Wow, great job pinpointing that leak and fixing it. I never cease to be amazed with your skills in building and maintaining this car.

 

Ryan,

Based on your photos, it appears that you pulled out 5 tubes from your core stack on your redesigned core. Given 14 tubes before and now 9, I am not surprised at all to see a 1psi dP increase through the core. This is making the assumption that your internal turbulator density inside the tubes is the same.

I work as an applications engineer at a Tier1 automotive heat exchanger supplier. Sizing IC's is one of the many things I do on the regular. If you'd like, we probably have a dataset close to what you are running on your IC. If you have internal air flow rate, post compressor (pre-IC) pressure, post compressor (pre-IC) temp, external (ambient) temp, and basic core geometry (number of tubes, types of fins, and fin densities) to share, I could possibly save you some iterative work and help optimize a core that should work best for your application. Toss me a PM if interested.

Awesome work as always!

 

That would be excellent. I'll shoot you a PM.

 

Congrats on the new Laguna Seca Miata lap record!

 

How many lap records has this car set now?

 

I'm gonna ask the same question with different words.

How many tracks has this car been on now?

 

Why thank you!




4 Miata lap records so far: Streets of Willow CW, Chuckwalla CW & CCW, Laguna Seca
Also, production car record at Chuckwalla CCW.

Sitting in 2nd at a couple more tracks, with one excuse or another for each one
Buttonwillow is coming up. I'm 2nd fastest there, 2 seconds behind 949/Supermiata. They ran in Unlimited with hoosiers, while I run street tires in Limited. Hoping to close that gap at GTA Finals in 2 weeks.

 

I'm excited, I get to play with Hyper this weekend

 

Laguna Seca flew by! We had an amazing weekend, filled with meeting lots and lots of fellow enthusiasts.

But what about the HyperMiata? On Friday we set out to take a crack at the Miata lap record. I had just got some heat in the tires with one warmup lap and did a single flyer and saw a 1:35.25 light up on the display. That's a new record! Going into turn 2 on the next lap the clutch failed. Man, I was just getting warmed up! There was definitely more in it. But in true Time Attack fashion, I didn't know it but I had just the one lap to get it done and I did. Will have to go back some time and drill that record down further



The rest of the weekend the car sat proudly on display in front of our garage:





Had a great time giving rides in the Budget NC Saturday and Sunday. It's not neck-snapping like the HyperMiata but it extracted a lot of passenger "Wow"s and "Holy Crap"s as we chucked it through corners and dove deep into braking zones. This car is a riot, it shouldn't be possible to build such a fun and capable car for so little.



By the end of the weekend I was aching to get back in Hyper and get just one more lap in. After so many laps that weekend I felt so much more 'up to speed' on the track than I had when I did those first couple laps Friday morning. Aaargh! Ah well, gotta have things to look forward to!

 

Was the clutch you killed the oem one?

 

And was the failure mode caused by too much torque with the sc?

 

Yes, stock (Luk) clutch. Point of complete failure was on a downshift at the end of the front straight, but that only means the downshift was the final straw, not necessarily the root cause.



Hard to say whether the rivets sheared or the disc broke apart first.

For GTA Finals I have a gamble on my hands. Put another Luk clutch in which we know shifts well but we can assume is a ticking clock until it inevitably fails like the one above... or put the SPEC clutch/flywheel back in which will not fail like the Luk but it never disengaged right on the MV7, so we'd be hoping that it works better in the MV5 (the Luk was always better than the SPEC in this regard, but it was still not perfect in the MV7 and it improved when we switched to MV5).

I decided to put the SPEC in.

 

Rivets on marcel plate let go first.

 

That's my thinking as well. Rivets sheared, then disc was free to move about and caught an edge on the flywheel which tore the disc up.

 

Did you ever get a chance to get meaningful data or opinions with respect to the rear fender skirts/extensions? Contemplating doing new rear fenders while I'm waist deep in composites right now.

 

Saw the SLB/GTA 2020 draft rules have been published requiring Limited class cars to run Yokohama Advan A052 ties, and Unlimited to run Advan 005 tires. Sizes are extremely limited for 15" wheels and looks like the Miata community will be severly handicapped unless someone can get creative. Thoughts? There are 240 width 13" tires in the 575 height which may work for the Unlimited guys w/ the 005, but for the A052, the widest is a 205 unless you go to a 225/50R15, which is awfully tall...

 

Not just the Miata community, basically everyone that doesn't run 17-18-19 got screwed.
But it is what it is and one way or another we'll make it work.

 

Unlimited on 17's got screwed too. Widest they make in the A050 is a 255.

 

When you're on 17's you're likely already running tire OD that can be swapped for 18" pretty easy.
Not the same if you're running ~23" tall tires...

 

In the A005 they have a 260/640R17, but that's only marginally wider than what you said above....

Need a find a way to get 17's or 18's on miatas if we want to be competitive in this series...

EDIT: I realize that unless you can find a 23" dia tire to fit a 17 or 18, then you will be no matter what be raising the COG on the car which will likely be detrimental to handling... But this may be worth it to get tire width back...