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One thing you can do to get an even better idea of the VTC values is to tune each of the values as well. Looks like the one making the most power down low is also the leanest by a long shot.
Is there some sort of limitation with that ECU not being able to flatten out the AFR curve? Down low it pops up to like 14 before getting fatter up top then starting to lean out again.
Power and curve overall look great though, gonna be a blast on track.
One thing you can do to get an even better idea of the VTC values is to tune each of the values as well. Looks like the one making the most power down low is also the leanest by a long shot.
Is there some sort of limitation with that ECU not being able to flatten out the AFR curve? Down low it pops up to like 14 before getting fatter up top then starting to lean out again.
Power and curve overall look great though, gonna be a blast on track.
I honestly haven't had a lot of time to dig into the ECU logic in regards to the AFR control, but I'm sure I'll do more digging on it in time. While I agree with you in general on the AFR curve (and my OCD likes seeing smooth lines), I am also far from an expert on what these engines are happy with long-term. (just as relatable example, my 2.0L DI LNF in my cobalt absolutely loved 12.9 AFR with 23psi of boost being crammed into it, which seems crazy lean to most engines but I've got multiple engines tuned for 100k+ miles that way). End of the day, I left the tune up to the expert who had multiple GLTC cars sitting in the shop. As long as the engine wasn't knocking (which it wasn't), my concern with the leaner portion of the curve really isn't warranted in my head. As mentioned, the power curve looks really nice given the setup.
Gave the car a much needed bath (first one since probably MATG 2019 if memory serves me right) and got the 10" wide wheels on the rear. This shot made me realize how stupid this car actually is for the street, but I love it.
Next on the list was getting the splitter mounted up. The splitter support bracket which I posted earlier in this thread worked out perfect. It gave me a ledge to rest the rear portion of the splitter on just like you can do on the OEM subframe.
From there, I needed to find a new location to mount my center cables for the splitter since I am running a radiator support bar now. Mounting the eyelets through the bar itself would make them too far forward, so I found this location as suitable.
Once I lengthened the center cables for their new location, it left me with this for a complete setup. Similar to what I've been running for years with just a couple noted tweaks.
Then I was able to get the barge boards mounted up under the car. I don't have the front end aligned yet so don't judge the ugly 16's on the front that are still there. I don't want my eyeball alignment to chew up my front rs4's as I have to drive to my buddy's place to get it on the rack for corner balance and alignment. Will swap front tires over when I get there.
Put these fancy little Quick Latch Mini's on the bumper so I no longer need to fumble around with the M8 head bolts that attach the bumper cover to the fender. Took a lot more messing around than I expected to install them snugly and keep a good looking body line/gap, but here they are.
Got the visible edge of the splitter roughly sanded and quickly painted, then was able to do final assembly on the front end.
Not looking too shabby from an aero standpoint under the car. By sheer luck, this setup fits the limitations on the ClubTR rulebook for GL perfectly.
It's been a busy couple days, but TLDR: I've got a running and driving Kmiata!
Drove the car 1.5hrs up to my buddy's shop to get it corner balanced and aligned. Went with the same alignment settings that I've always ran to minimize changed variables on my first event. -3.4F/-2.8R camber settings. -1/16"F/+1/16"R toe settings. Corner turn in with a little toe out in front has always been great, and the toe in for the rear should keep it pretty stable when on power for corner exit. Will see how it works now that I'm making twice the HP/TQ as before.
As part of the corner balancing, I had to snap some photos of w/ and w/o driver. The car was 2278 w/o driver the last time it was on the scales with BP power with a 1-2 gallons less fuel in it, so to take 40-50lbs out of the car and get it down to 2235 w/ 6 gallons (1/2 tank), I've been really happy with. I have some line of sight to get the car into the 21xx weight range without tearing out interior bits, but I'm getting to the point of diminishing returns on my dollar in regards to possible weight reduction.
