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As promised, the car made it's way out to Emmett Idaho this weekend for the local Porsche Club's "BrezelCross". First time out at this track, which was originally promised to be a 2 mile road course, and resulted in a 1/4 mile (?) oval with an infield. Still bitter about that.
Regardless, the track was about 1 hour from where I live, so I hit the road early and made my way there. I packed some extra tools for this one.
I need to remember to take more photos at these things. The venue is an old lumber mill, which has a really neat hanger/bay where we had our pits.
Overall the car did well. I targeted about 15 PSI for the first run in the morning, but after seeing coolant spike to 104 C I decided to back it off to ~12 PSI. I need to do some fine tuning of the boost control at higher boost levels. Reviewing the logs shows that the target of 15 PSI was spiking up to 18 PSI. I'm not too worried about that, but I don't see a point in setting a target if you're going to be way off.
The only other issue that the car really had was that my oil pressure protection was kicking in. I haven't had an oil pressure gauge for too long, so when I set up the protections I put in numbers that seemed appropriate to me. Most of those numbers were based on values I was seeing at WOT. Digging out of some of the low speed corners were triggering that protection. Oil pressure in those corners was 25-30 PSI around 2500-3000 RPM.
For some reason, I wasn't able to change that with MSDroid and I didn't bring my laptop. I was able to correct it though by changing the calibration on the oil pressure sensor to trick the ECU into thinking the oil pressure was higher than it actually was. This means all of my oil pressure values after the first couple runs are worthless, but at least I was able to drive.
Finally got some video for you guys too. Only the best, raw GoPro Hero 3+ footage.
So, overall a really fun day. I think I would've gained a lot of time on Sunday, but the event was already expensive for what it was. The car is still feeling solid and I'm not as worried about the turbo for now. Another friend felt the shaft play and noted that it was worse than factory new, but not something he'd worry about. Still on the list at some point, but not an immediate need IMO.
Lots of good friends out and about as well.
Running at our local venue on Sunday and then headed to Winnemucca in a couple weeks for the regional.
I'll hopefully have some more photos available soon, as there were a few photographers running around at the event.
Woo! Good stuff man, glad to hear you were able to persist through the little hiccups in the setup. Being able to come up with quick solutions in a short period of time is mandatory at the track. Can't let anything stop you from getting your god-given seat time! Lol.
I also have struggled with taking an adequate number of photos at the track recently. Dunno if it's laziness or maybe my car needs all that much more attention than before Sounds like a cool venue though and that course looks pretty Miata-friendly!
104C coolant temp doesn't sound too outrageous, especially on a tight course. I want to say that my car was running similar temps or maybe a touch cooler at 200whp in ~65* weather on a similar course. I usually start shutting it down on track at 110-113*C (230-235*F). With an autocross-style course, you're just spending very little time with the radiator pointed at the incoming airflow, at a high enough speed to provide ample cold air to the radiator.
I picked up a book on solo time trial/autocross racing techniques last week and the author had an interesting quip. He mentioned that in the average autocross event, you're hitting a new corner or changing direction five to seven times as often as the average road course racer. I might have the number wrong, but it was something like that. That's not nearly as much time spent with the radiator going straight into the wind.
Curious, are you running open or closed loop for boost control?
Edit: I started typing this post this morning, and didn't see the pic when I posted it. That photo is sick!
I have my protections set to lower the rev limiter at 110 C. I'm not too worried about 104 for now and realize that I probably could've ran more boost for the rest of the day. I think I got spooked at our first event when I was hitting 110, but the system does seem to be working better now.
I'm running closed loop boost control, but using the "simple" method that speeduino has. I've just started playing with PID for AFR correction and think I'll do the same for boost control at some point. I need to go do some testing in open loop to get some more data about what duty cycle equates to what boost level. I did more experimentation with that before the engine build, so most of that data is from 8-10 PSI. I have done a bit above that, but not enough apparently.
Ehh, better safe than sorry in regards to temps still I guess haha. Hey, now you know for next time haha. At any rate, it's good that the cooling system seems to be working more efficiently.
Ok, makes sense regarding boost control. I've never attempted using the simple closed loop control for boost, although the simple EGO control worked decent for me when I first set up my MS. Running PID closed loop boost has worked pretty well for me but I've noticed that it's very dependent on starting duty cycle. Interested to see how our duty cycle settings correlate when you set up your open loop control. Our setups are decently similar aside from intercooler and manifold. Post em up when you start dialing em in!
