I had the same issues with mine. Although, the flange on the DP wasn't the same as the stock mid pipe flange. So, obviously not the same situation but, still.

Shit had I known you were looking for a full exhaust I could have helped you out. You are local enough to have gotten it done.

Yeah, that would have been nice... I didn't realize the lead time was so long for artech stuff, so I didn't order it until I basically had the car done. Hasn't been too bad since driving a car with no A/C around here the last couple months would have been miserable, but it was nice today, and I was hoping to drive the car to work...

Every exhaust flange will appear warped if you bolt it up with a single bolt.

I ground enough of the bolt holes out to at least get bolts in and cranked them down. Could still see light through the middle. Bleh.

Sweet I've got an artech on order to go with my TSE EFR kit as well. Hopefully I don't have the same issue.

Maybe ask Andrew what the bolt centers are on the flange he uses. Abe asked me but I didn't take a measurement before I went at the artech flange with the die grinder and now it's on the car. It's got a great tone... until you drive it. It sounds like the exhaust is hitting the drive shaft or some crap now.

Sigh.

You can't just take to unmatched flanges and torque them down. You'll bow one or both of them to create the gap you saw in the middle.

The flanges will line up, more than likely you have a slightly tweaked hanger you didn't notice, but then you took a grinder to the flange, so nothing can save you now.

I ground out the bolt hole slots in one of the flanges. Didn't touch the face of the flange. They did not line up at first - the bolt hole centers were ~.25" off on each side. Look at the picture above - it was like this on both sides, holding both the downpipe and the rest of the exhaust unmounted outside of the car. I took a bit more material out of the bolt holes yesterday - it still wasn't quite straight - and they lined up with enough slack to wiggle the pipe a little bit. Clamped it down and it seemed to seal pretty well even without a gasket.

The car was tilted to one side when I installed everything, so tonight I'll jack the whole thing up and do the old loosen/tighten everything to see if that centers it.

Well I was only home for 9 days in the month of September... spent a few days out in Monterey working the IMSA race and hung out in San Pedro square one evening. Neat place, for those of you in San Jose. I'm headed back out to MRLS next week for the MX5 Cup Challenge, might have to check it out again.

Anyway, I drove the Miata into work this morning. Did a 3rd gear pull, does anything look out of place before I take it to the dyno? I think I can lean it out a little bit, and hopefully smooth out the fueling as well so it doesn't bounce around quite so much. Also, 10psi seems like a lot for wastegate pressure - Andrew, is there a chance this shipped with the medium spring instead of the light spring? Other than that, what say you, turbo gurus?

Thanks
Tyler

And because it's fun to look at... https://cimg1.ibsrv.net/gimg/www.mia...542283c33.jpeg

As I am in Seneca, please report back where you go for Dyno, and how the session went, and how successful it was.

Also, I would think you'd level out your VE table before going to dyno 11-12, back and forth on the VD plot looks quite bad. You want to be able to load test certain cells and then interpolate to the others. With the result you have now, you're going to need to tune every cell. When I get home tonight I will look at your tune to see what does not make sense.

1) I'm a fan of "Incorporate AFR Target" in Fueling Calculation. Then you and your trusted tuner (or you and MT.net) can decide on proper AFR table and simply adjust VE at the dyno.
2) EGO authority is crazy huge. If you need 25% then again, street tune before dyno. I use 15% at idle area only to accommodate hot restarts on my EV6 injectors. Nothing else is above 6%.
3) Why are you table switching Fuel and Spark; and on separate inputs?
4) What do you plan to use for knock sensing?
5) Do you plan to tune up to waste gate only?

