Did some tinkering this weekend but nothing too crazy. To keep on the flat shifting tangent, I tried removing the dog unload portion of the flat shift and that seems to have gotten rid of the gunshots. I'll get my settings in the Link subforum soon. I did miss third one time and ended up free revving to limiter, so there's something to work on there. Another time it looked like the shift aborted early or something? Maybe this is a glitch with the clutch switch, but I'm not sure. Regardless I'll keep monitoring that, because it basically defeats the point of having flat shift at all.

You can see below where the clutch is still engaged but the ignition cut (yellow) cuts out early and allows the car to rev to limiter (hence the fuel cut). Maybe that was related to wheel spin, but I'm not sure. 2nd is definitely starting to struggle for traction at the top of the RPM range.
https://cimg6.ibsrv.net/gimg/www.mia...9e815c4adf.png



Aside from that I finally broke down and got a 3d printer. A refurbished Ender 3 KE was about $160 from eBay. I designed/printed a new case for my new garage door opener remote so it would fit in the center console of the Miata. I'm going to revise this most likely to make it fit a bit better, but for now I'm pretty happy with it.

https://cimg9.ibsrv.net/gimg/www.mia...349dc041ca.jpg

I also opted to clean up some of the passenger side fuel bracketry. I didn't get a photo of the finished product, but I was able to get a decent bracket to hold the fuel pressure damper while removing the rest of the bulky brackets that weren't in use. Again, I need to revise that one as well, but I took the car on a drive today and the bracket didn't melt, deform or break, so that's a good sign (printed in PETG).

Basically all of the gold brackets in the photo below are going bye bye.

https://cimg5.ibsrv.net/gimg/www.mia...cc527df0cf.jpg
https://cimg6.ibsrv.net/gimg/www.mia...20cfe84b23.jpg


And... new tires. These Nankangs have been doing great this year but they're getting pretty worn. We've got a big event in Montana this weekend and I figured these were going to be replaced in the next event or two anyways, so might as well do it now for the big event and not have to stress about cording these ones. I'm also debating on getting another set of wheels so I can have a "beater" set of 200 TW's. Flyin Miata has their 15x9 Kogeki's on clearance for $159 a wheel and that's pretty tempting. Regardless, I'm going to be trying out the RT660+ this upcoming weekend and for the rest of the season. I like the RT660 for their bang for the buck, so I'm interested to see how the 660+ imrpoves on that.

This is the worst of the wear, but there are a couple spots like these around the tires. Probably could've ran them for another couple locals, but don't want to chance it for a bigger event. Also, these are CRS V1s and I think they're from 2022 or before. Still plenty of grip when hot and I'll likely try the CRS v2 at some point.
https://cimg4.ibsrv.net/gimg/www.mia...3ecb514ea4.jpg

I’m a simple man. I see a deletable bracket, I delete it.

+1 on the street wheels/beater tires idea. It’s super nice being able to run your freshest tires for events only and have your toasted tires to run on the street. I always felt guilty commuting and driving long distances and putting camber wear on my new track tires haha. Amped to see how the 660+’s work for you. If Falken comes through on their claims, they should be a killer tire.

I've got a set of 205/50/15's that I drive on most of the time, but I like the idea of having a set of stickier tires for events I care about and a set of last season's tires to burn up on track days and (potentially) the small time attack nights they've been having out at the local oval this summer.

It always seems like a bummer to toss a set of 200 tw tires with decent tread just because they're a bit too heat cycled for autocross.

My friend has to run the 660+ for his class (SSC) and he's been pretty happy with them. Sounds like they're a good step forward from the old 660s which I thought were pretty decent overall and really good bang for the buck. The only issue is that they heat cycle out way before they run out of tread. The Nankang's I'm on are close to cording and they still seem to have plenty of grip.

Interesting that the dog unload was the cause of the gunshots, but I'm glad to hear that's fixed. Do you intend to continue using ignition cut? If so it would be good data for us to know how the cat does.

Regarding the gear shift control disabling, it's not easy to tell without the log, but my initial guess is it went on lockout for TPS or Speed, either due to a slight lift or noise in your speed signal. Take a look at what the Gear Shift Control Status says.

I am still using ignition cut with -10 degrees retard. I played around with 0 retard and that seemed to work similarly and is likely what I'll end up running. On e85 the timing is advanced enough in boost for -10 to not be an issue but on pump gas it would probably get me into the negatives.

I did look and the log and I shouldn't have been close to the TPS or speed lockouts. One thing I realized is the gear calculations are done via a driven wheel, so wheel spin can cause the ECU to think you're in a different gear. It doesn't look like it based on the log but I'm wondering if the wheel slipped for a second and hit the lockout that prevents you from going past 6th gear. Seems like a long shot. I'll probably turn that lockout off anyway since it seems more suited to a sequential transmission.