Surprisingly, when you get the right parts, they fit. I didn't realize it until installing the exhaust and doing some research, but the NB1 subframe brace is not the same as the other generations (at least not all of them). The NB1 style has a single crossbar at the back of the bracing, as opposed to the 2 crossbars on other generations. I found someone locally who had the brace so I decided to throw $50 at the guy instead of trying to fab something up myself. It doesn't seem too difficult to fab up, as its mostly crushed steel pipe, but with all the proper bends and angles I figured it was worth buying the OEM part.
No wonder the exhaust was hitting on this bracing. It's way more narrow than the OEM part. When ordering the exhaust I specified it was a NB1 with sport bracing. I'm not sure if it would have fit if I ordered the NB2 configuration.
Hit that with a wire wheel and some rust converter to get it cleaned up a bit. There was a bit of rust/corrosion on the piece. Nothing severe, but I figured now would be the time to clean it up.
Amazingly, the brace bolted right up without contacting the exhaust at all. Kraken's fitment is spot on. Crazy how well the pipes wrap around the bracing. It's hard to tell from this angle, but the resonator does have a good amount of space.
And finally, after a short test drive the car is way more comfortable at highway speeds. Again, I just did a quick run on the freeway, but previously the passenger seat was shaking back and forth like someone was strapped to it and trying to escape. There's still a bit of vibration at highway speed, so I might try putting the front shock tower bracing back on now that the reroute isn't in the way, but I think I can roadtrip to Winnemucca as is.
Me every time I learn something through experience that is already established knowledge in the community.
Took the car out on Sunday for some autocross. Targeted 200 kPA with the Speeduino's simple boost control. I moved the sensitivity back to 50% and boost was on target from the logs I reviewed. I noticed a bit of oil around the oil fill cap though, so I think I'll be looking into enlarging the valve cover passages soon. It was cold outside, ~10 C as a high (~50 F), so I didn't have any heating issues/concerns.
Still planning on driving to/at Winnemucca. Likely with the boost turned down a few pounds.
I also noticed some oil on my power steering line which is right below the intake coming off the turbo. It seemed almost like the hose was sweating power steering fluid. I'm not sure if that's possible, but I didn't use an OEM hose. I believe what I grabbed for the hose was rated for power steering, but I might need to go double check. I wiped off the hose and will monitor going forward.
I did a few other things around the car. Finally added some medium density padding to the rollbar. Plenty of taller passengers at autocross have rested their heads on the rollbar and I've been needing to get that covered up for a while now. Even moreso for passengers on the road. The driver's seat is low enough and has a high enough back to keep me from whacking my head on the bar.
I added some trim to the intake box. I don't think it is actually sealing against the hood, but it looks way better and I'm less worried about myself (or more importantly someone else) slicing themselves to pieces on it now. This stuff seems to grip pretty well, better than I expected.
The last and most exciting change was getting the Knock Detective wired into the ECU. I can now datalog the output from the sensor. I'm still playing around with it, but I'm really excited to be able to get that data.
It wasn't too hard to get working, but I had used up one of my analog inputs (speedy only has 2 aux inputs) for AC idle up. I realized that could go to an unused digital pin (the Knock pin ironically) which freed up the analog input for the knock sensor.
I don't love plugging/unplugging the ECU, but it did give me a chance to go back and clean up some wiring. I've been getting used to these DuPont style connectors and am liking them, but there's a bit of a learning curve to them. I actually spent a while practicing random bits of wire to try to get the hang of it.
It's a good idea to make sure you're crimping the connector onto the correct side of the harness so you don't have to do it twice
Notice that the input for the oil pressure and the input for the knock sensor are on different sides of the harness.
Nice work overall. The trim does clean up the area well. That seems like the same insulation material I bought from amazon a bit ago, so will have to copy you on making a little box for my intake piping too!
Give us some logs or screenshots of what the knock input looks like in the ECU once you get all of it working. I'm interested to see what it looks like.
I had intended to on that last post but got rushed when writing it. Here's what a log from autocross looked like this last weekend Aux0 is the input from the Knock Detective
The signal strength of the output to the ECU is tied to the sensitivity **** that controls the LEDs (not the same one that controls the headphone output). I'm still playing with that a bit. I also am suspicious of my grounding situation right now, so I want to play around with that a bit and see how it effects the signal. I still plan to do a full review of the gauge when I've spent a bit more time with it.
