I think 13.0 is a-ok for N/A. Lean is mean or some such saying and makes more power. I think it's about ideal actually. I could be wrong but I think the ideal range for NA is 13-13.5. Non-turbo folks don't have to worry about detonation as much and a cooler combustion.

Yeah I’m with you. If I remember right, I was running my N/A NA at 12.8-13.0 at WOT the whole time I had it Megasquirted.

So anyways, I wanted to take a datalog with the new tune and come home to lay on the couch and watch some YouTube tonight. That didn’t happen. I ended up chasing a misfire for multiple hours instead.

I got the updated tune this afternoon and waited until around 8:30 once the suburban traffic died down to get out and rip on it. I pulled onto my usual “tuning” road and got a log of a 1st-4th gear pull, then pulled into a nearby parking garage to look at the data. Still a little lean near redline. I took a screenshot and saved the log to send to the tuner.

I spun the car around and did another pull in the other direction. Car starts breaking up at 6k in first gear but I barely feel it because it happens so quick. Second gear I feel it a little more but it’s gone as quick as it appeared. Third gear, it really starts breaking up at 6k and the check engine light starts flashing. F*ck. It’s never done this before, and I just installed the tune. Feels like an ignition misfire but maybe something in the tune is causing it. I pull codes and get a P0302, cylinder 2 misfire. Do another pull. Pulled over, flashed the stock tune back onto the ECU. The misfire is still there but just barely now. This caused me to believe that the tune was still a potential culprit.

I wasted some time reflashing the new tune and stock tune back and forth. The car’s misfiring consistently at 6Krpm/WOT now regardless of the tune, and I can’t get the car to throw a trouble code again, so I don’t know if it’s still only cylinder 2 or a random misfire. I took the car home, checked the coils and plugs. No obvious issues on any. I checked gaps and closed all 4 plugs up a little bit. Took the car back out. No change in the misfire.

Here’s where I went wrong. When I first bought the car, I read up a bunch about how the 06-08 NC’s had issues with Mickey Mouse wiring to the ignition coils. Common issues include pin fitment loosening over time and the power wires breaking inside their sheathing close to the coil connectors. When I got my car, I saw the wiring to the coils was wrapped in a ton of tape. So much so, that I just assumed somebody had already spliced in new coil connectors at some point. I never thought about it again until I pulled the car back into the garage tonight. Sure enough, I cut back all the tape on the cylinder 2 coil and was able to kill the cylinder by wiggling the power wire.

Anyways, I have four ignition coil pigtails on order now that should get here Saturday. I’m gonna do a quick and dirty wire repair tomorrow morning and confirm on the way to work that the issue is gone. Hopefully the connectors don’t show up too late on Saturday. My tentative plan was to leave early and hit some really cool mountain bike trails on the way to Buttonwillow, but I guess it’s only worth going to Buttonwillow if I have a car with four firing cylinders.

Anyways, thanks to all you guys for listening. I’ll have a more fun post at the end of this weekend!


https://cimg0.ibsrv.net/gimg/www.mia...b02c2c03d.jpeg


https://cimg2.ibsrv.net/gimg/www.mia...fb0b2ed2b8.png
Datalog showing the lean spot at 6,300+ rpm.

Spliced in a new section of wire into the power supply to the #2 coil this morning. Misfire resolved. The wire inside was so brittle that it kept breaking off along with the sheathing while I was attempting to strip it. Got it fixed and am gonna wrap it back up for now and just be ready to make repairs to the others if anything happens this weekend. It's a 5 minute fix so no big deal. I'll splice in new pigtails next week.

Now that I look at it, the entirety of the datalog above shows AFRs going up to ~13.4 before the lean spike at 6,300rpm. I'm sure that's due to incomplete combustion from the weak spark on cylinder 2. I'd surmise that incomplete combustion was the cause of the lean spike near redline too, but the log shows a drop in pulse width right there as well. I'll take another datalog during lunch and see how things look now.

man, you got me on the edge of my seat with these updates! What a mess with that wiring, jesus. Glad you found it and were able to fix it so quickly.