Drove the car the rest of the weekend without much hiccup. Currently have about 400 miles / 6 hours of seat time in the car without any leaks which is nice. No regrets in keeping heat and radio in it for the long drives. I do have a couple vibrations I need to sort out in time. One of them is header flange to subframe clearance vibration where the flange barely contacts the subframe and another is the dust cover vibrating against the adapter plate. Some light grinder work should fix the flange issue and some RTV should fix the dust cover issue.
I don't have my wideband wired to the Kpro at the moment either, so the car isn't able to trim fuel and run closed loop fueling which is causing some AFR variations between fuel blends. Cruising range AFR's need a little cleaning up as well. Glad to have the car running at the moment now is all. I have the cars first AutoX event coming up this Sunday, so we'll see how it does. Locally, I was a pretty solid top 10% car when I had the BP4W, so the kswap should make the car very competitive now that I'm not at such a HP deficit but you never know what will show up which is part of the fun.
The good news: I have my wideband analog inputs finally hooked up to the Kpro so I have fuel trims
The bad news: I'm commanding 14.1 during this point in idle warmup enrichment and seeing 18.1. Figured out I have an exhaust leak pre-o2 that is related to the 3 bolt header flange that was rubbing ever so slightly on the subframe. The hardware has loosened up a bit causing a leak, so after letting the exhaust cool off and making a bit more clearance there I should be able to tighten it all down again and solve the issue. *knocks on wood*
You win some days, and other days you lose. The AutoX on Sunday was unfortunately one of the latter
One of the reasons I went with the Kswap is the reliability. I expect to drive this car most everywhere just like I did with the BP. After burning through 3 tanks of gas in a week, I felt that the car was running well enough that I trusted to drive it 2.5hrs north to an awesome kart track that opens up for AutoX a few times a year. Technically its more like a time attack as there's no cones to hit or swerve around, but you get the concept. Get from start line to finish line as fast as possible. All seemed well for my first two runs (other than the fact I forgot to check my tire pressures that were WAY too high and the car sideways enough in most corners to give Travis Pastrana a run for his money in Gymkhana), but when I handed the keys over to the codriver after adjusting pressures to more reasonable numbers, the car completely died in an instant about 3/4 of the way through the track. Into the paddock it got pushed... time to diagnose
The first observation is the tach wasn't bouncing when you'd go to crank it over. That signal comes from the ECU. Went to look to see if the ECU power light was on when the key was on and it wasn't. The ECU had to have not been getting power, so we jumped into the ECU pinout diagrams to find the switched power pin. It was getting switched 12v. So if its getting switched power, the only other option for it not to power up is that it must not be getting a proper ground. We checked all of the grounds throughout the car (both grounds to chassis and grounds to the actual negative terminal of the battery) and they all checked out. How the hell can an ECU get both power and ground signal, yet still not turn on? Thinking the worst, did the Kpro somehow get fried? We asked around the paddock to see if any Kseries powered car was there that was running Hondata and sure enough there was an S2000 with one. We asked if we could jump in and swap his ECU with mine just to confirm mine powers up on a harness that is known to be functioning properly so we could eliminate either ECU or Wiring source as the problem. He said it wasn't a problem, so we swapped mine in and thankfully my ECU powered right up.
So now we jump back to my car knowing that something in the wiring had to be screwed up. The engine harness was really nice quality right from Kpower so I had some level of confidence that portion of the harness was good. All the fuses checked out and we verified all relays worked and signals were going where they should have been on the adapter harness. In an act of utter confusion, I called John from Kpower... He was just as confused as I was based on what I had already verified, but extremely helpful in diagnosis and understanding what wires controlled which circuits as I was more or less just blindly checking things prior to his call. Customer service on a Sunday afternoon FTW. After checking what seemed like everything over the course of 5 hours, I decided to just keep the key (switched 12v) on and start wiggling wiring looms, hoping that somehow, somewhere, there had to have been a loose wire that caused the ECU to trip out and not want to come on..... AND IT WORKED
There was a small 20ga jumper wire on one of the relays that I'm still not entirely sure what it does, but I can tell you that when I wiggled it around, it caused the ECU to sporadically turn on/off. I took the only thing I had available to me (painters tape for door numbers) and wrapped the hell out of the wire so it couldn't move, verified the ECU had signal, and the car fired right up!