I don't have any real pictures for this one, but I got the oil changed out last night, along with resealing the exhaust.
I'm not sure where, but I'm guessing either the flex joint in the downpipe or the 2 bolt flange (2.5" on one side and 3" on the other) is leaking. I pulled the gasket off yesterday expecting to see the rtv blown out, but it seemed to be in tact. I resealed it and tightened the vbands on the rest of the setup. It seems like once the car gets hot the exhaust is louder and more boomy. Not horrible, but I'd rather have it a bit quieter. I should've got the exhaust with a 2.5" flange, but I figured the 3" flange would be better if I get a different downpipe in the future.
We head out to Winnemucca tomorrow around noon. Probably around 10 or so people will caravan down. It's about 4 hours and part of the highway is absolutely garbage (just drove this way for a wedding last week). I'll have some good updates after the weekend hopefully.
Weird the exhaust seems to boom more when it's hot. I've only ever had exhaust leaks seal up better as the car warms up.
What Nate said, I'm jealous of the 10-folk caravan! Always a great time road tripping with buddies. Plus, strength in numbers when you're driving your car to the event! Looking forward to the recap. Both of your guys' actually!
Wow, what a busy weekend. I got the car packed up Thursday night and a bit of Friday. The trunk and passenger seat were pretty full up between tools, helmet, skateboard, tire sprayer, clothes, cooler, seat cushions, etc...
On the upside, the extra cargo helped smooth out some of the NVH for the drive.
Everyone met up about 3.5 hours away from Winnemucca, although I missed grabbing a spot for the photo op.
As much as I love dropping the top in my car, I do enjoy throwing the hard top on. I'm learning that this paint cleans up best if you scrub it with simple green instead of car washing soap.
A bit under 4 hours later we arrived. We were mostly cruising around 80 MPH, which was about 4K RPM for me. The turbo was begging to spool the whole time.
I cruised mostly around 15.1 AFR, but I haven't done a ton of mapping at 4K cruise, so it was going a bit lean at times, getting closer to 16. Once we arrived I looked at the logs I'd taken on the way over and added some fuel where appropriate.
Naturally, we hit the car wash when we got into town. After that it was off to the venue where we swapped wheels/tires and said hi to friends from other regions who had showed up. SMF Rabbit and the XB Impreza
I really like this site. It's very interesting, mainly because it has so many different surface types that each have different levels of grip. There are concrete sections and a couple different types of asphalt. Really fun courses too, where my car seemed to be really happy. I got into third both days, although the second day I was struggling to find the shift point.
The XB field was all people from our local region, but the competition was great. Nearly every run I was trading first place by a couple tenths. I ended up placing second in class on Saturday behind and s2k and third on Sunday behind the s2k and an RS3 (one of our local XB guys was borrowing it after his car didn't make the trip down). Overall, for the weekend I was 15th raw of ~100 drivers and 2nd in class.
That was cool, but the real victory is that the car made it 4 hours there, did 14 hard runs and then drove 4 hours home without skipping a beat. Rough estimate, but I averaged around 25 MPG when cruising at 80.
I'll try to get some video uploaded in the next day or two. I 3d printed a new mount for my GoPro and it didn't work out as well as I'd hoped, so the audio and video are a subpar.
Oil
A couple things I noticed are that my oil pressure after finish was around 20, which is lower than normal. I'm wondering if this is caused by the oil being sloshed around during the run. I am planning to run a bit more oil that previously and see if that helps. I've been running 1 gallon up until now (1 jug of rotella).
I've got a fitting on order to increase the breather size on my valve cover. For now I'm planning on leaving the PCV alone. I have seen a bit of oil around the oil fill cap, which I assume is coming from crankcase pressure. I noticed that when I turned the boost up a couple events ago, so I've been staying around 12 PSI for now.
Coolant
I was looking into the coolant temperature sensor filtering on my tune and realized the recommended value is 180 out of 240. I had run 120 originally and then dropped it down to 0 when doing some data collection to try and figure out why my temperatures seem to spike so much (I've started another thread on that). With the filtering I kept my max temps just at/below 100 C from the datalogs I took. Getting back into pits showed temps back around 85 C almost immediately. I'm going to lower the filtering a bit to see if I can find a happy medium for the time being.