Haha! Glad you feel the same way I do. It wouldn’t be fun if everything always (or ever) went as planned.

Ripped around on the new tune some more yesterday and this morning and took some datalogs comparing the two. At WOT, the Fab9 tune I was sent wants to target 12.9 from 2,300-4krpm, then 13.5 AFR up until around 4,600rpm, then it shoots for 13-13.4 until 6,300, where pulse width drops and it goes up to about 13.9 until redline. I don’t really like that. Knock sensor shows no knock happening but those numbers still don’t really sit well with me. The base tune from ECUtek that I’m allowed to mess with targets 13.7 AFR at WOT up until about 4,000rpm, where it drops into the low-mid 12’s then hops up to around 13 at 6,300rpm. Ignition timing and VVT appear to be the same between both maps. I tried modifying the ECUtek base map, which is unlocked, but couldn’t get the application to work. I’ll likely run the car on the base map tomorrow and try to troubleshoot the issue with ECUtek Monday so I can play with the tune myself. Also noteworthy is that the O2 sensor in this car isn’t a true wideband so maybe I’m just going on a wild goose chase here.

Headed up to Buttonwillow now. Wish us luck!

https://cimg3.ibsrv.net/gimg/www.mia...f34d5d887.jpeg

They’re probably targeting based off torque/torque request, rather than RPM. Peak torque is richest, and high rpm when torque and power are tapering off won’t benefit from an extra point of fuel.

Thanks, Curly.

Still seems too lean to be safe though, no?

I asked around as well and found out that the factory tune utilizes an “enleanment table” that leans the car out towards redline if conditions are right. Checks out based on what I’m seeing.

It also seems to be targeting richer afrs in higher gears. Just did another handful of pulls and the car’s hitting 13.3-13.4 at peak torque in first. Around 13.2 in second and third. Then in fourth, it hits 12.9-13. Still lean outside of 4k-6,300rpm.

Im gonna flash the stock tune on the car tomorrow and not worry about it until Monday lol.

Just chiming in on the AFR thing,

I don't think 13.2 at WOT is dangerous necessarily, it's just if I were tuning it I'd target a touch richer for cooling and safety on a track car. Really if the car isn't knocking it's probably safe with that map.

I had no idea the NC used a narrowband. This makes me wonder how it could possibly even log AFRs in that range.

This all makes me wanna re-visit the tune on my buddies NC track car. TBH he bought the tune through Fab9, which was supposed to come with free revisions but we were never able to get those out of him. Basically I flashed the tune for my buddy, we did a datalog and sent it out, and never heard back. The car has ran well enough we haven't touched it since, and he tracks the shit out of it, so I guess it's fine.

I shouldn't jump the gun here, my bad. But the upstream O2 in the NC is a 4-wire "AFR" sensor. I think it still has a pumping cell like a true wideband, but from what I've read, it's not as accurate as say a Bosch unit like what we use in the NA/NB's. Reports about its accuracy seem to vary across the board depending on who you ask. A couple guys on the FB group tuning turbo cars say that they'll remove it and install an external wideband while dyno tuning the car to confirm accurate AFRs.

My experience with the Fab9 tune has been almost exactly the same. Took three weeks to get the tune and follow-ups require lots and lots of messages before hearing anything back. I think Bryan, the tuner over there, is just stretched too thin.

Luckily, I ran the tune yesterday morning for the warmup session and it just... figured itself out. As soon as I got on throttle out of the pits, the ecu began targeting 12.7-13.0 AFRs through the whole rev range, leaning out to the low/mid-13s at redline. No further issue all day. Once it was hot outside, AFRs stuck around 13.0-13.2 until rising slightly at that 6,300rpm mark. I flashed back and forth between the stock tune and Fab9 tune quite a few times this week and maybe just didn't give it enough time previously to set fuel trims at WOT? I don't have full access to this map and am not gonna pretend I know all the strategies it employs. Not gonna complain either, though.