By this time, the timed portion of the events were over and there were only fun runs left to go. A buddy and I hopped in and gave the car one last rip before needing to head home. I missed a gear (thanks OEM 6spd shifter), my driving was lack luster after being mentally burnt out from the 5 hrs prior, and the RS4's were pretty unhappy about the thought of grip in the cold, but I had fun in the run and finally a little taste of what this Kmiata life is about. The car is fast.. like real fast... like "231whp shouldn't feel this fast" fast... and revving it out higher than Dogecoin stock spikes is addicting and works very well with what is typically short 6spd/4.30 ratios.. The only thing more horrible than my excuses for being slow on the day is the quality of the video below, but better than nothing. At the very least, enjoy the noises.
TLDR: Car made it 5 hrs round trip to an AutoX event because streetcar, but spent 5 hrs at the track broken down because racecar due to a intermittent connection on the Kpro adapter harness.
In my limited driving so far, I've grown to dislike the OEM shifter feel on the 6spd trans... This isn't an uncommon review from what I gathered online. Based on a quick internet search, GRacing and MiataRoadster were the two shifter options on the market. The MR comes with a lot of extra parts that I frankly don't need given my shorty console, so the price was reflected in that. Reviews on the GR seemed good enough that I thought I'd give it a shot and save the money on unnecessary accessories. I took a bit of that savings and upgraded to the short carbon **** in the hopes that it stays cooler to touch than the standard metal **** option. Haven't gotten it installed yet, but it appears to be a really nice quality piece. Will post video review once I get it installed.
Next up was fixing the wiring gremlin that left me stranded at the AutoX event. Here you can see this pin on the relay harness was crimped around the insulation, causing an intermittent connection when you'd wiggle the wire. I cut off the connector and crimped a new one on to fix the issue.
Nut and bolt check the car before Miata Meetup
One of the main points of the kswap for me was to retain n/a reliability with the addition of power. That includes driving to and from the track. The first leg of the trip on the way to Gingerman was rain. It cleared up before getting into Chicago so it wasn't too bad. Made it to the track without a hiccup.
Here's a candid shot of us MT members on our way to drivers meeting talking about the color purple. I haven't figured out how I want to photoshop this image yet, but it needs explosions and kittens.
Car had a few tiny little hiccups (mostly related to NVH issues), but overall the car laid down 3 hours of track time with needing nothing more than fuel. I was only at Gingerman once before (for Miata Meetup in 2019) and the car had the BP4W back then. Naturally, I was a bit rusty on the course and very rusty on the car that had changed drastically since then. Most of Saturday was spent dialing in tire pressures, sorting braking zones, optimizing what gears to be in for each corner, and just brushing the rust off of myself. I couldn't find my GoPro at home, so I didn't take video or record any of my laps over the weekend, but by Sunday I was hovering around the 1:45-1:46 second lap zone from what my friends spectating were able to time me at with a stopwatch. The car is a riot to wheel around the course with the K24 power under the hood, and the 6spd/4.3 combo really proved to work out well in conjunction with 8500rpms to use. The biggest area that I have to work on is consistency in braking zones and corner speeds, but I won't beat myself up over that too much given the circumstances. I had a blast and that's all that matters. Practicing and improving the driver mod is the fun part of the build!
Pic of the Kswap cars at the event. NB is obviously the answer.
Had to use the picture of my car behind yours huh?
Good to meet you in person. That session was the most fun one I had all weekend. My Chinese hood pins started failing that afternoon, so I had to cut things short.