@redursidae I've attached the log files here. I looked at the gear shift status (thanks for the tip on that) but didn't see anything abnormal. The gear shift duration is only being noted at 16 ms though, so maybe the clutch switch signal was bouncing and ended the shift early and then hit the re-activation timeout. It doesn't show the clutch switch (digital input 1) bouncing in the logs, so if it was I'm assuming it was just for a split second.

I will look at the log later tonight, but I see from your settings in the other post that you may be running an older version of the firmware that I believe had a bug with this. I dont remember the specifics as it was discovered months ago, but I do recall AdamW saying it only happened in very seldom cases where the ECU erroneously saw the input complete. I didn’t have it happen, but I would say you’ve used it more than me by now. In the current firmware there is a maximum shift duration setting and they supposedly remediated the problem as well. So I suggest upgrading the firmware if it is indeed older.

There is also a chance that if you took a PC log it wasn’t fast enough to catch the event. DI 1 is the clutch switch at the top of the pedal, so I wouldn’t think it’s the culprit unless it’s faulty. Your thought about the speed sensor spiking is a good one, but you’ll need to take an ECU log with faster frequency to catch that. I have seen my speed sensor spike during launch control, but not on gear shift control.

I looked through your log and don't see what could have caused the problem either. My initial thought is like yours, that maybe the clutch switch dropped for a split second and hit the reactivation timeout. I do see the Gear Shift Status goes from 5 to 9, which is from upshift to torque reintroduction, so the ECU "saw" the shift end. Maybe configure the ECU logging to grab the gearshift status, clutch switch and other relevant runtimes at 250-500Hz in case it happens again?

2025 Top Gun Autocross
 

Last weekend was Top Gun, a regional autocross event hosted in Helena Montana. I've been going to this regularly for the past 3 or 4 years and it's always a blast. Big venue, plenty of entrants and lots of good people.

As usual I prepped the car by installing the hardtop and loading it to the brim with tools, clothes and camping gear. We left around 5 AM on Friday to start the ~9 hour drive. We sacrifice an hour or two in the car and opt to take the scenic routes since the 9 people we were driving with were all in their autocross cars.
https://cimg0.ibsrv.net/gimg/www.mia...89d4d1e98b.jpg
https://cimg2.ibsrv.net/gimg/www.mia...aeb7a4da9e.jpg


It's always a scramble when we arrive, swapping wheels, setting up tents, grabbing food/drinks, etc... We only got one course walk in before dark. I had another guy in our club carry my fresh set of 660+'s and a couple jugs of e85 for me to run.


https://cimg3.ibsrv.net/gimg/www.mia...59528d7499.jpg


My class (XB) was mostly Miata's. I thought @Ironhydroxide was bringing his red Mazdaspeed, but he surprised me when he showed up in the VQ35 swapped car he's been working on lately. Somehow I didn't grab any photos of it, but I believe it was on 305R15 Vitour's and making something like 330-350 WHP. Also in the mix was a really well done K swapped NB that is usually at this event.

https://cimg3.ibsrv.net/gimg/www.mia...40efdc424d.jpg


https://cimg9.ibsrv.net/gimg/www.mia...67889e2c04.jpg
This thing looked so gnarly. Peep the paper/sticker headlights. Also note the VQ Miata in the background.

https://cimg5.ibsrv.net/gimg/www.mia...819cce4c0c.jpg

The car ran pretty well the whole weekend. I ran in the latest group on Saturday so it was pretty warm. The car ended the 4th of 5 runs at 105 C coolant temps. Hot, but acceptable. This site is pretty nuts. It's huge and this year they set it up with some majorly quick courses. Both Saturday and Sunday I topped out at 88 MPH based on some logs/calculations. I'm not sure how many autocrosses I'll do where I'm getting pretty deep into 4th gear.

The car did cut out each run on one corner on the infield where the elements are tighter. At first I thought it was oil pressure protection but after looking at logs I can't see anything that suggests that was the case. I'm guessing it was fuel starve now. I was at about a quarter tank and the corner was a medium speed left hander.

I didn't use flat shift this weekend. I've played around with it more and am still having issues with it ending the shift early. I did try taking some ECU logs with higher sampling rates on the relevant sensors but that still didn't show anything. If it was a local I might have given it a shot but I didn't feel like taking my chances when I still had an 8 hour drive home.

Overall on the weekend I ended up 3rd in XB behind IronHydroxide and his codriver who owns the car they were in. 38th Pax overall and 22nd Raw for the weekend in a field of 126 drivers, so I'm pretty happy with that.