Auto rev-match on the downshifts is awesome. Flat shift is awesome.16k/9k spring rates on the Xidas are STIFF! I'm gonna swap back to my RX8 sways this week. Supermiata recommends softer bars even for 255 tires on lower spring rates and the other guys I know running 14k/8k and 16k/9k on this car are running stock bars or RX8 bars at most. You'll see the stiffness I'm referring to in my in-car vid.

Ran a 2:06.7 yesterday though! Faster again than I was expecting to. Only 1.7 seconds off of my first time with the turbo NA running 210whp, 225s and aero. Super stoked on it. I had too much footage to go through so here's a random, pretty clean lap aside from having to make a pass in Riverside. Seriously amped on how much pace the car had yesterday. I'm racing TT6 class at Buttonwillow with NASA this coming weekend and think I should be able to stack up pretty well.


The rest of the weekend went killer. Left home late Saturday morning, stopped for a couple-hour bike ride on the way up to Buttonwillow, and got there in time to hang with a handful of the homies Saturday night before knocking out. Yesterday's track day was damn near flawless. The car just worked. Run groups were stacked but they gridded us by lap times and I hardly got stuck in any traffic, all I had to do to my car was check lug torque between sessions. Camping and hanging out with my buddies from San Diego that I only see every so often was icing on the cake.


https://cimg5.ibsrv.net/gimg/www.mia...12930e462d.jpg

Yesterday's only mechanical was our buddy's 1981 Corolla. One of the pins to the external voltage regulator loosened up and the charging system didn't like that. Easy trackside fix luckily. Homie drove the car 4 hours up from SD, tracked it, then drove it home. Not his first rodeo, but still, brave man.

https://cimg7.ibsrv.net/gimg/www.mia...bd925d138a.jpg

Shouldn't have much to report this coming week. I should have some parts for the 2.5L arriving midweek but I'm leaving on Friday again to hit Buttonwillow with NASA. Gonna be racing TT6 and instructing between sessions. If all goes well, I'll be able to get my instructor license after this weekend and coach non-first timers if the need arises from here on out!

Sick update! Damn looks like you had a blast out there, and nice wheeling. Maybe overdriving a little but I think that's your bar setup making it so snappy over the curbs. Great job keeping it under control though, it looks like you are really comfortable with it already. That no lift shifting looks TITS, I really gotta get that setup on my car, so cool. And the diff looks to be working really well, is it the factory tochigi fuji diff? My buddy burnt his out (or broke the teeth off it?) and it basically became an open after 2 years of tracking it. Something to keep an eye out for. And the rev match downshifting looks to work really well too. You know, kinda jealous of the pace you get out of an NC with minimal mods, to be honest. Glad my turbo car is dialed or else I'd be contemplating some dumb decisions.

Thanks, Nate! Haha, yes I was definitely overdriving the car a bit but was doing everything in my power not to. This track's super bumpy and there's at least two sections where the fastest line is to hop the curb. My two options seemed to be: slow down and take mellower lines, or hit the optimal lines and just deal with the car ricocheting off the curbs lol. As you can see pretty easily, the car gets very unsettled with how stiff it is currently. Hopefully the lower-rate bars help with that next weekend. If not, I might grab softer springs to run in the interim (Ed did tell me that these springs would be big overkill until I had aero and wider tires on the car).

Aside from that, yeah, super comfortable with the car already. My experience has been that the NC drives almost identically to my NA. Very minimal change in technique, if any, required going from one car to the other. Coming from an NA/NB, I think you'd feel fully acquainted with it after a session on track or two. My only gripe with it is how touchy the brakes are compared to my NA with the 1" master. Currently looking into swapping a G37 master cylinder into my car (same bolt pattern, just 1" diameter vs the factory 7/8") with a couple adapters for the brake lines. Maybe after the new engine goes in...