Not too much for updates recently. Car has been running well, so I've just been enjoying driving it around everywhere. Entered the Flyin' Miata car show and took first place in the spicy NB category. Won $50 in-store credit, a tshirt, and some sick stickers. Now if only I had anything from FM that I actually needed to buy...
Adding to the multiple uses of the car, it works well to haul beer pong tables for weekend parties.
Maintenance days are always good times. Did the first oil change on the Audi and did some nut/bolt checks on the miata. Still need to clearance the header flange a bit as it vibrates on the subframe under certain conditions.
On Tuesday, I brought both the Audi and the miata to the drag strip. Track prep wasn't great and I honestly didn't care enough to worry about changing the setup on the miata for the purpose of launching or reducing drag, so I just ran it as-is on my exact road course setup. Overall, seeing a 13.37 @ 102 is something I walked away really happy about. The car when completely stock previously ran 15.5 @ 87 as a point of reference. I surprised a fair number of opposing cars and had them peeking through the hood vents trying to see what was under the hood. Pulling some aero off, dropping tire pressure, adjusting dampers, and better prep would likely get this car really really close to a 12.99 @ 105 if I had to guess, but maybe next time. Not too worried about trying to impress anyone at the strip when the car was built exactly NOT for that.
Overall, best times on both cars is shown below. The Audi is just a 1/4 mile freak for a factory showroom turbo 4 banger sedan. Getting 1.7x 60' times on 225 all seasons at 40 psi is stupid. It is extraordinarily consistent on times as all the runs that car made were within .1 seconds and 1 mph on trap speed. It makes drag racing look easy. Can't wait to get a tune on it...
The thread has been quiet here lately, so I think I'm due for a brief update as to the reasons why. A lot of you already know, but for those who don't, I made a fairly big leap of faith and took a new job back at the end of March at Harley-Davidson as a powertrain design engineer. Designing powertrain parts was always a goal of mine since I was a kid, so it's awesome to now be able to say "I MADE IT". As one could expect, working at an OEM has its ups and downs. It can be stressful, but is very rewarding at the same time. Nothing beats being able to go throw a leg over and test all of the safety factors that you tirelessly put time/effort into designing on your components. The obvious "cool factor" perks of the job are that I get to take home bikes for any vast variety of engineering evaluation reasons (or sometimes just for fun!).
One of these bikes is the new 2021 Pan America 1250. The plethora of positive online reviews for it speak for themselves. My feelings on the bike are overwhelming positive as someone who never EVER previously considered a Harley Davidson product. I've been enjoying putting miles on both the Kmiata and a variety of HD products the last few weeks. They sure do look pretty next to each other in the garage.
No other updates from me though! Plan on doing a nut and bolt check on the Kmiata and driving it down to MATG in a week and a half! See you all there!
Congrats on the new gig! You're getting to the point on this build where you get to just drive and dial in the car! Not a bad place to be!
Thanks!
And yeah, the car is honestly pretty damn close to where I envisioned it to be. I've got plenty of ideas for further updates and improvements, but lately it's just been nice driving and enjoying the car without bleeding money into it like I was for a solid year while piecing the kswap together. I feel like everyone that builds a car for 5+ years has these phases.
To give a flavor of what I've got left to really touch: Hubs: currently are original 145k mile units from what I know... Probably should give them attention before I have a failure on track, but so far have had no signs of them being bad. Brakes: currently just running Hawk DTC's on OEM NB1 calipers/rotors all around. They give me plenty of stopping power, so the only real reason to upgrade would be for overall brake system weight savings and having pads that last longer (slight consumable cost benefit) Paint: the car was never a show car (nor do I want it to be), but there's some cosmetic items that I'd like to take care of with a vinyl wrap eventually. Cooling System: the OEM rad setup works, but it's not as clean as I'd like it to look. Being the cooling system engineer I am, I've got a plan to tidy it up (possibly this winter) Interior Wiring: The Kmiata harnesses are a bit long.. would like to tuck them better and clean up the ECU mounting as well as finish up my power window switches Power Adders: This is the furthest down the road idea, but it is feasible to build 2.5L K-series ripper of an engine and shoot for 300whp N/A. Have been in contact with 4Piston to get details on the best way to shoot for this goal. Or for less money, toss boost at it with the miata 6spd being my weak link. Each have pros/cons and I'm in no real rush to do either as the car is a joy the way it sits. Plenty of time to research!
