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So, I tried to do the worst possible job of applying grip tape to my clutch and brake pedals. I succeeded. Seems I can't do anything right in the footwell. Gross. I'm leaving it anyway.
After studying the base AFR map, I decided it is insanely rich and leaned it out toward common sense. (The spark table is also very conservative, which is a good thing for now.) Then, I decided to use the table generator to create a new map, the output of which looks about like I would expect for a N/A car. It is really close to what I made, so I'm going to use it.
This thing:
Squirted out this thing.
Looks about right to me. Anyone see any red flags?
The values are based on verified dynos I have seen of well-tuned cars with similar setups. Although, now that I think about it, I wonder if HP and torque numbers are supposed to be WHP or BHP? The documentation doesn't say, so I suppose I will generate another map tonight with guesstimated brake numbers for the sake of comparison. BHP makes the most sense, now that I think about it. Probably won't change things much.
Anyway, with a new table in hand, I set about auto tuning the no load portion of the map in the garage, which a shop fan blowing into the radiator. Surprisingly, that actually worked really well. This showed me that the new map was running very lean, with each cell starting in the high 15s and low 16s AFR. So, I scaled the entire VE table to make it richer, and that moved measured AFRs much closer to the targets in the map. Satisfied that the car was now safe to drive, I took it out on the roads near my house. Those roads are mostly straight and flat and have speed limits of up to 60MPH, which is just high enough to do some meaningful tuning.
What followed was 2 hours of driving in the right lane with the hazards flashing and pretending to drive on ice, while slowly accelerating each gear up to 4K RPM, or a little above the speed limit, whichever came first. I tried to stay in each cell for several seconds, since I couldn't exactly watch the screen to see when a cell would stop changing. Changes were saved every 5 minutes, starting right after the first time my laptop crashed. I cannot tell you how many times a person honked with delight or made a hand signal to tell me I was number one!
Once most of the VE table was tuned below 4K RPM, I moved the limit to 5K, then 6K, then 7.5K. At the end, I was able to run WOT through 1st and 2nd gears without any lean spikes. At this point, probably 75% of the map is pretty well in the ballpark, and the car would be safe to drive to work on city streets or whatever. Next up is highway tuning, where I can pull harder in higher gears and tune the high speed / low load areas of the map. After that, the car will be safe to drive to the shop for dyno tuning, which is when and where I obviously plan to address ignition tuning. Prepare to be amazed by the dyno plot I bring back showing all of 130WHP!
Believe it or not, I actually know that! I bought a book at Half Price Books a few months ago and actually read it and underlined important stuff. Because I'm old, and that's how we fart!
I noticed the table generated by Tuner Studio is still a bit on the conservative side, but I decided to roll with it for now. The low load cruising areas of the map are the easiest to re-tune, and I figured I would identify which cells specifically could be leaned out with this engine, then go back and make the edits and re-tune those areas. Or, just wait and do it on the dyno in a few weeks.
While I now know I can complete the tuning process myself, it still makes a lot of sense to me to do it on the dyno all at once. Being that I will be tuning for maximum N/A "power," I will need a lot of measurements of "power," as timing is dialed in. That can be done in a couple of hours on the dyno, but would take days or weeks to dial in on the street using Virtual Dyno. The new track season just started, and I need this car ready ASAP,
This is stupid rich up top. You can get away with 13.5 tapering to 13 at redline. Stock ecu is even leaner. Won't make more power going richer. These are my findings from tuning two identically set up n/a nb2 on the dyno. Will make a thread about it sometime in the future.
^ I agree that table is on the rich side of typically published target ranges.
I have looked at AFR tables long past having my eyes glaze over, and have read every scrap of information I can find on what the targets should be. But, one more can't hurt anything. Do you mind posting the table you describe?
Just for giggles, this is the base map I pulled off the MS right after I fired it up the first time:
I am probably too ignorant to realize why this is probably a dumb question, but why would the base map exceed 100% fuel load and extend to only 6000 RPM? Expecting some people to drive on this with a turbo, so building in some boost safety? Why the limited RPMs though? Base maps not really specific to the car in question, remembering this is a PNP?
Hmmm... The published value for an NB2 is 143BHP. 33HP seems like a lot of drivetrain loss at 23%. Anyway, I have attached the tune, if anyone wants to pick it apart.
Hmmm... The published value for an NB2 is 143BHP. 33HP seems like a lot of drivetrain loss at 23%. Anyway, I have attached the tune, if anyone wants to pick it apart.
Some do a bit more, some a bit less, but stock motor & stock ECU NBs are all around 110 hp on a dynojet. Lots of stock dyno plots on this miata.net thread:
Just finally got around to reading up on drivetrain loss and discovered 23% is really not that bad, and that the 15% number everyone on the brilliant forums of the interwebs quotes is ridiculous.
Thanks to codrus for forcing me into the swamp that is miata.net, but that certainly adds some perspective. I had it in my head that NB2s make 115 at the wheels, so I have gained virtually nothing. Eight is always better than 3, but it's still not much, and is pretty close to the margin of error for any given dyno.
I didn't expect much from bolt-ons, but I did expect a little more than this. Is it the tune? Is it the VTCS? Is it the engine? All of the above? More work to do. This thread is interesting. In context, I am down 10HP on what emilio normally sees, even with VTCS. Hmmm...
Just to review, the "power adder" bolt-ons on this car currently are:
1. K&N intake w/ MAF delete
2. Racing Beat header
3. Roadster Sport 2.5" midpipe
4. Racing Beat Power something or other muffler that came with the car
4. MS3Pro PNP ECU
5. AEM X-Series wideband
Very interested in what you find out, as another FBO VVT owner in the DFW area hoping to go MS3 this summer. It might be worth it to snag a VICS manifold to see what happens. They pop up on the local facebook group pretty frequently for around $75-100. My buddy just snagged one for $50 the other night.
The penalty for being a luddite with no social media presence is more than a few bucks, it seems. I have a VICS on the way here for $130 shipped. I just couldn't get one delivered and installed in time to make an Oct 28 track day. We shall see. Eventually.
In the thread I linked above, emilio talks about getting 128WHP even with a VTCS on CA91 with very similar bolt-ons to mine. With TX93 (the good stuff), I should be able to do a hair better than that. At the 138 he mentions with a VICS, I might be a happy, reliable N/A guy and forget about F/I. But, at 118, not so much.
I obviously have no idea about the differences in calibration and environment between the two dynos (emilio's and MER's), and I need to do some baseline pulls for Virtual Dyno for a second opinion on my power rating. I will do that in the coming weeks. Things might line up pretty well, though. Here is a dyno of an '01 VVT with VICS with double my mileage after tuning on the same dyno mine was on (was given to me by the shop owner). Hmmm... That looks like 137 or 138WHP, which sounds familiar.
Having said all of that, the car is still MUCH nicer to drive. It at least has some throttle response and acceleration now. I always felt like it was a dog, and there was something wrong with it. I drive a lot of other people's Miatas at the track, and they all make mine feel like I'm trying to accelerate through molasses. Floor it, and absolutely nothing happens. At least that situation seems to be improved. I'm still going to do thorough and careful compression / leak down testing as soon as I have time to find out exactly how strong this engine is.
So, this doesn't have anything to do with my Miata, because it doesn't meet BMW CCA rules for convertible safety, so I "had" to take that terrible awful RX-8 thing of mine instead, but I did a thing:
09-22-2017, 08:23 PM
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