After racing on Sunday it was another scramble to get the cars packed and prepped for the drive home. Thankfully we did most of the drive on Monday so it was a relatively short drive to the AirBnb on Sunday after the event. We did hit a crazy storm at one point and even on full blast my windshield wipers were barely keeping up. I was honestly super thankful I still had AC in the car because without it the windshield was filling with fog. Even with that going I almost pulled over.

https://cimg0.ibsrv.net/gimg/www.mia...cc5b07fe75.jpg


Overall I'm really stoked with how the weekend went. I'm always a bit stressed worrying about the car breaking 8 hours away from home. Flying down that runway at nearly 90 MPH definitely makes me think about the safety gear in the car and what I want to do about that going forward. I was only registering about E50 on the flex sensor, but the power level felt good to me, especially given the longer course.

That seems like a hell of a weekend and a good result too! VQ35 Miata sounds like a lot of fun.

Sorry to hear you're still having trouble with the gear shift control though. Have you had a chance to try upgrading the firmware?

That's a lot of driving! Glad you had traveling companions, a good event, and made it home safely. :D

Sheesh, that's a fast course. And long. Looks awesome, and great driving, the car looks fast!

Thanks guys! Higher power cars definitely had an advantage this weekend and I wouldn't be surprised if that's why I was able to get the win on the K swapped car. Most of my runs were around 80 seconds long which is double a lot of our local layouts.

I did get the firmware updated in the Link, but I still didn't see the option you were talking about. I don't think it would help my situation anyway (I believe you were talking about a maximum shift time and not a minimum). Iron and I were talking about it this weekend and he was thinking there might be some background magic that ended the shift if the car detected certain conditions (can't remember the exact idea). I tried one shift on the way home and made it very deliberate, no twitching on the throttle pedal and a straight in/out on the clutch and it still ended the shift too early.

I'm not terribly worried about it. I mostly set it up for fun, but if/when I get the car to the drag strip this year then I'd like to have it working.

My thought was it used either the Driveshaft speed sensor, or vehicle speed. and if either goes FASTER during the shift it thinks the clutch is engaged and will then kill the shift.

Simba - that's my bad for confusingly mentioning the max shift time. I meant that is a signal that you were not running the latest firmware and not as a suggestion to test. Those shift times (min and max) are for other methods of control, not digital clutch switch.

Iron, I see the logic there. When using Digital Input as the End Shift Mode it's supposed to only end the control when it sees the input change state. At least it isn't documented that an increase in speed would cause the shift control to end, but being closed loop I guess a drastic change in speed could make it think the gear has increased, and assume the shift completed.

I'm really out of suggestions other than taking a log at 1kHz to see if there is noise with the clutch or speed signal. Other than that maybe post the log and tune in the Link support forums and see what one of them has to say.

I appreciate the input guys. Doing some higher speed logging to see if there's any noise is the next step I had planned on. The only thing I can think of based on my understanding of the system is that the clutch switch signal is bouncing.

Because I love beating a dead horse, I wanted to try another thing to see if I could get the car to hold temps with AC on. Once everything's up to temp the car is fine but as soon as AC is turned on the temps climb to concerning levels within a couple minutes. I was reading another thread and someone said that they were able to fix a similar issue by mounting their radiator at a 45 degree angle to create more airflow.

This got me thinking about adding some clearance under the intercooler where things were sealed off previously.
https://cimg6.ibsrv.net/gimg/www.mia...ebeac65882.jpg


So, naturally, with a newly acquired 3d printer I decided to try printing some spacers for the underside of the intercooler. This is likely unnecessary, but I was bored and wanted to try designing/printing something.


https://cimg1.ibsrv.net/gimg/www.mia...9fd5f5b6e6.jpg
https://cimg3.ibsrv.net/gimg/www.mia...8dc9b3004c.jpg



https://cimg4.ibsrv.net/gimg/www.mia...29999dee4b.jpg



So these added ~3/4 of an inch under the intercooler. With other recent modifications I've got a bit above the intercooler as well. Minimal testing shows that this is still a fruitless endeavor and I'll just be pulling AC in the near future. I'm pretty frustrated with trying to get it working and considering I haven't been able to use it in the past 3 years I think it might finally be time to accept that I'm just not going to get it working.

I think if you really want to keep A/C you are going to need the bumper bar delete. That really opens up a lot of flow around the I/C.

I'm gonna have to agree with this, especially if you're keeping that intercooler.

IC on my MSM is about half your size, and my fans pull easily triple yours do.

That's an improvement. Also look at the sides, opening them up to better allow air around the IC and condenser.

I'm in your boat too, tilting at this windmill.