Another long overdue update. On my way to MATG, I managed to hit a ~4" tall heat heave in the road at 80mph when following a semi. By time I saw the semi hit it, there was nothing I could do but go along for the ride and pucker the butt cheeks. The splitter and front bumper assembly somehow survived, but the rear 1/8" steel splitter bracket got mangled beyond recognition to the point where the only thing holding the splitter on the car was my 4 cables. The toe on the alignment got knocked out slightly (based on inner front tire wear patterns). The 2-1 section of the exhaust was pancaked flat. The oil pan got a light dent in the front sump, but no leaks. Overall, it could have been worse. Big shout out to Marcus for dropping by the cabin so I could bend the splitter bracket back into shape. Here was the splitter bracket when I got it off the car. It is supposed to only have 2 bends in it haha
Once the car was repaired, it was back to regularly scheduled programming. Led the spirited run on Friday morning up to the Dragon hill climb. Had a really solid turnout of ~45 cars.
Overall, MATG 2021 was another success! Car managed 2300 miles without much of a hiccup other than the heat heave scenario mentioned above which is no fault of the car. Gained a lot of confidence in the build overall, which was much needed. Was getting about 23-24 mpg in it on the highway at 85mph (5000 rpm) cruising. Managed to take a classic boat launch photo the morning before leaving.
Since MATG however, I haven't really done much with the car. On the way home from it, I noticed a whirling sound that was speed dependent which is likely pointing towards a wheel bearing going out (not surprised given they are 146k mile originals to my knowledge). I need to get the car back on the rack and redo the alignment and the 4 year old plywood splitter is really starting to look bad. Time to fix it all.. BUT
Instead of focusing on car repairs, knowing that the baller billet hubs I want will be a decent amount of cash for not a lot of "feel good" return, I decided to focus efforts on finishing up my garage space when the weather is still nice outside as winter is fast approaching. As of last weekend, I'm happy to see that is DONE!
1 year and 2 weeks from what I started with...
Professionally repaired and epoxied floor
Full insulation (walls / ceiling) with overpriced covid OSB throughout
New Wifi garage door opener
9 gallons of paint (screw painting OSB, but I'm happy now that its done)
10 8' LED lights. I'm pretty sure I could get a tan from the light output in this garage. Not a shadow to be seen!
Another Husky tool cabinet for storage of the awkwardly large items
Refurbished the old house fridge and painted it for a beer fridge to match
Really looking forward to having a clean, insulated, and organized place to be working in this coming winter. Having a space like this definitely motivates a guy to actually want to spend time out there compared to what I had before.
It doesn't look like much, but I got the garage buttoned up.
Reorganized and wiped down all of the toolboxes which took forever
Set up the 500w stereo
Hung an extra 32" TV I had laying around in the basement and bought a Chromecast so I can stream videos to it w/ audio through the stereo
Hung up some garage decor
Started procuring parts for the radiator project this winter. An aftermarket 1985 VW Scirocco rad is what I've found that fits all the criteria I need, but more to come on that later once I get it roughly fit into place.
Lastly, I've been getting sick of being hunched over in the corner of the garage while working on the engine bay OR not being able to get under the car. My solution was to make a set of wooden cribs to roll the car throughout the garage as needed and also set it at a comfortable work height for both above and below work.
The paint on the car was never wonderful, and it hasn't gotten any better after years of spirited driving both on and off track... so it's time for a change
04-11-2021, 02:34 AM
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