!)...  more to come.  Need to unpack the trailer, and download data and video....

The TL;DR version:

Car ran perfectly and everything worked as intended.  Despite lower grip, smoked my previous best on this track by 4.5 seconds.  And won my TT class.  Couldn't ask for a much better day at the track.  

The rest of the story...

Since we moved, INDE Motorsports Ranch is now our 'home' track.  That's a good thing, because it's our favorite track in AZ.  But this is the first time we've been there since March of 2023.  Between retiring, moving, K swapping the Miata and life in general, we just hadn't made it out there.  Yesterday was the day, and we would both be driving HPDE and I would be competing in the time trial comp, first time for the new setup.

We had dropped our trailer on Friday, knowing the paddock would be crowded, and it was.  I always like to take a stroll around the pits once we have the car unloaded and ready.

One of the more interesting cars was the Rush SR.  There were three of these, and they were running with the open wheel cars.

I talked to the owner for a bit, because these cars are pretty interesting.  He told me he was into the car for ~$45k, ready to race including a few upgrades like a fire system.  He was running lap times about the same as I was, but the faster drivers in his group were about 5 seconds faster.  IMHO, that's pretty good performance/$$... probably not as good as an older formula car or sports racer, but better than most street cars.  My hesitation with these is I wouldn't want to run one with regular cars in a run group.  It's a small car...  He said he had done some events where they were running with normal cars, and he wasn't that comfortable with it.

Another cool car was this LS3 powered Z...

They were still shaking it down, and not particularly fast, but both he and his wife were driving it and having fun.  And that's what matters most!

Anyway, we were dialed up and ready to go...

First session out, I had my fingers crossed, but it ran perfectly.  Once I got a couple laps of knowing I could get it to redline without it cutting out, I started working on my braking points, which had changed substantially...  The car was running great, but definitely didn't have the best grip, especially in the lower speed, long, sustained corners of which there 3 on this track.  This set of Toyos were on their 8th track day, so not much left in them.  I came back in after the first session with a best of 1:48.88, up almost 4 seconds on my previous best.

Second session, I was getting my braking dialed in, and decided to carry 4th through one corner instead of downshifting to 3rd.  My best dropped to 1:48.09, and that would be my best for the day.  Temps were going up and I didn't expect things to get better. 

I went out for my first TT session at noon.  We always try to sort the grid with the faster guys up front, so nobody is catching a slower driver in the competition sessions.  It doesn't always work, but usually it's pretty good.  My class was six cars:  me, another Miata, Mustang, Firebird, Veloster N and a Corvette.  The classing is straight weight/hp, with a tire modifier.  On our out lap, we got a little bunched up at the end of the straight, and while we were trying to spread back out the Mustang in my class (a newb) passed six of us, not knowing any better.  Of course that held every body up until we could get clear of him... and he didn't know enough to lift when he gave a point by.  That cost me three laps before I finally got clear and got a lap with no traffic, and on the next lap I caught a Nissan GTR from one of the quicker classes doing about 50mph on the racing line before start/finish. So I got one clean lap for the session, 1:48.93.  Not happy.

Fortunately, when I came in and looked at the results, I was leading my class by 3.5 seconds, so I breathed a big sigh of relief!

Though it was warm, we had a nice breeze through the trailer to keep us cool in the pit, and the coolshirts to keep us cool on track.  Track dog Kona is always cool...

Our second TT session was 3PM, and it was now over 90*F, so I wasn't expecting anything to improve.  There was also a guy in my class (the other Miata) that missed the first session.  This time there was no berkeleyup in the que, but I seriously overcooked my braking zone at the end of the straight on the first hot lap and had to take the escape road.  That put me back out at the back of the pack, and I had to deal with Mr. Mustang again... who apparently didn't learn anything from the talking to he got after the first session.  Two laps wasted before I got clear, but I managed a 1:48.83.  When I got back to the pits, I was happy to see no one else in class had improved from the first session times, so I had the win. 

I'm very happy that we finally seem to be past our teething issues, and that I was able to collect a win the first time out in our new TT class.  

Data dive...

First, as I noted above, everything worked!  Engine, brakes, data, video... everything.  That's a first since the swap was complete.

Mechanically, the engine seems to be a happy camper.   Ambient temps were into the low 90's, and the coolant temp never exceeded 190*F on track.  Oil temps stayed in the low 180s, which is a surprise for me, because everyone says these K motors like to cook the oil.  Maybe it's because my coolant temps stay low?  IATs remained at ambient, so my 'cold air' inlet appears to work well.

This weekend was the first day where I have solid data from a previous date at the same track with the BP engine and solid data post swap.  Although the first dataset is from a cell phone app (RaceChrono), and the new data is AiM, I have some confidence in the previous numbers.  Biggest difference was ambient temps... in March 2023 (the previous data) the day started out at ~55*F and went up to 63*F.  This trip it was 80-91*F. 

So both my previous best and current best were set on the same set of tires...  they were brand new in 2023 when we were last at INDE, and were on their 8th event yesterday.  In the slower, longer corners I was seeing .1-.15g less than the 2023 numbers, and it was a difference that could be felt.  On the other side of the scale, I was more comfortable driving the car on the slip angle, something I credit to a lot of SIM racing over the last year or so... since I didn't really have a lot of actual seat time.  It's interesting that in some of the quick transitions, and the corner between straights, speed improved.  I think that might just be my willingness to send it...

Speed deltas were obviously large.  Here's a track map with peak speeds between corners and minimum speeds in corners.  Black numbers inside the track are 2023 numbers with the BP engine, red numbers on the outside are K24 numbers from yesterday.

Can't argue with those numbers.  15mph improvement on the main straight, 11mph on the back straight, and big improvements almost everywhere between the corners.  If I can get the corner speeds back in a couple of places, I think low 1:47s are in the cards.

Stay tuned for video...

Video

In reply to Rodan :

Re: The NC, Nice! Super clean under there. You're really cooking in the track Miata.

Thanks!

I edited a couple posts, because I need to keep better (or at least more accessible) tire records.  When I pulled the wheels today as part of my post-race examination of the car, I realized I had already flipped the tires on the wheels.  I went back and looked at my records and these tires went on in February 2023, and now have 8 events on them.  Great tire life, but definitely not good for fastest laps.  Had I realized that I might have thrown the Kumho V730s on for a session...

Some pro pics from Saturday

Since this was the first event post-swap where we really put in some laps, I did a thorough post-race inspection.

I was happy to find no real issues.  Bolts stayed tight, and no leaks.

I do have one thing to note:  the KPI swap oil pan comes with these plastic oil drain washers.  I think they're Dorman parts, and they're crap.  Won't hold torque, and start to seep pretty quickly.  I should have known better than to use them in the first place.  I've now replaced them all with copper washers.

Since the NA is all good, it's back in the corner of the shop for now.

Love that Capri in the background. I had a 1974 2.8 V6 in the early eighties. those bumpers are/were seriuosly heavy.  Car handled and drove way better without them.

In reply to Milburn Emery :

Thanks!  I also had a '74 V6 Capri back in the 80s...  Here's my Capri thread...