I've also noticed my coolant reservoir seems to be leaking out of the cap. I saw coolant on the reservoir at one event, and have seen dried streak of coolant after cleaning it. I'm not sure if that's an issue with the cap on the reservoir (cheapish and used piece) or something else. I'm not too worried about it for now, but something I'll keep an eye on.
Exhaust
The exhaust is rubbing/vibrating against the subframe on high speed corners. Only right handers IIRC. Again, something to note, but not something I'm going to worry much about for now.
Overall, a fantastic weekend. Super wiped out today as we drove home after packing up the event yesterday and got home after 10 PM.
PS, there was a DPrep Miata who was running a naturally aspirated BP. I didn't get to talk to the guy, but I heard he was running 11 or 12 compression pistons with a 0.80" head shave. Apparently the effective compression on his setup is 14:1 and makes around 230 HP, revving out into the 8000s. Sounds like wildest NA BP's I've ever heard of, and the car took top raw time for the weekend.
Maybe it's time to put a MAP sensor in your coolant system
Don't worry about 20psi idle pressure. That's normal. I have a stage 2 BE pump, 3 shims, and still idle around 25 when hot. You said "when done with run", so I'm assuming idle.
Curly, the MAP sensor as coolant pressure sensor has occurred to me, but it is water not air - is that for real, and do you have to do any prep, or just bolt it up?
Well you use a fluid pressure sensor, not MAP I guess. But MAP sensors just read vacuum to 60ish psi of pressure. Pressure sensors start at 0 and typically read 50, 100, 150+psi. Not sure there internals are physically different than a MAP sensor.
These are the pressure sensors I use, and from the description, is certainly sounds like the MAP pressure sensors are the same as fluid pressure sensors:
High-quality sealed sensor housings are virtually impervious to automotive fluids (360-degree welded wetted area)
Gee, I assume he was probably running E85 but unfortunately I didn't get to talk to him. If they've taken the car that far I assume they're using the best fuel allowed by the class.
I also wonder if you could install a coolant pressure sensor in a housing like this Coolant Sensor Housing
Curly, correct on the oil pressure. After slowing down through the finish I saw my gauge around 20. After sitting in pits with the car off between runs it would be around 27-30 when I restarted the car. I do have it logging to the ECU, so I'll sit down and check how it looks throughout a run soon.
Unfortunately I don't have an available input for another sensor, although I could always swap which sensor I had plugged in. I realize that I also have some open ports in the reroute where I could install that. Is your thought that coolant pressure is a better indicator of the health of the system, or to trigger a failsafe on?
For what it's worth, I went and looked at one of my logs and I think I've been sampling coolant at ~5Hz.
Slow, I have several locations open to me for a pressure sensor, but thanks for the suggestion. To answer your question to Curly in part, my intent is to use coolant pressure as a warning indicator of a coolant leak, or a catastrophic rupture dumping out all the coolant - coolant temp needs coolant to register, and a total loss means little to nothing to register an overheat event. Please don't ask me how I know this.
Curly, thanks for those links, I was having trouble finding one at or around 15-20psi, trawling the products there I notice they 'boast' of a 15psi pressure sensor, but not listed in the products available. I will contact them to see what the availability is for that.
They quote a 1% accuracy for the SS gauges, so a 100psi gauge operating in the 0-20psi should be accurate to 1psi, good enough for that application. I'll also see what they say about the brass ones, but being1/3 of the price my expectations would be low.
Last edited by Gee Emm; 05-21-2024 at 01:01 AM.
Reason: expanded
Good points on the upside of a pressure sensor. I realized I have a couple unused ports in my reroute housing if I want to try and add that at some point.
I got a video of the event uploaded. Don't mind the shuffle steering, it was an early run and far from my fastest of the day, but the video turned out way better with the top down. Most of my fastest runs were with the top up.
I'm realizing that if I've got time to shuffle the wheel around, I'm not driving fast enough.
I don't mind the camera angle, but way too much noise is transmitted through the roll bar currently. I have some rubber gasket material on part of the mount to try to isolate it a bit, but I guess I need to add some to the other side as well. The old Hero 3+ also doesn't have HDR, which becomes very apparent with the top up.
04-30-2024, 12:15 PM
PCA BrezelCross
1
Sounds like a cool venue though and that course looks pretty Miata-friendly!