Here is 3D picture of your VE table:


https://cimg6.ibsrv.net/gimg/www.mia...436b55e041.jpg

Thanks for the feedback. I haven't gone over the VE table yet because I'm not done autotuning. My typical method is to let autotune get it to where it's happy and then smooth it by hand using the 3D map you showed above. I plan to do this before going to the dyno, but before doing any more wide open pulls I wanted to make sure everything looked good. Look at the AFR trace in the MSL, it's not as bad as the virtualdyno makes it look. Some of it is just noise from the analog signal and it trying to curve fit those values rather than doing some sort of RMS calculation.
1. I haven't done that because I'd have to start over on fueling, but I agree that would probably be a long term better option
2. Haven't ever needed that much authority, but it's been that way for the last 2 years I've driven the car (N/A) so I had no reason to change it. It's not active in boost cells anyway?
3. I'm not, those must be leftover values from the MSLabs base map
4. I have the knock sensor from my VVT engine wired in but I still have some exhaust rattles and such that I think are triggering it. I plan to use detcans on the dyno.
5. I plan to tune to 225ft-lbs... maybe 12psi? My plan would be to run wastegate pressure at the track and turn it up a smidge for putzing around on the street/canyons.

I've used Pompeii's mustang dyno in the past and it did the job. I've made some friends down in Atlanta that have offered to let me use their dyno for free though, so that's the plan in a few weeks.
I'll be at the Clemson game this weekend - if you're around we should meet up and grab a beer.

Dyno session and first track day complete. At around 11psi I settled here for my "street tune". "Track tune" was wastegate pressure and made 220whp/200 ft-lbs. No issues at all on the dyno.
https://cimg8.ibsrv.net/gimg/www.mia...53dac93383.png

Track day was not as smooth. First three sessions I would get some sort of spark/fuel cut when going wide open throttle. The car was plenty fast at 60% throttle so that's what I did for the rest of each session, but still disconcerting... First I thought it was boost spike, because in my log from a session I saw 175kpa (185kpa limit with 10kpa hysteresis?), but then the third session the CEL came on and it turned out to be a sync loss. Only under boost when transitioning to wide open throttle quickly coming out of a corner. After my third session, I pulled off the front and rear passenger side grounds and cleaned them up with a wire brush and put them back on. Ate lunch, then came back a couple hours later for session 4 and now my wideband (Innovate LC-2) is stuck warming up.

Help!
I tried redoing the free-air calibration but it won't get past the warmup stage anytime my sensor is plugged in. I plugged my sensor into someone else's Innovate MTX and it took a while to heat but worked fine. So it seems the controller has taken a dump? Does anyone have any experience with this?

Well, the lc2 is out and an Aem x-digital is in. Hooked up over CAN and running well. The data comes in so much cleaner digitally. Why doesn't everyone do this instead of the lc2/can box combo?lsu 4.9, everything hooks into the gauge and has can support out of the box for $180

Wideband sounds nice!

you were in fact hitting over boost btw.

Where can you see this in the datalog?

For any who are curious - analog vs digital wideband readings (these are not from the same log, but both from WOT). Will it get you more power? No, but EGO and autotune will work better, and the setup costs less than an LC-2 and is easier to install...
https://cimg3.ibsrv.net/gimg/www.mia...ea7461f9aa.png

Just from what you said, it was cold, acting like boost cut, 185kpa with a 10kpa hysteresis means it'll do something at 175...

Which is which, and what smoothing settings were you using with the analog?

Analog is the red. Default LC-2 settings (500ms reporting I believe). I think the sampling rate looks lower on the digital in this graph because it was a 2nd gear pull vs a 4th gear pull.

It's been a while since I posted in here, but I took the car out to Road Atlanta last weekend. Since last post I've ditched the LC2 altogether and moved to an AEM x-series WBO2 wired to the megasquirt over CAN. Way more stable than the 0-5v analog output I never really trusted from the LC2.
https://cimg6.ibsrv.net/gimg/www.mia...2f361e72c5.jpg

Weather was 95 degrees with ~72 degree dew point. Hot and humid, as Atlanta usually is in the summer. Running wastegate pressure (~8.5psi, 220whp/200wtq on a dynojet), with my 10+ year old suspension and 3 year old BFG Rivals I managed a 1:47 and change. I've got no doubt with some real suspension and better tires I would be under 1:45. The car ran with no issues except for the need to manage heat. Coolant temps reached 220F after about 15 minutes of hard running, at which point I would cool down for about half a lap and temps would return to 205 or so. Staying in 4th for turns 3 and 5 seemed to help.