No lift shift is super sick, if for no other reason than it feels sick as f*ck haha. One of my buddies was filming me on the front straight and said the car sounded cool as hell when flat shifting from 3-4, so that's another plus haha. The LSD is the factory tochigi diff too, feels really similar to an NA/NB torsen, I've never driven on anything better, so I'm happy with it currently! The PO gave me the old open diff and housing, and I've heard the OSG diffs are supposed to "transform" this car in low speed corners, so one of those is probably on the list eventually.

Amped on the pace the car carries as is. It's supposed to be 5-10 degrees cooler this coming weekend. Between that and the more compliant sways, hopefully I can crack down into the low 2:06s here. Sh*t man, I'm hyped hahaha.

Lookin good Zak! Looks like you were driving the s**t out of the car, I wouldn't call it overdriving. It looked pretty neutral to me but maybe a touch on the loose side. Looks like at the higher speed stuff/bumps/elevation changes the rear gets a little loose but you did a great job staying on throttle and countersteering. Not sure how the stock aero is but I'd guess at some point if you get a big wang again it'll tame the rear down a bit. Nice driving and looks like fun!

Hell yeah, thanks Teg! I was trying to squeeze everything I could out of the car without completely overdriving the thing. Easier said than done with all the bumps/curbing/elevation changer on this track. No aero was a first for me too, I've never driven here without a wing and a splitter. Aero's going to come after the engine swap. Very excited to see how the car handles with it!

You should see the fast S2K guys running out here (there's a lot of them). They're countersteering more than normal steering :rofl:

Haha ya I've seen a lot of s2k vids at BW. I can't remember what a "fast" time is for an s2k but I thought it was something around the 2min flat mark. That looks like an awesome track and one of these years I'll have to come out to CA to rent a car to run BW. It looks like you're really pushing that thing and sliding it around. :likecat:

mate looks fantastic. bikes and car chef kiss combo.

have you seen the release of the FM NC turbo kit? whats your thoughts on it? seems a pretty stout mid 200hp option. apparently it might fit the 2.5?

That BW vid was pretty rough, springs are one element, did you play with shock settings? Looking at the vid, I would have set it at full soft for the next run, then worked up from there based on what (if any) difference it made.

Good to see you out on track with it, go kick some ass!

Oof, that's rough. Looked kinda fun, but not compliant at all, especially over bumps. Gee Emm's probably has the right idea, your dampenings either way up or I would have maybe tried disconnecting the rear sway. Car never looked like it too a set, looked like a low powered car with a welded diff more than anything...

It’s on my radar! I believe the kit’s going to be 2.5 compatible and assume it’ll be well-sorted. I’ve got my eye on the Fab9 EFR turbo kit right now, though. Low mount manifold to keep the heat away from the engine bay which seems to be a big issue among the track guys with turbo setups.

Yeah guys, compliance was not the name of the game Sunday haha. I was recommended by 949 to run the clickers at or near full closed due to the nature of the stiffer springs needing more rebound damping. I kinda just figured that dropping the damping would result in even faster rebound and more deflection over the bumps. I’ll play with it more this weekend and drop the damping a bit. The Progress sway bars I had on the car are seriously beefy and stiffer than what 949 recommends even with 255 tires. I pulled those bars out and reinstalled the smaller RX8 bars that the car came with tonight.


https://cimg5.ibsrv.net/gimg/www.mia...2fb966ff5.jpeg

Man, you're really making me want to upgrade from my old GoPro to an Insta360. That camera angle gets everything and the exposure actually works in and outside the car.

Glad to see you back behind the wheel! The car certainly looks like it keeps you on your toes, but it looks like you're well on your way to sorting that out.

Haha, funny you'd say that. I actually just have the camera because my roommate used to work with the founder of the company and has two or three sitting around that he never uses. This camera isn't even the current generation, it's actually a first gen! The exposure works really well, my only gripe is that it needs to be set on the phone app every time you turn the camera on. I run -2.0 or -2.5 compensation depending on conditions and the default 0 compensation is basically a total whiteout when the camera is inside the car.

Glad to be back behind the wheel! I was getting scared I'd forget how to drive after my little hiatus haha. Still got tons of improvement to make, but I appreciate it man.