I've got the top and bottom of the radiator pretty well sealed but I still have to do the sides, and come up with some kind of ducting to the oil cooler (mounted in the FM steering rack location). Does anyone else run track days with their cooler in that location? Looking for some ideas. Also, what is the consensus of running an oil temp gauge in the drain plug slot until I have reason to remove the pan to drill another hole?

All in all, pretty happy with the car's performance. I was able to drive it back on the trailer, which is a success in my book.

A video of a couple of laps in which I cruise around and water temps get pretty high. Transient response is pretty great on this setup - check out the near-direct correlation between throttle and boost. Intercooler seems to be doing a good job too given the ambient conditions.

Finally got the car back out on the street again. Spent quite a few hours (and dollars) overhauling the suspension - wasn't pushing it at this track day, but my annual bonus was burning a hole in my pocket and my 170k bushings were quite sad. Out with the old business:
https://scontent-atl3-1.xx.fbcdn.net...10&oe=5C0DAB47

In with the new
https://lh3.googleusercontent.com/Z9...P=w715-h953-no

XIDAS, 800/500, yadda yadda. Dual purpose alignment. Running the stock front bar with no rear bar until I find an RB front bar for cheap. I've had the chance to drive them around on some local (mostly city, poorly maintained) roads and let me say those of you who say "XIDAS on full soft are so comfy!" are full of shit. I had to stiffen them up about halfway before the bouncing stopped. Surprise! Higher spring rate requires more damping. You guys running around on full soft are morons. That said, they're still not what I'd call "comfortable" - my Mazda 3 with Koni FSD shocks on stock springs is comfortable. Tolerable is the right word. But, we buy these to go fast, not to be comfortable. Will have to take it to the track to confirm, but I'm not sure 800/500 is the correct rate for a car with no cage because it seems that, without one, the chassis isn't rigid enough to properly make use of rates that high. Anyone else run rates that high on a street-driven car with no cage?

My XIDA GS at 5.5" ride height are cadillac comfy on full soft, though the front tire hops if I try to push the car too hard.

If you turn it up a few notches, the wheel hop stops and the car is still tolerable over large bumps (but noticeably stiffer).

I would imagine that 800 front would probably hop even more at a given shock setting. But if you're setting them to full soft, you're not supposed to be driving fast. That's a setting for taking grandma to church.

I had same shocks & springs on my car with no cage. I'd agree- the ride was punishing on the street and possibly too stiff on the track (the tracks I ran didn't have the best asphalt). Hitting aprons on the track upset the car more because it was SO stiff. But the car cornered real fast. Wish I'd have gone 700/400 or even softer on the springs and run the car 1/2 inch higher.

I love watching you guys videos on track because it is often ones I've played in driving games. This is one of them. Possibly Forza learning track i think. Always loved the chicane to anger people for late braking :D

I've got door bars, frame rails, and a roll bar with 800/500 xidas. Chassis feels great.
I only run at +2-4 clicks from the softest on the street. There is no way I'd run +10-12 from soft, I'd bounce right off the road. Maybe my old, worn out bushings add enough compliance. The image broke so I can't see what bushings you put in, but I'll assume it's poly or SadFab Delrin.

How do you like the door bars? I'm considering those next. I already have the FM frame rail braces and I've welded the door/A pillar seam and the seam under the front fenders. I put in energy bushings. The bushings only really effect the higher-frequency impacts - think expansion joints, cracks in the road, etc. Those aren't what are so bad, it's the larger inputs like potholes that make the whole cowl shake. I'm wondering if a three-point strut tower/firewall brace might also help close that box in as well.
I spoke with an FIA cage designer this weekend and asked what the biggest bang-for-buck would be on an NA with a 4-point roll bar already and he recommended a petty bar. Too many options...

Door bars helped me significantly.

So much that I think I wasted money on the butterfly brace :vash:. It'll make seat mounting more tricky, but there should be plenty of space to the door and the seat.

They don't interfere with the seats in my experience. And yes, they are much more useful than butterfly braces.

Another great weekend at Road Atlanta - this time with Chin track days. The weekend was not without problems, but I had a great time nonetheless. It was my first weekend with Chin and they are definitely a top notch group! First things first, I bought a truck, so I'm no longer borrowing one from my generous friends.
https://cimg7.ibsrv.net/gimg/www.mia...e85c7ce517.jpg

This was also my first weekend on the new Xidas, and because it would be a waste to run fancy new suspension on tired old tires, a fresh set of BFG Rival S 1.5 tires. Weather this weekend was set to be in the 60's, so I picked up a "low boost" actuator to hopefully fix the overboost issues I've intermittently experienced in cold weather over the last couple years. With 4mm preload and no boost control I was seeing a solid 6.5-7psi. More than enough for me to have some fun with, and I was rewarded in my second session with a 1:44 lap, a solid 3 second improvement over the best I achieved last weekend. I would attribute most of that to the tires, but the car felt pretty stable with no snap tendencies, and some mild turn-in understeer. This was with the stock front sway bar and no rear bar. An upgraded front bar is probably in my future.
The car ran solidly for the majority of Saturday, with the exception of the power steering belt slipping off one rib. I'd feed it back on, and by the next session it'd be off a rib. In the last session on Saturday it launched the belt off completely, so I spent the rest of the weekend without power steering as the Miata gods intended. Neither the crank nor the p/s pulley had any visual runout, so I'm not sure what the root cause is... but I'll just take it as a sign that I should remove the P/S completely.
More seriously, on Sunday AM during my look over the car, I noticed a bit of an exhaust leak around the manifold to head connection. One of the nuts was loose, so I tightened and...
https://cimg3.ibsrv.net/gimg/www.mia...31bbdc831e.jpg
https://cimg5.ibsrv.net/gimg/www.mia...f3f54d1711.jpg

It wasn't the first time I'd found this nut loose, and it looks like the face of the manifold isn't quite flush where the nut is supposed to seat. So I'll have to either grind down that nub on the manifold, or come up with a spacer of some sort so the nut has something to bite on. New studs and nuts are on the way from Mazdaspeed. I still managed to put in about an hour and a half of track time on Sunday, including a successful check ride for Chin's red group. I still can't keep up with a well-driven 911 or Corvette, but I can give some of the Mustang and Camaro guys a hard time. Hopefully my gopro caught the 1:44 lap and I'll have it posted soon.

Next up, air management... Splitter, under tray, brake ducting, hood vents and likely a rear spoiler. Has anyone used a NACA duct from a splitter/undertray to feed brake ducts and/or an oil cooler?

I think you'd then need to put the rear bar back on. From Supermiata: "Disconnecting the rear sway bar on a lowered Miata allows the inside wheel in a turn to droop further...For track use, save yourself the headache and leave it on."

Paraphrasing from the aero thread, there's not much air under the splitter if its doing its job. The under splitter design only works if you've got fans pulling air. You should be pulling air from as close to the center of the bumper as possible. Mine are far out and don't do much.

Yeah, the plan would be to put the stock rear bar back on with an upgraded front bar. I didn't have the upgraded front bar in time for this event, and leaving the eibach rear bar I had on there before would make it super tail happy.

So I'll probably nix that idea for the brake ducts and run some from the front grill opening. For the oil cooler, I was thinking of something almost diffuser shaped to feed air up to it. Maybe a small ecu-controlled SPAL fan? Trying to think of ways to mount it without taking flow from the radiator or exceeding my fabrication skills...

Video from last weekend. My fastest lap was when it was spritzing rain - I must be a mad man, lol.

You can see the witness marks in your photos where the bolt head was interfering with the manifold:
https://cimg9.ibsrv.net/gimg/www.mia...6ca0c25721.jpg
https://cimg1.ibsrv.net/gimg/www.mia...5c4c1d05ae.jpg
It was the combination of that cantilever load on the bolt and the vibration of the manifold that lead to the crack. You can see the clamshell pattern where the bolt failed, that's a fatigue fracture.

Just grind the spot off the manifold where it was interfering and you should be good.

Chin does do awesome track days, they're my favorite. That's a fast time for RA!!

Yep, that's the conclusion Andrew and I came to as well. Pretty interesting failure. Going to be a pain to basically remove everything to get to it.

Well I still haven't fixed the exhaust (made some progress, but not much). I did however find this picture from the last track day, which I thought was pretty sweet.
https://cimg7.ibsrv.net/gimg/www.mia...dccbcd2d9d.jpg

Another thing.. My bumper was clean before that weekend. There's no black smoke when in boost, but it does shoot flames sometimes when I shift (I'm told). It very rarely pops. Any suggestions for reducing that?
​​​
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Shift less? Drive FLATOUT more.

I think there are some adjustments in TS if you are running a MS to get rid of that.

I'm running an ms3. I'm guessing decel enrichment is where I should start for that?

Another successful track day this past weekend at VIR. Fears of rain were unfounded - couldn't have asked for better weather. Cool and sunny, I had no heat issues (saw 209F water temp maybe once) and the car made great power. I put Thumpetto's wilwood dynapro/11.75" kit to good use, though I thought I might be able to get away with HPS pads. I was wrong - 2 or 3 laps in they were getting hot and I had to swap over to the DTC60's. We ran the north course on Saturday and the full course on Sunday. Some highlights:
* No issues with brake fade once the DTC60's were in (running Pagid endurance pads on the rear).
* The only mechanical issues I had were an exploded shifter bushing (thankfully I pitted next to flatout racing, who had a spare) and tearing the bottom seam off the back window of my soft top. Time for a new one!
* Hitting 130mph on both the front and back straights on the full course (!!!). 6500rpm in 5th gear, almost RPM limited
* Definitely need some aero work, as the steering gets a little light above 125 or so, especially over the hill on the back straight
* Had a ton of fun harassing well-driven E46's and Caymans :naughty:
* Ran a 2:15.00 on the full course with 225 Rivals, which was about a second faster than the well-driven spec E30's and SM's that were at the event
* Made the round trip from Greenville SC (about 4.5 hours each way in the rain) on a single tank of gas. 36 gallon tank and 17mpg for the win.
* Speaking of gas, I can't make a full day without refilling anymore, so I need to buy a 10gal can or two
* No issues with the exhaust manifold studs this time around; the 3/4 washer seems to have held
* The racecapture makes timing and data display super simple - no more messing with the bluetooth GPS receiver, RaceChrono and MSDroid; just start the app and drive.
* The highlight of the weekend may have been passing 4 spec miatas racing nose-to-tail on the back straight, and having all 4 guys come over after the session to see what was going on

Video to come!

Video of a faster lap. I can brake later and probably carry a bit more speed through the top of the uphill esses but I wasn't that brave :)

Let me know the next time you're coming down to RA, I'd like to ride along to check out those Xidas. I'm sitting on the bump stops with my Bilstein/FM spring setup and need to upgrade, but I'm undecided on which spring rate to go with. I was thinking 700/400.

I'll be at AMP with Jzilla this Sunday

And the latest on my string of not-directly-boost-related failures: rear wheel bearings! Finally time for replacement. I didn't realize they were this bad early on (didn't have any play when I did my usual inspection before the weekend), but they definitely got loud enough before the end of the day that I parked it with a couple sessions left. The car was pretty fast, if a little loose, and I set a new personal best of 1:34.2. Video below. No long 5th gear pulls on this track, but I added fuel up high anyway after seeing those AFR's at VIR.

GridLife South! Ignore the wideband, the data logger was clipping at 11.9 for some reason.

No major issues this time around - just a little bit of heat on a couple days. What a great event - totally exceeded my expectations. GLTC winner ran a 1:36 and change in his K Miata too... talk about hustling.